It is cost to implement a new renewable energy source (solar power) based power plant vs a non-renewable energy source (coal) based power plant. I would have been happy even if the cost to build a solar power plant was 10 times the cost of a coal based plant as the latter has a negative long term impact on health and environment. The very fact that it is just 1.5 times the lower end of coal tariff is something to be happy about.
