The Intertubes are ablaze with news that the Earth holds 530,000 potential sites for pumped hydro energy storage in its hot little hands. If that sounds too good to be true, well, maybe. The devil is in the details. On the other hand, the number-crunching does indicate that a massive amount of energy storage capacity is already close at hand, even without fancy new breakthroughs in battery technology.
What’s The Big Deal With Pumped Hydro Energy Storage?
For those of you new to the topic, pumped hydro energy storage refers to pumping water uphill to a reservoir. After that, gravity does all the work. The stored energy — in the form of water — is let loose on turbines to generate electricity on demand.
Pumped hydro has limited utility when fossil fuels do the pumping. It is mainly used for load balancing, meaning the reservoir typically refreshes once a day.
With renewables on the scene it’s a whole new kettle of fish. In a mixed grid, pumped hydro facilities respond to shifts in wind and solar production as well as demand.
If that sounds pretty simple, it is. For all the hoopla over the latest battery technology, pumped hydro “water batteries” still account for more than 90% of global energy storage, and they are still the lowest cost, scaled-up form of energy storage.
530,000 New Sites For Pumped Hydro Energy Storage (Or A Fraction Thereof)
Until recently, the industry consensus was that suitable sites for new pumped hydro facilities are limited. The discovery of 530,000 potential sites is a real game changer.
Don’t get too excited just yet, though. The aim of the new study was to develop GIS-based algorithms that can speedily identify all of the potential sites for 0ff-river pumped hydro within an entire country or other large area.
The methods used in the study could also be applied to other opportunities, such as sites adjacent to lakes, abandoned mines or an ocean.
The key word is “potential.” Feasibility requires a more granular approach. The dirty work of weeding out the unsuitable sites is considerable. As the researchers note, their algorithms identified 530,000 sites that met basic physical characteristics. They did not vet the sites from a commercial, geological, hydrological, environmental, or heritage perspective. They did not address land ownership issues either, though they did exclude national parks and urban areas.
That doesn’t leave much wiggle room for actual pumped hydro development.
Still, the study does upend the existing industry consensus on global pumped hydro resources.
Lead researcher Dr. Matthew Stocks explains:
Only a small fraction of the 530,000 potential sites we’ve identified would be needed to support a 100 per cent renewable global electricity system. We identified so many potential sites that much less than the best one per cent will be required…The perception has been there are limited sites for pumped hydro around the world, but we have found hundreds of thousands.
For more details check out the full study in the journal Applied Energy under “Geographic information system algorithms to locate prospective sites for pumped hydro energy storage.”
Meanwhile, Energy Storage Over In The USA…
It’s no surprise that the US is among the world’s pumped hydro leaders, but there is plenty of room for improvement.
The Federal Energy Regulatory Commission recently toted up the numbers, which sound pretty impressive…
The Commission has authorized a total of 24 pumped storage projects that are constructed and in operation, with a total installed capacity of over 16,500 megawatts.
…until you realize get to this part:
…Most of these projects were authorized more than 30 years ago.
On the bright side, the US Hydropower Association paints a somewhat rosier picture:
The U.S. has more than 20GW of pumped storage capacity today, with facilities in every region of the country. Developers have proposed an additional 31GW, primarily in the West, to support an increasing amount of variable generation that is coming online.
In addition to new facilities, technology upgrades at existing sites can add significant capacity.
One good example is the Duke Energy’s pumped hydro makeover at its Bad Creek plant in South Carolina.
Bad Creek went into operation in 1991 (yep, almost 30 years ago) as the world’s first hydropower facility with a built-in pumped storage feature. The upgrade will add another 300 megawatts in capacity, partly by replacing the pumps — which were designed more than 30 years ago.
As more renewable energy enters the grid, the bottom line incentives for upgrades also increase. That’s the case in Michigan, where the 45-year-old Ludington pumped hydro energy storage facility is in the middle of a makeover.
Ludington currently has a capacity of 1,900 megawatts. When completed later this year, the rehab will boost capacity to 2,172 megawatts.
US Is Pumped Hydro-Curious
That’s small potatoes compared to what’s coming next. Last December, the US Department of Energy tapped two proposed hydropower facilities for a techno-economic study that will assess the value of pumped hydro energy storage with renewable energy. DOE explains:
…increases in variable renewable generation have changed how plants are operated and the value they provide to the grid. For example, instead of generating during the day and pumping at night, many plants now change operational modes multiple times per day and are relied on to provide quick ramping or frequency response.
If all goes according to plan, the results of the study will motivate additional pumped hydro development in the US.
One proposed project in the study, called Goldendale, would store energy from wind farms in the Pacific Northwest. It would add a total pumping capacity of 1,552 megawatts to the nation’s energy storage capacity in one fell swoop.
In Wyoming, the DOE will study the proposed Banner Mountain Project. That project weighs in at 400 megawatts in capacity and is also aimed at making the most of regional wind energy resources.
That’s more than enough to keep local TV sets humming along when the wind doesn’t blow.
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Image: Global pumped hydro energy storage sites via ANU.
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