Green Power credits
To calculate your project’s required green power purchase quantity for the Green Power credit, choose one of the methods below according to your project type and calculation method. See these pages for more guidance on Green Power credits: NC EAc6 | CS EAc6 | Schools EAc6 | CI EAc4 | EBOM EAc4
For LEED-NC and Schools projects
Calculation Based on Design Energy Cost
Total Required Green Power Quantity = Design case total electricity usage X 35% X 2 years
- The Design case total electricity usage may be obtained from EAc1 calculations or energy model results. If an energy model was used to document compliance with EAc1, the data from the energy model must be used as the basis for determining the electricity consumption for this credit.
- Confirm accurate threshold percentage to achieve desired LEED points.
- LEED-NC and Schools projects will calculation 35% of the electricity use to achieve EAc6.
- Exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. will be achieved for all projects that purchase 100% of their electricity use from renewable sources.
Calculations Based on Default Electricity Consumption
Total Required Green Power Quantity = Size of project (sf) X default value electrical intensity based on building type X 35% X 2 years
- Confirm accurate threshold percentage to achieve desired LEED points. Exemplary performance can be achieved for all projects that purchase 100% of their electricity use from renewable sources.
Actual Consumption Calculation
If a project’s utility bills for a year’s worth of electricity usage are available, project teams can use this information to calculate the total required green power quantity.
Total Required Green Power Quantity = Actual electricity consumption (kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu.) X 50% X 2 years
- Exemplary performance will be achieved for all projects that purchase 100% of their electricity use from renewable sources.
For LEED-CI Projects
Design Energy Cost Method
Total Required Green Power Quantity = Design case total electricity usage X 50% X 2 years
- The Design case total electricity usage may be obtained from EAc1 calculations or energy model results.
- Confirm accurate threshold percentage to achieve desired LEED points.
- LEED-CI projects will calculation 50% of the electricity use to achieve EAc4.
- Exemplary performance will be achieved for all projects that purchase 100% of their electricity use from renewable sources.
Default Electricity Consumption Calculation
Total Required Green Power Quantity = Size of project (sq) X 8 kWh X 2 years
- Exemplary performance will be achieved for CI projects that double their purchase to 16 kWh.
Actual Consumption Calculation
If a project’s utility bills for a year’s worth of electricity usage are available, project teams can use this information to calculate the total required green power quantity.
Total Required Green Power Quantity = Actual electricity consumption (kWh) X 50% X 2 years
- Exemplary performance will be achieved for all projects that purchase 100% of their electricity use from renewable sources.
For LEED-CS Projects
Using Default Electricity Consumption Calculation
Step 1: Determine % of building that is CS: (Building Gross Square FootageSum of the floor areas of the spaces within the building including basements, mezzanine and intermediate-floored tiers, and penthouses with headroom height of 7.5 ft or greater. It is measured from the exterior faces of exterior walls or from the centerline of walls separating buildings, but excluding covered walkways, open roofed-over areas, porches and similar spaces, pipe trenches, exterior terraces or steps, chimneys, roof overhangs, and similar features. – Building Usable Square Footage) / Building Gross Square Footage X 100
- The calculation above uses ANSI / Building Owners and Managers Association (BOMA) Standard Z65.1-1996 to determine the CS electricity usage (based on square footage).
- If the calculation below is less than 15%, use 15% as the minimum input value. For example, if a project calculates the percentage of CS square footage as only 8%, you will need to run the calculations as 15% of the building.
Step 2: Calculate Total Annual Electricity Consumption: Result from Step 1 X default value electrical intensity based on building type
- Refer to the LEED Reference Guide table, copied at right, for default values based on building type.
Step 3: Calculate Required Green Power Quantity: Result from Step 2 X 35% X 2 years
- Confirm accurate threshold percentage to achieve desired LEED points.
- Exemplary performance will be achieved for all projects that purchase 100% of their electricity use from renewable sources.
Using EAc1, Option 1 Whole Building Simulation Data
Step 1: Determine % of building that is CS: (Building Gross Square Footage – Building Usable Square Footage) / Building Gross Square Footage X 100
- The calculation above uses ANSI / Building Owners and Managers Association (BOMA) Standard Z65.1-1996 to determine the CS electricity usage (based on square footage).
- If the calculation above is less than 15%, use 15% as the minimum input value. For example, if a project calculates the percentage of CS square footage as only 8%, they will need to run the calculations as 15% of the building.
Step 2: Calculate Total Annual Electricity Consumption:
Result from Step 1 X EAc1 Energy Model results for total building’s annual electricity use
Step 3: Calculate Required Green Power Quantity: Result from Step 2 X 35% X 2 years
- Confirm accurate threshold percentage to achieve desired LEED points.
- Exemplary performance will be achieved for all projects that purchase 100% of their electricity use from renewable sources.
10 Comments
EAc1 model and EAc6 calcs
Note that according to a 4/1/12 addendum from USGBC, "If an energy model was used to document compliance with EAc1: Optimize Energy Performance, the data from the energy model must be used as the basis for determining the electricity consumption for this credit." I assume most teams would do this anyway, but it's a useful clarification.
Purchasing REC's for international projects
We're doing a LEED 2009 NC submission for an over-seas university dormitory project. We're not familiar with a local RECA Renewable Energy Certificate (REC) is a certificate representing proof that a given unit of electricity was generated from a renewable energy source such as solar or wind. These certificates are able to be sold, traded, or bartered as environmental commodities, where an electricity consumer can buy the renewable energy attributes of electricty to support renewable energy, even if they are consuming generic grid-supplied electricity that may be supplied by nonrenewable sources. purchasing service. Can our project buy REC's from a US supplier, and will it be accepted for LEED credits?
Yes you can and it should be accepted.
Markus, Thanks for your reply.
can i take a credit for on site renewable energy for green power
I have PV panels on my project building. Can i deduct the annual energy produced from the pv panels when calculating the amount of Green Power to purchase?
If you have sold your RECs then you use the total electric consumption of the building. If you own the RECs (and agree not the sell them during the two year purchase period) then you can subtract the solar output from the total electric consumption.
We've provided Green Power to hundreds of international LEED projects - please let me know if I can help! lmalone@renewablechoice.com
Green Power and on-site renewables
Can a project pursuing this credit reduce it's green power RECA Renewable Energy Certificate (REC) is a certificate representing proof that a given unit of electricity was generated from a renewable energy source such as solar or wind. These certificates are able to be sold, traded, or bartered as environmental commodities, where an electricity consumer can buy the renewable energy attributes of electricty to support renewable energy, even if they are consuming generic grid-supplied electricity that may be supplied by nonrenewable sources. purchase by the amount of green power to be generated on site via a new solar array? If so, does this calculation occur automatically within the referenced LEED Online EAc1 template, or is this an additional manual subtraction after the EAc1 template (Table 1.8.2(b) - Energy Cost and Consumption by Energy Type - Performance Rating Method Complianceresult)? The template language ('subtracted from model results to reflect Proposed Building Performance') is not perfectly clear to me. Thanks. John
Yes. The renewable energy inputed in section 1.6 of the template shows up in table 1.8.2b. If you have an all electric building you could uise the Total value at the bottom of this table, but if you have gas consumption you would need to factor that out. The total electricity purchased for EAc6 would be the modeled kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu. minus the renewable kWh.
Marcus, that helped, thanks,. John
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