In the transition to renewable energy, the US state of Hawaii is already punching above its weight, with a plan to reach 40 per cent by 2030, and a mandated goal of 100 per cent by 2045.

But a new report from the Rhodium Group and Smart Growth America has found that it would be cheaper and better for the economy of the Aloha State to double down on that trajectory, and shoot for as much as 84 per cent renewables by as early as 2030.

“It’s cheaper to go faster than to stick with our current targets,” said the report’s authors.

The report, commissioned by seed funding NGO Elemental Excelerator, says a target of 58-84 per cent renewables by 2030 could generate up to $US2.9 billion in new investment for Hawaii, $3.8 billion in energy system cost savings and a massive 70 per cent cut in power-sector oil demand.

Even shooting for 100 per cent by 2030 – although this would be more expensive than the 58-84 per cent scenario – would be cheaper than the current energy mix, the report said, under most oil price and renewable energy cost futures.

“The cheapest thing for ratepayers in Hawaii, and the smartest thing for the state’s energy security, and the best thing for the state’s economy, is for the state to go even faster,” said John Larsen, director at Rhodium Group.

Why? As the report’s title – Transcending Oil – suggests, a big chunk of the projected cost savings would come from a 70 per cent cut in oil demand. Hawaii’s electricity system is made up of a series of five isolated island grids that have traditionally burned fuel oil to make electricity.

“Our analysis shows that it is cheaper to use less oil in the electric sector than current policy mandates require through at least 2037,” the report says.

Meanwhile, innovation and scaled deployment of renewables have slashed the cost of solar and wind to the point that they are cheaper than oil in many applications, it says.

And recent clean power purchase agreements prices are lower than the price of conventional power plant fuels (See figure ES.2).

As to the how, the report outlines a number of ways Hawaii could ramp up its renewables ambition. But first, a bit of history.

Having legislated a 100 per cent renewable energy target in 2015 – it is the only US state to have a mandated 100% target – renewable energy now makes up 25 per cent of all the power generated in Hawaii, up from 6 per cent in 2008.

And, after some initial resistance, the state’s utility, Hawaiian Electric, is well and truly on board. Last year it claimed it could reach the 100 per cent target five years ahead of the 2045 deadline.

Nonetheless, there is much work to be done, and much ground to be made up, and the report recommends a number of ways to grease the wheels.

For the electricity sector, one of those would be changing energy market regulations to let utilities profit from cutting oil consumption. Essentially, a price on carbon for the power sector.

It also recommends lifting limits on the rollout of distributed energy – and establishing fair tariffs for rooftop solar – so those technologies can deliver all the system benefits they have the potential to provide.

And of course, the electrification of transportation is also key.

To this end, the report recommends boosting the state’s electric vehicle uptake, despite this also being well ahead of most other American states – Hawaii ranks second in the nation in EVs per capita.

On top of the existing government incentives, and the $US10,000 rebates offered by Hawaiian Electric – and the statewide goal of 100 per cent renewable ground transportation by 2045 – the report recommends adopting California’s ZEV standards to require more EVs be sold in the state by 2025.