A photovoltaic power plant, also known as a solar garden, is a large-scale photovoltaic system (PV system) designed for the merchant's electricity supply to the power grid. They are distinguished from most of the above-ground and other decentralized solar applications as they supply utility power, not to users or local users. They are sometimes also referred to as solar farms or solar farms , especially when located in agricultural areas. The utility utility scale utility is sometimes used to describe this type of project.
The source of solar power is through a photovoltaic module that converts light directly into electricity. However, this is different from, and should not be confused with concentrated solar power, other large-scale solar generation technologies, which use heat to drive various conventional generator systems. Both approaches have their own advantages and disadvantages, but to date, for various reasons, photovoltaic technology has seen wider use in the field. In 2013, the PV system exceeds the concentrate amount of about 40 to 1.
In some countries, the name plate capacity of photovoltaic power plants is rated in megawatt-peak (MW p ), which refers to the solar power output of the solar array. However, Canada, Japan, Spain and some parts of the United States often determine the use of lower nominal power output that is converted in MW AC ; a measure that is directly comparable to other forms of electricity generation. The third and less common rating is the mega-volt ampere (MVA). Most solar parks are developed with a minimum of 1 mb p . As early as 2017, the world's largest photovoltaic power plant has a capacity of more than 800 megawatts and projects up to 1 gigawatt are planned. By the end of 2016, approximately 4,300 projects with a combined capacity of 96 GW AC are solar farms larger than 4 MW AC .
Most of the existing large-scale photovoltaic power plants are owned and operated by independent power producers, but the involvement of community-owned projects and utilities is increasing. To date, most have been supported at least in part by regulatory incentives such as entry rates or tax credits, but because costs have gone up significantly in the last decade and grid parity has been achieved in a number of increasing markets, perhaps shortly before external incentives no longer.
Video Photovoltaic power station
History
The first solar park 1 MW p was built by Arco Solar in Lugo near Hesperia, California at the end of 1982, followed in 1984 by 5.2 MW p installation on the Carrizo Plain. Both have since been deactivated, though the Carrizo Plain is the site for some large plants being built or planned. The next phase follows the 2004 revision of feed-in tariffs in Germany when a large number of solar parks are built.
Several hundred installations of more than 1 MW p have been installed in Germany, of which more than 50 more than 10 MW p . With the introduction of feed-in tariffs in 2008, Spain became the largest market, with about 60 solar parks over 10 MW, but this incentive has been withdrawn. The United States, China, India, France, Canada, and Italy, among others, have also become major markets as shown in the list of photovoltaic power plants.
The largest site under construction has a capacity of hundreds of MW p and projects with a scale of 1 GW p are being planned.
Maps Photovoltaic power station
Siting and land use
The area of ​​land required for the desired output power varies depending on the location, and on the efficiency of the solar module, the slope of the location and the type of installation used. Fixed tilt solar arrays use a typical module of approximately 15% efficiency on a horizontal site, requiring approximately 1 hectare/MW in the tropics and this number rises to over 2 hectares in northern Europe.
Due to the longer shadows of array arrays when tilted at steeper angles, this area is typically about 10% higher for adjustable slope or single-axis trackers, and 20% higher for the 2-axis tracker, although the numbers this will vary depending on latitude and topography.
The best location for solar parks in terms of land use is considered to be a brown field site, or where no other valuable land uses are used. Even in the cultivation area, a significant proportion of the location of the solar pond can also be used for other productive uses, such as plant growth or biodiversity.
Agrivoltaics
Agrivoltaics is co-developing the same ground plane for both photovoltaic solar power as well as conventional farming. A recent study found that the value of solar-generated electricity coupled with the production of resistant shade plants resulted in a more than 30% increase in the economic value of agriculture spreading agrivoltaic systems than conventional farming.
Coworkers
In some cases, several different solar power stations, with separate owners and contractors, developed in adjacent locations. This can offer the advantages of projects that share the costs and risks of project infrastructure such as network connections and planning approval. The solar farm can also be placed along with the wind farm. Sometimes the title of 'solar park' is used, rather than individual solar power plants.
Some examples of such solar clusters are Charanka Solar Park, where there are 17 different generations of projects; Neuhardenberg, with eleven plants, and Golmud's solar park with total capacity reported above 500MW. An extreme example is calling all solar farms in the state of Gujarat in India one solar park, Gujarat Surya Park.
Technology
Most Solar parks are ground-mounted PV systems, also known as free field solar power plants. They can be either fixed tilt or single axis or double axis solar tracker. While tracking improves overall performance, it also increases system installation and maintenance costs. A solar inverter converts the array power output from DC to AC, and the connection to the utility network is made through high voltage, three phase transformers typically 10 kV and above.
The composition of the solar system
A solar array is a subsystem that converts incoming light into electrical energy. They consist of many solar modules, mounted on supporting structures and interconnected to provide power output to an electronic power conditioning subsystem.
A small number of utility-scale solar parks are configured in buildings and also use solar panels installed in the building. The majority are 'free field' systems using structures mounted on the ground, usually of one of the following types:
Array fixed
Many projects use a mounting structure in which the solar module is installed on a fixed slant that is calculated to provide an optimal annual output profile. Modules are usually oriented towards the Equator, at a slight slope angle less than the latitude of the site. In some cases, depending on local climatic regimes, topography or electricity prices, different tilt angles may be used, or arrays may be offset from normal East-West axes to support morning or night output.
The variant on this design is the use of arrays, whose slope angle can be adjusted two or four times each year to optimize the seasonal output. They also need more land to reduce internal shadows at steep angles of winter. Since an increase in output is usually only a few percent, it rarely justifies the increased cost and complexity of this design.
Double axis tracker
To maximize the intensity of incoming direct radiation, solar panels must be oriented normally to sunlight. To achieve this, arrays can be designed using a two-axis tracker, capable of tracking the sun in orbit every day in the sky, and as its elevation changes throughout the year.
This array needs to be spaced to reduce inter-shading as the sun moves and the orientation of the array changes, so it needs more land. They also require more complex mechanisms to maintain the array surface at the required angle. Increased output can be from a 30% sequence in locations with high direct radiation levels, but the increase is lower in temperate climates or those with more significant diffuse radiation, due to overcast conditions. For this reason, double axis trackers are most commonly used in subtropics, and are first used on utility scales at Lugo's plant.
Single axis tracker
The third approach achieves some of the output benefits of tracking, with lower penalties in terms of land area, capital and operating costs. This involves tracking the sun in one dimension - in its daily journey across the sky - but not adjusting for the season. The axis angle is usually horizontal, though some, such as the solar garden at Nellis Airforce Base, which has a slope of 20 Â °, tilts the axis toward the equator in north-south orientation - effectively a hybrid between tracking and a fixed slope.
Single-axis tracking systems are aligned along the North-South axis. Some use inter-line relationships so that the same actuator can adjust multiple angle lines at once.
Power conversion
The solar panels generate direct electric current (DC), so the solar park requires conversion equipment to convert it into an alternating current (AC), which is a form delivered by the power grid. This conversion is done by the inverter. To maximize their efficiency, the solar power plant also incorporates the maximum power point tracer, either inside the inverter or as a separate unit. This device stores every string of solar arrays close to its peak power point.
There are two main alternatives for configuring this conversion tool; central inverters and strings, although in some cases individuals, or micro-inverters are used. A single inverter allows optimizing the output of each panel, and some inverters increase reliability by limiting the loss of output when the inverter fails.
Centralized inverter
These units have relatively high capacity, usually of the order of 1 MW, so they condition that the output of a large array solar block, up to maybe 2 hectares (4.9 hectares) in the area. Solar parks use centralized inverters often configured in discrete rectangular blocks, with corresponding inverters in one corner, or central block.
Inverter string
String inverters are substantially lower in capacity, than 10 kW sequences, and output conditions of a single array string. This is usually the whole, or part of, a row of arrangements of solar panels inside the entire plant. String inverters can increase the efficiency of solar parks, where different parts of the array experience different insolation levels, for example where it is set at different orientations, or packed tightly to minimize the area of ​​the site.
Transformer
The system inverter usually provides power output at the voltage of the order of 480 V AC . The electrical network operates at a voltage much higher than the order of tens or hundreds of thousands of volts, so the transformer is combined to produce the required output to the grid. Due to the long waiting time, Long Island Solar Farm chose to keep the backup transformer in place, because the failure of the transformer will make offline solar farms for a long time. Transformers typically have an age of 25 to 75 years, and usually do not require replacement during the lifetime of photovoltaic power generation.
System performance
The performance of solar parks is a function of climatic conditions, equipment used and system configuration. Primary energy input is the radiation of global light in the field of the arrangement of the sun, and this in turn is a combination of direct and diffuse radiation.
The main determinant of the system output is the conversion efficiency of the solar module, which will greatly depend on the type of solar cell used.
There will be a disadvantage between the DC output of the solar module and the AC power sent to the grid, due to various factors such as loss of light absorption, mismatch, decreased cable voltage, conversion efficiency, and other parasitic losses. A parameter called 'performance ratio' has been developed to evaluate the total value of this loss. The performance ratio gives the output size of the delivered AC power as the proportion of total DC power that solar modules should be able to provide under ambient climate conditions. In modern solar parks, performance ratios typically have to be over 80%.
System degradation
The output of the initial photovoltaic system decreased by 10%/year, but in 2010 the average degradation rate was 0.5%/year, with modules made after 2000 having significantly lower degradation rates, so the system would lose only 12% of output performance in 25 years. Systems that use modules that degrade 4%/year will lose 64% of their output over the same period. Many panel makers offer performance guarantees, typically 90% in ten years and 80% for 25 years. The output of all panels is usually secured by plus or minus 3% during the first year of operation.
Solar garden development business
Solar power plants are developed to deliver merchant electricity to the power grid as an alternative to other renewable, fossil or nuclear power stations.
The factory owner is an electric generator. Most solar power plants are currently owned by independent power producers (IPP), although some are owned by companies owned by investors or the public.
Some of these power producers develop their own portfolio of power plants, but most of the solar parks were originally designed and built by specialist project developers. Usually developers will plan the project, get planning and connection approval, and arrange financing for the required capital. The actual construction work is usually contracted to one or more EPC contractors (engineering, procurement and construction).
The main milestones in the development of new photovoltaic power plants are approval planning, network connection approval, financial closure, construction, connection and commissioning. At each stage of the process, the developer will be able to update the anticipated performance forecasts and factory costs and financial returns that they should be able to generate.
Planning approval
Photovoltaic power plants occupy at least one hectare for each megawatt of rated output, requiring large areas of land; which is subject to planning approval. The possibility of obtaining approval, and the time, cost and related conditions, varies from jurisdiction to jurisdiction and location to location. Many planning approvals will also impose conditions on site maintenance after the station closes in the future. Professional health, safety and environmental assessments are usually undertaken during the design of a PV power plant to ensure the facility is designed and planned in accordance with all HSE regulations.
Network connection
Availability, locality and connection capacity to the power grid are key considerations in new solar park planning, and can be a significant cost contributor.
Most stations are located within a few kilometers of the appropriate network connection points. This network should be able to absorb the output of the solar garden when operating at its maximum capacity. Project developers usually have to absorb the cost of supplying the power grid to this point and establish a connection; in addition to the frequent costs associated with upgrading the grid, so it can accommodate the output of the factory.
Operation and maintenance
Once the solar park has been commissioned, the owner usually enters into a contract with a suitable partner to perform operations and maintenance (O & M). In many cases this can be fulfilled by the original EPC contractor.
The reliable solid-state system of a solar power system requires minimal maintenance, compared to a rotary engine for example. The main aspects of the O & M contract will continue to monitor the performance of the plant and all its major subsystems, which are usually done remotely. This allows performance to be compared to the anticipated output under actual climatic conditions experienced. It also provides data to allow scheduling of both repair and preventive maintenance. A small number of large solar farms use separate inverters or maximizers for each solar panel, providing individual performance data that can be monitored. For other solar farms, thermal imaging is a tool used to identify non-functioning panels instead.
Power delivery
The solar park revenue comes from the sale of electricity to the power grid, and its output is measured in real-time by reading the energy output provided, usually half an hour, for balance and completion in the electricity market.
Revenue is influenced by the reliability of equipment inside the plant and also by the availability of the grid network it exports. Some contract connections allow transmission system operators to limit the output of solar parks, for example when demand is low or the availability of other generators is high. Some countries make legal provisions for priority access to power lines for renewable generators, such as those under European Renewable Energy Directive.
Economy and Finance
In recent years, PV technology has increased the efficiency of electricity generation, reducing installation cost per watt and energy recovery time (EPBT), and has reached grid parity in at least 19 different markets by 2014. Photovoltaics is increasingly becoming a viable source of major power. However, prices for PV systems show strong regional variations, far more than solar cells and panels, which tend to be global commodities. By 2013, the price of utility-scale systems in highly penetrated markets such as China and Germany is significantly lower ($ 1.40/W) than in the United States ($ 3.30/W). The IEA explains this difference due to the difference in "soft costs", which include customer acquisition, licensing, inspection and interconnection, installation labor and financing costs.
Grid parity
Solar power stations have become increasingly cheaper in recent years, and this trend is expected to continue. Meanwhile, traditional power plants are becoming more expensive. This trend is expected to lead to a crossover point when measurable energy costs from solar parks, historically more expensive, correspond to the cost of traditional power plants. This point is often referred to as grid parity.
For a merchant solar power plant, where electricity is being sold to an electric transmission network, the measured solar energy costs will need to correspond to wholesale electricity prices. This point is sometimes called 'wholesale grid parity' or 'busbar parity'.
Some photovoltaic systems, such as roof installations, can supply power directly to power users. In this case, installation can be competitive when the output cost matches the price at which the user pays for electricity consumption. This situation is sometimes called 'retail box parity', 'socket similarity' or 'dynamic grid parity'. Research conducted by UN-Energy in 2012 shows bright areas of the country with high electricity prices, such as Italy, Spain and Australia, and regions using diesel generators, have reached the parity of the retail grid.
Incentive mechanism
Since the grid parity point has not been reached in many parts of the world, solar power stations require some form of financial incentive to compete for electricity supply. Many legislatures around the world have introduced such incentives to support the deployment of solar power stations.
Feed-in rate
The feed-in rate is the price determined to be paid by the utility company for each kilowatt hour of renewable electricity produced by a qualified generator and put into the grid. These tariffs typically represent premium wholesale electricity prices and offer guaranteed revenue streams to help power producers finance the project.
Standard of renewable portfolio and supplier obligations
These standards are an obligation on utility companies to source their electrical proportions from renewable generators. In most cases, they do not prescribe which technology should be used and the utility is free to choose the most appropriate renewable source.
There are some exceptions where solar technology is allocated partly from RPS in what is sometimes referred to as 'solar set aside'.
Loan guarantees and other capital incentives
Some countries and states adopt less targeted financial incentives, available for various infrastructure investments, such as the US Department of Energy's loan guarantee scheme, which encourages a number of investments in solar power plants by 2010 and 2011.
Tax credits and other fiscal incentives
Another form of indirect incentive that has been used to stimulate investment in solar power plants is the tax credits available to investors. In some cases, credits are associated with the energy generated by the installation, such as the Production Tax Credits. In other cases, credits are associated with capital investments such as the Investment Tax Credit
International, national and regional programs
In addition to free-market commercial incentives, some countries and regions have special programs to support the deployment of solar energy installations.
The EU's Renewable Directive sets targets to increase the rate of dissemination of renewable energy in all member countries. Each has been asked to develop a National Renewable Energy Action Plan that demonstrates how these targets will be met, and many of them have specific support measures for the spread of solar energy. This directive also allows countries to develop projects beyond their national boundaries, and this could lead to bilateral programs such as the Helios project.
The UNFCCC Clean Development Mechanism is an international program in which solar power stations in certain qualifying countries can be supported.
In addition, many other countries have specific solar energy development programs. Some examples are JNNSM in India, Superior Programs in Australia, and similar projects in South Africa and Israel.
Financial performance
The financial performance of a solar power plant is a function of revenue and cost.
The electrical output of a solar park will be related to solar radiation, plant capacity and performance ratio. Revenue from electricity output comes primarily from electricity sales, and any incentive payments such as those below the Feed-in Tariff or other support mechanisms.
The price of electricity may vary at different times of the day, providing a higher price when the demand is high. This may affect the design of the plant to increase its output at such times.
The dominant cost of a solar power plant is the cost of capital, and therefore any financing and depreciation are linked. Although operating costs are usually relatively low, especially since no fuel is required, most operators will want to ensure that adequate operation and maintenance are available to maximize the availability of the plant and thus optimize the revenue to cost ratio.
Geography
The first places to reach grid parity are those that have high traditional electricity prices and high levels of solar radiation. Currently, more capacity is installed in the roof than in the utility scale segment. However, the distribution of solar parks around the world is expected to change when different regions reach the grid parity. This transition also includes a shift from the roof towards the utility-scale plant, as the focus of new PV deployments has changed from Europe toward the Sunbelt market where a ground-mounted PV system is preferred.
Due to economic background, large-scale systems are currently being distributed where support regimes are most consistent, or most profitable. Total PV factory capacity worldwide above 4 MW AC is rated by Wiki-Solar as 36 GW at c. 2,300 installations by the end of 2014 and represents about 25 percent of the total global PV capacity of 139 GW. The countries with the greatest capacity, in descending order, are the United States, China, Germany, India, England, Spain, Italy, Canada, and South Africa. Activities in major markets are reviewed individually below.
China
China reported in early 2013 has surpassed Germany as a country with utility-scale solar capacity. Much of this has been supported by the Clean Development Mechanism. The distribution of power plants across the country is wide enough, with the highest concentrations in the Gobi desert and connected to the Southwest China Power Network.
German
The first multi-megawatt plant in Europe was a 4.2 MW community project in Hemau, commissioned in 2003. But it was a revision of German feed-in rates in 2004, which provided a powerful impetus for utility-scale formation. solar power plant. The first to be completed under this program is the Leipziger Land solar park developed by Geosol. Several dozen plants were built between 2004 and 2011, some of which are the largest in the world. The EEG, a law that sets German feed-in rates, provides a legislative basis not only for the level of compensation, but other regulatory factors, such as priority access to the power grid. The law was amended in 2010 to limit the use of agricultural land, since then most solar parks have been built on so-called 'development lands', such as former military sites. Partly for this reason, the geographic distribution of photovoltaic power plants in Germany is biased against former East Germany. As of February 2012, Germany has 1.1 million photovoltaic power plants (most of which are small kW roofs installed).
India
India has risen to the leading countries for the installation of utility-scale solar capacity. The Charanka Solar Park in Gujarat officially opened in April 2012 and at that time is the largest solar power generation group in the world. Geographically most stations are located in Gujarat and Maharashtra. Rajasthan has managed to attract the development of the sun. Rajasthan and Gujarat share the Thar Desert, along with Pakistan.
Italy
Italy has a large number of photovoltaic power plants, the largest of which is the 84 Watt Montalto project in Castro.
Jordan
By the end of 2017, it was reported that over 732 MW of solar energy projects have been completed, which accounted for 7% of Jordan's electricity. After initially establishing the percentage of renewable energy that Jordan is targeting to produce by 2020 by 10%, the government announced in 2018 that it seeks to beat that number and aim for 20%. A report by pv magazine describes Jordan as a "solar power plant of the Middle East".
Spanish
The majority of the spread of solar power plants in Spain to date occurred during the booming market of 2007-8. The stations are well distributed throughout the country, with concentrations in Extremadura, Castile-La Mancha, and Murcia.
United Kingdom
The introduction of Feed-in rates in the UK in 2010 prompted the first wave of utility-scale projects, with c. 20 factories were completed before tariffs were reduced on August 1, 2011 after 'Fast Track Review'. The second installment wave is under British Renewable Bonds, with the total number of connected plants at the end of March 2013 reaching 86. This has reportedly made Britain the best market in Europe in the first quarter of 2013.
The British project was originally concentrated in the Southwest, but was recently scattered in the South of England and to East Anglia and the Midlands. The first solar park in Wales began operations in 2011 in Rhosygilwen, north of Pembrokeshire. In June 2014 there were 18 schemes generating more than 5 MW and 34 in planning or construction in Wales.
United States
The spread of US photovoltaic power plants is largely concentrated in the southwestern states. The Renewable Portfolio Standards in California and surrounding countries provide special incentives. The volume of projects under construction in early 2013 has led to estimates that the US will be a major market.
Solar garden to watch out for
The following solar parks are, by the time they become operational, the largest in the world or their continent, or are well known for the reasons given:
The solar power plant under development is not included here, but may be on this list.
See also
References
External links
- Interactive project mapping worldwide over 10MW
- The Solar Energy Industry Association - The Big Solar Project in the US
- The 10 best solar PV generators in the world (2014)
- List of 1000 largest photovoltaic power plants (in 2011)
Source of the article : Wikipedia
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