A CHP machine is just a fossil fuel powered electricity generating machine that recycles the wasted heat as warmth for your home. So far many of these machines have been tried out across the land but normally in large commercial buildings or community housing projects. It really hasn't scaled down as far as being generally applicable inside someone's house. However, domestic boiler sized machines have been developed and are being trialed. What does this all mean? Well, you will still get some of your power from the main grid supply. However, when you need hot water or space heating you switch on your CHP box and whirs into life generating the electricity for your house. If you don't use all the electricity it generates then you can sell it back to the grid. Whist electricity comes out of the box for your lights and TV a lot of heat comes out too and this is used to heat your home. Waste not, want not. Efficiencies of 80% are claimed although, with the advance of the condensing boiler, these figures are only slightly better than conventional technology. What is more, rumour has it that trials of domestic CHP have not proven that successful. Besides, have you ever seen a CHP machine for sale? No? Neither have we. Although the enthusiasts would like to use them there simply are none available to the domestic market at time of writing. This could change but fitting CHP will still be quite low down on your list of priorities when Ground Heat Pumps and Solar Thermal are so well established and easily obtainable. Hence much of the interest in CHP has moved back to where it started - in district heating systems where a community shares a single heating system. There is also far less emphasis on using such systems with fossil fuels. Now the talk is all of Biomass CHP. Large plant is more efficient that small plant so there are some economies of scale if many homes club together for such a system. It is much the same story for community wind turbines featured elsewhere on this web site. In the UK alone it is expected that CHP could contribute 103 TWH of heat and 34 TWH of electricity from biomass. We can also burn waste materials with an energy equivalent of 5 million tonnes of coal annually. Burning this would mark a remarkable reversal in fortune for the solid matter burner in our communities. Recoverable heat from waste could contribute 22 TWh of heat and 7 TWh of electricity in the UK. There are two other words we will need to research. These are "gasification" and "pyrolysis". Pyrolysis of 400,000 tonnes of used car tyres can deliver 2.4 TWh of energy through an 80% efficient CHP process. So the technology is here to stay, although there is probably nothing the average man or woman living this post-carbon life can do about it as an individual. Doing things as a community represents a sea-change in the way social policy has drifted over the last 100 years. As such it means a revolution in the very meaning of the word "community". Are we ready? | 
