A power distribution control system that could shut down appliances or lower air-conditioning thermostats for participating customers to meet power demands during peak periods, a battery storage system and smaller fuel-powered generation units have been thrown into the mix of options as Maui Electric Co. considers alternatives to a proposed 69-kilovolt transmission line in South Maui.
Earlier this month, Mayor Alan Arakawa, a frequent critic of MECO, applauded the utility's change in direction regarding the installation of a proposed transmission line from the Maalaea power plant to a Kamalii substation. Utility officials brought up the new alternatives at community meetings about the proposed transmission lines earlier this month.
The utility has been holding public meetings on the utility line for the past two years, which it said was needed to meet the energy needs of a growing South Maui community. The region had the third highest energy load, or 23 percent of the island's total energy use as of April, MECO officials said in late August.
Over the past two years, MECO has hosted public meetings to get community feedback on a number of options for the transmission line connecting the Maalaea power plant to a Kamalii substation.
In December 2011, the utility solicited community input on options including an all-overhead mauka corridor, an all-overhead double circuit existing route, an overhead and underground Piilani Highway route, an all-overhead Piilani Highway route and a hybrid route corridor.
"Much has changed in electricity usage and electricity generation" for the region since the need for the transmission line was established, said Kau'i Awai-Dickson, MECO spokes-woman.
The addition of power from Auwahi Wind Energy in Ulupalakua, reduced demand due to conservation efforts and a "substantial increase" in photovoltaic use have "reduced the risk to the South Maui system," she said.
"They have not eliminated it," Awai-Dickson added.
She said that "this change in environment, coupled with feedback from the community, has opened the possibility for other options."
Those options include reducing energy use and adding energy storage or generation in South Maui, she said. The alternatives being considered:
* Demand response. This is a power-use management system in which participants partner with the utility - for monetary compensation - to quickly reduce their electric demand. Using smart meters, the utility could control selective appliances, such as turning off a water heater or reducing the thermostat on an air conditioner, during periods of peak demand, Awai-Dickson explained.
* Distributed generation. Small-scale fuel-powered generating units would be put in where power is needed, as opposed to the concept of a central generating station such as the Maalaea power plant, she said. The unit would be a firm source, fed maybe by diesel or another yet-to-be-determined fuel, and would be near customer usage. This would eliminate the need for long power transmission lines from a central power source, like Maalaea.
* Battery energy storage system. The battery system would provide power when needed and during low voltage situations, said Awai-Dickson.
She said the exact type of battery has not been determined as yet.
Doug McLeod, energy commissioner, said that there are lead acid batteries that are good for long-term storage and lithium-ion batteries, which can release a lot of watts for short periods. The batteries can store 10 megawatt hours of power, a small amount. He noted that peak loads on the island are 200 megawatt hours.
"Batteries are a localized solution," he said Monday.
Awai-Dickson said that "the solution could be one or a combination" of the three options.
"It's important to note that the cost to our customers will play heavily on our decision," she said. "It's a priority for us to not only provide reliable electrical service and find ways of using more clean sources of energy but doing so in a way that is as cost-effective as possible."
The proposed transmission line was not a cheap prospect as well. A 2013 Integrated Resource Planning Report, filed in June by MECO's parent, Hawaiian Electric Co., put the five-year cost of the Kamalii substation and transmission line at $31.5 million. McLeod indicated that the utility was going to have to raise rates to fund the "old style" proposal.
"We are excited about change of the direction, and we are waiting to see the details," said McLeod, adding that the mayor's administration is looking for "follow through."
Awai-Dickson said that the utility is "currently researching and evaluating" the options and hopes to present its findings to the public at meetings early next year.
The Public Utilities Commission needs to approve the plan.
* Lee Imada can be reached at email@example.com.