Alternative Energy Resources In Buildings Construction Essay

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As of April 2010, homes and businesses will be expected to play a major role in the UK's carbon reduction program in order to reduce 1990's figures by 34% by 2020. This will be achievable through the increased use of small scale, low carbon energy production (Department of energy and climate change, 2010) due to the fact that home energy use is responsible for 25% of the UK's carbon emissions (Energy Saving Trust, 2009). Feed in tariffs will be introduced to reward projects for every kW of energy they produce. Further rewards are received for projects which are able to export any excess electricity to the grid. In practical terms, the use of a well placed 2.5kW PV cell could provide savings of £140 a year with possible income of £900 per year. This policy can provide rewards in order to make this reduction a real possibility by 2020. To date, there have been 8321 applications for grants for the installation of Biomass boilers, PV cells and wind turbines in UK homes (Department of energy and climate change, 2010).

One such project was the Essex energy village in Colchester. This project consisted of 8 terraced houses using a range of renewable energy resources. The main aim of this project was to gain a better understanding of practical issues involving installation and operation as well providing a platform for the supplier to enter the renewable energy market. As well as using a Wind turbine and Photovoltaic (PV) solar cells, the project also used a wide range of sustainable features in order to provide an efficient, low carbon community. Solar water heating systems were used to heat water while the PV cells, Wind turbine and Ground and Air source heating systems were used to generate electricity. A biomass system was proposed but the proposal was dismissed due to planning and cost issues as well as energy metering problems.

Three energy sheds were erected to the rear of three properties. The energy sheds each contained the heat source pumps along with a PV cell on the roof in order to create a "plug-and-play" renewable energy system. The energy shed also meant that any noise produced from the heat pumps was kept separate from the dwelling in order to reduce the amount of intrusive noise. One dwelling at the end of the terrace had a PV cell on the roof in order to take full advantage of solar gains due to its orientation.

A 20kWp Quiet Revolution turbine was erected in a car park to the rear of the properties although it was connected to the grid rather than the row of terrace but there are plans to connect the turbine to a nearby building which is to be converted for commercial use.

In terms of cost, the cost of the renewable energy equipment ranged from £6,000 to £45,000. The wind turbine cost £25,000 with an annual output of 7,300kWh/year with COâ‚‚ reductions of 4,150kgCOâ‚‚/year. For the wind turbine, costs almost doubled due to the requirements of reinforced foundations, a plant room and three-phase supply. The PV unit used for the roof of the first dwelling cost £13,530 and provided 2,016kWh/year with COâ‚‚ reductions of 1,145kgCOâ‚‚/year. This project will be monitored over its useful life in order to gain valuable information on any problems with the everyday operation of such systems in order to prevent such problems happening in future.

The solar water heating systems use solar collectors on the roof to absorb heat from the sun. Cold water is fed via tubes through the collector and heats the water that can be stored in an insulated tank for when it is required. This water can then be heated by a conventional boiler when required, therefore using less energy because the water is already warm. In this project, the solar water heating systems were seen as the most successful aspect as they were easily installed and user friendly. Although this report is concentrating PV cells, biomass and Wind power, it is important to highlight that renewable energy can be used in other ways in order to produce a more efficient, energy saving system.

The PV cells also proved very successful although their future use has been questioned in relation to their initial capital costs. Heat pumps were more difficult to analyse though there were a number of issues with their installation. It was however concluded in future, a joint system would be more effective rather than individual systems. Although each system seemed to work effectively, the combination of solar water heating and heat pump systems needed further commissioning in order to work effectively as a hybrid system.

This project also helped to highlight problems that came about due to the lack of central management on behalf of the contractors. Many sub contractors worked on this job and their responsibilities were often unclear. A lesson learned from this job is that one contractor should be responsible for organising all subcontractors and suppliers including those involved with the renewable technologies and not solely the construction sub contractors. This would mean that the main contractor would have to have sufficient knowledge of renewable technologies and in future jobs, a contractor with relevant experience would be the most attractive option.

The main aim of this project was to gain experience in using renewable energy resources in residential housing. This project has proven that the use of PV cells was successful as long as their capital cost can be kept to a minimum where as additional costs have come to light when using Wind turbines which must be taken into account. The main conclusion that can be taken from this project is that the use of more energy efficient building fabrics should be used in order to reduce energy consumption before renewable resources are used and the use of other systems such as solar water heating can be used to produce a more effective, low energy environment (Energy Saving Trust, 2010).

In recent years, there has been an increased use of biomass boilers in buildings. An example of this is the Blackwater Valley Museum in Benburb, County Tyrone. This 200kW boiler operates on a continuous feed system and as well as providing heat for the museum, it produces clean renewable energy for approximately 400 local homes. The system was designed and built in Northern Ireland and is the world's first downdraft, heat and power system to operate on a continuous feed. Wood chips are delivered twice a week by lorry and fed into a storage system. From here, the wood chips are moved into 2 units where they are dried using waste heat from the engines cooling system. The wood chips are then heated in a restricted flow of air where they are converted into a combustible gas. This gas is cleaned and mixed with air where it is fed into the engine. Through combustion, the gas is used to rotate the engine shaft and drive the generator which produces electricity. The heated engine exhausts are then used to heat water which is pumped into radiators in the museum for space heating and operates on an efficiency of about 70%.

The system can operate 24 hours a day independently for 6 days when the residual charcoal must be cleaned out and wood chips replenished. The system has roughly the same life expectancy as conventional steam plant although it has the advantage of being more economically friendly. The system produces 400kW of heat for use in the Museum and a further 200kW of electricity at 415 volts which is transformed to 11kV which is exported to the grid.

This combined system effectively provides the Museum with free heat while providing an income due to the exported electricity. This project aimed to boost the employment and the local economy in the field of renewable energy. The boiler will operate on a fifteen year electricity contract over which an estimated £1 million will be spent locally on fuel and labour, therefore providing substantial local investment and employment.

The problem with this technology is the considerable capital cost, approximately £250,000 and has a simple payback period of 7 years. This was offset by approximate grants of £170,000 through the EC INTERREG programme which equates to a substantial portion of the initial cost. Compared to a similar oil powered system, the biomass boiler will have produced a saving in COâ‚‚ emissions of 1,700 tonnes while producing the same amount of energy.

This project again was used as a pilot study for small scale wood gasification energy production in order to learn from the experience while providing a commercial demonstration to try and promote the use of similar technologies. B9 Energy Biomass Ltd worked in conjunction with Armagh City and District Council to finance this project and they are committed to further expanding this technology in the UK and Republic of Ireland in order to provide for a greener future. (energie-cites website, 2001)

In the UK, there has been a substantial increase in the number of rural homes that rely on Wind turbines for their electricity supply. In a remote area in Perthshire in Scotland, a home owner called George Jarvis was unable to get his home connected to the national electricity grid for his power supply. This meant that Mr Jarvis was forced to rely on a diesel generator running on full capacity for his electricity and heat supply. The generator was extremely noisy and costly so Mr Jarvis looked into the use of alternative energy resources.

After making enquiries, Mr Jarvis was advised to use a 2.5kW Wind Turbine due to the strong winds experienced in remote areas in Scotland. The Wind Turbine was installed in 3 days and provides Mr Jarvis with a 24 hour supply with less noise and lower running costs than the diesel generator. The Wind Turbine has allowed Mr Jarvis to reduce the use of the generator by around 90% which equates to an annual fuel saving of £330. Together with carbon reductions of 2,145kg COâ‚‚/year, this project has been a success in saving money for the client as well as helping to reduce carbon emissions in the UK. Compared to the Essex Energy village, Mr Jarvis' Wind turbine cost £14,106.75 but he did receive a grant from the Energy Saving Trust of £4,000 which is a substantial proportion of the initial capital cost.

Mr Jarvis was delighted with the savings the Wind Turbine provided as well as supplying him with a free, clean and endless energy resource. He was very happy with the investment he made and believed that the project was successful in fulfilling his requirements (Energy Saving Trust, )