Hawaii utility commits to highest-in-nation level for rooftop solar on circuits, but can grid handle it?

Hawaii utility commits to highest-in-nation level for rooftop solar on circuits, but can grid handle it?

A pitched battle that stopped a solar boom in Hawaii is over, at least temporarily. Rooftop installations are increasing again for the first time in two years.

The biggest utility in the Aloha State, Oahu-based Hawaiian Electric Co., or HECO, has reopened a blocked pathway to adding more local photovoltaics. It will allow new rooftop systems on crowded circuits that the utility had all but shuttered 18 months ago. The utility at the time said the move was needed for safety reasons, as a bounty of solar came on the grid and threatened stability.

HECO now says it can handle more solar and is clearing a backlog of applications from homeowners who have been waiting to get rooftop systems connected. The utility has processed requests from 2,543 customers on Oahu, with 206 still in queue. HECO has cleared 333 applications on Maui and 336 on the Big Island.

Solar companies said some households have been waiting two years to connect rooftop PV systems, while HECO said the delays were shorter.

"We are committed to increasing the amount of solar, rooftop-distributed generation, to triple it in the coming years," said HECO spokesman Peter Rosegg. Of the crowded circuits, he said, "We are looking, based on experience and experimentation, to find a higher level [of PV] that's safe."

The policy change follows pressure from the state's Public Utilities Commission. It also takes place as HECO, which is part of Hawaiian Electric Co. Inc. (HEI), seeks to merge with renewable power developer NextEra Energy Inc. in a $4.3 billion deal. The PUC will have to approve the marriage before it can proceed.

HECO promised the PUC it would eliminate its installation waiting list by the end of April. That appears to have quickly had an effect. Applications to add rooftop systems on Oahu -- the most populous island -- increased last month versus a year earlier, the first time in two years that there's been a bump, said Marco Mangelsdorf, president of ProVision Solar on the Big Island. He tracks the data.

At the same time, there remains a question about how the utility will change its policies and rate structure amid a surge toward solar, which has cut into its traditional customer base. HECO doesn't earn money from electricity sales but must justify the need for any plants or projects that it wants ratepayers to fund.

"It's very important to keep the utility alive," Mangelsdorf said. "There is no existing or near-term or even midterm alternative to the utility company as we know it today, and talk of significant, let alone mass grid defections, is more hyperbolic than reality-based."

Can circuits handle a new threshold?

Hawaii leads the nation in the portion of utility customers with rooftop solar. It's now at about 13 percent, and that's likely to rise when HECO clears the backlog of applications, Rosegg said. Locally based solar generates about one-quarter of the peak load on Oahu.

Solar adoption ballooned in 2012 and 2013 because the Aloha State uses fuel oil to make electricity, and prices for it jumped during that period. Electricity bills for moderate-sized houses averaged $250 or more per month.

Then HECO in September 2013 largely barred new solar on any circuit at 120 percent of daytime minimum load, or the low point of the total power used by customers connected at the site. The utility at the time said that step was necessary because energy from rooftop photovoltaics exceeded neighborhood demand. Excess power could flow back into substations or to nearby circuits, it argued, potentially damaging equipment.

Some critics charged that the utility was trying to protect its profits as residents flocked to solar. The policy change, while in force, cut in half the number of new rooftop PV systems added each month on Oahu compared to a year earlier.

After testing at the National Renewable Energy Laboratory showed it was safe, HECO now says in most cases it will allow solar on circuits until they reach 250 percent of daytime minimum load. That would be the highest level in the nation. Those wanting to install solar must have systems with inverters that can quickly switch off power if they detect voltage exceeding normal levels.

A group representing solar installers welcomed the news, while saying it was circumspect about HECO's plans.

"They were slapped down pretty heavily by the PUC," said Robert Harris, spokesman for the Alliance for Solar Choice, a coalition of companies including SolarCity Corp. and Sunrun Inc. "Right now, they're trying to figure out what to do next.

"I don't see how they can argue anything else, because publicly they've said they can go up to 250 [daytime minimum load]," Harris added. "They are licking their wounds and being temporarily good, but I think they're trying to figure out what their next step is."

PUC President Randy Wasa in February asked HEI's president and CEO, Alan Oshima, to sign a letter saying that the utility will link customers with solar, Harris said.

"Simply stated, the policy is that the HECO companies have an affirmative duty to interconnect a potential customer ... where that project does not affect circuit or system level security and reliability," the Feb. 27 document signed by Wasa and Oshima said.

But Mangelsdorf, president of ProVision Solar, said there will have to be changes made to accommodate more renewable power on much of Hawaii.

HECO saying it will allow circuits to go to 250 percent of DML is laudable, Mangelsdorf said, "but there's no way that the grid that we know it today, tomorrow or in a year is going to be able to handle all circuits, or most circuits going to 250. It's too much power."

Source: E&E Publishing LLC

Smart Grid Bulletin March 2019

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