Hawaii Electric Co. launched one of the biggest energy storage proposals in the country last week, quietly opening up requests for proposals of 60 to 200 megawatts of storage project to help manage the solar and wind power that’s wreaking havoc with Oahu’s island grid.

Friday’s announcement from HECO subsidiary Hawaiian Electric asks for proposals for “one or more large-scale energy storage systems able to store 60 to 200 megawatts for up to 30 minutes.” That means the utility is looking for projects of at least 60 megawatts, with an eye on several separate projects to meet different grid needs around the island, HECO spokesperson Peter Rossegg said in a Monday interview.

We want someone to do the whole project, from design to testing to commissioning,” he said. “Beyond that, we could own it, we could turnkey it, we could do it on a provider basis. We’re trying to cast as wide a net as possible.” The Kauai Island Utility Cooperative put out a much smaller RFP in March and received nearly 100 responses, he noted, and HECO is expecting many more for Oahu.

Indeed, Friday’s energy storage request is one of the biggest to date from a single utility, outside of the state-mandated procurements targets that California’s three big investor-owned utilities. It’s also on an accelerated timeframe: proposals are due by July 21, and HECO wants winning projects to lay out how they can be brought on-line by the first quarter of 2017.

"This is already -- I don’t want to use the word 'crisis,' but a severe emergency,” Rossegg said. The emergency he’s referring to is driven by the flipside result of solar and wind power’s success in Hawaii.

Nearly 11 percent of HECO’s customers have rooftop solar, and some neighborhoods are so solar-heavy that they’re causing backward power flows at the sunniest times of the day -- a situation that’s led HECO to put a halt on new PV interconnections, angering solar backers in the state. HECO is also facing system-wide pressures, as its already-expensive oil-fired power plants are being forced to ramp down production during solar's midday peaks, making their power even more expensive.

HECO isn’t looking to energy storage to shift that solar generation for hours at a time, however. Instead, it’s seeking “this middle range of about 30 minutes, where if there’s a drop-off in wind or sun, we can maintain our delivery of electricity while we bring other running reserves into play,” he said.

As for technologies, “we’re agnostic, as they say. There are a number of different technologies that could be deployed,” including batteries, mechanical flywheels, capacitors, compressed gas systems, pumped hydro storage or a combination of the above.

On the all-important question of costs and revenues, much remains still in development, he said. Friday’s announcement states that “potential contractors will be evaluated on the overall cost of their proposals and non-price factors such as design concept and feasibility, implementation and operational viability and operating flexibility.”

“It’s going to be a complicated decision, but we’re trying to come up with the best deal with our ratepayers,” Rossegg said. “The goal is to put together a fairly comprehensive RFP that would allow for a wide variety” of options for HECO to explore, he said. Any project selected with a cost of $2.5 million or more must be reviewed and approved by the PUC.

While the storage projects being requested are meant specifically to help stabilize the effects of wind and solar power, they aren’t tied to specific renewable energy projects, as Puerto Rico’s new storage regulations are, he added.

HECO’s new storage proposal comes just days after the utility received a severe rebuke from the state’s Public Utilities Commission, which rejected its integrated resource plan -- something that rarely happens in the utility regulatory world. In a series of orders issued last week, the PUC also demanded that HECO improve its approach to solar PV integration, develop a demand response plan, and improve grid reliability (PDF).

GTM Research analyst Cory Honeyman reports that the PUC’s orders require HECO to perform a distributed generation capacity analysis, make a distribution grid improvement plan, and create what it calls an “Advanced DER [distributed energy resources] Technology Utilization Plan,” described as: 

“Near-, medium-, and long-term plans by which customers would install, and utilities would utilize, advanced inverters, distributed energy storage, demand response, and EVs to mitigate adverse grid impacts starting at the distribution level and up to the system level.”

That sounds like a list of ingredients for what Greentech Media refers to as the grid edge, and for the most part, they belong to customers, not utilities. So far, HECO has a scattered few customers that have installed energy storage on-site, Rossegg said. HECO is exploring incentives to encourage these customers to store excess solar power at peak generation times, whether for system-wide or local grid stabilization needs.

Several government and corporate-backed grid-scale battery projects are underway in Hawaii, including Honeywell’s automated demand response pilot on Oahu, and the joint U.S.-Japanese research projects going on in Maui. Wind power developer First Wind has installed several megawatts of batteries at projects on Maui and Oahu, including the ill-fated Xtreme Power installation at Oahu’s Kahuku wind farm, which burned down in 2012.

The current Oahu energy storage proposal is aimed at larger-scale, grid-integrated projects, Rossegg said. But on a broader scale, HECO is also exploring the potential for distributed, customer-owned energy storage to play a role in its plans, he said.  

“Many of our rooftop solar customers already have small” devices like backup batteries installed at their homes or businesses, he said. Demand response and plug-in electric vehicle integration are also on HECO’s roadmap, he said.

Hawaiian Electric is also restarting its long-delayed plan to bring a smart meter to every customer by 2018, he said. In February, HECO picked Silver Spring Networks for a deployment that’s meant to include customer energy management portals, direct load control, volt/VAR optimization, prepayment options, and distributed generation integration, as well as smart meters.


To learn more about how utilities are integrating storage to manage distributed energy resources, join Greentech Media at Grid Edge Live in San Diego June 24-25.