1.   The Green Deal

The Green Deal is the new Government initiative to make it easier for householders and business owners to install low emission energy measures by giving them access to a loan, which they pay back as they save money. The advantage compared to normal loans is that it is underwritten by the Government and there will be a system of quality control that accompanies it. The rate of interest however, albeit comparable with market rates, is not insignificant and therefore if outright purchase of energy measures is possible, then this may be cheaper to the householder or business owner in the long run.


2.   The Renewable Heat Incentive

The Renewable Heat Incentive (RHI) is a UK Government support mechanism for the supply of renewable heat.

An uplift is paid on each unit of heat supplied from a renewable resource and the size of the uplift is dependent on the technology. There are two categories of the RHI – commercial and domestic.  Technologies covered include:

Biomass boilers

Anaerobic digestion

Solar thermal

Geothermal heat

Air source heat pumps

Ground source heat pumps

Contact Wattcraft for more information on the Renewable Heat Incentive.


3.   Feed-in Tariffs

Feed-in tariffs (FITs) are the Government mechanism for support of small scale electricity generation.


FITs are a fixed price per unit of electricity generated specific to technology and a fixed price for export. They are applicable up to a capacity of 5MW and include the following technologies:


Anaerobic digestion_________________________

Micro CHP

Micro hydroelectric

Wind turbines

Solar photovoltaics (PV)

Micro hydroelectric

Contact Wattcraft for more information on how FITs might help you.



4.   Renewables Obligation Certificates (RO)



5.   Smart Energy



6.   Electricity Market Reform



7.   The Energy Hierarchy



8.   Combined Utility Integration




9.   Technology versus behaviour change





10.                 JSME

Rupert Blackstone, Managing Director of Wattcraft, represented the Institution of Mechanical Engineers (IMechE), together with the IMechE President, Professor Rod Smith and Ian Arbon, colleague on the Energy, Environment and Sustainability Group (EESG) committee, on a visit to Japan in March 2012 for the purpose of exploring collaboration with the Japan Society of Mechanical Engineers (JSME), particularly in the area of new energy infrastructure. Below is an account of the visit.

The devastating impact of the earthquake and resulting tsunami in March of last year has presented significant engineering challenges and therefore JSME decided to set up meetings to address these, with input from other countries’ engineers. The hope is that not only can Japan learn from practice in the US and Europe, but also that Europe and the US can learn from Japan, not least because the catastrophic events have provided an opportunity for a radical overhaul of the approach to generating and supplying energy.

The visit included:

  • Tour of the Miyagi Prefecture, Tōhoku region, which was hit by the tsunami, with visits to a gas-fired power station and a nuclear power station
  • JSME/IMechE/ASME round table meeting
  • Post-earthquake engineering lessons learnt conference.

The American Society of Mechanical Engineers (ASME) was also invited to participate and sent two experts on nuclear safety standards.

Further to the devastating earthquake and tsunami that occurred in Japan on 11th March 2011, the vulnerability of Japan’s energy systems was exposed through the resulting serious accident that occurred at Fukushima Daiichi nuclear power station. The vulnerability exposed was not only technical and economic but also concerned the support of the Japanese public towards nuclear power. The incident raised questions about how nuclear power could be made safer, how the communication of engineers with the public could be improved and also what alternatives to nuclear power should be developed.

There has been, over recent months, a developing relationship between the IMechE and JSME including participation by representatives of JSME at the Future Climate Conference held at the IMechE in London in September 2011. The value of collaboration between the institutions in the areas of energy and climate was recognised for the following reasons:

  • There are distinct differences in the approach towards energy supply and consumption between Britain (as well as other countries in Europe) and Japan and through understanding these differences and their effects, we can learn what might work best for our respective countries.
  • Both countries are currently committed to nuclear power and together they can work out what role would be most suitable for nuclear power in their future energy mix and how the various challenges of nuclear power may be addressed so that that role can be fulfilled.
  • The UK and Japan have a history of industrial collaboration and this foundation can be built upon to take advantage of the innovation and enhanced delivery capability that can arise from engineers from different backgrounds and circumstances working together.

Tour of the Sendai Region

Bus tour Miyagi Prefecture, Tohoku


Figure 2 - Foundations of buildings and pile of debris in Sendai Region

Figure 1 Foundations of buildings and collected damaged cars, Sendai Region

Figure 1 Foundations of buildings and collected damaged cars, Sendai Region

Over the course of the bus tour of Miyagi Prefecture, Tohoku, the group observed some of the impact of the earthquake and tsunami on Sendai (city and surrounds), Ishinomaki area and Onagawa Port (and surrounds). Much clearing up had been done over the course of the year that had passed since the devastating events and the extent of this was impressive. We saw piles of debris behind fenced-off areas and crushed vehicles collected together in compounds, but there was very little in the way of stray debris. Occasionally near to the coast badly damaged buildings could be observed and presumably in some cases a decision might not yet have been made as to whether to rebuild them or pull them down. There were large areas near to the coast where there were once parts of villages or towns, with the only significant evidence of their previous existence being the outline of the foundations of buildings. There are questions as to the extent to which there will be rebuilding in these areas that are so vulnerable to tsunamis.

In the area where we stayed in Sendai City, which in parts was very badly affected by the earthquake, there was no observable residual damage and indeed it was very impressive to see how well designed most of the buildings must have been. In the past and currently in other parts of the world where earthquake-resistant building design is not so advanced, it would be expected that the damage would be far greater for such a magnitude of earthquake.

Figure 3 - Damaged building in Onagawa area

Figure 3 - Damaged building in Onagawa area

      Figure 4 - Warehouse foundations, Onagawa Por

      Figure 4 - Warehouse foundations, Onagawa Por

Sendai Combined Cycle Gas Turbine (CCGT) Power Station

General information on power plant

 Figure 5 – Sendai Thermal Power Plant

 Figure 5 – Sendai Thermal Power Plant

Sendai Thermal Power Plant is a modern Mitsubishi high-efficiency 446 MW CCGT plant managed by the Tōhoku Electric Power Company and is situated within around 300m of the coast.

Impact of the Tsunami

There were at least three waves, minutes apart, which arrived at Sendai Thermal Power Plant. The turbines were installed on the 2nd floor of the power station and so were not directly affected. The 154kV transformers were completely flooded as well as the ground floor controls and it took 8 months to replace the transformers. There was also destruction of an outbuilding as well as external pipework. Further damage was caused through the process of checking the plant. The workers had time to evacuate to the top of the nearby hill before the tsunami hit.

If a comparable tsunami hit the power station again, it was suggested that there would be similar damage, but there would be measures in place for reduced time of rebuilding. Currently there is little margin between supply and demand of components.

Onagawa Nuclear Power Plant

General information on power plant

Onagawa Nuclear Power Plant is a 2,174 MW 3 unit plant, managed by the Tōhoku Electric Power Company. Toshiba, Hitachi and General Electric (GE) were involved in its construction with Toshiba being the lead contractor and GE the main technology provider and it was the most rapidly constructed nuclear power plant in the world. The highest actual tsunami wave was marginally lower than the site level. However in spite of the tsunami not exceeding the site level, there was still significant flooding via the sea water intake structure. The water passed up through the level transmitter channels in the seawater chamber and through the pipe and cable duct into the power plant basement. In the basement there was then flooding of one of the raw water cooling (RWC) pumps, but one of them fortunately remained in service and was supplemented by 8 temporary pumps. One of the RWC heat exchangers was also flooded. Onagawa nuclear power plant was not far off suffering a similar fate to the Fukushima Daiichi power plant, but the main difference at Fukushima Daiichi was that that the tsunami height (13m) was greater than the site height (10m).

The Onagawa plant is currently out of operation and current major projects towards operational capability and required safety level include building of a sea wall and re-blading the low pressure (LP) and intermediate pressure (IP) steam turbine rotors, which suffered rotor-to-stator contact as a result of the earthquake rather than the tsunami.

JSME/IMechE/ASME Round Table Meeting

The round table meeting comprised a series of presentations by representatives of JSME, IMechE and ASME on engineering lessons learnt from the Fukushima incident and proposals for revised ways of thinking about energy in Japan. Most of the JSME members were involved in nuclear energy and the main messages that they were presenting were:

  • Improvement to risk assessment is required
  • Communication with the public by engineers on the safety of nuclear power needs to be improved.

There was a general consensus amongst the JSME members that the Japanese public had lost trust in engineers since the Fukushima incident. Whilst the incoming JSME president, Prof Shigehiko Kaneko (in position from April 2012), is involved in smart grids in his work, in general there was little presentation on alternatives to nuclear power or on ways of reducing consumption. The current president, Dr Jun’ichi Sato, did make reference to the extent of renewable energy in Japan, showing that it was very limited and that most of what there was hydroelectric. He explained how much constraint there is in Japan on renewable energy of various forms. Key challenges for renewable energy development are as follows:

  • Onshore wind energy. On the main island of Honshu in particular the plains are densely populated and the mountains are not suited to wind farms, generally being steep and inaccessible.
  • Offshore wind energy. Sites are limited due to steep shelving of the seabed off the coast. Floating offshore wind may be a potential future solution, but this is still under development and very expensive.
  • Bioenergy. For similar reasons as for wind energy there are constraints on available land for biomass production.
  • Solar energy. Solar photovoltaics (PV) make an important contribution and due to the high summer cooling load in Japan, the output from PV is better aligned with demand there than it is in northern Europe. However the availability of roof space and other space for installation restricts the extent to which it can satisfy demand (based on currently available technology).
  • Hydroelectric power. Most of the potential for large scale hydro has already been exploited, but there is still some potential for smaller schemes.
  • Tidal energy. The tidal range is not high in Japan and so there is limited viability of this technology.
  • Wave energy. The wave resource is not strong in Japan (due to relatively low wind speeds and deep offshore water).
  • Geothermal. Some geothermal energy has already been exploited and there is the potential for more. One of the main constraints here is that some of the best sites are in national parks and there will be planning resistance to the development of power stations.

Jun’ichi Sato in his presentation referred to the strong link between energy consumption and gross domestic product (GDP). He presented the breakdown of electric power supplied in Japan as follows:

Type of electric power supplied

Proportion of electric power supplied (%)











Other renewables



At the time of the visit there were 54 nuclear power plants in Japan and at the time of our meeting there were only two remaining in operation and both were due to close within a month. In order for them to reopen, the local authority for each power station needs to grant approval, and with the level of anxiety of the Japanese people, this was destined to take some time.

Old low-efficiency thermal (fossil) back-up power plants have been brought back into action to compensate for the loss of nuclear power. Japan has managed to achieve a saving in electrical power consumption of 5-10% since the earthquake - to a large extent this had been achieved through scheduled and rotating power restrictions, with cooperation from some major consumers of power. For example Honda had imposed new working patterns on their staff such that, instead of having a predominant pattern of Monday to Friday working, there was a shift towards weekend working. This is helping to spread the electrical load and reducing the need for peaking capacity to be provided by the old fossil power plants. However emergency diesel generators were also being deployed which increased the need for oil imports and was raising cost prices. Furthermore, whilst people were willing to adapt in an emergency situation, it was considered that there was a limit to how long peoples’ sacrifices could be sustained.

Prof Rod Smith, in his presentation, emphasised the need to adopt a balanced approach in assessing the real risk through comparing the impact on health and mortality with other forms of energy generation and other accepted human activities. He did however underline the fact that, in a democracy, perception is the reality that dictates action. Rather than dismiss people’s fears, it is important to ensure people are armed with the facts and engineers have a role to play in achieving this.

Rupert Blackstone (EESG/IMechE) presented on distributed energy systems network balancing and explored similarities and differences in this area between the UK and Japan. Areas that were covered included load management, energy storage and integration of electrical generation systems with electric transport (or indeed the production of synthesised fuels). In terms of electrical network balancing, significant differences that Japan has compared to the UK include the high electrical load for cooling in the summer and also the high electrical load for heating, giving more scope for energy demand management. There appears significant work on smart networks being undertaken in Japan and Toshiba is one of the leading companies in this area. With the incoming president having an interest in smart networks, there is the potential to explore the field and how there may be synergies between approaches in the UK and Japan.

Post- Earthquake Engineering Conference

The main conference was entitled, “One Year after 2011 Great East Japan Earthquake International Symposium on Engineering Lessons Learned from the Giant Earthquake”. This was a joint initiative of the following organisations:

  • Japan Association for Earthquake Engineering
  • Architectural Institute of Japan
  • Japan Society of Civil Engineers
  • Japanese Geotechnical Society
  • Japan Society of Mechanical Engineers
  • Seismological Society of Japan.

The conference covered a wide range of topics from seismology, through building design to energy. The focus of the energy presentations was on nuclear safety.


Figure 13 - Ian Arbon's keynote talk on the Energy Hierarchy

Ian Arbon gave a keynote talk on “The Energy Hierarchy Approach to Optimum Use of Energy Infrastructure – Sharing Ideas from the UK and Other Parts of Europe”. He emphasised the point that the use of the word ‘energy’ throughout the event was misleading, because it was invariably being applied to electricity only. Ian explained that it had been difficult for him to obtain figures on heat consumption in Japan. He pointed out that electricity was only one part of the energy mix and nuclear (which was such a focus of the event) represented only a proportion of electricity (around 30% electricity is nuclear in Japan and around 36% of energy is electricity; therefore only around 11% of energy is nuclear). Ian outlined what he viewed as major challenges that applied to Japan’s future energy systems:

  • Increasing global population and competition for resources
  • Japan’s lack of indigenous fossil energy resource
  • Japan’s high level of energy consumption.

In line with the Energy Hierarchy developed by IMechE, Ian indicated that it was fundamental that priority should be given to reducing energy consumption and then more efficient use of energy. He suggested that reduction in consumption had to be driven primarily by Government, but that many of the solutions would be developed by engineers, whereas with energy efficiency engineers would take the lead with support from the Government.

Rupert Blackstone met with JSME again on a visit to Japan in October 2012 and together established the basis for further collaboration in the energy field between JSME and IMechE.

11. Transol



Wattcraft is the UK agent for Transol. Transol is a tool for design, calculation and optimisation of solar thermal systems. Transol makes dynamic simulation simple (using the TRNSYS engine) through a user-friendly interface. It incorporates weather data for the entire world and an extensive database for solar collectors, storage tanks, insulation materials, etc. and provides detailed performance and economic reports. This tool has been developed through an ambitious project carried out by Aiguasol in collaboration with the French research centre CSTB (Centre Scientifique et Technique du Bâtiment).

To find out more about the tool or to order it, please contact Rupert Blackstone by email  to rupert.blackstone@wattcraft or by telephone on +44 (0)20 81442110.

You may purchase a licence for Transol directly via: http://store.aiguasol.coop/english/transol-v31.html


12.                 Solar thermal

Wattcraft can offer a wide range of services in solar thermal energy and had the full support of Aiguasol, who have been working in this field since 1999 and have more than 30,000sqm of designed and installed collector area. The following full range of services is offered:

·       Product design and optimisation

·       Research and Development in all areas of low, medium and high temperature systems

·       Development of technology solutions, strategy and tools at local, regional, national and international levels

·       Development of optimisation methodologies such as Metasol (upon which the official Spanish validation software for solar thermal installations (CHEQ4) is based)

·       Specialised software for systems evaluation and optimisation, such as TRANSOL.

·       Systems and tools for public authorities for the support of local and regional solar thermal regulations

·       Project delivery engineering services from preliminary design to construction

We can provide solar thermal service for a wide range of sectors:

·       Residential

·       Commercial

·       Tertiary (public and private)

·       Industrial

A full range of technologies can be assessed:

·       Low temperature: flat plate collectors of all sizes and configurations

·       Medium temperature: evacuated tube, including heat pipe

·       Medium and high temperature: fresnel, parabolic trough

·       Air collectors for HVAC integration

Wattcraft can cover a range of applications:

·       Domestic hot water production

·       Space heating

·       Solar cooling

·       Heat for industrial processes

·       District heating and cooling networks

In summary, Wattcraft is capable of offering independent advice and a comprehensive range of services related to the field of solar thermal energy, providing innovative solutions backed by the extensive experience gained by Aiguasol through nearly 13 years working in the field and being a noted reference in the European market.

13.                 Sustainable Energy Services for Developers

With energy moving up the agenda for building development, are you interested solely in compliance, or in positioning yourself as market leader demonstrating more than just good practice? Either way Wattcraft can help, as it is recognised that even compliance can be very challenging and, with there being so many possible routes to compliance, there are significant cost saving opportunities with the right balance of measures delivered.


What is Wattcraft, and why would you want to work with us?

Wattcraft is a specialist sustainable energy engineering consultancy.  We have experience of a wide range of renewable energy and CHP projects both within and outside the built environment.  With an understanding of energy demand and all-round sustainability aspects of building developments we can offer a valuable service to developers.  As an independent consultancy with a good understanding of a range of sustainable energy solutions, and the flexibility to meet varying client requirements, we can help you arrive at the solutions that suit you in a targeted, tailored and cost-effective way.


Complying with Building Regulations Part L 2010 and beyond

With successive step changes in the requirement for CO2 reduction, the technical and economic challenges in meeting building regulations are increasing.  Not only are there major challenges with on-site requirements, but there are opportunities to reduce costs by optimising allowable off-site solutions.  Wattcraft together with its associates can cover the spectrum of on-site and off-site energy solutions considering bringing not only technical solutions, but determination of a range of financing options and means of delivery to give best value to the developer.


Understanding Energy Performance Certificates

Wattcraft and its associates can help the client navigate the relationship between energy compliance for building regulations and that for EPCs minimising unnecessary duplication.


Meeting Planning Energy Targets

Planning energy targets vary nationally, but may result in stringent obligations on the developer both in terms of energy demand side measures and energy supply side measures.  Wattcraft can help the client develop the most cost-effective way of satisfying planning requirements in a way that can be communicated effectively and robustly with the planners to maximise the chance of acceptance.  Appraisal of risk to the developer should be part of the development of appropriate technical solutions.


Optimising your Carbon Reduction Commitment (CRC)

For clients with an extensive property portfolio, Wattcraft can provide energy solutions for optimum CRC compliance through determining the technical and economic viability of energy options versus the cost of certificate procurement/penalty payment.


Taking advantage of the Renewable Heat Incentive (RHI) and Feed-in Tariff (FiT)


Where clients have an interest in the operational costs and revenues associated with energy supply, Wattcraft can help with implementing the most cost-effective solutions with environmental benefit, taking into account potential revenue streams from the Renewable Heat Incentive and Feed-in Tariff.


Getting the benefit from loans – Carbon Trust and the Green Deal

Wattcraft can help clients determine what loan options may be available to minimise up-front payments on energy systems if there is the opportunity to transfer payments to the building occupant.  Guidance is given in particular on finance routes which are especially geared for this purpose, including the Carbon Trust loan service and the forthcoming ‘Green Deal’.



Do you want to reduce your school energy costs, freeing up finances to spend on other services?

Do you want to reduce the dependence of your school on fossil fuel supplies and find the most reliable and best value sustainable alternatives?

Would you like to explore how to engage both staff and pupils in sustainable energy practice?

Wattcraft can help you find the energy solutions that suit you and help you deliver them.

School Energy Services








Wattcraft provides renewable energy and sustainability services with a focus on engineering consultancy. We have wide-ranging in-house skills and also a network of specialist collaborators whom we can bring in to address specific project needs.  In this way we can provide a highly versatile and effective service.


Energy efficiency

Renewable energy



You will be working with people who have extensive experience of modelling energy systems.  We understand how local factors affect your choice of energy measures.  The local climate, local energy costs, local energy resource, economic support mechanisms, planning constraints, national best practice, school occupancy patterns, school facilities and a whole host of other factors will affect what energy systems you put in place.

We will work closely with you to ensure we understand your specific needs such that we can offer solutions that are best for your school and its future.



Do you want to reduce your energy costs, freeing up finances to spend on other services?

Do you want to find out how to use your land to make money from renewable energy?

Do you want to cushion yourself from the volatility of the fossil fuel market?

Farm Energy Services






Wattcraft provides renewable energy and sustainability services with a focus on engineering consultancy. We have wide-ranging in-house skills and also a network of specialist collaborators whom we can bring in to address specific project needs.  In this way we can provide a highly versatile and effective service.


You will be working with people who have extensive experience of modelling energy systems.  We understand how local factors affect your choice of energy measures.  The local climate, land condition, market value of land use options, local energy costs, local energy resource, economic support mechanisms, planning constraints, national best practice, and a whole host of other factors will affect what energy systems you put in place.

We will work closely with you to ensure we understand your specific needs such that we can offer solutions that are best for your farm and its future.


We can offer services covering a wide range of technologies including:

¦ Wind energy                        ¦ Bioenergy                ¦Solar energy

¦ Energy-from-waste             ¦ Heat pumps ¦ Combined Heat and Power

¦Energy efficiency                 ¦ Smart solutions       ¦ Practical sustainability



What are the characteristics of the farm and its environment?

What are the farm core activities and associated energy requirements?

What are the possible energy management models and will you get the benefit of the energy savings?

Energy demand modelling

Renewable energy options assessment

Summary advice, concept development and design

Functional specification of systems

Client’s engineer through procurement process and overseeing delivery by contractors

Measures for reduced energy consumption and energy efficiency






















16.                 Green Electricity

Green electricity refers to electricity the consumer purchases that originates from renewable energy generation. This is not generally a direct physical link, given that the electricity the consumer receives is the vibration of electrons in their local network, which is ultimately connected to a wide range of different types of generation.  The link is more commercial in that the electricity produced by renewable energy generation is allocated to the green electricity consumer.  If consumers were not offered green electricity as a product then everyone would be consumers of standard electricity, which would have a renewable energy component based on the renewable energy generation feeding into the electrical network.  This renewable electricity would be largely driven by the support mechanisms available to it (in the form of the Renewables Obligation (RO) and the Feed-in Tariff (FiT) in the UK).  The existence of the green electricity market to a large extent results in the renewable energy generation that is happening anyway being allocated to green consumers, thereby reducing everyone else’s allocation of green electricity.  This in itself would not result in an increase in renewable energy generation.  However to be able to call the electricity supplied ‘green’, its purchase must result in new renewable energy being installed.  Therefore a proportion of the premium paid for green electricity must be directed towards new renewable electricity generation.  The extent to which suppliers do this varies. The other argument for green electricity is that it creates a market for renewable energy and with increased consumer demand there will be additional pressure on the delivery of new renewable energy, rather than just depending on Government support mechanisms.


Frequently asked green electricity questions

What is green electricity?

It’s renewable energy isn’t it?

But isn’t that renewable energy happening anyway, driven by the Renewables Obligation (Government imposed economicmechanism linked to targets)?

Most of it is, but some of it may drive new renewable energy through the retiring of renewables obligation certificates (ROCs) i.e. a proportion of the renewable energy supplied does not count towards the Government targets.

Do all green electricity suppliers retire ROCs?

No, and the extent of ROC retirement varies for those who do.

So the premium on the electricity in part goes towards stimulating new renewable energy, and the rest to make the green electricity consumer greener at the expense of everyone else becoming less green?

Yes, but there is also the argument that by consolidating green electricity a market demand is being cultivated that will justify further expenditure on renewable energy projects.

Isn’t most renewable energy wind energy and isn’t that heavily constrained by planning independently of the green electricity market?

This may be true to a large extent but with increasing offshore wind energy, smaller distributed wind energy projects and also forthcoming developments in wave and tidal power, amongst others, there are various avenues for investment in new renewable energy.  Furthermore changes in the planning system should allow more onshore wind energy development.

What if we all bought standard (predominantly) brown electricity and waited for the Government to set higher targets?

Support for higher targets may filter less effectively through the voting system than voting with custom, and in the end consumers collectively will have to pay for any premium on green electricity whatever the mechanism.

Isn’t it better to install renewable energy on-site and retire all the ROCs in the knowledge that all the money will be invested in new renewable energy?

There are cases when on-site generation may be an attractive proposition, but the advantages of green electricity can be that larger more efficient projects are supported and there is no capital outlay for the consumer along with the risk that that may entail.

With renewable energy being largely intermittent, won’t we soon get to the stage where we are unable to balance supply and demand effectively?

We are still a fair way off this point in the UK but, in conjunction with increased renewable energy generation, we need to introduce further measures to balance supply and demand – these may include energy storage, increased continental interconnection and demand side management helped by greater electrification of demands that do not need instantaneous response such as electric vehicles and heat pumps.

Is it a good idea to switch to electric vehicles now to support renewable energy increase, or do they currently result in higher emissions due to the electricity mix being predominantly brown?

Even now electric vehicles can result in the emission of less CO2 per passenger kilometre than internal combustion engine vehicles running off fossil fuel.

Won’t I be better off spending my extra money on energy efficiency measures than spending it on green electricity?

In line with the energy hierarchy priority should be given to energy demand reduction over renewable energy supply.  In economic terms there are energy efficiency measures such as certain levels of insulation that may result in lower cost, but with increased measures there comes a point where the marginal cost of CO2/fossil fuel reduction through renewable energy is less that that that from additional energy efficiency measures.

Why is green electricity generally more expensive than brown electricity and will renewable energy eventually become cheaper than fossil fuel energy?

Whilst renewable energy generation may currently be more expensive than fossil fuel energy, it should be remembered that fossil fuel generation has had decades of investment that renewable energy has not had.  Furthermore the true costs of the damage caused by fossil fuel generation are not paid for by the consumer, and if this were the case then the economic comparison would be very different.  There are likely to be further advances in renewable energy generation that will bring down the costs of manufacture and with increased pressure on the environment and security of supply, its value should be bolstered in other ways.

Given the criticality of the environmental situation and security of supply, shouldn’t we be investing our money in cheaper more conventional options such as ‘clean’ coal (with carbon capture and storage) and nuclear power?

Fossil fuel power with carbon capture and storage (CCS) is not yet established and accelerates the consumption of fossil fuel and neither is nuclear technology that can operate reliably without significant depletion of known stocks of uranium. Advances may be made with these technologies, but the question is how much investment should be directed towards generation from finite resources at the expense of that from renewable resources.

If we assume the Government target of 80% reduction in CO2 from 1990 levels by 2050, what is the best way of getting there and what can we do to drive it?

It is hard to predict a path exactly, but with appropriate policy and market interventions encouraging the most effective energy systems to thrive combined with consumer demand for green energy we may converge on the target.  Selection of energy suppliers with particular energy generation portfolios will influence the course towards the target.


What do you think?  What should our energy future should look like?*  What balance of generation will you go for?  Take your pick


*You can build your own future energy scenario using the DECC 2050 Pathways tool (https://www.gov.uk/government/publications/2050-pathways-calculator-how-to-use-the-calculator-and-develop-your-own)


17.                 Business Energy- General

What can reducing your energy consumption do for you?

It pays to give attention to energy consumption in a commercial organisation even if it is not perceived as a large part of the overall business costs.  An energy survey is generally a good investment as, for relatively low expenditure, thousands of pounds per year may be saved, depending on the organisation.  The priority should always be on avoiding energy consumption, and it is generally possible in a typical business to reduce energy consumption by 20% without too much capital expenditure, for example through the adjustment of controls.  Further to this there are a number of measures that can be put in place that give you a return on investment.  A first step may be to commission an energy survey by an energy consultant to determine your patterns of gas and electricity consumption, what can be done to reduce the consumption, the cost of this and how to go about it.  From this there may be measures that you can apply straight away, or if you are constrained by capital and also want to reduce risk, a route towards more extensive energy efficiency interventions may be through an energy service company adopting the energy performance contracting (EPC) model.


Why might you think about generating your own energy?

There may be opportunities for you to generate your own energy on your premises.  Aside from reducing your carbon dioxide emissions, this could make you money.  You may be able to obtain financial support for renewable energy generation and combined heat and power (CHP).  Revenue through Renewables Obligation Certificates (ROCs), Feed-in tariffs (FiTs) and the Renewable Heat Incentive (RHI) can help you pay back your investment.

Wattcraft can show you how.


18.                 Heat Pumps

What are heat pumps?

Heat pumps are a relatively low energy way of heating or cooling buildings compared to conventional boiler systems.  Heat pumps transfer heat between zones of different temperatures to provide either heating or cooling, depending on what the requirements are at the time.  A heat pump is similar to a refrigeration circuit in that heat is transferred between a circulating fluid and its surroundings.  In the case of a refrigeration circuit heat is transferred from the refrigerator to the low temperature fluid circulating through the unit (the working fluid or refrigerant) thereby evaporating it.  The working fluid is then compressed (with a pump) and condensed (through cooling by air or water) and then enters the refrigerator again.  A heat pump in cooling configuration operates like a refrigerator, and a heat pump for heating operates like a refrigerator in reverse.

The following two main types of heat pump may be used to supply heat to a building:

·       Ground source heat pump

·       Air source heat pump.


Heat sink (building)

COMPRESSOR (temperature and pressure increase)

CONDENSER (heat transferred to building circulation)

EVAPORATOR (low boiling point fluid evaporated by heat source)

EXPANSION VALVE (temperature and pressure drop)

Heat source (air or ground)

Electricity input













Schematic of a heat pump circuit in heating mode


Ground Source Heat Pumps

Ground source heat pumps (GSHP) move heat (or coolth) from the ground (heat source) to the building (heat sink).  The temperature below ground does not vary as much as the air temperature through the year with the result that the source temperature is closer to the sink temperature for ground source heat pumps.  In the winter (in the UK or other northern countries) the ground temperature is generally higher than the ambient air temperature, and so heat may be transferred efficiently between the ground and the air to heat buildings.  In the summer the ground temperature is generally lower than the ambient air temperature, thereby allowing cooling to be provided efficiently to buildings.

Air source heat pumps

Air source heat pumps (ASHP) during the heating season transfer heat from the outside air into the building.  The principle is the same as for the ground source heat pumps, with the main difference being that, with the outside air being much colder than the ground, much more work has to be done to reach the internal temperature required in the building.  This means more input energy is required and therefore the system is less efficient.  Similarly in cooling mode more work has to be done by air source heat pumps than ground source heat pumps in transferring heat from inside the building because the external air temperature is likely to be higher than the ground temperature.  Thermodynamically, more work has to be done in moving heat to a across a higher temperature differential. The efficiency of a heat pump is expressed in terms of the coefficient of performance (CoP), which is the ratio between the energy supplied (either heating or cooling) and the input electrical energy.  For a ground source heat pumps the CoP may be over 5, whereas for an air source heat pump the average is unlikely to be over 3 with currently commercially available technology.  In summer, in the UK for example, the ground temperature is lower than the target building internal temperature and in this case ‘free cooling’ is a possibility, whereby there is direct heat exchange between the working fluid and the building circulation without the need for operating the heat pump.  This allows much higher CoPs.

Installation and cost comparison

Ground source heat pumps

Ground source heat pumps require pipework to be installed underground. Heat is transferred between the ground and the working fluid through the walls of the pipework.  The most efficient ground source heat pumps require vertical boreholes, typically to a depth of around 100m.  This requires significant capital outlay and may be difficult where there is restricted space, for example in a row of terraced houses with small gardens.  There are also local geological considerations that may constrain the potential for boreholes.  The boreholes need to be far enough apart such that they do not interfere with each other in thermal terms.  For new buildings with pile foundations, the boreholes may be integrated into the piles.  This can reduce costs but allows no access to the pipes in case of failure.  Access is still likely to be a problem if the boreholes are introduced below a building even if they are not integrated into the piles.  If there is plenty of outside space available but capital is restricted, then horizontal pipes may be more suitable for heat exchange with the ground.  The efficiency of this kind of heat pump system will not be as high, since nearer the ground surface the temperature is more similar to surrounding air temperature than further down.

Air source heat pumps

The cost of air source heat pumps is lower than that of ground source heat pumps, and installation much easier.  However there will need to be space for a box next to the building.  This may also be unsightly and make some noise, so some consideration may need to be given to aesthetics.

Building heating system

For the reason that heat pumps operate most efficiently when there is the lowest temperature differential between heat source and heat sink, heat pumps are most suited to lower temperature heating systems.  Lower temperature heating systems require larger areas of heat transfer to provide the same internal air temperature and therefore under floor heating is most suited to heat pumps.

How do I go about it?

The first step might be to decide which suits best – ground source or air source heat pumps.  This will depend on a range of factors including:

·       Available space

·       Available capital

·       Heating demand

·       Whether your current heat supply is gas, oil or electricity and the associated cost

·       Available support tariff.

Wattcraft can help you work through this.


19.                 Microhydro

Microhydro generally refers to hydroelectric power systems up to a rating of around 300kW.  These may be small pelton wheel systems or run-of-river turbine systems.  Energy is extracted from both the potential energy (related to the height or head) of water and the kinetic energy (related to the flow rate of the water).  Microhydro may be suitable if you have a river running through your property, and in particular if you have existing weir infrastructure, such as at a mill.  The civil engineering costs of microhydro schemes may be significant and the economics are generally much more attractive if the microhydro turbine can be integrated into an existing weir. If you think that there might be the potential for microhydro on your site, then you should engage with a specialist to assess further.


20.                 The CHP/Renewables Roadshow: London, Thursday May 30th, 2013

Rupert Blackstone of Wattcraft  is speaking on “Industrial-scale renewable energy versus community renewable energy projects” at the CHP/Renewables Roadshow: London, Thursday May 30th, 2013. Programme [REPLACED]


The CHP/Renewables Roadshow: London, Thursday May 30th, 2013

Rupert Blackstone of Wattcraft  spoke on “Industrial-scale renewable energy versus community renewable energy projects” at the CHP/Renewables Roadshow: London, Thursday May 30th, 2013. Programme


21.                 Links


Green Cars


What are the different ways in which the car may develop towards having a reduced impact on the environment?  What changes are needed to make this form of transport supportable in the long term?  We consider the possibilities.


In industrialised countries people have become largely dependent on cars and see them as essential for their personal freedom.  However it is increasingly agreed that our ecosystem is not able to support the emissions that are produced and the reduction in finite resources caused through driving cars.  This is exacerbated by increasing population and industrialisation and therefore there is a need for concerted attention to be given to technical and sociological solutions that will lessen the impact of this form of transport. 

The relationship between cars and other forms of transportation

The way in which the car currently compares with other forms of transport very much depends on the model of car being considered and the way in which it is used.  Buses are generally acknowledged to be the most efficient form of land transport if they are fully utilised, and it is also widely assumed that trains give lower emissions per passenger kilometre than cars.  However these comparisons are not always clear cut, as for example in the UK there may be less carbon dioxide emissions per passenger kilometre for an efficient diesel car carrying four people than for a train, given the inefficiencies of current rolling stock (note that this does not mean that a switch of four passengers to using the train will result in reduced emissions for an individual journey when the train will run anyway).


Cars generally emit less per passenger mile than planes, but a large car may release more emissions per passenger mile than a plane on a long haul flight.  Whilst it is acknowledged that cars have a significant environmental impact, the high demand for cars has driven great innovation and increase in efficiency, more so than with other forms of transport such as trains.  Now that fuel efficiency is more of a priority for all forms of transport, the question may then be what role cars should play in a future transport system with efficiency improvements across the board.  


Most car journeys are used for short journeys.  In the UK, over 70% of journeys are under 5 miles, and in the US over 70% of journeys are under 40 miles, which is a short distance in the US.  These kinds of distances are within the range of new propulsion systems which have not got the same on-board energy density as internal combustion engine (ICE) cars, and these are discussed further on in the article.  Very short journeys are too short to warm up the car’s engine fully and therefore the engine will run more inefficiently, burning more fuel and polluting more.  It may be argued that these very short journeys should be carried out on bicycle or by walking.


There are those who suggest that the embodied energy in the food required to propel a person riding a bicycle or walking is greater than that in the fuel for required for the equivalent car journey.  It is beyond the scope of this article to either challenge or verify this assertion, but even if it were true there are other benefits to walking or cycling that would need to be taken into account, such as increased fitness and health, although it could be argued that activities leading to prolonged life place a greater burden on the planet’s resources.  It can be seen that the global sustainability arguments are complicated, and it is probably fair to say that more research and consensus is needed before they become conclusive.


The extent to which cars are needed depends on the population density of the places being travelled between.  Although there is increasing urbanisation, there remains a need for rural transport.  As with many rural services that are not cost-effective in their own right, public transport has attracted reduced support when fares from the passengers do not cover the running costs.  Coupled with the fact that public transport that is not fully utilised may give a less efficient use of resources, it can be seen how there may be a continued role for cars in areas of less dense population.


In this case, how can the use of these cars be made more efficient?  Car sharing is advocated as a way of reducing the manufacturing burden of cars and also as having the potential for increased utilisation through encouraging more passengers per car.  There are however significant social challenges to be overcome before car sharing becomes widespread. 


As has been suggested already,  people are attracted towards cars for the freedom they give, and there is resistance to anything that acts to restrict this freedom.  Therefore the design, function, and cost of shared cars will need to be such as to make them a more attractive proposition to the user than having their own car.  A range of designs available for different uses could in fact give people more freedom.  For example a small car may be used for quick visits and a larger estate may be used for carrying goods.  


If we consider the model of buses or trains being used over long distances or between urban centres and cars being used locally on a shared basis in areas of low population density, then it is important that the overall journey is as uninterrupted as possible for people to be attracted to this way of travelling.  Car pick-up depots would be needed at critical nodes, either bus or train terminals.  The transition from one form of transport to the other could be made smooth through the use of smart (data) cards to access vehicles. 


It should also be added that bus travel might need to be made more comfortable than it is currently to attract the majority of the population.  Bus travel could possibly be made more attractive than cars with reduced travel time through using bus lanes and increased onboard facilities such as internet access and refreshments.  

Design and development

There are several different designs towards reducing the environmental impact of cars in operation.  Whilst they may not be environmentally benign in their own right, the common feature is generally that they lend themselves to being fuelled by renewable energy either now in the future as the energy supply changes. 


There are also improvements in efficiency of fossil fuel consumption which are reducing the impact of cars.  It should be noted that over the last 10 years the internal combustion engine has seen efficiency improvements of around 1.6% per year, and whilst fossil fuel is still being burnt, this contribution is worth noting. 


As we make the transition towards greener technology there is much we can do to reduce the impact of our existing cars, such as slower acceleration, reduced speed and reduced weight.  This requires both education and incentives or regulation.  It is not clear yet what new technologies will dominate, but some of those that are showing promise are described below.


Little or no modification is needed for an engine to run off biofuels.  However the main issues that need addressing with biofuels are their energy ratio and land area requirements.  The energy ratio (energy available in fuel divided by the energy required to produce the fuel) is often below 2 for the current generation of biofuels, thereby giving less than a 50% saving in CO2 emissions as compared to mineral fuel, assuming mineral fuel is used to produce the biofuels.  If instead it is assumed that the fuel used to produce biofuels is also biofuel, then the impact can be translated into increased land use. 


With the current generation of biofuels there is a question as to whether there is enough available land to meet all our current transport needs by this means, although there are significant areas currently not fully exploited that could be brought into production.  The next generation of biofuels, using more woody crops, promises both better energy ratios and the ability to use marginal land that cannot easily be turned to agriculture, thereby removing any conflict there might be with food or other land uses.  These second generation biofuels are still under development and have yet to be proved viable. 


If we consider the efficiency of energy conversion of land with energy crops for liquid biofuels and land covered in solar arrays, solar arrays may convert more than 20 times the sun’s energy than the energy crops over the same area, and when this is converted into motive power for transport, the factor may be nearer 50. From a land use perspective therefore, it can be seen that solar power would offer an advantage over biofuels, but there is currently a great difference in cost which makes biofuels more commercially attractive.


Other forms of renewable energy, such as wind power use even less land and are less costly than solar, although are not currently as cheap as liquid biofuels as an energy source for transport.  While internal combustion engines remain the main source of car power it seems likely that liquid biofuels will make a significant contribution.   

Electric cars

Electric cars give a local reduction in emissions as compared to ICE cars, and in the UK they already give a reduction in CO2 emissions when compared to ICE cars, taking into account the grid CO2 burden, transmission losses, pre-combustion emissions and relative conversion efficiencies.  However for electric cars to give the required reduction in overall fossil fuel consumption and associated emissions, the electricity will need to come from renewable resources, and given the current struggle to make a sizeable renewable energy contribution to existing electrical demand, this is not without its challenges.  


Electric cars have not yet reached the performance of ICE cars.  The range of electric cars is less, their power is less, and their energy storage (usually batteries) takes up more space and is very heavy.  Electric cars approaching an equivalent performance may be over 5 times more expensive than their mineral fuel equivalent, and therefore have a long way to go before they become attractive to the average customer.  


There are three main types of electric vehicle: electric vehicles (EV), which use a battery driving an electric motor; hybrid electric vehicles (HEV) in which an internal combustion engine charges a battery; or plug-in hybrid electric vehicles (PHEV). 


Because HEVs have two motive power systems, they are heavy and struggle to match the efficiency of modern diesel engines.  For EVs and PHEVs, which are charged from the electrical network, attention needs to be given to the mechanism for charging. 


With current battery technology it is impractical for most motorists to wait around every time for the time it takes to charge a battery whenever they need a refill of power.  One possibility is to have battery stations, as with petrol stations, where motorists can exchange their depleted battery for a fully charged one.  Clearly this will need increased uniformity in battery use for this to be viable. 


Alternatively flow batteries could be used whereby they could be charged by pumping new electrolytes into the system and pumping out the discharged electrolyte.  There is a concerted focus by manufacturers on the reduction of charging time of batteries. One manufacturer claims it is on track to develop an electric car with 26 minutes' charging time. 


There are serious environmental constraints on the widespread use of batteries in vehicles, with the use of scarce materials in their manufacture and the release of toxins when disposed of.  However advances in battery technology promise longer lifetimes as well as higher efficiencies and deeper discharge.  

Fuel cells


Another form of energy conversion that uses an electric motor is the fuel cell.  A fuel cell differs from a battery in that there is a constant flow of fuel through the battery to supply the electrochemical reaction, so although there are significant maintenance requirements, the electrochemical potential is not depleted as it is in a battery.  


Fuel cell cars (and buses) are already in production, but are disadvantaged by the low energy density of hydrogen storage, thereby limiting their range.  In addition their widespread use would depend on the introduction of a hydrogen infrastructure, which would be extremely expensive. 


If fossil fuels are used to produce the hydrogen, there are no significant energy gains through using fuel cells, and therefore for fuel cells to be green there is a need for production of hydrogen with renewable energy.  However, it should be noted that the overall efficiency of conversion for a fuel cell using renewable electricity via an electrolyser is significantly less than that of a battery electric vehicle. 

Compressed air vehicles


Compressed air cars work by storing air at high pressure in a tank and releasing the air through pistons that drive the wheels.  Developers of compressed air cars claim lifecycle emissions comparable to those of battery vehicles, assuming the air compressor is powered from the same mains electricity that would charge a battery. 


They have the advantages that they do not need expensive batteries to be replaced every few years and they take a fraction of the time to charge.  These are still under development, but could potentially have a significant role to play.  

Impact on the electrical distribution network


One challenge faced by electric vehicles is the dealing with the impact that they will have on the electrical network.  In the UK there is a projected shortfall of capacity based on current electrical demand, and anything that will add to capacity requirements will be difficult to support with our existing infrastructure and planned generation. 


To maximise uptake of electrical vehicles with existing electrical generation capacity, there is the possibility of limiting the charging of electric vehicles to night-time when demand is low, thereby utilising spare capacity rather than adding to the burden on existing capacity.   


Whilst the theory would appear to be sound, to ensure that this happens in practice would require fairly radical new measures such as a draconian tariff structure that  would ensure that day charging would be negligible. 


It would inevitably be the case for battery cars that they would run out of power on occasions through the day, and if this was not to put extra demands on the generation capacity and infrastructure, then local electrical storage may be necessary.  It has been suggested that electrical cars could be used as distributed electricity storage for the electrical network while not in use.


The challenges facing this initiative include the possible reduction in battery life through frequent shallow cycling and also difficulty in ensuring the total storage capacity is in line with requirements at any one time, given the unpredictability of car usage. 


Many proposals for the widespread introduction of electric cars assume charging at the extremities of the network (i.e. at 240V), with the typical model being that people would plug their car in at home. 


Aside from the network capacity issues, at this low voltage the losses would be significant.  A separate high voltage network may address this, and would also support the rapid charging model referred to earlier, but this would require huge Government investment. 

Car manufacture and embodied energy


The question is sometimes asked as to whether it is worth replacing an old inefficient car with a new more efficient one, given the investment of embodied energy in the new car. 


The ratio between the embodied energy in the manufacture of a car and the total energy used over its life including its operation does of course vary considerably with different car models and different usage patterns, but to give an idea of scale a range of 15-25% currently appears to be typical ie 15-25% of the lifecycle energy consumption of a car may be from its manufacture, assuming a normal lifespan.


If the car is scrapped prematurely, the proportion of embodied energy in the lifecycle will increase. Other factors that should be taken into account are whether or not the old car continues to be used by someone else and whether or not there is a rebound effect of the driver covering more miles because the fuel bill is lower. Care should therefore be taken when replacing a car purely on energy-saving grounds.  

Making it happen


Whilst there are people for whom environmental concerns will be the dominant factor when they choose their car, for most people other factors are as important or more important, and these include styling, brand loyalty, reliability, function and cost.   All these factors need to be addressed for the successful uptake of green cars.  There are already noticeable shifts occurring towards more fuel efficient cars because they can give a great reduction in cost to the user. 


If there is to be a move away from ICE cars, then there will need to be significant infrastructure investment, which will need to be centrally funded and coordinated.  Given that non-ICE cars vary in their infrastructure requirements (eg fuel cell cars using hydrogen versus battery electric cars), then it may be supposed that one type of car will dominate when there is an emergence from the current niche markets. 


Whatever technological solutions are chosen, in the same way that we may follow a waste hierarchy or energy hierarchy, we might also follow a transport hierarchy: 1) Use transport less 2) Use fuel efficiently 3) Use renewably powered transport.


15 June 2009

 by Rupert Blackstone CEng IMechE


Further reading: Hybrid electric vehicles (HEVs) – how efficient are they?



Green Tariffs versus Green Wash


Article by Rupert Blackstone - Energy, Environment and Sustainability Group (EESG), IMechE, 10/12/2008


On the 1st December, EESG hosted a talk given by Juliet Davenport, Chief Executive and founder of Good Energy.  Good Energy is a supplier of green electricity, and Juliet’s presentation was to explain what ‘green tariffs’ actually mean and what difference they can make to the total installed capacity of renewable generation.


Rather than promote the virtues of Good Energy as a company, Juliet’s talk gave an overview of the context of green electricity and the various types of green electricity on the market.  She started off by explaining how far the UK needs to go in meeting its 15% renewable energy target as a share of the total EU target of gaining 20% of energy from renewables by 2020.  She pointed out that in the European Union, only Luxembourg and Malta have less renewable energy supply than the UK (currently less than 3% of primary energy consumption).


Good Energy claims that their customers will receive 100% of their electricity supply from renewable energy.  A common criticism of green electricity in the UK is that green electricity suppliers are just allocating to consumers renewable electricity that is being generated anyway as a response to the Government Renewables Obligation financial mechanism, and which is constrained not so much by the market, but largely by planning.  Following this argument, more is needed than a claim of 100% renewable energy supply to demonstrate that the sale of green electricity is actually resulting in new renewable energy capacity.  Juliet covered in her presentation the main additional measures taken by green electricity suppliers.  These included:

a)     Retiring Renewables Obligation Certificates (ROCs) gained for renewable energy generation from the market, thereby increasing the incentive for renewable energy to be generated elsewhere. Juliet was not in support of this entirely, as she believes that ROCs drive technology solutions, given the differentiation in support to different technologies, whereas green electricity supports units of renewable energy supply (one would presume then that it would favour the cheapest).

b)     Green Funds guaranteeing that a certain amount of money is invested by the energy supplier in environmental projects beyond Government commitments

c)     Offsetting carbon dioxide emissions.  Juliet’s concern about offsetting was not only that it may not be diverted into renewable energy, but that it is not generally transparent and auditable. 


Juliet emphasised the need for transparency with green electricity, something that is often not evident for the public when reviewing green electricity websites, and she supported auditing as an inexpensive way of improving customer confidence.  Juliet believes that green electricity has an important role in stimulating the market for renewable energy, and that it can realise potential that regulation and policy interventions will not reach alone.  Although the impact of buying green electricity on new renewable energy generation may be limited at the moment, Juliet explained that the investment in green electricity is not for today, but tomorrow when the market is further developed.


22.                 Energy Savings Opportunity Scheme (ESOS)

Why choose Wattcraft for your ESOS assessment?

What is ESOS?

When is the ESOS deadline?

What happens if you miss the ESOS deadline?

What energy use is within the scope of ESOS?

What do you have to do to comply with ESOS?

Is your organisation subject to ESOS?

Where can ESOS lead?

Why choose Wattcraft for your ESOS assessment?

There are those who sell ESOS services by offering the minimum required to comply. This can suit some clients who are happy with a commoditized package that enables them to meet the short term objective of avoiding the penalty.

Wattcraft offers something more than this as a specialist energy consultancy. If you are interested in turning your ESOS assessment into a real opportunity for saving energy in your organisation, then Wattcraft can help you move on with delivering the energy improvements.

Wattcraft can provide you with qualified ESOS Lead Assessor sign-off  as well as empowering you to put the recommendations into action and make genuine savings.

ESOS is focused on energy efficiency and indeed reducing the demand for energy should always be a priority. However working with Wattcraft you will have the opportunity also to assess the potential for renewable energy measures, either in parallel with, or following on from the assessment of the energy efficiency measures required for ESOS. This will help you establish the overall most cost effective and high impact energy measures for your organisation.

What is ESOS?

ESOS is a mandatory energy assessment scheme administered by the Environment Agency for organisations in the UK that meet the qualification criteria.

Why choose Wattcraft as your ESOS consultants?

When is the ESOS deadline?

Organisations must notify the Environment Agency by a set deadline that they have complied with their ESOS obligations.

The deadline for this year is 5 December 2015, by which all qualifying organisations must carry out their ESOS assessment and notify the Environment Agency.

If your organisation cannot comply by the 15th December and expresses this to the Environment Agency, then an extension until the 29th January may be allowed.

It is now past the 29th January, but if you still have not complied, then you give this priority and get it done straight away - this is likely reduce the chance of penalisation by the Environment Agency.

Why choose Wattcraft as your ESOS consultants?

What happens if you miss the ESOS deadline?

Failure to comply with ESOS by the deadline may result in the following penalties:

Why choose Wattcraft as your ESOS consultants?

What energy use is within the scope of ESOS?

Generally all energy that is both supplied to and consumed by your organisation is within the scope of ESOS. However you are allowed to exclude 10% of your total energy consumption from any audit or alternative compliance measures.

The 10% exclusion can be on the basis of:

Why choose Wattcraft as your ESOS consultants?

What do you have to do to comply with ESOS?

For organisations with an ISO 50001 energy management system

If your organisation has an ISO 50001 energy management system covering all your energy use at the compliance date, then this counts as your energy assessment. You then need a board director to confirm that your organisation is compliant based on the findings of your ISO 500001 certification and make a corresponding notification to the Environment Agency.

For organisations without an ISO 500001 energy management system

If your organisation is subject to ESOS and you do not have an ISO 500001 energy management system in place, then you must carry out audits of the energy used by their buildings, industrial processes and transport to identify cost-effective energy saving measures. These assessments have to be repeated every 4 years.

You need to appoint a qualified ESOS Lead Assessor to sign off your compliance. Rupert Blackstone of Wattcraft is a qualified ESOS Lead Assessor and can help you through this process.

Why choose Wattcraft as your ESOS consultants?

Is your organisation subject to ESOS?

Your organisation is subject to ESOS if it qualifies as a large undertaking on the qualification date. For the first compliance period, the qualification date is 31 December 2014.

A large undertaking is  a UK organisation that:

Why choose Wattcraft as your ESOS consultants?

Where can ESOS lead?

ESOS is focused on energy savings, which should always be a priority in accordance with the Energy Hierarchy (avoiding energy consumption before considering sustainable sources of energy supply). However, it makes sense to consider more sustainable energy supply options (including renewable energy) alongside ESOS requirements, as with limited finances to invest in improvement measures, there is a threshold beyond which energy supply improvements give a more favourable yield in cost terms than energy efficiency measures. For example, increasing thickness of insulation has diminishing energy and cost benefits and there comes a point whereby combined heat and power , heat pumps or biomass heating may become a more attractive proposition than further increase in insulation.

The output of ESOS gives a ranking of energy efficiency measures in lifecycle cost terms, but when taking sustainable/renewable energy supply options into account, this priority and what you might do in reality if you are interested in making real savings, might change. Wattcraft, with expertise in sustainable energy supply, can help you work out what the appropriate balance will be and then support you in the delivery of the most attractive options.

Wattcraft is an engineering organisation, which means that technical rigour will be applied to your energy assessment and there will be a focus on what is practical and able to be delivered based on your resource constraints.

Please contact us to find out how we can help you with meeting your ESOS obligations. We are based in Gloucestershire and can serve the whole of the South West and nationwide, according to specific requirements.

Why choose Wattcraft as your ESOS consultants?

[print_gllr id=684]


23.                 IMechE Heat Energy Report

The Institution of Mechanical Engineers has published a report entitled “Heat Energy – The Nation’s Forgotten Crisis”. The lead author was Professor Ian Arbon, past Chair of the Energy, Environment and Sustainability Group (EESG) at the IMechE and Rupert Blackstone of Wattcraft and current Chair of EESG was one of the contributors.



When people think of renewable energy in the UK, foremost in their minds is generally renewable electricity. However we are far further away from meeting our renewable heat targets than we are our renewable electricity targets. We are also considerably worse than many other industrialised countries in following the energy hierarchy by trying to avoid the consumption of energy in the first place before we consider more sustainable heat supply. This report addresses our shortcomings and offers solutions to heat energy in the UK. The report is to be launched formally at, and supported by, an event planned to be held in Birmingham in October and preliminarily entitled “Heat Energy – Solutions, Strategy and Storage”. Further information will be made available on the IMechE website nearer the time.


24.                 Features

IMechE Heat Energy Report

The Institution of Mechanical Engineers has published a report entitled “Heat Energy – The Nation's Forgotten Crisis". The lead author was Professor Ian Arbon, past Chair of the Energy, Environment and Sustainability Group (EESG) at the IMechE and Rupert Blackstone of Wattcraft and current Chair of EESG was one of the contributors.

Further information


Japan post-earthquake engineering visit

Rupert Blackstone of Wattcraft represented the Institution of Mechanical Engineers addressing new energy solutions at Japan post-earthquake engineering conference and meeting with Japan Society of Mechanical Engineers + tour of tsunami-hit region. Account of visit

25.                 Hybrid electric vehicles (HEVs) – how efficient are they?

What is a hybrid electric vehicle?

Hybrid electric vehicles (which do not have plug-in facility) are vehicles with an internal combustion engine (petrol or diesel), which have increased efficiency (compared to combustion engine only vehicles) through the use of a battery and electric motor. They are relatively heavy due to the doubling up of the drive systems and this can make a petrol hybrid vehicle compare unfavourably to a standard diesel engine vehicle, but the technology has been improving significantly over recent years.

How does a hybrid electric vehicle work and what are the savings?

Combustion engine efficiency varies according to its speed and acceleration. The battery in a hybrid vehicle helps optimise the performance of the combustion engine by driving the electric motor at times when the combustion engine would be operating at sub-optimal efficiency. This is particularly the case in start-stop driving in the urban environment. HEVs show significant energy and emissions savings in the urban environment, but for steady driving over long distances for which the combustion engine is operating optimally they do not show significant advantage.

The theoretical maximum thermodynamic efficiency of an internal combustion engine is around 50% and the most efficient petrol engine on the market has a maximum efficiency of around 38%. The difference in efficiency between urban and highway driving may be in the order of 30%, so an HEV fuel efficiency can only improve upon that of a standard petrol car by 30%, although in practice this will be significantly less due to charging losses in the battery and losses in the electric motor, as well as in most cases not all driving being urban.

What are the test conditions for an HEV and how do they differ from reality?

In Europe official fuel efficiency figures are obtained from a series of tests known as the New European Driving Cycle (NEDC), which is intended to be representative of real conditions, but invariably there is a significant discrepancy between the test-based prediction of fuel efficiency and the fuel efficiency experienced in practice.

The NEDC comprises two parts – an ‘urban cycle’ to reflect slow stop-start driving in the urban environment and an ‘extra-urban’ cycle to reflect driving on faster roads. The results of these tests are combined to give a figure for ‘combined’ fuel economy and carbon dioxide emissions.

The urban cycle test conditions are:

·       Starts with a cold vehicle

·       Stop-start journey of 2.5 miles at an average speed of 12mph

·       Maximum speed of test vehicle to be reached (briefly): 31mph

The extra-urban test conditions are:

·       Starts with a warm vehicle

·       Journey of 4.3 miles at an average speed of 39mph

·       Maximum speed of test vehicle to be reached (briefly): 75mph

The combined fuel consumption figure is arrived at through the average of the urban cycle and the extra-urban cycle, weighted in accordance with the distances covered in each part.

A typical range of the battery in a hybrid car running on its own might be 2 miles. The NEDC test allows the battery to be already charged at the beginning of the test and the fuel associated with charging the battery is not taken into account in the efficiency calculation. Therefore in this case the fuel consumption for only 0.5 miles of the 2.5 miles covered in the urban cycle is accounted for and so the official fuel efficiency figure ends up being considerably higher than the reality. Additional practices that do not reflect the reality of car use are also commonly adopted at test stage, including disconnecting the battery during testing, minimising the weight of the car, using special lubricants that are not supplied with the production vehicle[RB1]  and testing at ideal operating temperatures that are not realised in practice.


{Test results; Calculator; regenerative braking}


26.                 Grid services through onsite energy storage and generation

If you have a high level of electrical consumption at your premises, you may be able to make significant cost savings through onsite energy storage and generation. The opportunities for this are as follows:

  • Capacity market – reduce or shift electricity consumption when electricity demand is higher than the generation that is available
  • Balancing services
  •       ♦ Frequency response – adjust consumption in real time to help balance the grid (response time in seconds)
  •           ◊ Firm frequency response
  •           ◊ Enhanced frequency response
  •       ♦ Reserve
  • Peak avoidance – shifting electricity consumption away from times of peak demand to avoid high energy costs (DUoS and Triad charge avoidance)

Wattcraft can help you take advantage of these opportunities through:

  • Modelling your energy demand
  • Technical and economic modelling of cost saving measures matching your energy demand
  • Delivery of measures that meet technical and economic requirements, including development of approach towards procurement and operation.

Possible solutions might be:

  • Demand side management
  • Battery storage, potentially in conjunction with solar photovoltaics (PV)
  • Gas engine, potentially in combined heat and power configuration (CHP) providing both heat and electricity

 [RB1]C:\Users\RupertBlackstone\Dropbox\d\Transport\Cars\Fuel economy\Real MPG - NEDC test cycle vs real world MPG figures.pdf