How do PV and biomass compare in terms of energy generation for a given area of land and what are the advantages of each?
Photovoltaic (PV) systems and biomass energy generation offer different approaches to converting solar energy into a usable form, each with its own efficiency of conversion.
The efficiency of conversion of solar irradiation energy into electrical energy by PV panels can exceed 20%, with some reaching up to 22-25%.
The high efficiency of PV systems is due to a direct conversion process, whereby photons from sunlight are directly converted into electrons that produce electric current.
The process of converting solar energy to biomass and then to electricity is far less efficient. Photosynthesis, the process plants use to convert solar energy into chemical energy in biomass, has an average efficiency of about 0.5% to 1%. This is due to the inherent limitations of photosynthesis.
When biomass is converted to electricity, the overall efficiency further decreases. The conversion efficiency from biomass to electricity (through processes such as combustion or gasification in conjunction with a steam turbine, gas turbine or gas engine, for example) typically ranges from 20% to 40%. Combining this with the low efficiency of photosynthesis, the overall solar-to-electricity efficiency of biomass energy is significantly lower than for PV systems (less than 0.5% as compared to potentially greater than 20%).
The efficiency of conversion of the sun’s energy is not the only factor, however, in the determination of which out of PV and biomass is the most suitable for a given application.
As well as offering a higher conversion efficiency, PV systems have lower operating and maintenance costs, and are scalable and versatile. They are suitable for a variety of locations and have minimal environmental impact during operation.
Biomass on the other hand can be a way to utilise waste and provide a sustainable energy source if managed responsibly. It offers the advantage of energy storage and the ability to provide baseload power. Biomass projects can also promote local employment and have economic benefits, especially in rural areas.
In summary, while PV systems have a much higher efficiency in converting solar energy to electricity, biomass has benefits in terms of waste utilisation, baseload power generation, and socio-economic impacts. The choice between these technologies often depends on local conditions, such as land availability, sunlight intensity, available biomass resources, and specific energy requirements.