A complete solar electric system is made up of several building blocks. First, there are solar cells. Cells are manufactured from semiconductor materials such as silicon, sometimes boron and phosphorous, wired together to form a solar module. Modules (or “panels”) are wired together in series and parallel to form the array. PV systems produce direct current (DC) electricity. In order for a PV system to produce electricity that a typical business can use, the DC electricity must be converted to alternating current (AC) electricity. The inverter converts DC electricity to AC electricity. The design and size of the PV system determines whether there will be a single large inverter or several smaller inverters. The balance of system (BOS) includes racking, fasteners, switchgear, junction boxes, inverters, conduit, grounding equipment, meters, the Data Acquisition System (DAS), etc.
The capacity of a PV system is stated in terms of the number of watts, kilowatts or megawatts it produces in standard sunlight conditions (STC). For the northeastern United States, a good estimate is: For each kilowatt of PV capacity AC-installed, the system will produce approximately 1,000 to 1,300 kWh (kilowatt-hours) per year. For example, a 100 kW system will generate about 100,000 to 130,000 kWh per year.
The size of your system depends largely on how much electricity you are currently consuming. The less energy you use the smaller the system you may need.
Shade on PV panels naturally decreases a system’s output. While some shading can be acceptable during certain times of the day (early morning and late afternoon), it is important to minimise the impact that shading from trees, nearby buildings, roof mechanicals and other factors can have.
All of the PV systems engineered and maintained by SES are “grid-tied,” and as such do not store electricity. The grid therefore provides power when the PV system is not generating. The grid accepts all excess energy production during times when the PV system is producing more than is being consumed on site. The most common way to store energy from an “off-grid” PV system is in a battery. While battery storage allows a customer to be independent from the grid, batteries also add to the expense of the system, may be large, require special handling, and can emit toxic gases.
If a PV system is designed, installed and maintained well, it will operate for as many as 40 years. All solar modules utilized by SES carry a 25-year warranty.
PV systems require very little maintenance. Rain will typically be sufficient to clean the modules. But on occasion they may need to be washed, and debris (e.g., leaves) will need to be removed. SES standard maintenance contract includes any cleaning, ballast inspection, label inspection, inverter inspection and checking for module and rack degradation. By means of a Web-based Data Acquisition System (DAS), SES will track and verify system performance relative to weather adjusted projections.
A solar PV system is a long-term investment that is guaranteed to pay dividends. On-site power generation reduces the amount of billable energy you will consume from the utility grid, thereby leading to appreciable savings on energy costs. In addition to the money saved on energy bills, policies like net-metering allow PV system owners to profit from their system’s excess generation. Moreover, a solar system will allow you to lock in a price per kWh thereby protecting you from rising future energy costs. Additionally, a PV system adds value to your property and will confirm a company’s “green” commitment, ensuring new customers and attracting employees.
Photovoltaic Power Plant or Station or PV Plant, also known as a solar parks, is a large-scale photovoltaic system designed for the supply of merchant power into the electricity grid They are differentiated from most building-mounted and other decentralised solar power applications because they supply power at the utility level, rather than to a local user or users. They are sometimes also referred to as solar farms or solar ranches, especially when sited in agricultural areas.
The power conversion source is via photovoltaic modules that convert light directly to electricity. This differs from the other large-scale solar generation technology concentrated solar power.
Photovoltaic power stations are typically rated in terms of the DC peak capacity of the solar arrays, in mega watt - peak (MWp), or of the nominal maximum AC output in megawatts (MW) or mega volt-amperes (MVA). Most solar parks are developed at a scale of at least 1 MWp. The largest operating photovoltaic power stations have capacities of hundreds of MWp; projects up to 1 GWp are planned. The cumulative worldwide capacity of plants of 10 MW and over as at March 2013 was reported to be 12 GW.
Most of the existing large-scale photovoltaic power stations are owned and operated by independent power producers, but the involvement of community- and utility-owned projects is increasing. To date, almost all have been supported at least in part by regulatory incentives such as feed-in tariffs or tax credits, but capital costs have fallen significantly in the last decade and are expected to progressively reach grid parity, when external incentives may no longer be required.
Photovoltaic Array (or Solar Array) is a linked collection of Solar Panels. The power that one module can produce is seldom enough to meet requirements of a home or a business, so the modules are linked together to form an array. Most PV arrays use an inverter to convert the DC power produced by the modules into alternating current that can power lights, motors, and other connected loads. The modules in a PV array are usually first connected in series to obtain the desired voltage: the individual strings are then connected in parallel to allow the system to produce more current. Solar panels are typically measured under STC (standard test conditions) or PTC (PVUSA test conditions), in watts Typical panel ratings range from less than 100 watts to over 400 watts. The array rating consists of a summation of the panel ratings, in watts, kilowatts, or megawatts
The land area required for solar parks varies depending on the location, and on the efficiency of the solar modules, the location of the site and the type of mounting used. Fixed tilt solar arrays using typical modules have improved significantly to about 18% efficiency on horizontal sites, need about 5 Acres/MW.
Because of the longer shadow the array casts when tilted at a steeper angle, this area is typically about 10% higher for an adjustable tilt array or a single axis tracker, and 20% higher for a 2-axis tracker, though these figures will vary depending on the latitude and topography.
The best locations for solar parks in terms of land use are held to be brown field sites, or where there is no other valuable land use, due to low rainfall and year around higher temperatures. Even in cultivated areas, a significant proportion of the site of a solar farm can also be devoted to other productive uses, such as biodiversity.
In some cases several different solar power stations, with separate owners and contractors, are developed on adjacent sites. This can offer the advantage of the projects sharing the cost and risks of project infrastructure such as grid connections and planning approval. Solar farms can also be co-located with wind farms.Sometimes the title 'solar park' is used, rather than an individual solar power station.
Some examples of such solar clusters are the Charanka Solar Park, where there are 17 different generation projects; Neuhardenberg, with eleven plants, and the Golmud solar parks with total reported capacity over 500MW. An extreme example is calling all of the solar farms in the Gujarat state of India a single solar park, the Gujarat Solar Park.