According to GTM Research, the cost of utility-scale solar projects has fallen 67% in the past five years; $1 per watt would be another 44% in the next couple of years.The resulting cost structure is leading to highly competitive prices for solar energy versus fossil fuels.ccording to GTM Research, the cost of utility-scale solar projects has fallen 67% in the past five years; $1 per watt would be another 44% in the next couple of years.