Solar Energy Power (Photovoltaic Systems) - Dissertation Example

?Solar Energy: Installation and Economic Benefit of Photovoltaic Systems [Due Introduction Solar energy has been the most dominant energy source since the dawn of civilization, though indirectly. But with the rise of industries and heavy machinery, solar energy has lost its importance and the use of fossil fuels has become commonplace. But as early as the 1970s, there have been researchers enjoining governments to find alternative energy sources. For example, in 1971 Farrington Daniels said: As [coil, oil and gas] diminish, atomic and solar energy will eventually become important: atomic energy in large multi-million-dollar installations near large cities and in areas where solar radiation is low, and solar energy in small inexpensive units n rural areas where solar radiation is abundant and the cost of electric transmission is high. (Daniels 1971: 490) Meanwhile in 1973 another researcher, George O.G. Lof said that the man has to find other energy sources as the use of fossil fuel is unsustainable. For him, the development of technology that captures solar power is much more important. He expounds: The raw energy, in the form of electromagnetic radiation, reaches the earth’s atmosphere at a rate of 170 trillion kilowatts. Even after about one-fourth is scattered into space by clouds and dust, the quantity of energy reaching the land area of the United States is more than 700 times the current demand for all types of energy. (Lof 1973:53) For Lof, fossil fuels have to be replaced with renewable sources of energy because its inventory is finite and will soon run out. Moreover, as supply of petrol fuels decrease, its cost will increase steeply. More than 40 years after Lof’’s pronouncements, the world is now experiencing the repercussions of the indiscriminate use of petrol fuels. For one, price of petrol fuels are at record high levels. As of April 2, 2012, the price of unleaded petrol is recorded at ?141/liter, up by ?1.5 from the previous week (Department of Energy and Climate Change 2012a). Meanwhile diesel is at ?147.7/liter from ?146.6 the previous week (Department of Energy and Climate Change 2012a). As the price of petrol fuels increase, so do the prices of products and services that use it. Proof of this is the updated report released by the Office for National Statistics which rated inflation as of February 2012 at 3.4% and consumer price index for electricity, gas and other fuels at 142.9 compared to 130.3 in December 2011 (Gooding 2012). Aside from the increasing energy prices, there is also the issue of climate change, which is believed to be the outcome of the rapid build-up of greenhouse in the atmosphere because of anthropogenic activities. To avert the devastating effects of climate change, numerous countries adopted the Kyoto Protocol which mandated signatories to reduce emissions of greenhouse gases, particularly, carbon (UNFCCC 2012). This has prompted the parliament to pass the first legally binding framework to tackle the dangers of climate change – the Climate Change Act of 2007. But this was just the start of legislation aimed to protect the environment. In 2008, the first Energy Act was given the Royal Assent to provide support to new technologies aimed at capturing carbon and developing emerging renewable technologies. Thanks to these laws, solar power has been rediscovered and is now one of the most promoted renewable source of energy because it can be found anywhere. In a speech by Greg Barker (2011) he said, “to date, solar has been by far the most popular technology with consumers. It is easy to see why: it’s simple, accessible, reliable and fits discreetly into homes and communities”. An advocate of decentralized energy generation (or microgeneration), Barker launched the feed-in-tariffs (FITs) for households and communities wanting to install a solar photovoltaic (PV) system. This way, people can invest in “small-scale low-carbon electricity, in return for a guaranteed payment from an electricity supplier of their choice for the electricity they generate and use as well as guaranteed payment for unused surplus electricity they export back to the grid” (Department of Energy and Climate Change 2012b). At present, there are now more than 100,000 PV installations in the United Kingdom (UK) and with the FIT, this number is bound to increase. In lieu of this trend, the next part of this paper provides an overview of PV systems to assist anyone who wish to utilize this technology. Much of the work in PV installation has to do with system sizing and site survey which will be discussed in the next sections. Solar Site Survey: Finding the Right Location for the Solar Panels Photovoltaic (PV) power systems are just one form of solar energy generation, but it is also the most popular. When one talks of solar power or solar electricity, they often mean solar PV. As its name implies, PV systems convert sunlight into electricity that can meet a household’s normal energy demand. Contrary to common belief, PV systems do not need direct sunlight in order to work, even during cloudy days. Of course, the most effective systems are still those that are installed in direct sunlight. Before one decides to install a PV system, one has to do a solar site survey. The site survey attempts to answer two basic questions: (1) Does your location get enough sunlight? (2) How much sun can an obstacle (tree, posts, buildings, etc.) block? To address the first question, the installer has to determine how much sunlight the installation area receives. For UK, various organizations produce a solar radiation map which can be utilized for this purpose. One such organization is the European Commission (EC). Figure 1 shows a solar irradiation map for UK.1 Figure 1: Global irradiation and solar electricity potential; Optimally-inclined PV modules (M et al. 2007) To address the second question, one has to do a Site Obstacle Survey. To do the obstacle survey, one has to download a sun chart. The installer can can use the University of Oregon Sun Radiation Monitor for this purpose.2 One must specify the location through the longitude and latitude, specify a location and time zone and the tool can plot position of the sun for a particular day. The installer may want to plot average radiation for various months to get an idea on how much sun an area gets. Next, the installer will need two copies of a solar elevation and azimuth gage3, one of which will be setup where the collector will be. The other will be a used to measure the azimuth and will be placed on a table such that the 180th angle on the azimuth is facing true south (Build It Solar 2006). When this is done, the installer can now do the site survey. Here is an instruction coming from an expert solar panel installer: Measure the azimuth and elevation angles for each of the high points along your horizon.  Start from northeast and work your way around through south to the northwest.   To measure the azimuth angle of a object, site along the pointer that you attached to the azimuth gage, and move it until it is lined up with the object.  Then read the azimuth angle off the azimuth gage where the pointer passes the azimuth angle number scale.  Measure the elevation angle for the same object by sighting along the Sight Line on the Elevation Gage.  Read the elevation angle where the string crosses the elevation angle scale.  Make sure that the string is not binding on the gage when you make the reading.   Mark the azimuth and elevation angles of each high point on the Sun Chart as you go with a dot.  Mark the position of the horizon on your sun chart by drawing lines between the elevation points you marked on the chart. (Build It Solar 2006) When this is done, the installer should have something like figure 2. Straight five to six hours of direct sunlight can generate an entire home’s daily electricity demand. If the chart shows that there is a blockage within this six-hour period, then the installer has to evaluate how big the blockage is using the same method outlined above. If the blockage is serious, it is best to move the collector to a better location. This procedure can be done over and over in order to find the area which gets the most sun. Figure 2: Sun chart with obstacle horizon marked Installing the Photovoltaic System Grid-intertied PV systems are connected to the electricity grid and generate electricity to offset the household’s energy demands. In case of surplus, the electricity is routed back to the electric utility grid. Instaling grid-intertied PV system is like living with grid power, except that much of the household’s electricity needs comes from solar electricity. In the UK, FITs provide credits to the homeowner’s account when it sends electricity to the grid. In turn, when the home needs more electricity that its PV system can create, it uses electricity from the grid. Of all PV systems, this provides the greatest amount of savings to the customer (Endecon Engineering 2001:5). Figure 3 below shows the various components of a grid-intertied PV system (definition of components may be found in the glossary of this paper). Figure 3: Grid-intertied solar-electric system components (Home Power Magazine 2012) Meanwhile, grid-intertied PV system with battery backup works the same way as grid-intertied PV systems except that it has the capacity to store some of the electricity it produces. This PV system is more expensive because of the battery and tend to have lower energy efficiency, but it is useful in areas with unstable grid connection. It is most useful during blackouts to keep some of the home’s most basic electricity needs running. For example, it can keep the lights on, or the water pump running. Figure 2 shows the various components of a grid-intertied PV system with battery backup. Stand-alone PV systems or off-grid electric systems are typically installed in remote locations that are not serviced by the grid. Homeowners with stand-alone PV systems do not pay electric bills, and since they are not part of the grid, they do not experience blackouts due to grid failure. Figure 1: Grid-intertied solar-electric systems with battery backup, system components (Home Power Magazine 2012) These systems provide all of the household’s energy demands, so it has a back-up generator. People who choose to live with off-grid power may want to avoid the high cost of bringing grid lines to their home. Sometimes, it may be due to the reliability of the solar-power system that the off-grid PV provides. Figure 3 shows the various components of the off-grid PV system. Figure 2: Off-grid solar-electric system components (Home Power Magazine 2012) The diagram above also makes it easier for a non-technical person to understand how grid-connected systems work, however, this is not usable for installers. In another PV installation guide, it presented two schematic diagrams for two types of installations: domestic and commercial. Figure 4: Schematic diagram for domestically-installed, grid-connected PV systems (BRE et al. 2006) Note however that these diagrams are for general guidelines only, and should not be used for any particular installation without system sizing. System sizing may be defined as the process of designing the PV system. It takes into account the types of materials used for the entire installation – from the PV module, the DC components, the inverter, the mounting of the PV array, and many others. In a sense, system-sizing is custom-fitting a PV installation based on the unique characteristics of the area where it will be installed. When looking at the schematic diagrams in figures 1 and 2, one has to remember that the components may change depending on the circumstances of the installation area. Figure 3: Schematic diagram for commercially-installed grid-connected PV system Standards and Rules for Installation Once the site survey is completed, the installer has to review various documents which provide the standards and regulations of PV installation in the UK (BRE et al. 2006): (1) Engineering Recommendation G83/1 (2003) for small scale generators up to 16A connected with public, low voltage distribution networks. (2) Engineering Recommendation G59/2 (2010) for connections to power plants of licensed distribution networks. (3) BS7671, particularly Part 7-712 for requirements on electrical installations. (4) BS EN 62446 (2009) to learn the requirements for documenting, testing and inspecting grid connected systems. System Sizing: Ensuring System Security To avail of the credits for microgeneration, homes and buildings with PV installations have to be energy-efficient. Hence, initial work have to be done in the area before the actual PV installation is done. Once this initial work is finished, then it is now time to choose the material which will be used for the PV installation. This is an integral part of system sizing as this ensures the long-term safety of the system. PV systems have to be tailored for the installation area. “The designer and installer of the PV system must consider the potential hazards carefully and systematically devise methods to minimize the risks” (BRE et al. 2006:5). One important decision that the installer has to do is the type of PV module, as well as the required PV area for the installation. The rule of thumb is that 1kWp needs 10 square meter (m2) PV area. Table 1 summarizes the area requirement to produce 1kWp depending on the PV cell material. Table 1: Required PV area to produce 1kWp by cell material (Deutsche Gesellshaft fur Sonnenenergie 2008: 151) Cell Material Required PV Area for 1kWp Mono-cystalline 7m2 to 9m2 High performance cells 6m2 to 7m2 Polycrystalline 7.5m2 to 10m2 Copper indium disenlenide (CIS) 9m2 to 11m2 Cadmium telluride (CdTe) 12m2 to 17m2 Amorphous silicon 14m2 to 20m2 Other considerations include the size of the available space for installation and the expansion gap per PV module. Suggested gap between modules is 6mm to 10mm. Crystalline PV cells have to comply with the IEC 61215 while thin film types have to comply with the IEC 61646 standard. To ensure the quality of the PV modules, they must carry the CE mark (BRE et al. 2006: 9). Class II modules are highly commended, particularly for applications of more than 120 Volts. For crystalline silicon PV modules, all DC components (cables, switches, connectors, etc.) must have minimum voltage rated at Voc(stc), Isc(stc) I x 1.15 and current at Isc(stc) x 1.254. Meanwhile, all other module types must be computed. Using the standard test conditions provided by the manufacturer, voltage and current can be computed using the temperature range of -15°C to 80°C and irradiance of 1250 W/m2 (BRE et al. 2006). The maximum values have to be assessed, taking into consideration the maximum voltage and current which can be handled by the PV array. For a more efficient sizing of DC components, an installer can utilize a simulation program such as the DASTPVPS5, the Greenius6, PV-DesignPro7, INSEL8, SUNDI9 and many others. There are also design and service programs that can analyze the overall system and help support the design process of the grid-connected PV installation. An important program is the SITOP developed by Siemens which helps the installer choose the right wiring configuration of Siemens converters. Meanwhile the SolarSizer program, developed by the Center for Renewable Energy and Sustainable Technology, is used for designing and sizing PV systems. An important feature of the program is the cost and energy calculations it offers. Cost-Benefits Analysis of Installing Photovoltaic Systems In order to update the prices of solar PV modules, the Department of Energy and Climate Change (DECC) has again commissioned Parson’s Brinkerhoff to survey 13 UK suppliers and 7 other sources. Survey was done between January 10th to 13th, 2012 to get the latest prices. High, low and medium costs were also developed. Their data are presented in tables 2 and 3 below. Table 2 summarizes the cost for installing the PV system (capex). A quick glance on the estimates will reveal the downward trend in prices. According to the data, prices of new and retrofit installations are bound to drop by 2.5% to 9.9% drop from January 2012 to the end of the year. Meanwhile, expected drop in prices from January 2012 to 2030 is estimated between 27.23% to 30.79%. In terms of aggregrators below 4kW, prices drop between January 2012 to end of the year is estimated at 1% to 10%. On the other hand, prices of aggregators above 4kW is expected to drop by 10% to 50% in just one year. 40% of capex costs are connected with PV modules, estimated price drops may be due to the development of PV technology (Ernst & Young 2011:4). Table 2: Capital cost for PV systems (Parsons Brinkerhoff 2012:9-15) Low-Cost Estimate Jan-12 End 2012 2013 2015 2020 2030 Fixed-cost installation (?/installation) New build domestic (2kW) ?734 ?661 ?595 ?548 ?535 ?508 Retrofit domestic (2kW) ?734 ?661 ?595 ?548 ?535 ?508 Aggregators 4 kW - - - - Marginal cost (?/kW) New build domestic (2kW) ?1,716 ?1,201 ?901 ?730 ?508 ?338 Retrofit domestic (2kW) ?1,716 ?1,201 ?901 ?730 ?508 ?338 Aggregators4kW ?1,030 ?515 ?386 ?313 ?206 ?123 Medium-Cost Estimate Jan-12 End 2012 2013 2015 2020 2030 Fixed-cost installation (?/installation) New build domestic (2kW) ?1,249 ?1,187 ?1,127 ?1,039 ?968 ?875 Retrofit domestic (2kW) ?1,249 ?1,187 ?1,127 ?1,039 ?968 ?875 Aggregators 4 kW - - - - - Marginal cost (?/kW) New build domestic (2kW) ?2,542 ?1,907 ?1,621 ?1,356 ?1,050 ?774 Retrofit domestic (2kW) ?2,542 ?1,907 ?1,621 ?1,356 ?1,050 ?774 Aggregators4kW ?1,650 ?1,238 ?1,052 ?880 ?612 ?407 High Cost Estimate Jan-12 End 2012 2013 2015 2020 2030 Fixed-cost installation (?/installation) New build domestic (2kW) ?2,288 ?2,231 ?2,175 ?2,089 ?1,937 ?1,665 Retrofit domestic (2kW) ?2,288 ?2,231 ?2,175 ?2,089 ?1,937 ?1,665 Aggregators 4 kW - - - - - Marginal cost (?/kW) New build domestic (2kW) ?3,60 ?3,245 ?2,921 ?2,636 ?2,264 ?1,831 Retrofit domestic (2kW) ?3,60 ?3,245 ?2,921 ?2,636 ?2,264 ?1,831 Aggregators4kW ?2,700 ?2,430 ?2,187 ?1,974 ?1,609 ?1,315 Meanwhile, summarized in table 3 are estimated of the operating cost of maintaining the PV system. Because most PV modules are durable and are low-maintenance, operational cost is less than ?100 and it bound to decrease over the years. The importance of this is that it signifies that PV modules are good investments because they are easy to maintain. If the PV installer has been certified by MCS (Microgeneration Certification Scheme), then the system is eligible for Feed-in-Tariff (FIT) scheme. The system could receive energy credits up to ?670 per year. From this figure alone, a PV system may earn ?16,750 in 25 years. If a household will install a 3 kWp system costing ?10,000 today, then the system is paid off by the energy credit in the 15th year. Aside from the incentives that the system receives from the government, it can also save on the electricity costs. Take for a property located in Clerkenwell, London, paying a monthly electric bill of ?400, and an Energy Performance Certificate (EPC) rating of band D or better, the installation can earn ?358 from FIT and receive ?26 income from grid export. Moreover, it can save ?61 on its electricity charges. Annual income for this property is ?445. By quantifying it’s the amount of carbon dioxide (CO2) saved by the solar panel in 25 years, total benefit from this PV installation is at ?2956 (Energy Saving Trust 2012). For less efficient households annual income is only ?240. Total benefit is at ?-1,713 because FIT credits is much lower. From this analysis, one can already see the importance of retrofitting the property for less energy demand. Of course, if a property is old, it will need renovations, the amount of which has not been included in this analysis. Using the earlier analysis, one can see already that renovations above ?5,000 can be paid off by the FIT and around 25 years. In conclusion, one may say that the FIT scheme is a good program because it helps the property owner to pay off the capital for the PV installation. Installation of PV modules is then a good investment, aside from the fact that it also a clean technology which will benefit the environment in general. Table 3: Operating cost of installed PV systems (Parsons Brinkerhoff 2012: 16-21) Low-Cost Estimate Jan-12 End 2012 2013 2015 2020 2030 Fixed-cost installation (?/installation) New build domestic (2kW) ?45 ?43 ?42 ?41 ?40 ?38 Retrofit domestic (2kW) ?45 ?43 ?42 ?41 ?40 ?38 Aggregators 4 kW - - - - Marginal cost (?/kW) New build domestic (2kW) - - - - Retrofit domestic (2kW) - - - - Aggregators4kW ?16 ?16 ?15 ?15 ?14 ?13 Medium-Cost Estimate Jan-12 End 2012 2013 2015 2020 2030 Fixed-cost installation (?/installation) New build domestic (2kW) ?65 ?63 ?63 ?61 ?61 ?60 Retrofit domestic (2kW) ?65 ?63 ?63 ?61 ?61 ?60 Aggregators 4 kW - - - - Marginal cost (?/kW) New build domestic (2kW) - - - - Retrofit domestic (2kW) - - - - Aggregators4kW ?25 ?25 ?24 ?24 ?23 ?21 High Cost Estimate Jan-12 End 2012 2013 2015 2020 2030 Fixed-cost installation (?/installation) New build domestic (2kW) ?110 ?110 ?110 ?110 ?110 ?110 Retrofit domestic (2kW) ?110 ?110 ?110 ?110 ?110 ?110 Aggregators 4 kW - - - - Marginal cost (?/kW) New build domestic (2kW) - - - - Retrofit domestic (2kW) - - - - Aggregators4kW ?35 ?35 ?35 ?35 ?35 ?35 References BRE et al., 2006. 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Available at: http://unfccc.int/kyoto_protocol/items/2830.php [Accessed April 5, 2012]. Read More