NEW DELHI: US-based SunEdison, the world's largest developer of green energy projects, has offered a tariff of Rs 4.63 per unit for a 500 mw solar power project being set up by state-run utility NTPC in Andhra Pradesh. This is the lowest tariff for solar power and beats the previous record of Rs 5.05 quoted by SkyPower for a 150 mw project in Madhya Pradesh.

"Delighted that an all-time low solar tariff of Rs 4.63 has been achieved during reverse e-auction conducted by NTPC," power minister Piyush Goyal tweeted.

The Andhra project will have 10 units of 50 mw each. A power ministry release said altogether 30 bids were received totalling to 5,500 MW capacity.

SunEdison's tariff was lower than Rs 4.80 per unit offered by SoftBank of Japan and Rs 4.79 quoted by China's Trina Solar Ltd. Italy's Enel Green Power SpA, Reliance Power Ltd, ReNew Power Ventures Pvt Ltd, Solar Arise, Acme Solar and Orange Renewable Power offered bids of less than Rs 5 per unit.

Solar power tariffs had stood at Rs 18 per unit in 2012 and has been declining on the back of advancing technology, rising scales and government's thrust on ramping up solar capacity to 100 gw (giga watt) by 2022.

"The country is changing. With integrity, honesty and economies of scale, the price has come down to near-grid parity. So India will lead the world in its solar thrust," according to new and renewable energy minister Piyush Goyal.

"Solar projects have levelised tariff that remains same throughout the project life. Unlike thermal power stations where fuel tariffs rise with fuel cost. In solar, it takes little to operate and maintain—maybe two persons per mw," renewable energy secretary Upendra Tripathi had told TOI recently.