They are just green enough to convince a bunch of gullible idiots to invest a ton of money in them and their associated infrastructure which they then declare to be actually bad for the environment and demand that it all be torn out. It is all a ruse to waste time and money.
Remember when the greenie leftists forced oil companies to add MTBE to gasoline? Then they discovered how dangerous it is and insisted oil companies remove it. Somehow they then managed to lay the blame on oil companies for using it in the first place.