I could understand that, but when you rise taxes enough to make the project nonviable is a big problem, as government you want to have a diversified matrix of energy, that is more important than the tax value, believe me, in my country have a lot of problems with that, small country, small economy and just few players on almost all services, that end in political corruption, collusion and problems to get new players.
Just last year was a huge scandals about collusion, more than 10 years rising prices in food companies, pharmacy complete colluded (not an appreciation, a proved fact), huge overprices (we are talking more than 500% sometimes), etc etc...