Dear UH forum, I've not modeled a PV system that required compliance with 90.1 Appendix G (it's actually a 179d tax credit model), so I'm carefully reviewing the parts of 90.1 that I'm less familiar with. One of those parts is G2.4 (copied below).
In short, I do not understand what it's saying and how it impacts my preparation of the energy model.
- I know how to include energy costs / tariffs of various types
- I think it's saying that a cost credit should not be given for site-generated renewable energy (the owner just pays less to the utility)
- I don't understand why (as it seems to say) one cannot include energy from renewables in the Proposed model
- I don't know what is meant by a "backup energy source" and how that affects the Baseline model
All assistance appreciated. Thanks in advance.
G2.4 Energy Rates. Annual energy costs shall be determined using either actual rates for purchased energy or state average energy prices published by DOE’s Energy Information Administration (EIA) for commercial building customers, but rates from different sources may not be mixed in the same project.
Exception: On-site renewable energy sources or site-recovered energy shall not be considered to be purchased energy and shall not be included in the proposed building performance. Where on-site renewable or site-recovered sources are used, the baseline building performance shall be based on the energy source used as the backup energy source or on the use of electricity if no backup energy source has been specified.
