The blueprint for New York State’s lofty clean-energy goals relies on the technologies of the future: The state, officials have promised, will draw half of its electricity from renewable and clean energy sources like wind and solar power by 2030.

But as the plan takes shape at the state’s Public Service Commission, talk of still-young technologies has been overshadowed by something of a throwback: the state’s aging nuclear power plants.

The commission is considering a proposal that makes the state’s three upstate nuclear plants important parts of its efforts to wean itself off fossil fuels, offering nearly $1 billion in ratepayer-financed subsidies over the next two years to save plants battered by rising costs and competition from cheap natural gas.

The subsidy is likely to grow into the multibillion-dollar range over the 12-year period proposed by the state, a sum that has caused watchdogs to question whether the state is about to approve a major industry bailout with minimal public scrutiny — even though it is the public’s utility bills that will grow.