At the recent Chugach Electric Virtual Candidates Forum, candidates were asked to discuss a plan that has been proposed to achieve 100% renewable power not just for Chugach Electric, but the entire railbelt electric grid. Although the proposal has been presented to the Board of Directors of Chugach Electric, Golden Valley Electric, Matanuska Electric and Homer Electric, as well as the Alaska Energy Authority at Governor Dunleavy’s request, it became clear that none of the other candidates were aware of it.
Phase I of the plan calls for developing Pumped Energy Storage (PES) at the Eklutna Lake Hydroelectric Project in connection with the mitigation study which the operators of the Eklutna plant (Chugach Electric, Anchorage ML & P and Matanuska Electric) are mandated to conduct. The beauty of PES is that it is a closed-loop water flow system and can be designed to add water to the existing natural watersheds by utilizing wind power to pump water uphill to maintain reservoir levels that are more than sufficient for expanded power generation, drinking water consumption and healthy river ecosystems. The renewable energy used to move the water uphill is recovered when it flows downhill through the generators to produce electricity.
Another point to be made is that PES does not require megadams, such as what was proposed for Susitna-Watana in the past. PES gets the hydraulic head needed by the generators from the elevation difference between the reservoir and the power plant. This is already how Eklutna works, but the lake’s natural watershed limits how much power and drinking water are available. The power plant has a 40MW design capacity, but rarely runs at more than 10MW due to limits on the flow rate from the lake.
Governor Dunleavy has tasked the Alaska Energy Authority to conduct a formal feasibility study of the Eklutna PES+wind idea. That study is expected to take 6-8 months to complete. In the meantime, we are also taking a closer look at how the Eklutna PES system can mitigate the competing demands between energy generation, salmon recovery and Anchorage’s drinking water. If constructed using an aerial tram, it could reduce costs and impacts and improve access to remote areas of Chugach State Park. In addition, the Eklutna PES has the potential to help manage energy generation, assist with salmon restoration efforts and regulate Anchorage’s dwindling water supply from Eklutna Lake.