Renewable energy for your home
With gas boilers increasingly in the crosshairs in our fight to reduce carbon emissions, we thought it might be a good time to take a look at some more eco-friendly options for heating and powering our homes.
There are five main categories of renewable energy sources and these are wind turbines, solar power, micro-hydro power, ground source heat pumps and biomass fuels. Each one has a different set of requirements and the location or orientation of your property has a serious bearing on which of them are suitable for you.
We’ll start with solar power and the first thing to note is that there are actually two different types of solar power systems. Some generate electricity and some just heat water. In basic terms, both devices use the power of the sun to generate either heat or electricity. The latest generation of panels don’t need constant sunshine in order for them to work but, ideally, you need a south facing roof. It is sometimes possible with an east of west facing one, but not if it’s north facing. In England, most solar power systems don't need planning permission, but your roof will need to be able to support the weight of the panels. Additionally, a water tank is required for the water system and a battery is recommended in order to store excess power from the electricity generating systems.
Installing a solar hot water system in your home will cost between £4,000-£5,000, depending on the size of the property and the energy requirements. They do not tend to produce dramatic savings, but you can expect to reduce your annual bill by around £60 per year compared to a gas system (Energy Saving Trust - https://energysavingtrust.org.uk).
The good news is the price of electricity generating (photovoltaic) solar panels has fallen dramatically in recent years – down 82% since 2010. The cost of installing the average 3.5kW system is now around £4,800 and will reduce your household’s carbon emissions by over a tonne a year. It will save you money, too. If you’re home all day you and are selling any excess capacity back to the grid, you could save around £300/year, or £220 for nine to fivers. At those levels, it will take between 16 and 23 years to recoup the installation cost.
Wind power also comes in two different forms, building-mounted or, the more powerful, mast mounted turbines. Clearly, one of the key issues is whether you have enough wind to power it. You can do this by going to http://www.renew-reuse-recycle.com/noabl.pl?n=503 and entering your postcode. Turbines work much better in more exposed areas with consistent wind. You will almost certainly need planning permission and it is recommended that you also store excess electricity from a windy day in a battery linked to the system. Mast mounted versions are more expensive and require considerably more space. For a 6kW pole, the average installation cost is between £23,000- £34,000. It would typically generate savings of about £250/year and cut carbon emissions by 2.5 tonnes. In addition, you could earn up to £440 per year in Smart Export Gurantee payments (https://energysavingtrust.org.uk/advice/smart-export-guarantee/).
Ground Source Heat Pumps (GSHP) have been getting a lot of publicity lately and it looks like they will become compulsory for newbuilds in the not too distant future. They have very little environmental impact, using some very clever physics to create hot water for bathing and heating. In simple terms they extract heat from the ground and then intensify it by using a system of compressors and exchangers. The system heats up to between 75-125 degrees celcius before transferring into your domestic hot water system. You don’t need a huge garden, as the pipes can either be laid flat or, in a restricted space, they can go straight down. However, the relatively low heat levels generated by the system mean that you need a well-insulated home to produce an effective heating system. GSHPs work best with under floor heating, or with larger than normal radiators. Older, period properties may not be suitable and the savings for a well-insulated property with a modern condenser boiler are minimal. They require very little maintenance and can last up to 50 years. Electricity is needed to run the pumps, but you won’t need access to the gas network or storage tanks for oil etc. The Costs of installing a GSHP range from about £14,000 to £19,000. Annual savings are not huge, at £30/year, but this will vary greatly, depending on a number of factors, such as the insulation levels of the property and the type of heating system you are comparing it against. The same applies to its potential to reduce carbon emissions, the maximum reduction being about 2.7 tonnes/year.
Micro-Hydro Power: Most of us are familiar with the principals of hydroelectric power, but not many of us have thought about using the technology on a domestic scale. Clearly you would need access to a fast running river or stream and this rules most of us out of this sector. However, for those lucky enough to live near a suitable water source, it has the potential to be a truly green source of energy. Hydro power uses a turbine that is turned by the power of running water to produce electricity and as water flow can vary during the seasons, it may not produce sufficient electricity for the entire year. You would need to discuss your ideas with the local planning authority before committing any time or money to such a project. Because every case is so different, it is not easy to produce a cost guide for this type of technology. EST (https://energysavingtrust.org.uk) gives a guide figure of around £20,000 – £25,000 for a 5kW scheme, which would be suitable for an average sized family home. Any excess electricity that you produce could be sold back to the grid.
Biomass fuels: This is probably the most low-tech of all the renewable energy systems. Biomass fuels are divided into two different groups, woody ones, such as logs and wood pellets (the main domestic sources) and non-woody ones, such as food and animal waste and crops - rape, maize and sugar cane. These fuels are simply burnt in a stove, which then radiates heat around a room. The stove can also be used in conjunction with a back boiler, which will heat up the hot water system. This would, on the face of it, not seem to be a particularly green system. However, the theory is that when you burn a biofuel such as wood, you are only releasing carbon that the original tree had absorbed from the atmosphere. If you get the wood from a sustainable source, the tree that is planted in its place will then reabsorb the carbon emitted during the burning process, producing a neutralizing effect. To use this system you need to live in an area that is not a smokeless zone, which you can check on http://www.uksmokecontrolareas.co.uk/locations.php. The stoves are not cheap. A back boiler system, with an automatic pellet feeder, flue and fuel store will cost between £11,000 and £17,000. the savings are not particularly impressive. If you are replacing an electric system then you might save between £240-£7000/year but it might cost you £120 more than previously if you are replacing a gas system. If you accept the reasoning behind the carbon reabsorption theory, then you will be reducing your carbon footprint by an impressive 5 tonnes/year.
There is a government scheme to encourage householders to make their homes Greener. Under the Green Homes Grant Scheme (https://www.gov.uk/guidance/apply-for-the-green-homes-grant-scheme), homeowners and landlords in England can apply for vouchers worth up to two thirds of the cost of upgrading the energy efficiency of their home. The maximum contribution is £5,000. Those on low incomes, though, will be eligible for up to 100% funding, up to a maximum of £10,000
And, finally, there is the big question of whether all this green technology improves the value of your home. Most of the systems require an initial, large investment and, once done, the running costs for the property are considerably reduced. We spend, on average, over £1,200 a year on gas and electricity, so reducing those bills has a significant financial implication. Additionally, renewable sources can provide a degree of protection against the fuel cost rises that we have experienced over the last few years. It’s very difficult to put actual numbers to the value uplift but research carried out by builders merchants Wolseleys (https://corporate.wolseley.co.uk) found that almost 63% of adults in Britain were willing to pay more for an energy efficient home.