and recycling criteria are not defined. Solar PV has been suggested at public charging stations. Turkey's greenhouse gas emissions attributable to solar PV are estimated at around 30 g Co2eq/kWh for utility scale and 30–60 g for rooftop; emissions for coal and natural gas are over 1000 g and about 400 g respectively. Solar farms The largest solar farm is Karapınar, which started generation in 2020 and is planned to exceed 1 GW by the end of 2022. If a solar power plant is not cleaned for a year it can lose over 5% efficiency. Environmental groups say that half of opencast mines for brown coal (lignite) in Turkey could be converted to 13 GW of solar farms (some with battery storage) generating 19 TWh per year, as much of the electrical infrastructure is already in place for the 10 GW of the 22 adjacent lignite-fired power stations. Aluminium producers favour solar as they use a lot of electricity for electrolysis. Rooftop there is about 1 GW of rooftop solar, companies are installing a lot, and the government is aiming for 2–4 GW by the early 2030s. If total electricity generated by solar panels exceeds 50% of the capacity of the local distribution transformer no more will be approved in that area. Residential The limit for a household is 10 kW. The payback period is very long because electricity from the grid to householders is subsidised a lot. , the payback period of rooftop solar with net metering for homeowners and businesses was estimated at 11 years; removal of VAT and the fixed government approval fee, and attaching borrowing for installation to the property's mortgage has been suggested to shorten this. Non-residential In general non-residential grid power is more expensive than residential, so the payback period is much shorter. From 2023 new buildings larger than 5,000 square meters will have to generate at least five per cent of their energy from renewables. A 2021 study in Ankara found far more rooftop potential for public and commercial buildings than residential. The study also suggested increasing technical potential by suitable roof design in new buildings. Solar PV used with heat pumps may be able to make buildings zero energy in the Mediterranean Region. Aluminium producer claimed in 2022 to be installing the world's largest rooftop solar power system on the roofs of its buildings. Agriculture Farmers are financially supported to install solar