A photovoltaic power station, also known as a solar park, is a large-scale photovoltaic system (PV 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 generic expression utility-scale solar is sometimes used to describe this type of project.
The solar power source is via photovoltaic modules that convert light directly to electricity. However, this differs from, and should not be confused with concentrated solar power, the other large-scale solar generation technology, which uses heat to drive a variety of conventional generator systems. Both approaches have their own advantages and disadvantages, but to date, for a variety of reasons, photovoltaic technology has seen much wider use in the field. As of 2013[update], PV systems outnumber concentrators by about 40 to 1.
In some countries, the nameplate capacity of a photovoltaic power stations is rated in megawatt-peak (MWp), which refers to the solar array's DC power output. However, Canada, Japan, Spain and some parts of the United States often specify using the converted lower nominal power output in MWAC; a measure directly comparable to other forms of power generation. A third and less common rating is the mega volt-amperes (MVA). Most solar parks are developed at a scale of at least 1 MWp. As at the start of 2017, the world's largest operating photovoltaic power station has a capacity of over 800 megawatts and projects up to 1 gigawatt are planned. As at the end of 2016, about 4,300 projects with a combined capacity of 96 GWAC were solar farms larger than 4 MWAC.