Hawaii Needs More Rooftop Solar To Make EVs Economical

Electric vehicles in Hawaii should be a no-brainer. The limited island geographies make battery “range anxiety” either easy to solve through a few public charging stations or practically non-existent. The high gas prices make driving economically painful. And the abundant renewable energy there (solar, wind, and geothermal) means lot of potential for cheap, clean electricity.

But the U.S. Department of Energy “eGallon” website shows a critical disconnect. In most states, the equivalent “miles per gallon” of using electricity instead of gas for driving results in huge savings. The average U.S. gallon of gas costs $3.52, while the equivalent cost in electricity is $1.27. Pretty nice amount of savings, no?

Report Cover PageWell, in Hawaii, we have an outlier result. The extremely high cost of electricity (most is generated from burning imported diesel), coupled with the high cost of gas, results in an unfortunate comparison: $3.79 for a gallon of gas vs. $3.75 in equivalent electricity costs. So you’ll save 4 cents per gallon going electric! Pretty weak.

That’s where rooftop solar comes into play. For residents of Hawaii with these systems, they can pay almost nothing in electricity through the state’s net metering program.  This arrangement makes the savings from going electric probably greater than in almost any other state. In fact, in researching the report “Electric Vehicle Paradise” for Berkeley Law and Maui College last year, almost everyone I talked to who had purchased or leased an EV in the islands had rooftop solar.  And they were motivated to go electric because they were producing too much solar from their roof.

That’s why our report recommended that Hawaii’s utilities, especially Hawaiian Electric (HECO), remove barriers to installing rooftop solar. At the time, the utility privately claimed to me that they really didn’t have any barriers, such as expensive interconnection studies. But shortly after we released the report they began clamping down aggressively on rooftop arrays with these studies.

But change is in the works.  In response to an aggressive state public utilities commission directive, HECO now plans to go 65% renewable by 2030, which is great.  But the utility wants to impose a fixed monthly charge of $55 on solar customers, which could undermine the economics of going solar.  And HECO still needs to get rid of phony “interconnection studies” that can cost thousands of dollars for a property owner trying to install solar.

With rooftop solar, particularly in Hawaii, it’s not just about cleaning the electricity system — it’s about driving cleaner, too.  Not to mention that more EVs ultimately boosts energy storage in the islands from repurposed electric vehicle batteries. So let’s hope HECO does the right thing, because the whole movement to a cleaner, cheaper energy system in Hawaii starts with solar.


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