The number of tons of carbon emissions that Gov. Tom Wolf predicts Pennsylvania will emit by 2030, a reduction of 97 million tons. The state will join the Regional Greenhouse Gas Initiative, a multistate consortium that sets a price and declining limits on power plant emissions. The cap-and-trade program requires owners of fossil-fuel power plants with a capacity of 25 or more megawatts must buy a credit for every ton of CO2 they emit.