London-listed Essar Energy plc on Thursday said it will exit Kenya Refinery by selling its 50 per cent stake to the government of the African nation for $5 million. It said the decision follows extensive studies finding upgradation of the refinery economically unviable in the current refining environment. The Mombasa refinery has a nameplate capacity of 4 million tonnes per annum but could process only 1.6 million tonnes last year. Essar had planned $400-450 million investment in upgradation of the refinery to achieve optimal level of operation. "Essar Energy, through its subsidiary Essar Energy Overseas Ltd, has exercised a put option under the shareholders' agreement to sell its stake in Kenya Petroleum Refineries Ltd (KPRL) to the Government of Kenya, which owns the remaining 50 per cent interest in the Mombasa refinery," the company said in a press statement.