It’s the end of August, and many have just returned from the beach. If you’re like us, at some point you’ve stood in awe of the ocean’s power. Whether it was simply looking at the waves or positioning your beach chair to avoid (or maximize) exposure to the changing tides. In addition to the inevitable existential questions this imagery provokes, perhaps it also made you wonder if there is a way to harness what is yet another example of nature’s power.


The answer is yes!  Tidal energy has been around for over a thousand years, as there are documented records of Europeans using tidal flows to operate grain mills. In 1966 France constructed the Rance Tidal Power Station, a 240-megawatt (MW) facility that uses turbine technology akin to wind. In 2011 South Korea constructed the Sihwa Lake Tidal Power Station, a 245 MW facility that is currently the world’s largest. Unfortunately, that brings us to today. Tidal energy has not received the groundswell of support that wind and solar has, and therefore has not benefited from economies of scale or generally the focus of the wider engineering community.



Source: National Geographic

Let’s first talk about the cons. The two tidal energy facilities discussed above have an operating capacity factor of 25%*. This would put tidal energy slightly better than solar power, and worse than wind. Generally speaking, lower capacity factors weigh on the economics of renewable energy projects as higher capacity factors make generation more cost competitive relative to other forms of energy. Separately, the environmental impact of tidal energy is also significant. The silt these structures attract alters the seafloor, while a wide variety of wildlife (animals AND plants) rely on the tides as part of their daily and full life cycle. There are legitimate fears that tidal energy can devastate wildlife. Finally, the timing of the tides shifts slightly every day, meaning that only certain days the tides would be aligned with peak demand.

* – Capacity factor is the measure of how often a power plant runs for a specific period of time, typically actual electricity output divided by maximum possible output.

Tidal Energy

tidal energy

Source: Eagle Global Advisors

What about the “pros”?  It’s obviously renewable, and very predictable. It may not be timed perfectly as we discussed above, but we know exactly when the tides arrive. There are days or weeks where wind and solar underperform, but the tide is as regular as Cheers’ Norm. There are also studies that suggest the capacity factor for tidal energy can be materially higher if the facility is sited correctly. Earth Science 101 shows the further away from the equator you get the more drastic the tides. For example, Florida’s tidal range is roughly four feet on average, while Maine’s tidal range is roughly ten feet on average. So, while locations are limited, there are regions with significant tidal energy potential. Separately, the “energy density” of tidal energy is materially higher than other forms of renewable energy, meaning it can generate significant power even at slow speeds. It is also relatively inexpensive to maintain and can play a positive role in controlling damaging surge tides on unrelated onshore assets. 

Capacity Factor

capacity factor

Source: MDPI

To date there isn’t a perfect, cost-efficient renewable resource. Our quick analysis of tidal energy is no exception. The truth is each region has its own natural advantages, so while tidal energy may not be for Florida it could play a meaningful role in Maine, Alaska, Canada, or Scandinavia. The conclusion is yet again there are many roads through energy transition to a cleaner future, and there is no definitive answer to the “how we get there” question.

Or maybe like many others we simply want to prolong our vacation in the waning days of summer by talking about the beach one more time. Anything for a little more “summer wind”. 


RENEW Performance Tracker

Eagle Global Renewables Infra Index

perf 8.26

Source: Bloomberg *Please review disclosure information at the end of this post

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