If one makes the argument that renewable energy sources are "low-cost", one cannot then simultaneously insist that they must be taxpayer-subsidized in order to succeed.
If wind and solar power were useful, efficient and competitively priced, they would dominate the energy market by means of their intrinsic and comparative values.
Democrats however, are not interested in economic value or efficiency; they are motivated by power, control, and by the promise of spending other people's money in ways that make them feel virtuous.