Hawaiian Electric residential VPP economics

Hawaiian Electric is three regulated utilities under one brand: Hawaiian Electric on Oahu, Hawaii Electric Light on Hawaii Island, and Maui Electric on Maui, Lanai and Molokai (Hawaii PUC). Together they serve about 474,241 customers (Power Facts). Kauai has its own cooperative and is not covered here. Each island grid stands alone, and Hawaiian Electric buys power from its own plants and from independent producers under PUC-approved contracts.

Every deep dive on this site has one feature that changes how its economics read. On the mainland, a home battery’s best future often lies in a wholesale market: an independent system operator (ISO) such as PJM, CAISO or ERCOT pays for capacity and energy, and the question is whether the utility and the market can both pay for one device. In Hawaii that question never comes up. No island has an ISO, a capacity auction or a market price. The utility is the only buyer, and the PUC decides what it pays.

That makes the rate sheet the market. A kWh of rooftop solar has three possible values. Used at home, it avoids the retail rate, about 47¢ on Oahu in October 2026 (October effective rates). Exported under Smart Renewable Energy (SRE) Export, it earns 13.5¢ in the day, 32.9¢ from 5 to 9 p.m. and 18.9¢ overnight (SRE Export rates). Exported credits only offset the bill and expire at the annual true-up.

On Maui, midday solar earns just 6.6¢, the lowest credit in the state, against a retail rate of about 47¢. That gap is the battery’s whole business case. A grid with this much solar needs energy moved from noon to evening, and the export credits are set low at midday so that households move it themselves.

About 29¢ of Oahu’s retail rate is the energy cost recovery factor (ECRC), a monthly pass-through of fuel and purchased-power costs. It rose from about 18¢ in early 2026 to 29.06¢ in October, when a 500 kWh Oahu bill reached $246.44 (Oahu ECRC filing), up from about $195 in February (February ECRC). Because export credits are fixed for years, every swing in oil lands on the value of a stored kWh.

Time-of-use rates would widen the gap further. The PUC’s advanced rate design study tested daytime, overnight and evening prices in a 1:2:3 ratio from February 2024 and plans to make them the default for all customers on a schedule still to be set (PUC advanced rate design). Today no residential time-of-use or EV rate is open to new customers (Hawaiian Electric FAQ); Shift and Save closed on February 1, 2025 (Shift and Save).

BYOD Plus runs under Rule 33. The household picks a start time from the utility’s options, and the battery must discharge its committed kW for two hours every day. Exports in that window are credited at the higher of the retail rate or the underlying tariff rate. For non-net-metering customers that is paid as a fixed monthly credit: (retail rate − export rate) × committed kW × 70% × 2 hours × 30 days. On Oahu, with a 5 kW commitment, that is about $30 a month on top of the evening SRE credit. Leaving within five years means repaying a prorated share of the upfront incentive.

Uptake is slow so far. BYOD Plus had 334 customers and 2.78 MW by June 2026, 195 of them income-qualified (monthly CER report), against a 50 MW statewide cap with 25 MW reserved for low- and moderate-income (LMI) households. Its predecessor, Battery Bonus, enrolled 6,724 customers and 50.76 MW before closing (Battery Bonus); our Battery Bonus case study follows that money.

Water heaters are the other device. Under the first grid services purchase agreement, OATI and its partner Shifted Energy install free controllers and Hawaiian Electric pays monthly credits (Power Partners program page); Shifted Energy puts a typical home at $3 a month (Shifted Energy). The fleet delivers about 2.5 MW of capacity reduction, load build and fast frequency response (Resource Innovations). With nothing to buy, it is cash-positive from the first month.

With no market to sell into, stacking in Hawaii means combining utility tariffs. The rules are simpler than on the mainland, and the main limits are about not paying twice for one battery.

Stacking needs care, depending on M&V methodology. BYOD Plus verifies a battery from its own interval data and a two-hour discharge at the assigned start time, while SRE credits are measured at the meter. A battery that discharges into the house during the window lowers what the meter shows as export, which is why the fixed credit assumes 70% of the committed kW reaches the grid. Aggregator contracts have been fragile: Swell’s two agreements were terminated in January 2025, stranding 1,241 participants (Hawaiian Electric’s 2026 CER filing).

Take one hypothetical home with rooftop solar under SRE Export and a new Powerwall 3 at $15,647, the cost our Residential VPP Calculator uses; installed costs in Hawaii often run higher. The battery commits 5 kW to BYOD Plus and delivers 10 kWh into the evening every day, charged from midday solar that would otherwise be exported. Each delivered kWh is worth about the retail rate, whether it serves the home or is exported in the window, minus the daytime credit given up to store it.

Self-supply alone recovers about 69%. On Oahu, stored solar is worth about $1,180 in the first year. BYOD Plus adds $2,000 upfront, lifting the ten-year total to about 82% of cost; part of the stored-solar value arrives as BYOD Plus’s monthly credit. Maui’s low midday credit makes storage worth more there, about 98%.

Income-qualified homes come closest. The LMI adder doubles the upfront pay to $4,000, and the battery recovers about 94% in ten years. That may help explain why most BYOD Plus enrollees so far are income-qualified; backup power is the rest of the case.

Oil decides the margin. At January 2026 fuel prices, each shifted kWh on Oahu was worth about 22¢ instead of 32¢. The federal residential credit ended in 2025, and Hawaii’s state credit covers solar systems, with new limits from 2027 under Act 24 (Hawaii Department of Taxation); we do not count either for the battery.

Hawaiian Electric expects BYOD Plus to grow to about 850 applications and 9.75 MW in 2026, and says commercial projects will take a larger share (CER goals report). Default time-of-use rates, when they arrive, would raise the evening value of every stored kWh (PUC).

The future of VPP to grow at scale will depend on multiple assets in unison at any given site: solar, battery, water heater and, once time-of-use rates open, EV charging, dispatched together and measured as one resource. In Hawaii, the battery and water heater programs already run, but under separate agreements with separate verification.

Related: the Hawaiian Electric C&I deep dive, the Hawaii Battery Bonus case study, the Puerto Rico battery case study for another island grid, and the PG&E residential deep dive for a mainland solar market. To run other equipment, use the Residential VPP Calculator.