The largest scale of solar projects is utility-scale solar (also known as solar power plants). Typically sized anywhere from 1 to 5 megawatts (MW), solar power plants can be massive projects, often spanning multiple acres of land. Utility-scale solar projects are usually ground-mounted arrays. Sometimes, these arrays include solar trackers to maximize energy production.
The primary difference between solar power plants and other distributed solar options (such as commercial and residential installations) is that the electricity generated from a utility-scale project is not used directly at the host site. Depending on the installation's geographic location, the power produced at solar power plants is sold to wholesale utility buyers through a power purchase agreement (PPA) or owned directly by an electric utility company. Regardless of the exact structure, the initial customer of the generated power is an electric utility company, which will then distribute the generated electricity to residential, commercial, and industrial ratepayers connected to the grid.
Solar power plants aren't limited to photovoltaics – some utility-scale projects are concentrated photovoltaics (CPT) or concentrated solar power (CSP). However, photovoltaic installations are the most common type of utility-scale solar solutions. Solar power plants will often include storage technology to store solar electricity when the sun is shining and distribute it later during hours of little or no sunlight.
As mentioned above, utility-scale solar comes in multiple varieties, each harnessing energy from the sun in slightly different ways. Here are the two main types of solar power plants currently in use around the world:
Photovoltaic solar power plants are essentially large-scale versions of the solar systems used in houses. They consist of large grids of photovoltaic panels in open areas and feed energy directly into the grid or storage units for later use.
Concentrated Solar Power (CSP)
Concentrated solar power uses mirrors to focus solar energy to produce extremely high temperatures, which produce electricity by spinning a turbine. There are several methods to do this, including parabolic dishes, power towers, and parabolic troughs. Read more about CSP here.
Compared to traditional power generation sources like fossil fuels and nuclear power, there is one downside to solar power plants that's important and often difficult to overcome: intermittency.
Solar panels can only generate electricity when the sun is shining, while other traditional generation sources can supply energy 24 hours a day, seven days a week. Fortunately, solar can become available at all hours of the day with energy storage solutions like solar batteries.
An energy source that can provide power on demand, turn on and off, and has an adjustable power output is known as a dispatchable generation. Coal, natural gas, or hydroelectric plants are considered dispatchable generation because they can be turned on to provide power within a relatively short window (usually between seconds and hours.)
Solar energy is typically not considered dispatchable generation – it can only travel to the grid when the sun is shining, and you can't turn it on after the sun goes down. For utility-scale solar to be an effective dispatchable energy resource, batteries and other types of storage can be leveraged to accumulate solar energy that can then act as a dispatchable system when the solar panels aren't producing electricity at night. Solar power plant storage makes solar energy much more reliable and, therefore, much more attractive to utilities and their stakeholders.
Solar power plants can produce massive amounts of electricity, with some of the biggest boasting outputs of over 1,000 megawatts! This is especially impressive compared to the average solar panel, which has an electricity output of about 300 watts. (For reference, 1 megawatt is equal to one million watts) Here are the top 5 largest solar power plants in the world today:
Tengger Desert Solar Park, China (1,547 MW)
Sweihan Photovoltaic Independent Power Project, UAE (1,177 MW)
Yanchi Ningxia Solar Park, China (1,000 MW)
Datong Solar Power Top Runner Base, China (1,070 MW)
Kurnool Ultra Mega Solar Park, India (1,000 MW)
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