Onsite green power is not subject to traditional generation, transmission, and distribution losses, so it's more efficient that grid electricity. This benefit is reflected in your ENERGY STAR score and Source EUI by a site-to-source conversion factor of 1.0 rather than the 2.8 which is the current value that is used for grid-sourced electricity.
The electricity use from onsite solar and wind must be reported and included in your total energy consumption. The use of onsite green power is part of your building's energy consumption (i.e. the energy requirement of your property).
While you get this energy benefit regardless of whether you own the Renewable Energy Certificates (RECs), you will only get the benefit to your emissions if you own the RECs.
For more information, refer to our technical reference on Green Power.
*Note, prior to Aug 2019, properties who did not own the RECs were treated as if their onsite green power was grid electricity. This change was made to more accurately reflect the actual energy use at the property.