CHP and PA Tier II AECs: How Cogeneration Earns Credits

Combined heat and power systems are consistent generators of Pennsylvania Tier II Alternative Energy Credits — they run long hours at high capacity factors, and their output is already metered. This guide covers what the regulations actually say about eligibility and credit basis, how to calculate AEC volume, and when issuance begins.

What the credit is issued on

Two provisions govern this.

52 Pa. Code § 75.62(e) sets the qualification standard: a facility must demonstrate that it generates electricity from or conserves electricity through a Tier I or Tier II alternative energy source.

52 Pa. Code § 75.63 sets the credit basis. An alternative energy credit may be certified for each MWh of electricity generated by a qualified alternative energy system, and for each MWh of electricity conserved by a qualified alternative energy system or demand-side management measure.

Electricity generated, or electricity conserved. Measured in MWh. That is the entire basis.

PennAEPS, the program administrator, describes the same thing operationally: AECs represent 1,000 kWh of total electricity production from an alternative energy system, facility meter readings are recorded in PJM-GATS, and each MWh of generation produces one AEC.

Two eligibility pathways, set by system size

52 Pa. Code § 75.1 defines distributed generation as the small-scale power generation of electricity and useful thermal energy from systems with a nameplate capacity not greater than 5 MW.

That threshold is definitional, not conventional.

Under 5 MW — distributed generation. A CHP system below the threshold falls within the § 75.1 definition and is evaluated as a distributed generation system. AECs are issued per § 75.63 on metered electricity generated.

5 MW and above — demand-side management. A system above the threshold falls outside the distributed generation definition and is evaluated under a different Tier II category. Demand-side management is the applicable route, and § 75.63 provides for credit issuance on MWh of electricity conserved. The specific measurement basis for a given system is established during certification.

If your system is near the threshold, the pathway question should be settled before the application goes in, not after.

The calculation

Three inputs:

• Nameplate capacity (MW) × annual operating hours × capacity factor = annual MWh
• Annual MWh × 1 AEC per MWh = annual AECs
• Annual AECs × price per AEC = annual revenue

Two prices are worth modeling. The weighted average across the 2024–25 compliance year, per the PA PUC AEPS Annual Report, was $26.92/MWh. The Alternative Compliance Payment sits at $45.00 and functions as a practical ceiling.

### Worked example: 800 kW hospital CHP

0.8 × 8,760 × 0.85 = 5,957 MWh = 5,957 AECs

At $26.92/MWh: $160,362/year.

### Worked example: 2 MW manufacturing CHP

2.0 × 8,000 × 0.85 = 13,600 MWh = 13,600 AECs

At $26.92/MWh: $366,112/year.

### Worked example: 7 MW campus plant

7.0 × 8,200 × 0.50 = 28,700 MWh = 28,700 AECs

At $26.92/MWh: $772,604/year.

Note what capacity factor does here. The 7 MW plant at 50% produces roughly twice the output of the 2 MW plant at 85% — not 3.5 times, as nameplate alone would suggest.

Capacity factor is where estimates go wrong

Nameplate and operating hours are easy to state. Capacity factor is what separates a realistic projection from a fictional one.

Planning ranges by application:

These are planning figures, not substitutes for data. If the system has operated, the actual number is already in the generation meter — use that.

What pulls capacity factor down: thermal-following operation where electrical output is dictated by heat demand rather than electrical demand, scheduled and forced outages, and seasonal turndown.

What the meter measures

AEC volume equals the generation recorded by the certified facility meter and reported monthly to PJM-GATS.

That is the operative rule, and it resolves most of the questions people ask about measurement. Whether the recorded figure represents gross output at the generator terminals or net output at a downstream point depends on where the certified meter is installed — which is established during certification, not afterward.

Two consequences worth understanding:

Export does not change eligibility. AECs attach to generation, not to where the electricity goes. A system consuming all output onsite and one exporting a portion both generate credits on metered production. Net metering is a separate billing mechanism and does not govern AEC issuance. 52 Pa. Code § 75.13(i) reinforces the separation: a customer-generator eligible for net metering owns the alternative energy credits of the electricity it generates, unless a contract expressly assigns them elsewhere.

Meter placement is a certification decision. If you are specifying metering for a new system, or reviewing an existing installation ahead of an application, the meter's location and its revenue-grade accuracy both matter to what gets reported.

When issuance begins

AECs are issued from the complete application filing forward under § 75.63(i). Generation occurring before that filing does not produce credits.

For a system already running, this is the operative point: a CHP that has operated for years without certification remains eligible to be certified, but issuance begins at the complete application filing — not at commissioning. Prior operation earns nothing rather than accruing for later issuance.

The corollary is a running cost of delay. A 2 MW baseload CHP producing 13,600 AECs a year runs without earning roughly $30,509 per month at the $26.92 weighted average for every month before its complete application is filed. Those credits are never issued rather than deferred — issuance simply begins later.

Certification timing determines when revenue starts. It does not determine whether the system qualifies.

Heat recovery: what it does, and why it doesn't generate credits

This is the most commonly misunderstood point in the PA market, and the confusion has a specific source.

52 Pa. Code § 75.1 defines a distributed generation system as producing "electricity and useful thermal energy." Useful thermal energy is right there in the regulation. Reading that provision alone, it is easy to conclude that thermal output generates credits.

It doesn't. The § 75.1 language defines what kind of system qualifies — producing useful thermal is part of what distinguishes CHP from electric-only generation. The credit basis is set separately, in § 75.63, and it is MWh of electricity generated or conserved. Thermal output in MMBtu is not MWh of electricity and does not convert. The electric side is what becomes tradable, which is why we treat these as CHP alternative energy credits rather than thermal credits.

Definitional, not a credit basis. Two different provisions doing two different jobs.

A second source of confusion: other states do credit thermal output. The Massachusetts APS, for example, compensates CHP for useful thermal on a converted basis. Framing carried over from those programs does not apply in Pennsylvania.

What heat recovery does:

• Raises total fuel utilization from roughly 35% for electric-only generation to 65–80% for well-designed CHP
• Displaces boiler fuel, usually the largest single operating saving
• Supports federal Investment Tax Credit eligibility under IRA § 48
• Reduces Scope 1 and Scope 2 emissions for corporate reporting
• Contributes to EPA CHP Partnership recognition, a separate federal program

What it does not do:

• Contribute to AEC volume
• Serve as a Tier II qualification threshold. There is no combined thermal-electric efficiency floor governing AEC eligibility in Pennsylvania

Heat recovery belongs in the project's economic case. It does not belong in the AEC calculation.

Documentation

Certification requires substantiating that the system exists, operates as described, and that the applicant holds rights to the environmental attributes. Materials typically requested:

• Interconnection agreement with the electric distribution company
• Commissioning documentation and system specifications
• Meter specifications, location, and calibration records
• Generation history where the system has been operating
• Fuel supply documentation
• Air quality permit or exemption determination
• Documentation of environmental attribute ownership

That last item deserves early attention. Where a CHP system was financed or built under a power purchase agreement, energy services agreement, or ESCO contract, the environmental attributes may have been assigned to the developer or financing party rather than retained by the host. § 75.13(i) provides that a customer-generator owns the credits absent an express contractual assignment — so the contract governs, and it should be read before an application is prepared.

Frequently asked questions

Does a CHP system need to export to the grid to generate AECs?

No. AECs are issued on metered generation reported to GATS. Behind-the-meter systems serving onsite load generate credits on the same basis as exporting systems.

Can a CHP system generate AECs for periods before certification?

No. Issuance begins on the date a complete application is filed. Prior operation earns nothing rather than accruing for later issuance.

Does thermal output generate additional credits?

No. § 75.63 provides for credits on MWh of electricity generated or conserved. Useful thermal energy appears in the § 75.1 definition of a distributed generation system, but it is not a credit basis.

What if the system is above 5 MW?

It falls outside the § 75.1 distributed generation definition, which caps that category at 5 MW nameplate. Demand-side management is the applicable Tier II pathway. Measurement basis is established during certification.

How is capacity factor determined for a system not yet built?

Use the engineering estimate from the feasibility study or the manufacturer's projected operating profile. For an operating system, use actual meter data.

Who owns the AECs if the CHP was built under a third-party agreement?

§ 75.13(i) provides that a customer-generator owns the credits for the electricity it generates unless a contract expressly assigns them elsewhere. Review the PPA, ESA, or ESCO contract before applying.