Plug Power (PLUG) shares surged for a second straight session after the Treasury Department announced final rules on tax credits for producing clean hydrogen.

The tax credits were made available through the Inflation Reduction Act of 2022. The Treasury Department noted in its statement Friday that the rules underwent "significant changes and flexibilities that address several key issues to help grow the industry and move projects forward," while adhering to the emissions requirements included in the act.

Officials explained that the changes "clarify how producers of hydrogen, including those using electricity from various sources, natural gas with carbon capture, renewable natural gas (RNG), and coal mine methane can determine eligibility for the credit."

Deputy Energy Secretary David Turk said the rules "set us on a path to accelerate deployment of clean hydrogen," and will lead to new economic opportunities. Clean hydrogen is defined as the processes and methods used to produce hydrogen that emit zero or nominal fossil fuel or greenhouse gas emissions.

Constellation Energy Stock Also Rises Again on News

Constellation Energy (CEG) shares also were up again as the new rules also clarified how nuclear power generators can get tax credits for clean hydrogen production. Its stock was up nearly 3% after a 4% gain Friday.

Despite their 11% gains Monday morning—which followed a 13% jump Friday—shares of Plug Power remain about 30% lower over the past year.