Today marks the starting gun in a battle for market share over America's stagnant electricity mix. Seeking to follow through on President Trump's campaign promises to revive coal and nuclear power, the Energy Department is asking an independent federal agency to issue a rule that would help those two fuel types. The stated aim is to ensure the electric grid is resilient to power outages and other vulnerabilities.

We've created a card deck to get you up to speed fast on how each fuel type is poised to gain — or lose — under the proposed changes.

Gritty details: The Energy Department's proposed rule would allow power plants operating in competitive markets, which make up more than half of the United States, to recover costs if they have 90 days worth of fuel on site.

The Federal Energy Regulatory Agency is requesting comments to that proposed rule be submitted by today. Groups representing most energy types other than coal and nuclear power are worried, because it could erode their otherwise growing market shares and upend the power market as it's known today. FERC makes the final decision, and its commissioners have expressed caution about following through with the rule.

What's next: The Energy Department has asked FERC to make a decision after 15 days, but many don't expect the independent agency to act that fast.

Read more: Check out this Axios slide deck breaking down the market share for each electricity source.