The $45 ACP and Why Tier II REC Prices Are Surging

The economics of Pennsylvania's Tier II REC market are driven by a single powerful mechanism: the Alternative Compliance Payment (ACP). Set at $45 per megawatt-hour, the ACP represents the penalty that Load Serving Entities must pay to the Pennsylvania Public Utility Commission if they fail to procure sufficient Tier II RECs to meet their annual compliance obligations.

This $45 ceiling creates a natural price cap for the market — no rational buyer would pay more for a REC than the penalty for not having one. What is remarkable is how far prices moved toward that ceiling over the past five years. On the PA PUC's weighted-average series, Tier II credits averaged $1.92/MWh in reporting year 2020 and $26.92/MWh in reporting year 2025 — a 1,300% increase in five years. That repricing has largely run its course for now: RY2025 was essentially flat against RY2024's $26.47, up 1.7%.

To put that appreciation in context, a facility with an LED retrofit saving 1,000 MWh annually would have earned about $1,920 per year at the RY2020 weighted average of $1.92/MWh — hardly worth the administrative effort. At the RY2025 weighted average of $26.92/MWh, the same 1,000 MWh generates about $26,920 annually, roughly $25,000 more per year for identical energy savings. The difference between registering in RY2020 and registering now is the difference between a rounding error and a material revenue stream.

Several factors are driving this dramatic appreciation. First, the AEPS Tier II compliance percentages have been steadily increasing, requiring LSEs to source a larger share of their supply from qualified resources each year. The current requirement of approximately 10% of total retail sales represents an enormous volume of RECs needed statewide. Pennsylvania's total retail electricity sales totalled 136,554,641 MWh in RY2025, so the 10% Tier II obligation came to 13,655,464 AECs — about 13.7 million, trending toward 14 million as load grows.

Second, the supply of certified Tier II RECs has not kept pace with this growing demand. The retirement of several large waste-coal generation facilities removed millions of MWh of Tier II supply from the market. At their peak, waste-coal plants contributed over 8 million Tier II RECs annually. Today, remaining waste-coal capacity has declined to a fraction of that output, creating a structural supply deficit.

Third, Act 114's in-state requirement, effective since 2020, eliminated the ability of LSEs to purchase cheaper Tier II RECs from neighboring PJM states. Previously, waste-coal and hydro facilities in West Virginia, Ohio, and Maryland could supply Pennsylvania's Tier II market, keeping prices depressed. The in-state restriction focused all demand on Pennsylvania-based resources, accelerating the supply-demand tightening.

The demand side of the equation is equally important. Pennsylvania has over 60 competitive electricity suppliers and seven EDCs, all of whom must meet Tier II obligations. These entities compete for a limited supply of RECs, driving prices upward in a classic supply-constrained market. The PUC's annual compliance reporting shows that some suppliers have been forced to make ACP payments in recent years because they simply could not procure enough RECs at any price.

Forward market dynamics further support the bullish price outlook. Forward contracts for Tier II RECs — agreements to purchase credits for future compliance years — are currently pricing at $28-35/MWh for 2026-2027 delivery. This forward premium reflects market expectations that the supply-demand imbalance will persist or worsen, as compliance obligations continue to grow while legacy supply sources continue to decline.

For building owners, this market dynamic creates an exceptionally favorable environment. With the RY2025 weighted average at $26.92 and the ACP ceiling at $45.00, there is significant room for continued appreciation. Even if prices stabilize at current levels, the revenue from REC sales represents a meaningful addition to the financial returns on energy efficiency investments.

The risk of price decline is limited by several structural factors. The AEPS compliance obligations are enshrined in state law and would require legislative action to reduce. The retirement of waste-coal plants is permanent — these facilities will not return to operation. And the pool of unregistered efficiency projects, while large, will take years to fully develop and bring to market.

Historical data from other state REC markets provides additional context. Maryland's Tier I solar REC market experienced similar dynamics — rapid price appreciation followed by sustained high prices until supply eventually caught up with demand. The key difference with PA Tier II is that supply growth is inherently slower because it depends on building owners discovering and registering their projects, rather than developers building new generation capacity.

The strategic implication is clear: issuance begins at the complete application filing under § 75.63(i), so a qualifying project that goes unregistered is running without earning — nothing is forfeited, because nothing was ever issued, but the earning period starts later. Building owners should act promptly to certify their energy efficiency projects and begin generating RECs. Those who wait risk eventually entering a market where increased supply has moderated prices — capturing less value from the same underlying energy savings.

For portfolio-scale opportunities, the math becomes even more compelling. A multi-facility operator with 10 buildings across Pennsylvania, each saving 500 MWh annually, generates 5,000 RECs per year. At $26.92/MWh, that's $134,600 in annual revenue. Over a 10-year project life, cumulative REC income exceeds $1.3 million — and that's before accounting for potential price appreciation.