Shungnak power plant upgrades benefit the community and the solar projectPosted: May 11, 2021
Every rural Alaskan village has distinct characteristics, as well as some universal themes. Shungnak, AK, situated 150 miles east of Kotzebue on the Kobuk River, is unique in that large trees are abound and rolling hills act as a backdrop. Unfortunately, that far up the Kobuk, the river gets shallow making barge delivery an annual challenge. Like most all remote Alaskan villages, Shungnak residence are plagued with high utility costs, and costs get higher when fuel for heating and electricity has to be flown in.
In the September 2020 Ruralite issue, there was an article on the ongoing overhaul of the Shungnak power plant. Three engines with marine manifolds, three generators and all new automated switchgear were being installed. The new systems are now operational, but some of the finish work had to be postponed due to the harsh winter weather. As the weather warms up, Alaska Village Electric Cooperative (AVEC) field technicians will be back to work alongside local power plant operators. New decks will be constructed, pipes will be primed and painted, and the plant will be cleaned up inside and out.
The new diesel generators installed all have marine manifolds. This means that the exhaust manifolds on the engines are cooled using the same water-antifreeze mix that is used to cool the main engine blocks. The heat from the exhaust and engine block can then be transferred to other power plant buildings and community buildings. The City’s water treatment plant already had a heat recovery system in place. Now they can expect to get more heat from AVEC’s engines in the winter.
This past winter has seen a lot of preparation work on Northwest Arctic Borough’s (NWAB) Solar-Battery Project for Shungnak and Kobuk. Funded through USDA Rural Utility Service High Energy Cost Grant Program, NWAB awarded Alaska Native Renewable Industries, (ANRI), Huslia, AK, the contract to install a 224kW solar array and 235kW/383kWh battery storage system. NWAB, ANRI, and AVEC have been working out the details of how to install and operate the hybrid system for the greatest benefit to the communities. There is a 10-mile tie line from Shungnak to Kobuk that will allow for both villages to benefit.
Having a large solar array will offset fuel use by supplying additional energy generated from sunlight. Power from the solar array will either be used to directly supply community loads or be used to charge the battery. The diesel generators will work in conjunction with power created by the solar array and power stored in the battery to minimize the amount a fuel needed to keep the lights on. The diesel generators will still be the main source of power, but it is anticipated that during some summer days the diesels may be turned off completely for hours at a time.
The ability to make this happen relies heavily on programable logic controllers (PLCs), and high-speed communications between all the components in the system. AVEC took the first step in making this project possible by upgrading the power plant. Now NWAB’s Solar-Battery project will provide the renewable energy needed to reduce fuel burn. ANRI has hired Ageto Energy, Fort Collins, CO., to provide the controller to help integrate the solar panels being supplied by Daylight Energy Services, Fairbanks, AK, and the LFP battery from Blue Planet Energy, Honolulu, HI.
“The automated controls on the new engines will allow us to receive power from the new solar and battery system that will be installed this summer,” says Aimie Morgan, Electrical Engineer, AVEC. She is involved with the upfront design of new power installations and is responsible for the programming and testing before switching over to the new equipment. Diesel engines are most efficient when they are loaded at about 80% of their capacity. Understanding this, the state of charge of the battery, the battery charging and discharge rates, and the anticipated load from the community all go into programming the controls for efficiency, and reliability.
Without some kind of energy storage, installing a 224kW solar array on the small Shungnak-Kobuk grid would not be very efficient. Community loads in the summer average 125kW with peaks up to 200kW. Without storage, parts of the solar array would have to be turned off when there was not enough load to use the power. Morgan explains that in recent years, solar energy and batteries storage cost have decreased making it more affordable for projects of this scale in rural Alaska.
The benefits of having a large solar array, consolidates the maintenance and is collectively less expensive than having solar panels on individual residence. The communities of Shungnak and Kobuk plan to own and operate the solar array with the NWAB and sell the power generated to AVEC. Instead of buying fuel from international companies the money to buy power will be going back to the communities they serve.
As with all AVEC communities the single largest cost for producing power is the fuel required to run diesel generators. In most communities, the cost of fuel accounts for about 50% of the cost of electricity. In communities where fuel has to be flown in the cost is even higher. Water levels on the Kobuk usually rise with the spring thaw, drop through the summer, and rise again with fall rains. Often, barges can’t make it upriver in the spring because Hotham Inlet is still frozen when the river is high.
Constructing community scale solar is no small undertaking, especially in remote rural Alaska. Although resorting entirely to solar is unlikely in Shungnak, the community and environment will benefit from the new solar-battery installation. The joint effort between NWAB, Shungnak, Kobuk and AVEC makes way for lower utility costs and improving the technology for using more renewable generation in the future.