Low Carbon Living Programme
Carbonbusting: Green energy
Carbon based fuels such as coal, gas, petrol, diesel and wood all release greenhouse gases
when burnt to generate power. Once we have done all we can to reduce our power
consumption, the next step is to consider how we can source the power we do need from less
carbon-intensive sources.
TAKE ACTION
Switch to a less carbon intensive fuel.
Different fuels have different carbon intensities. Heating using mains gas can result in far lower carbon
emissions than using mains electricity for heating. Coal and heating oil are also very carbon intensive. When
possible, use the fuel with the lowest carbon intensity.
The amount of CO2 released per kWh of power for different fuels is as follows:
Wood: 0g Gas: 0.185g
Electricity: 0.545g Heating oil: 2.54g
Coal: 2.88g
Switch to renewable energy providers
Buying green electricity means that you are directly or indirectly (depending on the particular tariff) helping to
encourage investment in renewable energy – however the green energy market is complex and not all green
energy tariffs are the same! A “Green Energy Certified” label has been launched in an attempt to help
differentiate between so-called green products. A guide to choosing between green energy suppliers can be
found at: www.energysavingtrust.org.uk/generate-your-own-energy/buying-green-energy and some online
comparison websites such as www.which.net/switch and www.uswitch.com allow you to compare green tariffs.
Generate your own renewable energy
There are a number of options available to households interested in using renewable energy technologies for
space or water heating, or electricity generation. Further information about each technology can be found at
the following websites:
Energy Saving Trust ‘Generate your own energy’ section on their website
www.energysavingtrust.org.uk
Centre for Alternative Technology Information Centre http://info.cat.org.uk/
The Low Carbon Living toolkit has detailed information sheets on wood burning stoves and solar PV which can
be downloaded from the website www.lowcarbonliving.org.uk
Renewable electricity installations may be eligible for the Feed in Tariff, a payment made for every unit of
electricity generated. A Renewable Heat Incentive Scheme is also being set up for renewable heating systems
for homes that are not on mains gas. Both schemes are under review so do check the Energy Saving Trust
website for the latest news.
Invest in a community owned renewable scheme
If generating your own renewable energy isn’t for you, you can still get involved by investing in community
owned renewable energy schemes. Projects are springing up all over the country – there may be one near
you.
HELP AVAILABLE TO YOU IN OXFORD
If you are considering installing renewable energy technology, you may find the supplier and installer
comparison tool on the follow website useful. www.yougen.co.uk
www.lowcarbonliving.org.uk
YOUR QUESTIONS ANSWERED
Can I get all my electricity from solar PVs on my roof?
In practice, you are unlikely to generate all the energy you need when you need it because solar PVs generate
about 75% of the electricity they produce in the summer. A well positioned 1kWp array will generate about
850kWh of electricity per year in Oxford.
How much of my hot water would solar thermal panels produce?
On average about 60%. As with PVs, they produce most of their output during the six months from April to
October. It is possible to go for the whole of that six months on solar heated water if you are prepared to wait
until the sun is well up for your shower and save your washing up for sunny days!
Does it matter which way solar panels face?
Yes, absolutely. The best orientation is directly south but anywhere from SE-SW is ok. As panels get more
sophisticated, it is even worth thinking of them on an east or west facing roof, though the return will not be as
good, although these may be more suitable for solar thermal arrays. Any good installer should be able to tell
you exactly what is best on your house. The good thing with the new incentives is that you can’t get them
unless you use a product and an installer certified through the Microgeneration Certification Scheme.
Is small or micro-wind worth it?
There is much debate about this and the only answer to give is ‘it depends’! Again, any good installer should
advise you on how to understand the wind resource. Generally speaking, micro-wind fixed to houses built up
areas probably aren’t worth it. A small wind turbine put up in a big garden or green space probably is, if it is up
the hill or in the middle of a field.
What is a heat pump?
It is a fridge in reverse! It takes heat out of the air, or water, or the ground and heats water that then goes into
the heating system. They are very efficient because one unit of electricity used to run the heat pump produces
4+ units of heat out. They are most efficient when there is not much difference between the air/ground/water
temperature and the heating temperature. This means that they are much better for under floor heating that
runs at a temperature of 30 degrees than a normal radiator system that runs at 50-60 degrees.
MYTHBUSTING
Solar panels use more energy to make than they generate in their lifetime
For appropriately placed technology this is far from the case. The carbon footprint for a solar PV array
generating 1800kWh a year has been estimated at 3.5 tonnes1, giving a carbon payback of less than four years
Another study has estimated the payback to be as little as 2.5 years. 2
Carbon offsetting is a simple way of tackling climate change
According to DECC, carbon offsetting compensates for your unavoidable emissions by paying someone to
make an equivalent carbon dioxide saving elsewhere in the world. They highlight that offsetting is not a “cure”
for climate change; the most effective way to combat climate change is to reduce emissions.
FIND OUT MORE
David Mackay’s book ‘Sustainable energy without the hot air’ is a fascinating look at meeting our energy
needs through renewable sources – and is available to download free of charge on line.
1
How bad are bananas? Mike Berners-Lee p133
CAT website [viewed 26 October 2011] http://info.cat.org.uk/questions/pv/what-energy-and-carbon-payback-time-pvpanels-uk
2
This work is part of the Low Carbon Living Toolkit and is licensed under a Creative Commons AttributionnonCommercial-ShareAlike 3.0 Unported License. If you have any questions or tips to suggest please email
them to us at lowcarbon@hotmail.co.uk v1.4 16/07/12
Whilst we have made every attempt to ensure the accuracy of this leaflet, this information should not be relied
upon as a substitute for formal advice. LCWO will not be responsible for any loss, however arising, from the
use of, or reliance on this information. Low Carbon West Oxford is a registered charity 1135225.
www.lowcarbonliving.org.uk