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Harnessing rooftop PV potential of warehouses
This credit developed from conversations in the Warehouse-Distribution Center Adaptation Working Group (the work of which is seen in the W-DC (warehouse design & construction) credit requirements in the LEED rating system drafts). Working group members strongly believed that the large roof sizes of these space types presented excellent opportunities for generating renewable (specifically, solar) energy. Due to the typical size of these roofs, the capacity of the roofs to generate power often far exceeds the buildings’ ability to utilize the power. In order to optimize the use of the resource, the energy produced would be distributed to the local power grid. Financial and regulatory hurdles have to date limited the widespread adoption of this strategy, known as distributed generation for rooftop photovoltaic projects.
After many conversations with the Energy & Atmosphere Technical Advisory Group, the credit evolved into the version seen here. EA TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system. input strengthened the credit to prohibit counting the power from solar facilities in this credit for the current EAc6: Green Power; to prevent the project from claiming the environmental attributes; and to broaden it to all space types beyond warehouses and distribution centers.
While the solar facility size/generation capacity thresholds do not have associated points, since (as a pilot credit) this has not been incorporated into the broader collection of LEED credits. The multiple thresholds, however, are the way in which the EA TAG can monitor how well a project performs against the requirements. The three thresholds are listed in ascending level of difficulty and are intended to reward more points with higher levels of power generation.
Credit Submittals
General
- Register for Pilot Credit(s) here.
- Register a username at LEEDuser.com, and participate in online forum
- Submit feedback survey; supply PDF of your survey/confirmation of completion with credit documentation
Credit Specific
- Copy of structural engineer verification, indicating that the building and roof are capable of supporting the anticipated solar loads.
- Copy of the signed rooftop lease agreement that shows compliance with the solar size/capacity and schedule requirements. A letter of intent is not acceptable.
- Copy of the grid interconnection approval, signed by the local utility
- Indication of total kW size, module type, number of modules, and nameplate rating of module.
- Proof that the building owner does not have a claim to the Renewable Energy Credits from the project (in the roof lease agreement).
Additional Questions
- With what utility are is the project engaged for the distribution?
- What is the minimum and maximum allowable size of distributed rooftop generation systems in the project area?
- Is the project participating in a state- and/or utility-sponsored program? If so, which one?
USGBC
Excerpted from LEED Pilot Credit Library
Pilot Credit 56: Renewable Energy – Distributed Generation
Intent
To support the installation of distributed renewable energy generation.
Requirements
This credit is available for pilot testing by the following LEED project types:
- All Building Design & Construction rating systems
- All Existing Buildings: Operations & Maintenance rating systems
Obtain structural engineer verification that the design and constructing of the building is capable of supporting planned photovoltaic technologies on the roof.
AND
Enter into a rooftop lease agreement committing to provide renewable, solar energy for distributed generation1 that meets the following requirements:
The agreement must specify an expected commercial operation date for the solar facility that is within 18 months of building construction completion.
Capacity of the solar facility shall be determined by summing the photovoltaic module (PV) power listed on the nameplates of the PV modules in units of watt and then dividing by 1,000 to convert to kilowatt (kW).
The PV module power ratings are for Standard Test Conditions (STCSound transmission class (STC) is a single-number rating for the acoustic attenuation of airborne sound passing through a partition or other building element, such as a wall, roof, or door, as measured in an acoustical testing laboratory according to accepted industry practice. A higher STC rating provides more sound attenuation through a partition. (ANSI S12.602002)) of 1000 W/sq. meters solar irradiance and 25oC PV module temperature.
While projects may use electricity from the solar facility, the facility cannot count towards the achievement of EAc2: On-site Renewable Energy (BD&C rating systems) and EAc4 On-site and Off-site Renewable Energy (O&M rating systems).
The building is prohibited from receiving or claiming ownership of environmental attributes generated by the on-site renewable energy facility. Environmental attributes shall include, without limitation, any and all carbon credits, renewable energy credits, emissions reductions, reporting rights, offsets and allowances attributable to the electric energy produced by the solar facility.
1 Distributed generation is the use of small-scale power generation technologies located close to the load being served. These systems reduce the amount of energy lost in transmitting electricity because the electricity is generated very near where it is used. Distributed generation systems are typically smaller than 10,000 kW. For purposes of this credit, distributed generation systems must deliver power to the utility distribution grid rather than to an individual building.
2 As a pilot credit, project teams will earn one point regardless of the threshold achieved. USGBC is indicating multiple thresholds to display the credit’s intended structure.Potential Technologies & Strategies
Organizations
LEED Pilot Credit Library
The homepage for the LEED Pilot Credit Library. The LEED Pilot Credit Library is intended to facilitate the introduction of new prerequisites and credits to LEED. This process will allow USGBC to test and refine credits through LEED 2009 project evaluations before they are sent through the balloting process for introduction into LEED.
Articles
Foundations of LEED
Background for the LEED Pilot Credit Library is provided in this foundational document.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC.
9 Comments
Green Power Purchase for LEED NC 2009
Is there any on-going requirement beyond the initial 2 year contract for a green power purchase?
The Green Power purchase requirements are EA Credit 6, so you're best to verify the requirements there. As I recall though, the obligation is for a 2-year contract.
(This pilot credit forum for EApc56 is focused on large distributed generation projects, not green power purchase contracts.)
EBOM Pilot Credit 56
Does the building need to be a warehouse? Can the PV system be in the parking lot in lieu of a rooftop? Please advise.
As noted in the overview, one intent of the credit is to optimize the use of an underutilized resource (i.e large rooftops) to support distributed generation. Other developed areas of a site such as a parking lot (as well as non-warehouse space types) can therefore also qualify, so long as the other criteria are still met. Undeveloped land on the site should not be utilized for this credit.
Thanks Aaron,
Another thing I just noticed is that it may conflict with EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. EA credit 4, which is a 6 pointer that we are pursuing. Do you think that's "double dipping" if we do both?
Thanks
Thanks for your question. EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. EAc4 is for clean energy consumed by the project: "...for using renewable energy either through the purchase of green power (RECs and carbon offsets), the use of onsite renewable systems, or a combination of the two."
This pilot credit, by contrast, specifically targets situations where supplying clean energy to the project is not feasible. Instead it acknowledges a benefit to the environment by supporting larger-scale clean energy delivered 'wholesale' directly and exclusively to the grid even though there is not a direct benefit to the individual project.
The LEED project cannot claim the "clean" attributes of the energy from the pilot credit's renewable energy system. So in short, no double-dipping allowed!
Aaron,
You've helped me so much with understanding the subtle differerence between the pilot and the EAc4. Since I know our project uses energy from the PV's I will go for EAc4 and not PC56. You've been a big help, thanks for your time.
Maria
Dear Aaron,
We are also planning to go for large PV system over 500 kWp.
But due to the risk of leaks and ease of maintenance it might move to a free area of the project boundary.
We are not sure whether we can get it connect to the grid as a Net metering due to the legislation issues of our country.
In that case we might get registered as an Independent Power Producer which will make it unable us to claim the credit for On site renewable energy under NC 2009.
In that case would we be getting the benefit from this credit?
I don't know your location or the net metering regulations there, but a system designated as an IPP can qualify for this credit. In that case, the clean power attributes wouldn't be usable by the LEED project, in order to avoid double-counting. As for it being in an area other than the roof, other developed areas of a site such as a parking lot can also qualify so long as the other criteria are still met. Undeveloped land on the site should not be utilized for this credit.
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