New Energy  Future 

Pumped Storage Hydropower:

A new tool to power Alaska’s ~100% renewable energy future

Introduction

To meet, and ideally exceed, Paris Accord and zero emission by 2050 goals and avoid triggering critical tipping points, we need to think bigger, faster and smarter!  

In Alaska, an oil state, industry produces more than 50% of the state’s greenhouse gas emissions.  Nevertheless, transitioning our in-state energy use to more affordable renewable sources cannot be neglected.  

Alaska has the second highest energy costs in the nation.  Many remote communities are still dependent on diesel fuel that can cost upwards of $10 a gallon to generate electricity.  Alaska’s high energy prices, reliance on expensive fossil fuels, and vulnerability to climate change make our energy transition especially important. At the same time, our small and scattered electricity grids make the integration of variable renewable energy especially challenging.

Even Alaska’s largest energy grid — the Railbelt — has a much smaller capacity than most lower power plants in the lower 48. The smallest grids serve single villages. This means that if a wind or solar system is not producing energy, that energy cannot be imported from elsewhere. Instead, a fossil fuel plant must be ramped up or down instantly to match. At the same time, multiple sources of power must be kept running at all times to maintain reliability. This leads to inefficient use of fuel, wasted fuel (when a plant is running just for reliability), and continued dependence on fuel.

Windmills at sunset

Wind is the most promising renewable energy source in Alaska, where our northern latitude and high winter energy demand limit the percentage that solar can provide. Yet wind is the most variable energy source, varying not on a predictable day/night cycle, but on scales from minutes to months. 

To integrate more renewable energy, we need a cost-effective means to store it when supply is out of sync with demand.  Alaskan grids have made innovative use of storage technologies, including chemical batteries, flywheels, and using excess wind power to displace diesel heat. However every Alaskan grid that has broken the 50% renewable energy threshold has done it with the extensive use of hydropower. A hydroelectric reservoir provides a backbone of non-fossil fuel stored energy that can be released to match the fluctuations in other power sources. 

New hydro projects could be the answer for some communities. Yet for both topographic and environmental reasons, traditional hydropower isn’t feasible or desirable everywhere. Pumped Storage Hydropower (PSH) — a closed loop system that can create water-based energy storage at many different scales, could fill this gap for many Alaskan electric grids.

PSH is a tried and true, low-cost technology that already provides 95% of global energy storage.  It’s a semi, or fully closed-loop system with far fewer downstream effects on fisheries, wetlands and riparian ecosystems than conventional hydroelectric plants.  In some cases, PSH may even help restore salmon habitat or mitigate negative impacts from warming streams.   

ALICE has been working on the PSH concept for Alaska for several years.  A member of our energy working group, Kerry Williams, developed a concept to convert the existing Eklutna Hydropower Plant to PSH.  In 2020, the Governor ran across the concept on the Alaskans Know Climate Change page and requested a report comparing “the pros and cons” of Eklutna PSH with Susitna-Watana Hydro.  

In collaboration with several partners we produced Pumped Storage Hydropower: a path to lower energy costs for Alaska’s new energy future in Feb. 2020.   The PSH-renewables concept has steadily gained support in Alaska since its release.   

 

What’s Next?

Railbelt

In partnership with Native Village of Eklutna, we are seeking funding to analyze the benefits of Eklutna PSH for ongoing salmon recovery efforts, energy generation and to ensure the long-term drinking water supply for Anchorage in a rapidly warming world. 

Rural

In late 2020, ALICE was awarded a Denali Commission grant to take the PSH concept to rural Alaska. Our technical team is working to identify potential prospects for around 30 wind-PSH microgrids to serve more than 80 remote Native Villages. There’s still much work to be done but adding PSH to the storage and renewable energy integration options available in remote communities could eliminate the need for expensive diesel fuel and reduce rural energy costs significantly.

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