Once you have assessed and developed your Building Design you will need to consider your renewable energy requirements – whether it is of value to you and, if so, which do you use and how do you incorporate your requirements into your new home.
Renewable energy solutions can be incorporated into all our designs, be this solar water heating, ground or air source heat pumps, photo-voltaic panels or wind powered generators. These all have energy sources that cannot be depleted and that cause no long-term damage to the environment. They are a selection of the products which can easily be included within your design. The Benjamin Allen Renewable Energy Team is available to discuss your individual needs.
Sustainable energy is without a doubt safer, more environmentally friendly and healthier while at the same time being cost effective to buy, install and run. Designs that look good are pleasant to live in all year round; respect local surroundings and take advantage of natural resources are pre-requisites for any sustainable home.
What is renewable energy?
Renewable energy is energy from any source that is naturally replenished when used. Often called ‘renewables’, ‘green energy’, ‘microgeneration’ or ‘sustainable energy’, the main sources of renewable energy for the home are:
- Energy from sunlight
- Heat from the earth, the air or water sources
- Plants grown for fuel (biomass or biofuels)
- The movement of water (known as hydro) and wind
There are lots of different technologies available – usually used to produce electricity or to generate heat.
Why use renewables in your Self Build project?
There are lots of good reasons to use renewables. You will be:
- Making use of secure, local resources
- Reducing your dependence on non-renewable energy
- Helping to keep the air clean
- Helping to reduce the production of carbon dioxide and other greenhouse gases
- Saving and even earning money
The first stage is to understand the most common forms of renewable energies integrated in homes today – what they do, how effective they are and how many years they will take to pay for themselves (‘Pay Back Period’). We examine some options below.
Solar water heating systems use free heat from the sun to warm domestic hot water. A conventional boiler or immersion heater can be used to make the water hotter, or to provide hot water when solar energy is unavailable.
The benefits of solar water heating include:
- Hot water throughout the year; the system works all year round, though you’ll need to heat the water further with a boiler or immersion heater during the winter months
- Reduce your bills; sunlight is free, so once you’ve paid for the initial installation your hot water costs will be reduced
- Cut your carbon footprint; solar hot water is a green, renewable heating system and can reduce your carbon dioxide emissions
How do solar water heating systems work?
Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to heat up water which is stored in a hot water cylinder. A boiler or immersion heater can be used as a back up to heat the water further to reach the required temperature.
There are two types of solar water heating panels:
- Evacuated tubes
- Flat plate collectors, which can be fixed on the roof tiles or integrated into the roof
Larger solar panels can also be arranged to provide some contribution to heating your home as well. However, the amount of heat provided is generally very small and it is not normally considered worthwhile.
Solar Thermal is at the top of the renewable list and therefore something we highly recommend to all our self build customers interested in developing a sustainable home. The technology for this has been perfected over a number of years and is tried and tested. At Benjamin Allen we have an approved list for a number of registered installers through the UK. Benjamin Allen Timber Framed Homes would be able to assist you when integrating the technology into your self build.
Solar Photovoltaics (PV)
Solar panel electricity systems, also known as solar photovoltaics (PV), capture the sun’s energy using photovoltaic cells. These cells do not need direct sunlight to work – they can still generate some electricity on a cloudy day. The cells convert the sunlight into electricity which can be used to run household appliances and lighting.
The benefits of solar electricity include:
- Cut your electricity bills; sunlight is free, so once you’ve paid for the initial installation your electricity costs will be reduced.
- Get paid for the electricity you generate; the government’s Feed-In Tariffs pay you for the electricity you generate, even if you use it.
- Sell electricity back to the grid; if your system is producing more electricity than you need, or when you can’t use it, you can sell the surplus back to the grid. Read more about feed-in tariffs and selling electricity.
- Cut your carbon footprint; solar electricity is a green, renewable energy and does not release any harmful carbon dioxide (CO2) or other pollutants. A typical home solar PV system could save over a tonne of CO2 per year – that is more than 30 tonnes over its lifetime.
If your system is eligible for the Feed-In Tariff scheme it could generate savings and income of around £540* per year – you will get paid for both the electricity you generate and use, and what you do not use and export to the grid. If you know your system size, you can get a tailored estimate for your system using our Solar Energy Calculator.
* this is based on a 3kWp solar PV system eligible for a generation tariff of 16p/kWh. This is an encouraging move which, when coupled with the inevitable escalation of fossil fuel based energy prices, will see the payback period for photovoltaic installations reduce significantly. This in turn will result in more people turning their homes into micro power stations.
How do solar panels (PV) cells work?
PV cells are made from layers of semi-conducting material usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. Groups of cells are mounted together in panels or modules that can be mounted on your roof.
The power of a PV cell is measured in kilowatts peak (kWp). That’s the rate at which it generates energy at peak performance in full direct sunlight during the summer. PV cells come in a variety of shapes and sizes. Most PV systems are made up of panels that fit on top of an existing roof, but you can also fit solar tiles.
The main cost of the system is the materials, with the installation only taking around 4 days from start to finish. However it is important to use an installer who is MCS registered as you will not receive feed in tariffs on the solar PV system if you don’t.
Ground Source Heat Pumps
Ground source heat pumps use pipes which are buried in the garden to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home.
A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe called a ground loop, which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year even in the middle of winter.
The length of the ground loop depends on the size of your home and the amount of heat you need. Longer loops can draw more heat from the ground, but need more space to be buried in. If space is limited, a vertical borehole can be drilled instead.
The benefits of ground source heat pumps:
The benefits of installing a ground source heat pump to your new home:
- Could lower your fuel bills
- Could provide you with an income through the government’s Renewable Heat Incentive
- Could lower your home’s carbon emissions
- Can heat your home and provide hot water
- Needs little maintenance
Unlike gas and oil boilers heat pumps deliver heat at lower temperatures over much longer periods. During the winter they may need to be on constantly to heat your home efficiently. You will also notice that radiators will not feel as hot to the touch as they might do when you are using a gas or oil boiler.
Air source heat pumps are usually easier to install than ground source as they do not need any trenches or drilling but they are often less efficient than GSHPs.
How do ground source heat pumps work?
Heat from the ground is absorbed at low temperatures into a fluid inside a loop of pipe (a ground loop) buried underground. The fluid then passes through a compressor that raises it to a higher temperature, which can then heat water for the heating and hot water circuits of the house. The cooled ground-loop fluid passes back into the ground where it absorbs further energy from the ground in a continuous process as long as heating is required.
Normally the loop is laid flat or coiled in trenches about two metres deep but if there is not enough space in your garden you can install a vertical loop down into the ground to a depth of up to 100 metres for a typical domestic home. The diagrams below illustrate the difference between the horizontal loops and the bore hole ground source heat pump system:
Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, the air, or water is constantly being renewed naturally.
Heat pumps are a popular choice for Benjamin Allen customers as the technology is tried and tested providing a relatively short pay back period. They work best when combined with underfloor heating.
Biomass systems involve burning wood pellets, chips or logs in order to generate warmth to a single room or to power a central heating system and hot water boilers. With Biomass a stove burns logs or pellets to heat a single room. The fitting of a back boiler can provide water heating as well.
A wood-fuelled boiler could save you nearly £600 a year compared to electric heating.
The benefits of wood-fuelled heating:
- Affordable heating fuel; although the price of wood fuel varies considerably, it is often cheaper than other heating options.
- Financial support; wood fuel boiler systems could benefit from the Renewable Heat Premium Payment and the Renewable Heat Incentive.
- A low-carbon option; the carbon dioxide emitted when wood is burned is the same amount that was absorbed over the months and years that the plant was growing. The process is sustainable as long as new plants continue to grow in place of those used for fuel. There are some carbon emissions caused by the cultivation, manufacture and transportation of the fuel, but as long as the fuel is sourced locally, these are much lower than the emissions from fossil fuels.
Wood pellets are the best, but wood chips, or even logs, are used. Wood pellets are common in the USA and Europe but, as yet, there are only a few importers and suppliers in the UK, although their numbers are gradually increasing. At present, wood fuel costs are roughly the same as oil and gas but the boilers are twice the price.
When choosing a boiler we advise our clients that it is important to carefully choose the right design. By choosing the correct capacity it will save you time, money, and a whole lot of hassle. You should talk to someone that is experienced with fitting biomass boilers so that they can correctly identify your requirements. This will ensure that you are not sold something which will not do the job that you want it to.
If you choose the wrong type or capacity of boiler then this will actually result in increased fuel consumption, and a reduction in the efficiency. You should not run the risk of buying a boiler which is too big for the requirements; a system which is too large will result in an inefficient system.
Wind turbines harness the power of the wind and use it to generate electricity. Forty percent of all the wind energy in Europe blows over the UK, making it an ideal country for domestic turbines.
How do wind turbines work?
Wind turbines use large blades to catch the wind. When the wind blows the blades are forced round driving a turbine which generates electricity. The stronger the wind, the more electricity produced.
There are two types of domestic-sized wind turbine:
- Pole mounted: these are free standing and are erected in a suitably exposed position.
- Building mounted: these are smaller than mast mounted systems and can be installed on the roof of a home where there is a suitable wind resource.
Wind turbines are eligible for the UK government’s Feed-in-Tariffs which means you can earn money from the electricity generated by your turbine. You can also receive payments for the electricity you don’t use and export to the local grid.
The selection of a wind turbine to generate electricity will not just be an appraisal of the technology; it will also involve site assessment, visual appreciation, neighbour opinion and planning department reaction.
Why choose Benjamin Allen?
We believe that service is the most important factor when selecting a company to install new technology into your Self Build project.
Benjamin Allen is striving to be at the forefront for integrating this technology into self build homes. We design and build homes for a more comfortable future. We have brought together the most modern of construction materials and renewable technologies with the best, sustainable timber. Combine this with the expertise and caring attitude on which Benjamin Allen’s reputation is founded and you have a winning formula.
New technologies are becoming available to home owners to cut down on running costs, improve efficiency and reduce carbon emissions. The Benjamin Allen Renewable Energy Team are experts in incorporating such designs individually or jointly with other types of technology to maximise gains and pull back the installation costs quickly. We also understand that benefits verses costs is key and this is where our no-nonsense approach counts – we will always point out the positives and negatives to ensure you can make the right decision.
It is important that the system requirements are considered early enough in the programme to ensure they are compatible and to allow for the physical installation of the systems.
For more information on integrating renewable technology into your self build project please contact Benjamin Allen.