Rational Cause for Optimism: Pumped Hydro Energy Storage

02 | 01 | 22

Amidst the noise, haste, and chaos of modern life there are more positive developments for humanity than one might think. Everyone focuses on the disasters of the climate crisis, and while those do motivate our daily work, we also feel it’s important to highlight the hopeful – the very real innovations pushing our clean energy movement forward. The purpose of this new column on our blog is to explore noteworthy causes for optimism that we observe from ReVision Energy’s front row seat in the renewable energy arena.

by Co-Founder Phil Coupe

We begin with earth-shattering (pun intended) news about how to solve the difficult problem of wind and solar “intermittency” – the fact that the sun does not always shine and the wind doesn’t always blow. Modest progress is being achieved today with battery storage, primarily lithium ion type , whereby the battery in a home or small business can store excess solar power generated when the sun is shining, and then release that power when the sun goes down at night or behind clouds during the day. This approach is effective for relatively small-scale storage systems in single buildings or vehicles, but how can we have enough stored power to replace the electricity generated by a gas-fired power plant at the utility scale? Ultimately this is what we need to wean ourselves off the coal, oil, and gas-fired electricity that we’ve been relying on for more than a century.

‘Pumped hydro’ is an old-school technology with colossal potential to become one of the most important solutions to intermittency in the dawning new age of renewable energy + storage. Here’s a diagram of how it works:

Would you be surprised, perhaps elated, to learn that there is roughly 100 times more potential for pumped hydro energy storage than what is needed for a global transition to 100% renewable energy?!

According to researchers at Australian National University’s College of Engineering, there are 616,000 naturally occurring places on earth where a pumped hydro energy storage (PHES) facility could be installed. We can even repurpose old fossil fuel sites to pumped hydro, like this former Kentucky coal mine – creating jobs and a cleaner local environment. In the atlas of potential PHES sites below, notice the density in northern New England:

If we zoom in a little closer, we can see that Maine, New Hampshire, and western Massachusetts have significant potential to develop PHES facilities:

To illustrate the potential of this technology, it’s useful to know that China just announced the commissioning of the largest PHES system on earth. Located in Hebei province, the 3.6 gigawatt facility consists of 12 reversible pump generating sets with a capacity of 300 megawatts each. It has a power generation capacity from storage of 6.6 billion kilowatt hours. That’s sufficient electricity to power roughly 660,000 homes for a year!

3.6 gigawatt pumped hydro energy storage facility in China

We think the vast potential of PHES is a game-changer when it comes to envisioning a future without polluting fossil fuels. A key takeaway from this PHES data is that yes, we have enough large-scale energy storage potential to enable a global transition from fossil fuels to renewable energy. Another critically important consideration is the social justice implications of developing PHES facilities. At present there are multiple PHES proposals in the West that would encroach on land that is sacred to indigenous people. It is imperative we don’t repeat injustices of the past in our pursuit of the better future we know is possible for ourselves and generations to come.