Hawaiian Electric Company Battery Bonus info:
- https://www.hawaiianelectric.com/products-and-services/customer-renewable-programs/rooftop-solar/batterybonus
- On-going program for Oahu and Maui where ratepayers can install new PV+Battery, retrofit additional PV+Battery, and/or install just a Battery to an existing DER system and receive multiple financial incentives to offset system cost for committed performance capacity
- Basic assessment:
- Existing NEM customers have highest value proposition
- CGS, CGS+, and CSS customers also benefit greatly (in many cases, CSS customers can be switched to CGS+ for Battery Bonus) in initial and long-term incentives
- Since some program details for years 4-10 of the 10-yr. program are not yet defined by the utility, non-NEM customers can switch to new “BYOD” program to retain value at “year 4” if concerned for years 4-10
- Non-NEM customer systems must be “right sized” for solar self-consumption to retain optimum value (PV system produces daily kWh needs, and battery capacity minimum = PV daily production – daytime consumption in kWh)
Battery Operating Modes Will Optimize Value
- All batteries have storage efficiency losses from converting power from DC to AC, AC to DC, etc. The FranklinWH FHP has a roundtrip efficiency (RTE) of 89%
- This means that stored energy must be assessed against alternative options and value propositions for each program participant
- PV generation is the primary asset of value for energy independence, and batteries help to retain that value most especially for non-NEM customers by offsetting retail import costs (”self consumption”) and eliminating losses from reduced utility crediting (store rather than export)
- NEM Customers:
- With or without a battery, all exported energy is credited at retail rates (100% return)
- Because of RTE losses (89% return), primary value of battery for NEM customers is for backup use case
- Battery Bonus program requires discharging battery for 2hrs. while grid tied, but the initial incentives make this a good option (majority of battery cost is covered) for that 2hr. window of time, offsetting system cost
- Since NEM customers have a higher energy value return from exported PV (100% return > 89% RTE) than from the battery, they should only discharge battery while grid tied to fulfill Battery Bonus requirement (see graphic on next page)
- Non-NEM Customers Export Crediting (vs. Retail Rate)
- Oahu - 15.07¢/kWh (43.43¢/kWh) – exported PV is credited at roughly 34.7% of retail rates (89% RTE > 34.7%)
- Maui - 17.16¢/kWh (43.26¢/kWh) – exported PV is credited at roughly 39.7% of retail rates (89% RTE > 39.7%)
- Non-NEM customers have a higher energy value return from stored energy than from exported PV, so “right-sizing” of the battery is very important in order to prevent any PV export losses to the utility during the day
Battery Bonus Operating Mode Details
Please contact Jay Zarghami for any questions jay.zarghami@franklinwh.com