Renewable energy is the rage everywhere, promising huge changes in our relationship with nature, as well as huge profits. It's downright romantic.

Projects and installations abound. Everyone agrees Hawai'i is a great energy laboratory, but we still don't have energy storage. Can we afford not to?

The wind, solar and cable planned for the Maui quadrangle won't succeed without storage. Storage makes renewables efficient — it transforms nonfirm into firm energy. The more renewables you feed into the mix, the more critical storage becomes.

Hawai'i's grid wasn't built to handle renewables. A cable carrying peak loads only part of the time is inefficient. We need to establish primary storage at the power source. That way, we can right-size our transmission systems for balanced power.

We need to select a storage technology suited for Hawai'i, get the stakeholders to buy into it, include it in our energy timeline and then build it. The main choices are batteries, hydrogen, compressed air and pumped hydro.

It's been said that he who invents a utility-scale battery will win the energy wars. But batteries and hydrogen, along with thermal, flywheel and magnetic storage, aren't ready for bulk storage, and compressed air won't work in our volcanic subsurface. Pumped hydro is a better bet — it recovers 75 percent of the energy consumed and is the most cost effective, even though it requires large acreage, elevation and capital.

With pumped hydro, you pump water up a hill with nonfirm power and then let it come down through a turbine to produce firm power when needed. It requires lots of fresh water, but it can meet demand in seconds and continue for hours. There is more than 90GW of pumped hydro built around the world, most of it outside the U.S.

GREEN ISSUES

On the Mainland, pumped hydro facilities may take years for regulatory and environmental approval. In Hawai'i, we can expect that to be much longer and much more excruciating. To get ahead, we're going to have to change this.

The real problem is NIMBY. If you want to develop pumped hydro, you can expect plenty of self-interested opposition, even from those who support renewables. It won't be easy — dams are a dirty word in Hawai'i.

No doubt moving earth and water affects the environment and calls for an EIS. But will the public support storage? Do we want the "enviros" (those who only claim to be environmentalists) to make our choices? We must decide wisely, or bulk storage — and ultimately our energy policy — will be sidetracked.

Two-way turbines are best, the kind that will do double duty — pump the water up, using electricity to do it, and then generate electricity as the water passes down through them. This technology is not futuristic; it's generally available.

If you have storage capacity equal to production, you can deliver quality power 24/7, but that's expensive. If you want to smooth out ramp speed, or when the wind stops, the birds fly over or the sun goes behind a cloud, you can get along on storage capacity of a lot less, perhaps 10 or 20 percent of production.

The same concept applies at home. If you install PV on your roof and send the excess to the utility, you'd like to get firm smooth power for your contribution. But we can't do this at scale unless there is storage at the source. Ideally, we could install distributed battery storage facilities every few houses. But that will be more expensive than bulk storage. Who will spring for the cost?

BEYOND ROMANCE

HECO's been considering pumped hydro at Ulupalakua, and is waiting for the development of a windfarm in that area. Sunpower of California is installing a game-changing battery-inverter system to smooth out Castle and Cooke's new PV plant on Lana'i and transform the renewables into reactive, generator plant quality power there. Both projects will push the envelope for Hawai'i.

For now, these seem to be the only storage projects in play. We need more. HECO is putting storage parameters into its Power Purchase Agreements, requiring renewable developers to invest in storage. This will result in higher quality power, for which HECO is presumably willing to pay more, but it remains to be seen how these requirements will pencil out for developers.

Let's not get lost in the romance of renewables. The success of energy policy depends on the infrastructure. If we want to bring these renewables online, we must also build sufficient storage. If we don't, we'll regret the bottleneck later.

Jay Fidell is a business lawyer practicing in Honolulu. He has followed tech and tech policy closely and is a founder of ThinkTech Hawaii. Check out his blog at www.HonoluluAdvertiser.com|/Blogs