Eco-friendly power stations at homes
Small-scale production of heat and electricity at homes is undergoing a revolution centred on micro combined heat and power (micro-CHP) units. Producing energy at the point of use, these systems can replace or supplement grid electricity while they help avoid transmission losses. Solid oxide fuel cells (SOFCs) are increasingly being introduced to residential micro-CHP systems because they are highly efficient and thus produce less carbon emissions. The energy saving potential for users through SOFC CHP applications is the main driver behind a large number of publically supported research and demonstration programmes worldwide. The ASTERIX3 (Assessment of SOFC CHP systems build on the technology of htceRamIX 3) consortium made important steps towards commercialising this technology through several prototype developments and tests. Consortium members covered the entire value chain from research and development on stack core technology, system integration and heat management to market entry. The newly developed prototype systems running on natural gas generated electricity at efficiency of 30 %; when the heat was used, the total fuel conversion efficiency approached 90 %. This means that carbon dioxide emissions can be significantly reduced. Fuel cell durability is a key performance factor. After 5 000 hours of continuous operation, the prototypes demonstrated satisfactory performance degradation at less than 10 % per 1 000 hours. The system also proved that it could withstand 10 thermal cycles. To reduce heat losses, the project consortium used state-of-the-art methods such as thermal stratification. Looking 5 to 10 years ahead, project partners expect that the SOFC micro-CHP technology will be able to run on a wide range of fuels. In addition to natural gas, these should include hydrogen, methanol, ethanol, biodiesel and biogas. Cost-efficient and high-efficiency SOFC micro-CHP systems should provide a strong incentive for switching from conventional centralised power generation to distributed generation. This should lead to reducing energy distribution losses, thereby lowering carbon emissions.
Keywords
Fuel cell, heat, electricity, micro-CHP, SOFCs, natural gas
