As the world scrambles to transition to renewable energy sources, a stalwart old friend of the energy industry has been quietly serving our power needs for decades. Pumped hydro storage (PHS), the most common form of grid-scale energy storage, has been lauded as a reliable and efficient way to balance the grid. But the truth is, PHS is actually a major obstacle to the widespread adoption of renewable energy, and its dominance is stifling innovation in the energy storage space.
Learn more: Can the Solar Energy Revolution Really Depend on a 10% Improvement in Efficiency?
At its core, PHS works by pumping water from a lower reservoir to an upper reservoir during off-peak hours, using excess energy generated by power plants. When energy demand spikes, the water is released back down to the lower reservoir, driving a turbine to generate electricity. This process has been around since the 1920s and has been a mainstay of the grid ever since.
But here’s the thing: PHS is only viable in very specific geographic locations – namely, areas with steep terrain and a reliable water supply. This means that in many parts of the world, particularly in urban areas or regions with flat topography, PHS is simply not an option. And yet, the industry has been slow to adapt, with many utilities and grid operators clinging to PHS as the default energy storage solution.
Learn more: "Powering the Future: How Smart Microgrids are Bringing Energy Independence to Rural Communities"
One of the main reasons for this is that PHS is incredibly cheap – at least, it was, until recently. With the cost of solar and wind energy plummeting, the economics of PHS have become increasingly unfavorable. A new study by the National Renewable Energy Laboratory found that while PHS costs have dropped by 25% in the past decade, they still remain significantly higher than those of other energy storage technologies, such as lithium-ion batteries.
So, what’s holding back the adoption of more innovative energy storage solutions? Part of the problem is that the existing grid infrastructure is designed around PHS, making it difficult to integrate new technologies. But another major factor is the entrenched interests of the PHS industry. Utility companies and grid operators have invested heavily in PHS over the years, and they’re loath to abandon a technology that’s worked for them for so long.
As a result, the development of more innovative energy storage solutions – like flow batteries, compressed air energy storage, and even hydrogen fuel cells – has been stifled. These technologies have the potential to be more flexible, more efficient, and more widely applicable than PHS, but they’re often overlooked in favor of the tried and true.
It’s time for the energy industry to rethink its relationship with PHS. While it’s a reliable workhorse, it’s not the only game in town – and in many cases, it’s not even the best option. By embracing new technologies and innovative approaches to energy storage, we can create a more resilient, more sustainable, and more equitable energy system for all.
