Concentrator photovoltaics (CPV) is a photovoltaic technology that generates electricity from sunlight. Contrary to conventional photovoltaic systems, it uses lenses and curved mirrors to focus sunlight onto small, but highly efficient, multi-junction (MJ) solar cells. In addition, CPV systems often use solar trackers and sometimes a cooling system to further increase their efficiency. Ongoing research and development is rapidly improving their competitiveness in the utility-scale segment and in areas of high solar insolation. This sort of solar technology can be thus used in smaller areas.Especially systems using high concentrator photovoltaics (HCPV), have the potential to become competitive in the near future. They possess the highest efficiency of all existing PV technologies, and a smaller photovoltaic array also reduces the balance of system costs. Currently, CPV is not used in the PV roof top segment and far less common than conventional PV systems. For regions with a high annual direct normal irradiance of 2000 kilowatt-hour (kWh) per square meter or more, the levelized cost of electricity is in the range of $0.08–$0.15 per kWh and installation cost for a 10-megawatt CPV power plant was identified to lie between €1.40–€2.20 per watt-peak (Wp).In 2013 CPV installations accounted for only 0.1% or 50 megawatts (MW) of the annual global PV market of nearly 39,000 MW. However, by the end of 2014, cumulative installations already amounted to 330 MW. Commercial HCPV systems reached efficiencies of up to 42% with concentration levels above 400, and the International Energy Agency sees potential to increase the efficiency of this technology to 50% by the mid-2020s. As of December 2014, best lab cell efficiency for concentrator MJ-cells reached 46% (four or more junctions). Most CPV installations are located in China, the United States, South Africa, Italy and Spain.HCPV directly competes with concentrated solar power (CSP) as both technologies are suited best for areas with high direct normal irradiance, which are also known as the Sun Belt region in the United States and the Golden Banana in Southern Europe. CPV and CSP are often confused with one another, despite being intrinsically different technologies from the start: CPV uses the photovoltaic effect to directly generate electricity from sunlight, while CSP – often called concentrated solar thermal – uses the heat from the sun's radiation in order to make steam to drive a turbine, that then produces electricity using a generator. Currently, CSP is more common than CPV, especially in Spain and the United States, where concentrated solar thermal contributes a significant part on the overall electricity generation from solar power.