There are several methods of harvesting energy for a house but non of them are as important as providing excellent levels of insulation, air tightness and energy efficient appliances in the first place. Witness to this fact is the design of the PassivhausSee more on the Passivhaus standard. The PassivHaus Institute has pioneered a standard for low energy buildings. It includes very low energy usage and ways of achieving this. The word is derived from the idea of buildings which are fundamentally low energy and passive solar heated rather than using extra gadgets to heat them. See Passivhaus for the UK branch of the organisation. which is so well insulated and oriented towards the sun that it needs no central heating system. Energy harvesting is very site specific -
- Solar Hot Water is available to most houses providing there is a good southerly aspect or good aspects to both east and west
- Wind Energy is only really viable if there is a fairly constant wind and little turbulence from surrounding buildings, structures, woods etc.
- Pico Hydrovery small scale hydro electric generation - up to 5 kWkilowatt - a measure of how fast energy is flowing. e.g. electricity might flow through an electric kettle at the rate of 2 kW. is excellent if you have a source of constantly running water, preferably with a good head
- Wood Burning high efficiency boilers and stoves are now available
- Passive Solar Design is very possible given walls which are SE, S, or SW facing and get good sunlight
- PVPhoto Voltaic. referring to the generation of electricity from sunlight Solar Collectors although still very expensive to install, some people are making their houses ‘PV ready’ for when prices fall
- Ground Source Heat Pumps although enjoying a new found popularity need considering in the context of the electricity they use. If you don’t have a large area of garden to lay the pipes you can sink them downwards in bore holes
Clean Energy Cashback
There are government grants available to encourage the small scale generators of electricity such as solar, wind power and hydro. This is known as ‘Clean Energy Payback’ or ‘Feed In Tariff’ (FIT).
There are varying scales depending on the size and type of installation. There are four really worthwhile aspects to this -
- the tariff is set to encourage uptake of microgeneration by paying you considerably more per kWhkilowatt hour. This is a unit to measure an amount of energy. If you run your 30 kW gas boiler for 2 hours a day you use 60 kWh per day you generate than it costs to buy it from the grid. This is especially true for solar and wind.
- you get paid not only if you sell surplus energy to the grid but also for the energy you use yourself.
- the payment system is guaranteed for between 10 and 25 years (depending on the type) so the investment is guaranteed. It is also linked to the Retail Price Index to keep in line with inflation.
There are also grants available towards some of the types of energy harvesting under the Renewable Heat Premium Payment.
Community wide renewable energy
There is a current groundswell of community initiatives concerned with greener living and some of them are looking at generating sustainable energy at a community wide level. See the Community Energy website.
A community wide approach makes a lot of sense compared with trying to do it on your own -
- renewable energy is seldom close to a particular house
- economies of scale
- buying in expertise
- access to finance
- capital costs of generating equipment and infrastructure/distribution
- possibility of incorporating Combined heat and Power
- shared risk / insurance
- the positive social factors, particularly knock-on green initiatives
This has generally worked well in the more progressive countries in this field such as Denmark. (however there have been some setbacks in Denmark due to varying government support of community energy initiatives).