RGGI is a cooperative effort among the states of Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, Vermont, and Virginia to cap and reduce carbon dioxide (CO2) emissions from the power sector.

[5] RGGI establishes a regional cap on the amount of CO2 pollution that power plants can emit by issuing a limited number of tradable CO2 allowances.

An initial milestone program's development occurred in 2005, when seven states signed a memorandum of understanding announcing an agreement to implement RGGI.

[16] Alternate factors considered by the study included state Renewable Portfolio Standard (RPS) programs, economic trends, and natural gas prices.

A Clean Air Task Force (CATF) study investigated public health benefits arising from the RGGI states' shift to cleaner power generation.

[19] The study found that the RGGI states transition to cleaner energy is saving hundreds of lives, preventing thousands of asthma attacks and reducing medical impacts and expenses by billions of dollars.

The adoption of RGGI also has the potential to provide economic benefits through an increase in jobs, personal income, and $2 billion in gross state product through 2030.

[20] The highs and lows of the RGGI market can be largely attributed to declining emissions and allowance oversupply, price controls, policy intervention, and the Clean Power Plan of 2015 by the Obama Administration.

The oversupplied market related to RGGI can be traced back to the transition from coal to natural gas as well as a weak economy during the time of implementation.

In the world of carbon offset credits, allowances are shared through a cap-and-trade system to limit harmful emissions and catalyze pollution cuts.

[22] RGGI states have witnessed positive economic activity and a decrease in emissions, electricity prices, and coal generation.

[32] Any party can participate in the RGGI CO2 allowance auctions, provided they meet qualification requirements, including provision of financial security.

[39] The RGGI states are currently undergoing a 2021 Program Review, which includes technical analyses and regularly scheduled public stakeholder meetings to solicit input.

[29] On December 20, 2005, seven governors from Connecticut, Delaware, Maine, New Hampshire, New Jersey, New York, and Vermont signed a memorandum of understanding aimed at developing a cap-and-trade program for power sector CO2 emissions in the northeastern and mid-Atlantic region.

[53] On December 7, 2022, the Virginia Air Pollution Control Board (APCB), voted 4–1 with two abstentions to initiate the repeal of state regulations governing its participation in RGGI.

[56][57] On August 21, 2023, the Southern Environmental Law Center on behalf of the Association of Energy Conservation Professionals, Virginia Interfaith Power and Light, Appalachian Voices, and Faith Alliance for Climate Solutions filed a lawsuit in the Fairfax Circuit Court challenging the APCB's authority to withdraw the state from RGGI.

Governor Youngkin's administration maintains that his office does have the power to remove Virginia from RGGI, and that the regional carbon market program is a "regressive tax" that burdens residents.

[58][59] The lawsuit alleges the Commonwealth's constitution was violated by the APCB who "suspended and ignored the execution of law and invaded the General Assembly's legislative power.

On July 13, 2021, Pennsylvania's Environmental Quality Board (EQB) voted (15–4) to adopt the rulemaking entitled "CO2 Budget Trading Program", otherwise known as RGGI.

Further, the Independent Regulatory Review Commission (IRRC), which evaluates whether proposed rules align with public interest, had approved the rulemaking on September 1, 2021.

119) attempted to prohibit DEP from taking actions surrounding carbon pricing programs, including RGGI, without legislative approval.

[77] In response, on April 4, 2022, the Senate attempted to override the Governor's veto but failed (32–7),[78] just one vote shy of the constitutional two-thirds requirement.

[86] Secretary McDonnell alleged that on November 29, 2021, DEP, acting on behalf of the EQB, submitted to the LRB for final publication in the Pennsylvania Bulletin the "CO2 Budget Trading Program Regulation".

On July 8, 2022, the Commonwealth Court granted the state Senators' request for a preliminary injunction enjoining DEP from implementing, enforcing, participating, and administrating the RGGI program.

The Court found that the Senators had demonstrated irreparable harm per se by raising a substantial legal question as to whether the regulations constituted a tax requiring legislative approval as opposed to a regulatory fee.

In addition, the Court found that the preliminary injunction would restore the status quo and that the Senators had showed a clear right to relief by raising substantial legal questions about separation of powers issues, as well as whether the allowance auction proceeds were an unconstitutional tax.

[93] In response, the Senators shortly thereafter moved to vacate the automatic stay of the Commonwealth Court's July 8, 2022, order that was triggered by DEP's appealed.

[94][95] On January 19, 2023, the Commonwealth Court dismissed DEP's petition seeking to compel LRB to publish the RGGI rulemaking as moot.

The Court noted that it was undisputed that the question of law raised by the petition was moot due to the subsequent publication of the rulemaking on April 23, 2022.

"[98] The statement urges the Pennsylvania General Assembly to take action, "Should legislative leaders choose to engage in constructive dialogue, the Governor is confident we can agree on a stronger alternative to RGGI," the statement further said, "If they take their ball and go home, they will be making a choice not to advance commonsense energy policy that protects jobs, the environment, and consumers in Pennsylvania.