The solar battery revolution in Hawaii

Hawaii leads the nation in pairing solar installations with battery storage. In recent years, the large majority of new solar permits in the state have included a battery, a rate far higher than most mainland markets. In a place like California, that adoption is often driven by fear of rolling blackouts. Hawaii, as an island grid, generally has strong reliability and relatively few sustained outages. So what is actually driving Hawaii homeowners to add batteries at such a high rate?

The answer comes down to economics, not just backup power.

The end of full retail net metering

For years, Hawaii homeowners who installed solar could send excess power back to the grid and get credited at the full retail rate, a program known as net energy metering (NEM). That program closed to new Oahu customers in 2015. Read more about the history of that shift in our net metering explainer.

Without full retail NEM, the value of power you export to the grid is far lower than the value of power you use yourself. Current export compensation for new customers runs at a fraction of the retail rate, while retail electricity rates in Hawaii remain among the highest in the country. That gap is the single biggest reason batteries have become close to standard equipment on new Hawaii solar systems.

How a battery changes the math

Most homes only use a portion of their electricity during daylight hours, when solar panels are actively producing. Without a battery, all of the solar production a home does not use in real time gets exported to the grid, and paid back at that lower export rate rather than the retail rate the homeowner pays for electricity at night.

A battery captures that surplus midday production instead of exporting it, storing it for use in the evening when the sun has gone down and the home would otherwise be pulling expensive electricity from the grid. In effect, a battery lets a homeowner use their own solar production against their own electricity usage rather than trading it away at a steep discount.

The two-part return on a battery

A well-sized battery improves a solar system’s return on investment in two distinct ways:

1. Financial return. By shifting self-consumption of solar power from daytime to evening, a battery reduces how much expensive grid electricity a household needs to buy, which is a larger savings lever than exporting for a partial credit.
2. Resilience. While outages are not the primary driver of battery adoption in Hawaii the way they are in some mainland markets, having stored power on hand still matters. A battery keeps essential circuits, refrigeration, lighting, medical equipment, internet, running during a grid interruption without the noise or fuel logistics of a generator.

What this means for sizing a system

Because the goal has shifted from “produce and export as much as possible” to “produce, store, and use as much as possible,” system design in Hawaii looks different than it did a decade ago. A battery-inclusive design typically weighs:

• How much of your daily usage happens in the evening versus during daylight hours
• Your home’s overall energy consumption pattern across a full day
• Whether you want enough stored capacity to cover overnight use, an outage, or both
• Future loads, such as an EV or additional appliances, that will draw on stored power

This is a meaningfully different design exercise than sizing panels alone, which is why a proper energy audit matters more now than it did under the old net metering structure.

Choosing the right battery

Not every battery is designed the same way, and the right choice depends on your home’s usage pattern, your roof and electrical panel configuration, and whether backup during an outage is a priority alongside daily savings. Options like Tesla Powerwall and Enphase battery systems each have different strengths in terms of output, expandability, and how they integrate with existing solar arrays.

The bottom line

The rise of solar batteries in Hawaii is not primarily a story about blackout anxiety. It is a direct response to the closure of full retail net metering and the fact that Hawaii’s retail electricity rates remain some of the highest in the country. Capturing your own solar production for your own evening use, rather than exporting it at a fraction of its value, is where the real savings live today.

For more on how storage fits into a modern Hawaii solar system, see our overview of solar batteries, or get a free estimate to see what a battery-inclusive system would look like for your home.