Igiugig in-river power plant progresses
Village receives DOE grant for further enhancements to turbine system designed to reduce dependency on diesel electricity generation
Following a successful test last summer of a prototype in-river turbine power generation system, the U.S. Department of Energy has selected the village of Igiugig for a $1.5 million grant to further improve the design of the system. The village lies on a bank of the fast-flowing Kvichak River, not far from where the river flows out of Lake Iliamna in southern Alaska.
Ocean Renewable Power Co., a firm that specializes in hydrokinetic power generation systems, built a prototype device for placement in the river at Igiugig, with the eventual intention of replacing at least some of the expensive diesel-fueled power that the village uses. Hydrokinetic systems involve the placement of underwater turbine generators in river or tidal currents. The hydrokinetic device being tested at Igiugig has helical shaped turbine blades and sits anchored on the riverbed, with power cables connecting to an onshore power distribution system. ORPC tested the system at Igiugig during the summers of 2014 and 2015.
Local power“ORPC’s RivGen power system is allowing Igiugig to generate power locally without using diesel fuel or creating any carbon emissions,” said AlexAnna Salmon, Igiugig Village Council president, in response to the DOE grant. “Increasing our self-sufficiency is critical to our future and aligns with our core values of maintaining a subsistence way of life. This project is a model for other remote communities considering alternative power and will accelerate Igiugig’s path towards a sustainable energy solution, a long term goal of the village.”
“This is great news for Igiugig,” said U.S. Sen. Lisa Murkowski. “The Igiugig project is so important since the marine power device being developed there could be utilized in dozens of river villages statewide to reduce the high cost of energy. This truly could be the path to bringing affordable electricity to many rural villages if the efficiencies and the durability being pioneered in Igiugig can be replicated statewide.”
Design improvementsMonty Worthington, ORPC director of project development for Alaska, told Petroleum News that the DOE grant has a goal of enabling design improvements to make the turbine device easier to deploy, easier to retrieve, easier to maintain and more durable. Another objective is to make the components of the in-river device more modular in design, thus enabling routine maintenance to be carried out without the need for specialized expertise.
The Igiugig grant is one of three similar project grants and will cover the cost of the design and test planning for the system improvements. Next year DOE will select two of the three projects for further grants for system building and testing, Worthington said.
Although ORPC had conducted a successful test in 2014, deploying the system in the river and demonstrating that it would work, mismatches between the system’s electronics and the Igiugig power grid prevented the system from delivering power into the grid. Based on this experience, ORPC subsequently modified the electronic system. The company also made modifications to the device, to enable the device to be deployed in the river using one rather than two support vessels.
Some device improvements made with the assistance of a U.S. Department of Agriculture grant improved the device’s generation efficiency by around 30 percent.
“We designed and put a faring on it, to help direct the water through the correct part of the turbine,” Worthington said.
Power into the gridA second program of on-site testing in Igiugig during the summer of 2015 demonstrated that the modifications to the electronics worked effectively, with the system now able to hook into the Igiugig grid and displace some of the village’s diesel power.
“During full operations we were producing about a third of the load … that was also a big success,” Worthington said.
And, during the summer of 2015, a DOE grant supported work on the device’s control system, to enable the device to better accommodate rapid fluctuations in the river current resulting from turbulence in the river.
“We did a lot of testing through that program,” Worthington said. “It was all very successful.”
ORPC also mounted video cameras on the submerged river turbine to monitor any interactions between salmon and the device - the river is the site of a major salmon run each year. No impacts on the salmon were observed, with most salmon avoiding the fast moving water in the center of the river where the device was located and the few salmon that encountered the device swimming around it, Worthington said. Some small schools of smolt went through the device but appeared unharmed, he said, adding that ORPC plans more research into the smolt interaction.
The Igiugig project receives assistance through the Alaska Energy Authority’s Renewable Energy Fund, and through the Denali Commission. Under the terms of the state funding, everything had to be removed from the Igiugig site at the end of the summer testing. The turbine device was removed from the river by the end of September, with demobilization completed by the end of October, Worthington said.
Further testingThe next testing at Igiugig would target the generation of more than one-third of the village’s electricity load, with the possibility of turning off the village diesel generation system at times when the load is modest, Worthington said. However, the next field season will likely involve the testing of individual system components that come from the new design concepts. The whole system would then go in for further testing the following year, with the first fully commissioned device likely going into operation in 2018, Worthington said.
Ultimately, the in-river system can help stabilize the village’s power costs and tests conducted to date have already demonstrated that the sizable turbine equipment can be managed and operated locally, Worthington said. The concept is to leave the device in the river for much of the year, pulling it out for annual maintenance during the spring breakup, when ice tends to be carried down the river - current project funding includes the funding of a river-ice study involving the deployment of equipment in the river next winter.