Government subsidies are a misallocation of capital. It is wasted money. Instead of subsidizing exotic but not really usable technology the government should be not hindering the discovery and production of hydrocarbons. Within the jurisdiction of the United States is enough hydrocarbon for a couple of centuries and that will continually increase as technologies improve. And that's not even mentioning coal which is, for all practical purposes, unlimited. Hydrocarbons probably are not the final say in energy but their enthusiastic exploitation will keep the economy going so that a next stage can be discovered and/or developed.
Shutting down the economy to save the snails will ensue that there will be no real advances toward more efficient power sources, and more efficient i.e. cheaper power is the necessary goal, not greener or more politically friendly but only more efficient energy. Eating up assets to produce nonviable or less efficient energy simply delays the time or prevents it altogether when we transition to that next step of practical and cheap Fusion or something totally else.