The Green party candidate, via a peer-reviewed plan, showed that, by 2030, short term taxes on "the big polluters and wall street" (in the New York ads for the plan) would lead to a 50% cut in energy bills later.
The way renewables work is that if the upfront costs are paid for, then prices drop after. Its sort of "free energy" after the initial cost.
The strategy used in Germany is to offer above market value prices for a fixed period of 15-20 years for anyone willing to sell power produced by renewable means to the national grid. It appears to have worked as well - it's encouraged both big energy producers and private individuals to set up solar and wind powered production since the startup costs are essentially taxpayer subsidised. Wind, solar, biofuels and hydroelecticity make up about a third of the German electricity supply now.