Solar installations straining system

As a result of explosive growth of rooftop solar photovoltaic (PV) installations in 2013, Hawaii’s electric utilities are warning they are reaching the saturation point in some areas.

As a result of explosive growth of rooftop solar photovoltaic (PV) installations in 2013, Hawaii’s electric utilities are warning they are reaching the saturation point in some areas.


Meanwhile, Big Island PV system installers said they’re beginning to see demand for their services slow as competition mounts.

A combined total of 17,609 installations were performed across the state last year, adding more than 129 megawatts in capacity to the Hawaiian Electric, Maui Electric and Hawaii Electric Light Co. grids. That represents a 39 percent increase compared to what was added to the system in 2012.

As of Dec. 31, Hawaiian Electric companies’ grids had taken on a total of 40,159 photovoltaic system interconnections, generating a total capacity of 300 MW. That includes 5,355 installations on Hawaii Island, producing up to 38 MW of electric capacity. That number represents 7 percent of Big Island HELCO customers.

According to Hawaiian Electric, 96 percent of the state’s solar installations use net metering, a program started in 2001 with the intention of encouraging the adoption of rooftop solar. The program allows customers with rooftop solar to receive full retail credit for energy they generate and send to the electric grid. Then, they use that credit to offset the costs associated with energy they take from the grid when solar power doesn’t meet their needs, such as at night or on cloudy days.

The “unprecedented rapid growth” in rooftop solar created a situation where some neighborhood circuits host large amounts of PV systems, with an increasing number of those circuits reaching points where the connected PV systems generate more capacity than is used by the entire circuit.

“We have, this past year, encountered a situation where the amount of PV that people are applying to connect to the circuit reaches a point where we have concerns, either with the voltage quantity or safety issues,” said Jay Ignacio, HELCO president. “We’re currently at the level (on the Big Island) where 10 percent of our circuits have reached that point, where we have to tell people applying to add PV that they need to wait.”

Ignacio explained circuits that generate more electricity than is being used by customers can create situations where voltage is increased and damage can be done to electronic equipment in homes and businesses, including computers and other appliances that might contain sophisticated electronics.

“If there’s more generation than energy being used, the energy needs to go some place. … This is a difficult technical issue, and we’re not aware of another utility in the world that has addressed it. There’s no model for us to follow, no resource for us to tap into. We’re really creating new frontiers on this,” he said.

Ignacio admitted the delays because of the problem known as “transient over-voltage” can be very frustrating to customers, but said as of right now, it’s the only way to ensure the electric grid remains safe for all customers.

HELCO engineers are entertaining several different ideas for how to handle the problem, but have yet to settle on anything concrete.

One way might be to set up a system where HELCO can use appliances connected to the circuit to create more of a load when it encounters an over-voltage. By transferring the excess energy into something such as a water heater, the system can balance itself out. But, he said, many of those appliances were never designed for such a purpose, and setting them up to be used in such a way could be problematic.

Another concept being explored is a large battery bank that can store excess energy. That too, has its drawbacks, however.

“The economics of such a system just may not play out,” he said.

Marco Mangelsdorf, president of Hilo-based photovoltaic system installer ProVision Solar, said the delays customers are experiencing have not yet made a major impact on his business, but he can see the writing on the wall.

“I have maybe a handful of clients who have been put on hold because of a saturated circuit, with a number of customers who have been waiting a year,” he said. “I’m not able to proceed with a sale because of saturated circuits. But, I have a couple of colleagues on Oahu, areas with much higher population, where they’re running into this. They say that it could be 50 or 60 percent of their sales are getting the red light from HECO.”

Meanwhile, he said, last year’s boom in solar sales attracted a lot of competition.

“When we started in 1998, we had maybe five or 10 competitors. Now, there are dozens and dozens, including a number of folks from other islands. The competition is beyond fierce. And as the PV pie continues to shrink, which is what we’re witnessing, we know that the competition is going to be unsustainable at this profit level. I think we’re going to see a consolidation in the industry, where a number of major and minor players will be necessarily dropping out because of the contracting pie,” he said.

Despite the gloomy outlook, however, Mangelsdorf said he has been impressed with HELCO’s response to the technical issues helping slow his industry’s growth.

“The utility companies have been having a more and more challenging time to be able to accommodate this explosive growth in PV,” he said. “What HELCO’s been doing, and I solute them for this, is they are pushing the limits as to just how much an isolated island utility can actually accommodate in terms of non-firm power being generated and fed into the grid — not just big plants, but including mom-and-pop, residential systems.


“We are all participating in a grand experiment. How far can a utility go in accepting non-firm power? As of last year, more than 40 percent of the kilowatt hours sold by HELCO came from renewable resources. And that has progressively been going up.”

Email Colin M. Stewart at