Renewable Living | Warm Roofs, Solar PV, Wood Pellet Boilers


Key “Eco Energy” Terms – A Rough Guide

Key “Eco Energy” Terms – A Rough Guide

Governments, scientists, environmental sympathisers, reporters, architects, farmers, business and homeowners and all being slowly brought into a world previously inhabited by a small proportion of the population.

How long did it take for homes to recycle their waste? How long did it take for councils to provide doorstep facilities? The problem was identified some years before the solution became widely spread and before everyone understood what to do and why they needed to do it.

“Eco” is a broad term and possibly meaningless. However there is not one single term that covers every different form of energy that is is an improvement on fossil fuels.

Renewable Energy

Renewable energy is energy that can be replaced when used. Fossil fuels such as coal, oil and gas once used are not replaced. Fuels such as wood, energy crops, solar and wind can either be grown or exist to be harnessed.

Energy can be electricity or heat. Solar PV provides electricity, whereas solar thermal provides hot water.

Just because something is renewable does not necessarily mean its “good Eco”. There are a number of other factors to take into consideration.

Electricity is not in itself renewable. If you have solar PV – then yes. If you buy a green tariff then possibly, however if you drive past a power station that is burning gas or coal or oil – then it is clear – most of our electricity is not Renewable.

Gas is not renewable. Most of our gas was taken from the North Sea. We now import more gas. Once used it cannot be replaced. Gas can be made e.g. cows and methane. This would be renewable.

Nuclear power – is it renewable? No! Whilst possibly more plentiful, the process uses uranium which is mined.

Cost per kilowatt hour (p/kWh)

This is a measurement of how much your energy costs to consume. For instance electricity from the grid may cost 12p per kWh. If you use 5000 kWh’s a year for your electricity (TV, lighting, cooker, PC, alarms etc) then your bill will be £600 per annum.

Typically the average home (3/4 bedroom reasonably well insulated) uses 20,000 kWhs a year for heating. This is normally 4, 5, or 6 times as much as your electricity use. Electricity is quoted at between 12 and 14p per kilowatt hour, it is easily the most expensive form of heating. Other sources of heat include:

Solar thermal – free!
Wood Logs/chips – 2.9p
Wood Pellets – 4.2p
Gas – 4.8p
Oil – 5.5p
lpg – 7.6p

These prices are at a seasonal low (August 2012). Fuel is stored so prices will be at their lowest when stocks are high. During the winter prices rise. During a very cold winter prices rise considerably.

Self Sufficient

Self sufficient meant “The good life” to many in 1975. It was about small scale farming in suburbia where a couple wanted to have a self sufficient lifestyle. The garden farm produced all their food and even clothing. A debate about whether we can all be completely self sufficient was ended some years ago – however for some being self sufficient with regards to energy beats off any external threats that we may face over the next 20 years in terms of fuel or energy supply.

Solar self sufficiency – we often come across “off grid” inquiries. Solar PV can provide energy. Excess during the day can be stored in batteries. Solar thermal heat can be stored in efficient water tanks. There are a number of drawbacks. Have you enough space for all the equipment needed so that you cope when its dark or sun levels are low in the winter?

Biomass self sufficiency – if you have your own or a local sustainable woodland then you can have enough wood to provide heat. The drawback is the work needed to process the wood into a form that is effective for you. Logs have to be manually chopped, stored and loaded. Chips have to be “chipped” and then fed from a storage tank called a hopper. Wood pellets (compressed sawdust) need a lot of equipment and processing to make.


In some ways similar to self sufficiency. However you can purchase your fuel from a local source. The main advantage is that the fuel will not have traveled far and used a lot of fuel in transportation. A secondary advantage is not wanting to be reliant on fuel sources coming from far afield e.g. Russia or the far east, where we are reliant on a cartel that manipulates prices.

Environmental Impact Analysis

When scientists and economists examine a new fuel supply chain they look at the impact on the environment as a whole. This does not only include carbon emissions or a similar indicator, but a holistic big picture. This is because no solution is without its drawbacks. If you look at wind power locations are chosen based on “good locations” for producing lots of electricity, however local opposition is often found with respect to migratory birds, noise and aesthetics. Balancing the benefits of renewable electricity with local needs is hard as you cannot put hard costs on all the different factors.

Nuclear power is probably the most contentious fuel source as its potential impact on society stems from hazardous waste and risk of melt down. Whilst some scientists are in favour, others are not. As ordinary people we tend to be scared of what we do not understand and simply observe.

child leukaemia rates in the Welsh seaside town of Caernarfon are 28 times the UK average

Similar complex arguments exist over the production of palm oil – a renewable fuel often produced in warmer climates near or in rain forests. Whilst you can keep growing crops for fuel part of the difficulty is that you need land to grow these crops on. Can you cut down rain forest? If so what impact will it have?. Some of the “local” biomass plants proposed and newly opened in the UK use palm oil.

Other issues with energy crops relate to food – we cannot feed the world as it is. Planting crops on land that could have grown food seems to be a bad idea.

CO2 2050

The UK has agreed to cut CO2 emissions by 80% by 2050 as part of a world wide agreement to reduce climate change. Impacts on the UK of increasing world temperatures have been predicted to be a rise in sea levels and unpredictable weather (again the extent of this is argued to both extremes). However as we have made an agreement – if we do not keep it we (The UK) will have to pay for carbon credits from other countries. This is a fine – paid for by the UK tax payer.

The present government have promised to be the “greenest” ever and to introduce ways for the home owner, business and government organisation to reduce carbon emissions from principally cars, electricity production, heating and industry. Recently we seemed to be doing quite well, however reductions in CO2 seemed to be more about the recession rather than reality. Since 2009 our CO2 emissions have been rising.

With regard to heating and electricity production from “renewable sources” the government is keen for you to adopt these as it helps meet the carbon targets. The FiTs (Feed in tariffs) and RHI (Renewable Heat Incentive) are examples of policies to move everyone away from fossil fuels.

In the short term we are in a recession and in times of austerity. Not only does the government not want to spend money at the moment (as it has none), if business has to pay extra money for regulations and reducing their carbon emissions then they feel that economic recovery is even further away.

Is CO2 the only gas in town?

CO2 is the headline emission from combustion (power stations, engines and domestic boilers), however there are other emissions that are considered harmful. For instance NOx is formed through combustion and contributes towards the formation of smog and where levels are high, increasing lung disease and complaints. PM2.5 are small particles emitted through burning. PM2.5 particles are air pollutants with a diameter of 2.5 micrometers or less, small enough to invade even the smallest airways. These particles generally come from activities that burn fossil fuels, such as traffic, smelting, and metal processing. Again this contributes to pollution, and is found in its highest concentration in areas of high traffic and industry.

The clean air act was introduced into London and since many other urban areas of the UK to reduce the amount of deaths caused from smog – in 1952 it was estimated that there were over 4000 deaths in London in 1 year. This legislation concentrates on dark smoke, sulphur dioxide and grit. Whilst almost draconian in converting industry to superficially cleaner emissions it does not target NoX, CO2, or PM2.5 (for many the big issues).

What about pollution and renewable fuel?

Logs are a renewable fuel. In certain conditions you can burn logs and they can be very harmful to you in your home and contribute towards pollution in you local area. Studies in cities are concerned that the widespread use of biomass burnt improperly will give rise to more pollution in areas of already high pollution. For instance open fires, wet logs, stoking you wood stove (dampening down your wood stove for the night) are all activities that increase significantly NOx and PM2.5 even with DEFRA approved appliances. Studies in Scandinavia suggest that poor control of local biomass combustion will lead to increases in PM2.5 and NOX. If you use buffer stores (stored hot water), dry wood, and reduced or no bark, then the emissions fell considerably.

One of the issues around pollution is that to overcome concerns there is a need for further regulation. All MCS boilers have to be tested, and these regulations are to be made more stringent for the Renewable Heat Incentive. Within this it reduces the ability and choice of individuals to use their own fuel (sustainability) and limits fuels that may be produced as part of the waste stream e.g. sunflower husks, cherry stones.

Carbon Neutral Fuels

Carbon Neutral or sometimes “low carbon” are names given to fuels that have little if any carbon impact on the environment. For the production of home heating these are often given to be:

Solar thermal
Biomass wood pellets
Biomass Logs
Ground Source Heat Pumps
Airsource heat pumps

For production of Electricity the most popular way is Solar PV, although you can use biomass to produce electricity.

Again there are many arguments about the definitions. Burning wood does produce carbon emissions. Burning wood in an open fire is several times less efficient than a wood stove. A wood stove is less efficient than many accredited boilers. All forms of combustion produce carbon emissions, it would be good to do it in the most efficient way possible.

Wood is considered to be carbon neutral if you take wood from a sustainable forest. ie if the volume or weight of the wood cut down is the same or less than the wood grown. ie there is a neutral effect on the carbon absorbing qualities of the wood.

Groundsource heat pumps and Airsource heat pumps use electricity. If you buy your electricity from a carbon neutral source then you could have a low carbon source of heat. Do remember that you cannot produce enough electricity from Solar PV (4kW) to give you free heating (est 15-20kW for average home).

Solar thermal and Solar PV can claim to be CO2 neutral – or can they? There is carbon needed to make the collectors, however no carbon is emitted during the production of electricity or hot water.

Renewable Living

Renewable Living is a phrase coined by us to represent the struggle we all have in moving to a more renewable lifestyle. No solution is perfect. It will cost more, it will take more space, and you will have to do more work. Within this there is room to be cost effective and provide good value for money. We do not just design heating systems – we do help you buy.

Posted in: Guides

Leave a Comment (0) →

Leave a Comment


By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.