1. Wood to Warmth – Combined Heat and Power
Michael Beech
TV Energy
September 2010

2. Combined Heat & Power Biomass CHP (Combined Heat & Power)
Generation of electricity and use of the heat as the by-product
Match to a year-round base heat load (and/or cooling load via absorption chiller)
Technically challenging when using woody biomass at small scale (below 1MW electricity output)
Double ROCs available for electricity generated from clean biomass, plus ??p/kWh heat from Renewable Heat Incentive
Low heat to power ratio is an advantage
Must use the heat, otherwise very inefficient
Capital cost is high (typically £5,000/kWe for <100kWe)
September 2010

3. Combined Heat & Power
Steam boiler & turbine Steam from combustion of biomass in steam boiler drives turbine. 12% electrical efficiency at small scale, ~5:1 heat to power ratio
Stirling engine External heat engine. Hot gases from direct combustion of biomass or combustion of fuel gas from updraft gasification are routed to heat exchanger, driving reciprocating machine. 18% electrical efficiency, 3:1 heat to power ratio
September 2010

4. Combined Heat & Power
High speed turbine Hot gases from combustion process drives high speed turbine, 20% electrical efficiency, 3:1 heat to power ratio. Machine required to operate constantly at full output
Internal combustion engine Fuel gas from downdraft gasification to engine. Carry over tars and particulates difficult to eradicate, unless filtered/ scrubbed will quickly destroy engines. 25% electrical efficiency, 2:1 heat to power ratio
Organic rankine cycle Heat from combustion process to thermal oil turbine. 15% electrical efficiency, 4:1 heat to power ratio
September 2010

5. Combined Heat & Power Biomass CHP Steam boiler and turbine
September 2010

6. Combined Heat & Power Biomass CHP Updraft gasifier Stirling engine
September 2010

7. Combined Heat & Power Biomass CHP High speed turbine
Downdraft gasifier & IC engine
September 2010

8. Thank you
September 2010