Implementing renewable energy - Essay Example

? Challenges of implementing renewable energy to meet the goals for emission reductions and solutions to meet the target October 25, Table of Contents Challenges of implementing renewable energy to meet the goals for emission reductions and solutions to meet the target 1 October 25, 2012 1 1. Introduction 3 2. Understanding Solar PV systems, its Limits and Use in UK 5 3. Understanding Wind Energy, its use and limitations in UK 10 4. Solutions to meet clean energy needs 12 5. Conclusions 12 References 14 1. Introduction Across the world, fossil fuels such as coal, crude oil, natural gas, wood and other forms face high levels of depletion. There is a real danger of fossil fuels being completely depleted within our lifetime. While the threat of depleted fossil fuels is great, another more serious danger threatens us and this is the threat of global warming (Gamesa, 2010). In this context, renewable energy sources provide a way to overcome the threat of energy security and global warming. Common renewable energy sources available are solar and wind power. These energy sources provide clean energy that is non-polluting, the energy source is free and it will never be depleted (ECI, 2011). The UK government wants to develop this energy source as a viable and active contributor to the economy. However, developing and using these free energy sources is not very easy and a number of challenges and barriers need to be overcome. These challenges include technical, social and financial challenges (Scottish Power, 2004). This paper will examine renewable energy sources in this context and suggest solutions to overcome the challenges. 2. FIT and other renewable energy Schemes initiated by the UK government The UK government has undertaken a few projects to meet its obligations of reducing green house gases. As per the Kyoto protocols, a signatory to the protocols and this includes UK, have agreed to cut down their emissions to pre 1990 levels. UK faces a huge problem of reducing the carbon levels and emissions since it mostly relies on coal fired power plants and nuclear plants for power generation. For 2006, the total amount of Green House Gases - GHG emitted in UK was the equivalent of 7,076 million metric tons of CO2. It is estimated that from these emissions about 2344 Teragrams were due to CO2 emissions from the activities of standard and old electricity power grids (SmartGrid GB, 2012). Other than nuclear power, all other systems and plants generate excessive carbon. Domestic and household consumption in UK makes up for 60% of the power used while other users such as industries, utilities, offices and infrastructure consume the rest. Automobiles account for more than 75% of fossil fuel consumption (Williams, 2010). To promote the use of green and clean energy systems, the UK government has initiated a project that funds and supports solar energy by residential homes (Bullis, 2012). The proposal is called ‘Feed In Tariff – FIT’. This project involves encouraging households to install small solar panels with solar PV that can generate electricity. The Department of Clean Energy of the UK government has provided a number of subsidies, concessions and other benefits to householders who install these units. The UK government plans to buy back the power generated from these units and give tax breaks or a reduction in the regular utility power consumed by the householders (Lewis, 2006; Lock, 2007). There are different categories of FIT users and this depends on the amount of installed capacity of the plants. The installed capacity in UK for solar energy was 1000 Mega Watts and this is about 0.001% of the UK power requirements. With the FIT program, the government wants to provide solar PV to around four million homes and this should help to generate 22,000 MW of clean energy. As per the Kyoto protocols, the UK government must generate at least 12% of the total power consumed by means of renewable energy (EPIA, 2011). The above sections have highlighted the ambitious program of UK government to meet the clean energy requirements. However, a number of technical and financial challenges and barriers are present that can prevent the plans from being met. These are discussed as below. 2. Understanding Solar PV systems, its Limits and Use in UK A brief review of solar energy and wind energy is provided in this section. This will help to asses the challenges and barriers for renewable energy systems in UK. 2.1. Solar Power basics and challenges This section provides a brief overview of solar energy. The section will show that solar power is a very viable source of power in deserts of the Middle East and not necessarily in UK that is under snow and rain for many months. Small photovoltaic cells are used to generate solar power. The solar cells are made of photo conducting substrate that reacts when the cell is exposed to sunlight. The exposure helps to generate a negative charged electron. The electrons develop potential differences between the p-n junctions or the positive and negative junctions in the cell. The potential difference creates a direct current, this introduces a charge, and makes the electrons flow (Rayotec, 2012). Since a single solar cell generates only a very small charge, hundreds of solar cells are placed in a solar panel. Many solar panels are then bound together and combined in the installation and this produces a large solar power that can help to operate a solar pump or to provide solar heating for a home. Different types of materials are used in the substrate and some of them are mono crystalline silicon, polycrystalline silicon, amorphous silicon copper-indium selenide, cadmium telluride and others. Other expensive substrates are made of materials such as Copper indium gallium selenide, Light-absorbing dyes, Cadmium telluride, Gallium arsenide, and others (DECC, February 2010). Solar power has many advantages and the main advantage is that the fuel made of sunlight is free and unending. While some level of emissions occurs in the manufacture and assembly of the solar panels, inverters, wiring and other components, these are one time instances and expenses. Otherwise, solar power is free, carbon free and clean. Very little maintenance is required for the solar cells and just cleaning the top glass is sufficient (Harvey, 2012). 2.2. Cost Limitations of solar power While solar power and fuel is free, some limitations and barriers exist in the use of solar power. Some of them are cost of generation and availability of sufficient sunlight in UK. Even with cheap imports of solar cells from China, the infrastructure needed for solar power generation costs at least one US watt. The cost is due to the excessive cost of battery, inverters, wiring and the limited solar flux available. On a comparative basis, power from coal plants will cost less than six pence/ watt. The amount of solar power generated and this represents the solar flux in UK. It would need at least 10 square meters of solar panels in a equatorial or tropical nation to generate a power flux of 2400 WH/ year and this much power is needed to by a small residence. When large solar projects are involved that used concentrated solar power - CSP, the cost will reduce to 22 pence per watt. However, it is not possible to use CSP in UK since it requires the use of parabolic mirrors that focus and concentrate runs rays to heat water and turn it into steam (EPIA, 2010; Solar gis, 2011). Therefore, cost is a major barrier for widespread use of solar power. People can take up solar generation only when they are offered schemes such as FIT. The next section gives a description of solar ‘Insolation’ that is a great natural barrier to solar power generation in UK. 2.3. Solar Insolation Barrier A major problem that UK faces is in the form of ‘Solar Insolation’. This term is used to measure the amount of irradiation obtained form the sun in a particular area. A tropical nation from say Africa or the Middle East will have the maximum irradiation. The arctic regions will have very little and so, UK fall somewhere in the middle of these areas. The solar potential or the amount of power that can be generated depends on the solar insolation, the solar flux and other important features. This value is measures in kWh/ square meters. For solar power to be generated, the solar irradiation must have a minimum of 1200 kWH/ square meters. An area with 900 kWh will yield about 30% less power. Unfortunately, it is see that almost 50% of UK has solar irradiation of less than 1100 kWh/ square meters and this region is made up of mostly the cold and snowy regions. Solar maps are used to find out the solar potential of a place. Please refer to the following solar map of UK (Photon Energy, 2012). Figure 2.1. Solar map of UK (Photon Energy, 2012) 2.4. Angle of Incidence Limitation The amount of sunlight that falls on the surface is also important. As the angle of incidence between the suns rays and the solar panel surface starts, increasing there is a fall in the insolation. The solar energy that is generated in a region would depend on this angle of incidence. Ideal angle of incidence is 90 degree and this does not happen in UK for more than a few weeks (Barker, 2010). Please refer to the following figure. Figure 2.2. Solar angle of incidence (Barker, 2010) Thus, the theoretical power that can possibly be generated by solar power at a place would depend on the geographical location. The insolation, explained in the previous section for a region is calculated in terms of the incident light and specified mega joules per square meter MJ/m2 or J/ cm2 or Watt-hours per square meter Wh/m2. When the energy is calculated for a unit time, then it is called as irradiance and specified as watts per square meter - W/m. Almost all regions of UK are placed such that the angle of incidence is less than 30 degrees and this presents a great barrier to effective solar power generation (Solar gis, 2011). 2.5. Solar cell efficiency One of the major impacts on solar power generation is the efficiency of the solar cells. The best solar cells have a maximum efficiency of 33%. The high cost of solar cells combined with the low efficiency means that to generate more power, a larger array of solar panels is needed. It is not possible to increase the area under panels due to the high cost of panels. Therefore, when the barrier of solar insolation, angle of incidence and solar cell efficiency is concerned, the amount of sunlight that is actually available is less than 3-4 hours daily for a few months. Tracking devices are available that continuously tilt the solar panel array to face the sun and keep the incident light at the required angle. However, this arrangement consumes power, increases the solar cells mounting complexity and raises the overall costs (EPIA, 2010). 3. Understanding Wind Energy, its use and limitations in UK Wind power and wind farms are viable sources of energy and many nations particularly Netherlands have developed extensive on shore and offshore wind farms (BBC, 2010). A single wind turbine would not generate sufficient power and therefore more number of wind farms is placed in an area and the collective power is then drawn for use. The UK government has provided FIT schemes for wind power generation that helps to reduce carbon emission (Schleisner, 2000). This section discusses wind power and its limitations. 3.1. Availability of Sufficient wind speed Wind farms need an area that is hilly, that does not have towns in the immediate vicinity and that have a speed of at least seven to 10 miles per hour and this is the cut in speed where the turbine generates small amounts of usable power (Chowdhury, 2012). Wind speed should be available for at least 75% if the time. The rated speed or speed at which the turbine reaches the rated speed is between 25 to 35 miles per hour (SR020, 2009). When the wind speed increased by one or two mph, the power generated increases by two to three times. The problem is that in UK, winds appear with high speed in bursts and gusts. This makes wind power generation very insecure (Geolocation, 2012; Sweeting, 2007). Wind maps are used to asses the wind potential in a region. Please refer to the following figure. The overall assessment is that in UK, wind power cannot be generated in sufficient quantity. Figure 3.1. Wind map of UK (XCWeather, 24 October 2012) 3.2 Funding and costing of Wind farms Costs on wind farms and wind turbines are very high. Large turbines with rotors of more than 80 meters diameter should be considered when generating power for a community (Griffin, 2004). The cost of these wind turbines and other costs is more than 1.4 million Euros per mega watt of power (Maxwell, 2011; NREL, 2010). Such a high investment is possible only for large firms and not the masses (Guezuraga, 2012; Harrison, 2010). 3.3. Clearances for hazard and noise Wind turbines are noisy, cause a hazard for birds and there is the danger of a blade breaking away and falling down, smashing anything in its path (Jain, 2010). For this reason, wind turbines are located in remote areas that are wind and that are at least one kilometre away from any house (Kusiak, 2010). When the wind turbine is so far away, transmission of the power causes losses. Airplanes and helicopters also face danger from wind turbines (CAP 764, 2011). 4. Solutions to meet clean energy needs A hybrid system is proposed that will help to meet the requirement of green energy and reduction of carbon. In this system, solar power plants and win turbines and farms must be installed together with conventional power plants (Zhixin, 2009). Power developed by the clean energy systems can be used as feed to preheat the water used to run the turbines of the power plants. In this way, some amount of clean energy requirements can be met. At the same time, other solar PV systems under FIT scheme can continue and generate power to the extent they can (Wagner, 2011). 5. Conclusions The paper has examined the challenges and barriers that face renewable power generation in UK. Barriers for solar power in UK is the solar insolation, lower angle of incidence of suns rays, low efficiency of solar cells and the high costs of solar power. Wind energy has problems of insufficient wind speed, insecurity in wind availability, high investment costs and dangers to the society from noise and broken blades. A hybrid system is proposed that will combine conventional power plants with solar and wind. References Barker, 2010. Consultation on a Microgeneration Strategy. Microgeneration Policy Team, Department of Energy and Climate Change London, UK BBC, 2010. Wind farm money for communities. [Online] Available at [Accessed 24 October 2012] Bullis, K., 2012. Making Solar Power Competitive with Coal. [Online] Available at [Accessed 24 October 2012] CAP 764, 2011. CAA Policy and Guidelines on Wind Turbines. 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