As we work to transition from our current generation mix which is heavy on fossil fuels, a common refrain is the need for electricity storage, with the sub-criticism that it’s too expensive and won’t scale. The first at least has the merit of being true, in that we will need storage, if not nearly as much as most people think. The other two are simply wrong.
Pumped storage hydro has far more resource potential than required for a fully decarbonized grid and it’s cheap per megawatt-hour (MWh) of storage. The downside is that it’s slow to build, capital intensive, and heavily regulated right now in the United States. The Department of Energy FAST program aims to change that.
The reason why storage isn’t as big a deal as many detractors claim has two big parts. The first one is that we don’t need storage immediately but as part of the end game. We can continue to run fossil fuel plants on rapidly diminishing capacity factors for three decades and have them provide the backup for dead periods. That gives us time to get storage right. The second is that with continent-scale grids with added HVDC and good markets, electricity will flow from where it is generated to where it is needed a lot more easily than most people realize or accept. Much of the analysis for expensive storage requirements comes from highly geographically constrained studies. And as Mark Z. Jacobson’s recent 100% Renewables by 2050 points out, even those geographically or politically isolated areas such as Japan or Israel will be much cheaper on a 100% renewable mix than they are now.
As for expensive, a recent DoE storage study limited to 20 years found pumped hydro’s current cost to be half the projected 2025 cost of lithium-ion batteries with projected reductions. And pumped storage facilities are expected to have 80-120 year lifespans with basic mechanical maintenance and replacement. The expensive part is building the reservoirs and the tunnels, and they last a very long time. As my Scottish developer contact, Mark Wilson of Intelligent Land Investments, pointed out, they’ve taken a 125-year land lease for their Red John project on Loch Ness.
And as for the inability to scale? Well, CleanTechnica published my assessment of the Australian pumped storage study recently, which found 100x more resource potential globally (250x in the US) just in sites outside of nature reserves and near transmission lines. There’s more than enough potential to find very good sites.
What’s holding it up? Regulation and financing for the most part. Even closed loop pumped hydro storage with reservoirs smaller than New York’s Central Park that don’t impact any waterways are treated as if they are the Hoover Dam. The new speedier process still takes years and millions of dollars to gain approvals. And they are capital intensive projects. The four I’m close to in Scotland and the US are closer to $5 billion in capital costs than not.
What’s causing those capital costs? A big part of it is that tunneling for miles or kilometers through rock takes time, and uses very expensive equipment. It also has a big labor component. Construction schedules lasting years before any revenue starts flowing add up as well. Anything which can speed construction of pumped hydro storage can shrink costs rapidly.
And this is where we get back to DOE’s FAST program. That stands for Furthering Advancements to Shorten Time, which has to make it one of the more contrived acronyms out of government, but the intent is good and FAST is a good word too. In April 2019 the DOE announced the competition at a hydropower convention. About 30 competitors put forward proposals and pitched them in October.
The winners were (quoted directly from the FAST competition site):
- Reducing PSH Excavation Duration, Cost, & Risk – Tracy Livingston and Thomas Conroy, Team Livingston, combined excavation equipment modifications and process optimizations to achieve up to 50% reduction in excavation timelines.
- Use of Modern TBMs for Underground Pumped Storage – Doug Spaulding, Nelson Energy and Golder Associates, proposed use of tunnel boring machines for underground excavation, which can decrease excavation time by 50% and reduce costs.
- Accelerating PSH Construction with Steel Dams – Gordon Wittmeyer, Southwest Research Institute, presented a modular steel concept for dams that cuts costs by one-third and cuts construction schedules in half.
- Modular Closed-Loop Scalable Pump Storage Hydro – Tom Eldredge and Hector Medina, Liberty University, presented a modular closed-loop, scalable PSH system with a capacity range of 1–10 megawatt, adaptable to sites without natural bodies of water.
For CleanTechnica readers who have been following along on my extended series on pumped hydro storage (available through archives here), one of those names will be familiar, Tracy Livingston. And people with deeper memories will remember that he was one of the principal innovators behind the space-frame, carbon-fiber wrapped wind turbine mast. GE ended up buying that company from Livingston and his CEO Thomas Conroy.
Livingston reached out to me after one of my early explorations to have a chat about his solution and the project he’s developing in the southwest of the United States. We’ve since gone deep and wide on the subject, having discussions with a floating solar expert from Australia on the potential for that technology in pumped hydro, and with a clean economy public relations CEO on how to ensure social license for the project, published here and here.
The second article in this two-parter is a deep dive into Livingston’s winning proposal, with a side helping of machine learning.