Donnachadh McCarthy
3 Acorns Eco-Audits
Media Environmentalist and Eco-Auditor
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Donnachadh McCarthy3 Acorns Eco-AuditsMedia Environmentalist and Eco-Auditor |
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Donnachadh firmly believes that environmentalists should practice what they preach. He has therefore converted his 1840’s Victorian terrace home into a retro-eco home. It has solar electric panels, solar hot water panels, a rain-harvesting system, wood–burner, wind-turbine and catalytic converter gas fire.
While it is essential to a low carbon home to use the home efficiently and ensure all the basics such as insulation and energy efficient appliances are in place, certain technologies can help.
Since 2003 the house has been a net exporter of electricity but in 2006/7 Donnachadh achieve his dream of a not only a carbon neutral home but it actually become climate positive i.e. it is carbon negative exporting more green electricity to the national grid than it imports fossil fuels (gas)
The following were the environmental statistics for 2006/7 for Donnachadh’s retro-eco home:
| Energy Source | Consumption | CO2 |
| Gas Usage | 609 kWh | 116 Kg |
| Electricity Exported | 598 kWh | minus 257 Kg |
| Green electricity imported | 384 kWh | zero |
| Wood Burner | 6 400 kWh | zero |
| Solar Hot Water | 1 000 kWh | zero |
| Solar electricity (produced and used on site) | 420 kWh | zero |
| Net energy carbon footprint | minus 114 Kg* |
*(Average UK household carbon footprint = 6 tonnes (6,000 Kg))
Water
Consumption
28 litres of mains-water per day.
(London average mains water consumption = 160 litres per day)
Non-recycled
Waste Production
Donnachadh ended up in 2006/7 being a net importer of waste!
Domestic non-recycled waste: half a wheelie bin for entire year
Building waste: 3 wheelie bins for year
Imported Waste Wood for wood burner: 48 wheelie bins for year
Net Waste IMPORTED !! : 44.5 wheelie bins
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Donnachadh's house was the first private home in London to export solar electricity from the roof to London Electricity in 1997. The 1.2 kW rated system was installed by Sundog Renewables. In 2006/7, the house exported about 20% more electricity to the national grid than it imported. Following EDF energy’s energetic lobbying of the UK government to promote a catastrophic new generation of nuclear power stations, he is switching to exporting his green electricity to Good Energy’s micro-generators scheme. Link to Good Energy's Homepage The display on the right shows how much electricity the roof is producing, how much is being imported or exported and how much the house is consuming. In 1997 the system cost about £12,000. Solar electric systems today cost about the same but produce twice as much electricity. |
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The solar hot water
system was installed 2 years ago and supplies about 70% of the household's
hot water needs. The vacuum tube heat exchanger system was installed
by Southern Solar. In summer the system produces far more hot water than is needed and the temperature has to be regulated to prevent it from becoming too hot! The system cost about £4,200 but a £400 grant from the LowCarbonBuilding Programme and £500 from the local council brought the cost down. |
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Unlike open coal-effect gas fires which are less than 20% efficient and traditional radiant gas-fires which are about 65% efficient, flueless gas fires are extraordinarily 100% efficient. Using an embedded catalytic converter, all of the gas is converted to heat, with water being the only by product. This means that they are only useful in houses which have central heating in the background or have a regularly used wood stove, as these dry out the resulting condensation. In my house, whilst very rarely used since the installation of the wood burner, it acts as a very handy back-up system in case I am ill and cannot use the wood burner or if in the house for a quick half hour before going out again and I need a burst of heat. They cost about £500 and I got mine from Burley’s. |
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The
toilet in the
bathroom and a designated tap are supplied by a simple gravity
fed
rain-harvester system, which sits on the flat roof immediately above the
bathroom. It has supplied over 70% of the WC water needs since it was
installed 9 years ago. The main legal requirement for such systems is
that the rainwater cannot mix accidentally with mains-water and so
special valves are required if you want the system to be backed up with
the mains. The garden water needs are supplied from a tank that collects rain water from the lower roof run-off. It is now quite old but still does the job, with it's own tap. |
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Three
Acorns Retro-Eco House was the first house in London to gain planning
permission for a grid-attached building mounted domestic wind-turbine.
It was installed in November 2005 but has not been a success to date. It produced a recorded 16kWh last year, which is about £1.60 off the electricity bill. There have been no noise complaints from neighbours, which is great, but there is currently a vibration problem internally in the house. StealthGen, the providers, continue to experiment with the product and the jury is out as to whether such small urban wind-turbines will make a worthwhile contribution in the future, even if some pessimists rule them out completely. It cost £2,800 installed. |
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Last, but by no means
least, 3 Acorns Retro-eco House has a wood burner in the open plan
living room/dining room/ kitchen area. This is by far the greatest
contributor to reducing the energy carbon footprint of the house.
People often forget that electricity consumption on average is
responsible for only 30% of the average house’s carbon footprint,
whereas space and water heating account for the other 70%. I got mine from UK manufacturer Clearview Stoves. It cost about £800 plus £2,000 for installation and new chimney flue. |
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