I guess it depends on how many of the newly minted green voters have moved across because they have carefully read their policy offering and how many just wanted to vote not-Labour because they were unhappy (i.e. protesting) with the government. Things will become clearer next month and finally at the next general election.
Energy efficiency is great but we still need to get the power from our new shiny off-shore wind farms to where the population centres are. The original grid was very much designed to radiate power from the big generators which are more central (modulo the nuclear generators which tend to be coastal).

The high court decision is being appealed by the government so they can continue until the final ruling.