Researchers unveiled an innovative process that offers a flexible energy supply – electricity, fuel for vehicles and heating. The process provides a viable route to integrating renewables into buildings and transport, without having to dump any excess energy from sunny summer days.
The share of variable renewable energy sources in the energy mix is rapidly increasing over time. According to the latest renewable energy market forecast of the International Energy Agency, their capacity could expand by 50 % between 2019 and 2024. While the growth of renewables helps reduce carbon emissions and tackle climate change, balancing their availability with varying levels of electricity demand is quite challenging. For example, solar and wind energy technologies only produce energy during sunny and windy days, respectively.
Researchers working on the FLEXCHX project have successfully unveiled an innovative power plant that prompts a rethinking of how CHP is combined with variable renewables. “We have developed a flexible and integrated process that combines electrolysis of water with biomass gasification and catalytic liquefaction. This process produces heat, power and an intermediate energy carrier – Fischer-Tropsch wax – that can be processed to a transport fuel using existing oil refining equipment,” explains Kurkela. FLEXCHX plants can be integrated with various CHP systems, both industrial and district. “During summer, renewable fuels are produced from biomass and hydrogen; the hydrogen is produced from water electrolysis that is driven by low-cost excess electricity from the power grid. In the dark winter days, the plant runs on biomass, maximising the production of heat, electricity and Fischer-Tropsch wax. Most plant components are used throughout the entire year - only the electrolysis unit is operated seasonally,” adds Kurkela. Operating the same plant flexibly, either with biomass or combining it with renewable electricity, is radical. State-of-the-art biomass-fired district heating plants are usually operated only during cold days, approximately 5 000 h/year. By contrast, the annual operation time of conventional power-to-fuel units that exploit solar energy is limited to approximately 3 000 h. The main advantage of the FLEXCHX process is that it constantly produces electricity, fuel and heat all year long.