NEW DELHI: Renewable energy projects have received Rs 86,000 crore investment, most of it from private sector, in the last three years with Madhya Pradesh at top garnering Rs 14,313.80 crore."Most of the investment in renewable energy came from private sector. Total estimated investment in renewable energy power projects during the last three years is around Rs 86,000 crore," New and Renewable Energy Minister Piyush Goyal said in a written reply to Lok Sabha today.According to the statement, around 15,400 million units has been generated through solar power projects during the last three years.Madhya Pradesh remained at the top, recording maximum investment in clean energy projects at Rs 14,313.80. It was followed by Maharashtra at Rs 13,743.01 crore, Rajasthan at Rs 11,632.96 crore, Karnataka at Rs 9,586.31 crore, Andhra Pradesh at Rs 9,539.12 crore, Tamil Nadu at Rs 8,961.28 crore and Gujarat at Rs 6,646.35 crore.The minister also stated that Pondicherry, Laskhwadeep, Dadar & Nagar Haveli, Sikkim , Manipur, Meghalaya and Goa received no investment at all for renewable energy projects in last three years.According to a separate reply to the House, as on March 31, 2016, a cumulative capacity of 42.76 GW has been installed from various renewable energy sources, which include 26.78 GW from Wind, 6.76 GW from solar, 4.27 from small hydro power and 4.95 GW from bio power.In another reply to the House, the Maharashtra will require the maximum solar power generation capacity of 13,270 MW by 2021-22 as per tentative renewable purchase obligation (RPO) requirement estimated by the ministry.The ministry has estimated 1,02,021 MW solar power generation capacity to be installed in the entire country by 2021-22.After Maharashtra, Uttar Pradesh's solar power generation capacity by 2021-22 as per RPO requirement would be the second highest at 12,124 MW followed by Gujarat at 9,796 MW, Tamil Nadu at 9,398 MW and Rajasthan 6,953 MW.Under RPO, states are mandated by power regulators to have certain proportion of renewable energy capacity in their total power mix to promote clean and green sources like solar and wind.The minister in another reply to the House stated that the new pithead thermal power plants have the lowest tariff of Rs 3.75 per unit in the first year of operation compared Rs 4.5 per unit for solar, Rs 4.6 for hydro, Rs 4.94 for atomic power and Rs 5.49 for non-pithed thermal plants.However, the levellised tariff for hydro power plats is the lowest at Rs 4 per units compared Rs 4.5 for solar, Rs 5 for atomic power, Rs 4.57 for pithead based thermal power and Rs 7.57 per unit for non-pithead based thermal power plant.