Nominal power (photovoltaic) be described as having "one kilowatt-peak" in the meaning "one kilowatt of peak power". Similarly outside the SI, the peak power is sometimes written as "P = 1 kW" as opposed to "P = 1 kW". In the context of domestic PV installations, the kilowatt (kW) is the most common unit for peak power, sometimes stated as kW. The output of photovoltaic systems varies with the intensity of sunshine and other conditions. The more sun, the more power the PV module will generate. Losses, compared to performance in optimal conditions, will occur due to non-ideal alignment of the module in
Photovoltaic power station cost of energy from solar parks, historically more expensive, matches the cost of traditional electricity generation. This point is commonly referred to as grid parity. For merchant solar power stations, where the electricity is being sold into the electricity transmission network, the levelised cost of solar energy will need to match the wholesale electricity price. This point is sometimes called 'wholesale grid parity' or 'busbar parity'. Some photovoltaic systems, such as rooftop installations, can supply power directly to an electricity user. In these cases, the installation can be competitive when the output cost matches the price at which the user