I am one of five members of Surrey Green Party Carbon Reduction Action Group, monitoring our personal carbon footprints over the last nine years. What we find is that by following a careful green lifestyle the annual CO2 footprint is usually between 2 and 3 tonnes. Our system does not count travel by public transport (rather difficult) but adding 10,000 miles by car would add around 2 tonnes, maybe doubling the footprint and bringing it up to the national average of around 5.4 tonnes.
Introducing roof-mounted PV panels makes a very significant difference, transforming emissions of over a tonne from electricity consumption for the household into a small minus figure. Our solar water heater produces about 1,200 kWh per year, saving emissions of 0.2 tonnes of CO2.
Otherwise the factor that makes the most difference is the number of people living with you, as the homebased emissions are divided by the number of people. So a son or daughter leaving home will increase personal emissions while a person returning home from university will reduce them. The biggest element of our house’s footprint was the gas boiler, so a couple of years ago research turned to a possible low carbon biomass boiler. However, these seemed to be very heavy (200kg+) and to require an accumulation tank (water) which is also heavy and space-consuming.
Wood is considered a low carbon fuel, provided that trees are planted to take the place of those cut down. Eventually I contacted LC Energy of Albury, whose manager had talked to the Forum some years ago. They assessed the suitability of a small wood pellet boiler, using my figures on current gas consumption, and decided that it was a relatively easy task to install the boiler outside, next to the north wall of our single storey living room, with pipework running in the attic space. The ideal location would probably be a solidly built outhouse.
As LC Energy are primarily biomass fuel suppliers they passed me on to Ecolyf. By early 2014 we had agreed a price and I had arranged for a builder to construct a concrete base for the boiler. Ecolyf installed the boiler at the end of June 2014. It took a good week to complete. Much work had to be done in the attic over our utility room; relays to make the changeover between gas and biomass all had to be packed into a small space. I have added wooden trellis panels to screen the boiler, as you see in the photo.
Since October the boiler has been working and I have been loading 10kg bags (about 2 per day) into the pellet hopper, and cleaning out the ashes about every 6 days.
The lessons from this experience are:
– Retaining the gas boiler is essential as it can be more easily left to run if away for more than a day or two
– Having a solar water heater is very advisable as the biomass boiler can be shut down during the summer- it is not suited to light, intermittent loads
– The biomass boiler on start-up takes longer to produce heat than a gas boiler
– The outside location keeps the dust associated with the ash outside the house.
– The boiler is very quiet but there is noise associated with the pipework in the attic
– No accumulation (buffer) tank was necessary
My biggest concern has been the possibility of the boiler freezing while we’re away and the system is using the gas boiler. I have now commissioned Ecolyf to add glycol to the heating circuit so that it will be safe down to -10C.
Biomass boilers are not a universal solution to our domestic carbon problems – there is not enough home-grown wood for that. Also the total cost is about the same as a new car, but the Renewable Heat Initiative does make it a much more attractive proposition. A biomass boiler does need attendance to its regular needs but the feeling of removing a large part of one’s carbon footprint is very pleasant.
John Pletts, Guildford