Qualifying Ground Source Heat Pump in the APS

The eligibility criteria and requirements for qualifying a ground source heat pump system in the Alternative Energy Portfolio Standard.

General Eligibility Criteria

Eligibility Criteria

All Renewable Thermal Generation Units must:

  • Generate useful thermal energy using sunlight, biomass, biogas, biofuel or naturally occurring temperature differences in ground, air or water
  • Deliver a useful thermal load to a facility located in Massachusetts
  • Have an operation date January 15th 2015 or later

A ground source heat pump uses compression and evaporation to transfer thermal energy from the ambient underground or water environment to a thermal load as Useful Thermal Energy. There are several requirements in order for ground source heat pump Generation Units to be eligible.  For a list of eligibility requirements, please see the APS regulations, beginning on page 20. Please note while utilizing ground source heat pumps for cooling is allowed, only the Useful Thermal Energy used for heating is eligible to generate AECs. 

To submit a Statement of Qualification application (SQA), please visit the APS Renewable Thermal Application Portal.

For more information on renewable thermal in the APS, please visit our APS Statement of Qualification webpage.

Size Classification and Multipliers

Size Classification and Multipliers

The size classifications for ground source heat pump Generation Units are as follows:

Technology

Small

Intermediate

Large

Ground source heat pump

Output capacity less than or equal to 134,000 Btu per hour

Output capacity between 134,000 and 1,000,000 Btu per hour

Output capacity greater than or equal to 1,000,000 Btu per hour

The multipliers for ground source heat pump Generation Units are as follows:

Technology

Small

Intermediate

Large

Ground source heat pump

5

5

5

In addition to the above multipliers, any ground source heat pump installed in a building shall be eligible for an additional multiplier of 2 (added to the base multiplier) if the building meets any of the following criteria:

  • achieves Home Energy Rating System (HERS) rating of 50 or less
  • meets the Department of Energy definition of “Zero Energy”
  • achieves PHIUS+ Certification by the Passive House Institute US (PHIUS)
  • registers as a Certified Passive House Building or an EnerPHit Retrofit by the International Passive House Association (iPHA)

More information on these multipliers can be found in the Guideline on Multipliers for Renewable Thermal Generation Units.

Small ground source heat pump Generation Units

Eligibility Criteria 

All small ground source heat pump Generation Units are subject to the following eligibilty criteria:

  • the ground source heat pump Generation Units must supply 100% of a building’s total annual heat load and non-renewable supplemental heat sources are prohibited
  • be certified to the International Organization for Standards Standard
  • have a COP equal to or greater than the following:

Small GSHP System Type

Cooling Energy Efficiency Ratio*

Heating Coefficient of Performance**

Closed Loop Water to Air

17.1

3.6

Open Loop Water to Air

21.1

4.1

Closed Loop Water to Water

16.1

3.1

Open Loop Water to Water

20.1

3.5

*EER = (full load EER + part load EER)/2

**COP = (full load COP + part load COP)/2

  • be installed by licensed contractors and/or plumbers.  Meet National Electric Code and manufacturer’s specifications. Conform with all regulations.
  • have blowers that are multi-speed or variable-speed, high-efficiency motors.
  • use compressors that are two-stage, multi-speed, or variable-speed drives, unless they are water-to-water units. Single-stage water-to-water systems are eligible with additional provisions
  • have a minimum depth of 150 per 12,000 Btu/hr if vertically bored closed-loop systems
  • have a grout conductivity equal to or greater than anticipated earth conductivity of the drill site up to 1 Btu per hour-foot-degree Fahrenheit if closed-loop system
  • have at least 15 feet of separation between closed-loop bore holes
  • must comply with MassDEP Guidelines For Ground Source Heat Pump Wells, and Underground Injection Control Program
  • open-loop system wells must comply with MassDEP Private Well Guidelines or MassDEP Guidelines and Policies for Public Water Systems
  • be installed in conformance with 313 CMR 3.00: Registration of Well Drillers and Filing of Well Completion Reports
  • standing column wells must include bleed circuits and drywells
  • all systems must supply 100% of a building’s total annual heating; non-renewable supplemental heat sources are prohibited
  • all closed loop systems must be installed and tested in accordance with subsections 4 and 5 in section 1 of the “Closed-Loop/Geothermal Heat Pump Systems, Design and Installation Standards”, published by the International Ground Source Heat Pump Association. Pressure testing may also be hydrostatically pressure tested in accordance with ASTM Standard F2164
  • direct exchange heat pumps, which circulate a refrigerant through a closed-loop copper-pipe system, are prohibited

More information on these criteria can be found in the APS regulations, beginning on page 20. 

AEC Calculation

Small ground source heat pump Generation Units are eligible for preminting, which allows the owner to receive 10 years of AECs upfront. After reviewing and approving the application for the Generation Unit, DOER will calculate the 10 year strip of AECs to be minted. The calculation is as follows:

More information on this calculation can be found in the Guideline on Metering and Calculating the Useful Thermal Output for Renewable Thermal Generation Units – Part 1 (Calculations for Small and Intermediate Generation Units).

Application Requirements

All small ground source heat pump Generation Units are required to submit the following in their Statement of Qualification Application:

  • Site and facility information
  • Contact information
  • Equipment specifications
  • Design specifications
  • NEPOOL GIS information
  • AEC Service Agreement (optional, attachment)
  • Home Energy Rating System (HERS) certification (optional, attachment)
  • Affidavit of Zero Energy (optional, attachment)
  • Passive House certification (optional, attachment)

    Intermediate and large ground source heat pump Generation Units

    Metering Information

    Intermediate and large ground source heat pump Generation Units will receive AECs, based on their metered production, on a quarterly basis. Generation Unit owners should review the Guideline on Metering and Calculating the Useful Thermal Output for Renewable Thermal Generation Units – Part 2 (Metering for Intermediate and Large Generation Units) for information on metering requirements.

    Application Requirements

    All intermediate and large ground source heat pump Generation Units are required to submit the following in their Statement of Qualification Application:

    • Site and facility information
      • Site plan (attachment)
    • Contact information
    • Equipment specifications
      • Equipment arrangement drawing (attachment)
      • Annotated product literature for all major equipment (attachment)
    • Design specifications
      • Description of system controls and sequence of operations (attachment)
      • A process flow diagram (attachment)
      • A one line electrical diagram (attachment)
    • NEPOOL GIS information
    • AEC Service Agreement (optional, attachment)
    • APS Renewable Thermal Performance Workbook (attachment)
    • Independent Verifier request form (attachment)
    • A metering plan including a list of meters (attachment)
      • Annotated product literature for each APS meter (attachment)
      • Annotated product literature for the Data Acquisition System (DAS) (attachment)
    • Certified Performance Data Construct (intermediate Generation Units only) (attachment)
    • System Information Data Sheet
    • Home Energy Rating System (HERS) certification (optional, attachment)
    • Affidavit of Zero Energy (optional, attachment)
    • Passive House certification (optional, attachment)

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