Manufacturing photovoltaic panels in Hawaii might seem like a risky proposition given the competition from low-cost producers on the mainland and in Asia and Europe.
But Honolulu-based Greenpath Technologies Inc. is giving it a shot, producing a niche product at its facility in Kakaako that combines lightweight folding solar modules and a battery storage system that can provide power in remote areas.
Greenpath, which has been doing traditional rooftop photovoltaic installations in Hawaii since 2007, recently expanded into portable PV systems with the help of $150,000 from the government-funded Hawaii Technology Development Venture.
The company got a good response when it demonstrated its "Solar Transportable Alternative Energy Storage System" earlier this year at military and disaster relief exercises in the Philippines and Thailand, said Jim Chaney, Greenpath’s director of product development.
Greenpath also was one of just six companies selected from a field of 200 applicants to make presentations at a special session of the Asia Pacific Clean Energy Summit and Expo held earlier this month at the Hawai‘i Convention Center.
Greenpath said its product brings together several technological innovations that make it the most efficient portable PV system in the market.
The system’s folding solar panels are made by piecing together a series of individual high-efficiency solar cells made by a company called SunPower. The nonbreakable cells are laminated between sheets of clear plastic and stitched to a ripstop nylon backing that can be folded into a 6-pound package the size of a briefcase. One 125-watt panel can produce enough electricity to power a 60-inch flat-screen television, Chaney said.
The energy storage part of the system features lithium iron phosphate batteries that have a longer life and charging times that are 10 times faster than other batteries used in military applications, he said. The brain of the system is a charge controller/inverter that converts the solar energy to usable voltage for lighting, electric motors and other devices.
Up to 56 panels can be attached to a single controller for a maximum generating capacity of 7 kilowatts per unit. That’s about the equivalent of an average PV system on a single-family home. Energy from the solar panels is used as it is produced during daylight hours. Any excess energy can be stored in the batteries for use during cloud cover or at night.
At the Balikitan joint U.S.-Philippine exercise held in April in the Crow Valley on Luzon island, Greenpath’s solar power generator was able to run a water purification system producing about 5,000 gallons of fresh water a day, Chaney said.
"They were delighted we were able to power up their system in the middle of nowhere," Chaney said. "We exceeded the power generation that was needed at the end of the day. We ran the system and we charged the batteries so the next day we had a full bank to do it all over again," he said.
Following the demonstrations at Balikitan and the Crimson Viper exercise in Thailand in July, Greenpath received interest from four to five companies that want to do further testing of the system, Chaney said.
The SunPower cells used in the Greenpath panels convert 21.5 percent of the sun’s rays into electricity, the highest percentage of any solar cell in production, Chaney said. That compares with efficiency ratios ranging from 12 percent to 17 percent for standard PV panels. The higher efficiency of the Greenpath panels means they can be made smaller and lighter than panels made from PV film, a competing technology, he said.
There are five Greenpath employees working on the project, but that could grow if the company gets more orders, Chaney said.
Greenpath is fairly typical of companies funded by the Hawaii Technology Development Venture, said Harold Masumoto, the venture’s project director. Hawaii Technology Development Venture looks for technology companies usually with projects in the testing and evaluation stage that have potential for "dual" military and civilian use.
Hawaii Technology Development Venture is administered by the Pacific International Center for High Technology Research, which gets funding from the Department of Defense and focuses on locally developed technology in the areas of renewable energy, natural disaster management and agriculture.
