In what enthusiastic progressives are heralding as “one of the boldest acts of his presidency,” environmentalist groups are hailing as “the centerpiece of President Obama’s Climate Action Plan,” embattled red-state Democrats are warning are “disastrous new rules,” and industry representatives are branding a clear move “designed to materially damage the ability of conventional energy sources to provide reliable and affordable power,” the Obama administration has finally revealed the emissions regulations on existing power plants for which they have long been prepping. Via the AP:

The 645-page rule, expected to be finalized next year, is a centerpiece of Obama’s plans to tackle climate change and aims to give the United States more leverage to prod other countries to act when negotiations on a new international treaty resume next year. Under the plan, carbon emissions would be reduced 30 percent by 2030, compared to 2005 levels, putting in motion one of the most significant U.S. actions on global warming.

The proposal sets off a complex regulatory process, steeped in politics, in which the 50 states will each determine how to meet customized targets set by the Environmental Protection Agency, then submit those plans for approval.

“The glue that holds this plan together — and the key to making it work — is that each state’s goal is tailored to its own circumstances, and states have the flexibility to reach their goal in whatever works best for them,” EPA Administrator Gina McCarthy said as she formally announced the proposal.

The regulations are going to require individual emissions-cutting plans from each state to add up to a national 30 percent reduction, with different state-specific requirements based on how much electricity they get from coal and how much they have already done to reduce their emissions in recent years. The Obama administration doesn’t want to seem like it’s unfairly coming down too hard on state economies that happen to rely more on coal for their electricity needs (West Virginia, for instance, is going to get walloped, with 95 percent of their electricity currently coming from coal, while Idaho actually gets most of its electricity from hydroelectric power and exactly none of it from coal), and in that vein, the EPA claims that the regulations will offer plenty of “flexibility” for states to adjust to the changes:

Many states that rely heavily on coal will be spared from cutting a full 30 percent. West Virginia, for example, must cut 23 percent by 2030 compared to what the state was emitting in 2012. Ohio’s target is 28 percent, while Kentucky and Wyoming will have to find ways to make an 18 percent and 19 percent cut.

On the other extreme, New York has a 44 percent target, EPA figures show. New York has already joined with other Northeast states to curb carbon dioxide from power plants, reducing the baseline figure from which cuts must be made. But states like New York can get credit for actions they’ve already taken, lest they be punished for taking early action on climate change.

The fact that they chose 2005 as a baseline is also meant to be a mitigating factor, since our natural-gas boom along with increased fuel efficiency have already taken us part of the way there. Nevertheless, President Obama wants the EPA to finalize the rules by June 2015, and states are supposed to start submitting their implementation plans by June 2016 (with room to push their deadlines into 2018, depending on how they choose to approach the regulations) so that the rule can start having an impact before he leaves office — in theory. The legal challenges from states with a larger proportion of older coal plants are going to come hard and fast, not to mention some staunch lobbying efforts and less-than-uniform support from put-upon Democrats.