Green Energy

They built a couple of this near Las Vegas in Nevada, USA. The cost of construction was very high as was the cost of maintenance. They were only used while the research was ongoing as the power was never economical to produce. In fact, it would would have been the single most expensive source in the state.

Solar PV and wind on the other hand are some of the cheapest sources. With today's tech, grid connected batteries make even more sense than concentrated solar thermal and molten salt.