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Islamic University of Gaza academics attend a publicity ceremony for a wave energy project at Gaza Port in Gaza on April 22, 2018. Photo: Mustafa Hassona/Anadolu Agency via Getty Images

Tidal energy has been slow to develop into a reliable form of grid power, but recent demonstration projects suggest that might be changing. If the technology continues to mature, tidal energy could become a significant renewable power source in many countries.

The problem: Although energy developers have long sought ways to exploit ocean tides to generate electricity, few large-scale projects are actually running in the water. That's because operating in the ocean poses a frustratingly difficult engineering problem: Corrosion, biofouling and extreme wave and current forces all contribute to the slow destruction of devices.

Tidal power's benefits:

  • Tidal energy is dense: Seawater is 830 times denser than air. This means, at least in theory, that a tidal energy converter has a smaller physical footprint than a solar or wind array producing the same amount of power.
  • Tides are predictable and easy to forecast — not just hours in advance, but decades. The intermittency is predictable, which from a grid perspective makes tidal energy much easier to integrate.

What's new: Proving reliability through large-scale demonstration projects is a key step toward making tidal power a reality.

  • Last month, Atlantis Resources, a U.K.–based tidal energy developer, announced that its MeyGen project has cumulatively delivered about 6 GWh to the grid since it was connected a year ago. It produced 1,400 MWh in March alone, equivalent to the monthly energy consumption of about 1,500 U.S. homes.
  • Scotrenewables, another U.K. tidal developer, reports that as of last April its device generated a cumulative 2 GWh since August 2017.

The bottom line: Tidal energy still has a ways to go before it becomes cost-competitive with other renewable energy technologies, but these numbers point to a maturing sector that is reliably generating real power for the grid.

David Hume is a marine engineer contractor supporting the U.S. Department of Energy Water Power Technologies Office's marine renewable energy portfolio and founder of The Liquid Grid. The views expressed are his own.

Go deeper

Texas House probes school library books dealing with race and sexuality

Photo: Brittany Murray/MediaNews Group/Long Beach Press-Telegram via Getty Images

Texas state Rep. Matt Krause (R), chair of the Texas House Committee on General Investigating, announced Wednesday that he's initiating a probe into schools' library books, according to a letter sent to the state's education agency and other superintendents.

Why it matters: The probe focuses on books that discuss race, sexuality, or "make students feel discomfort, guilt, anguish, or any other form of psychological distress because of their race or sex," Krause wrote in the letter.

4 hours ago - World

Iran agrees to resume Vienna nuclear talks in November

Ali Bagheri (R) with Enrique Mora in Tehran on Oct. 14. Photo: Iranian Foreign Ministry handout via Getty

Iran's new chief nuclear negotiator said following a meeting in Brussels on Wednesday that Iran would resume negotiations in Vienna before the end of November, with the exact date to be set next week.

Why it matters: The Vienna talks have been frozen since Iran's new hardline president, Ebrahim Raisi, was elected in June. This is the most direct commitment from Raisi's government to return to the negotiating table.

Dan Primack, author of Pro Rata
9 hours ago - Politics & Policy

Democrats' billionaires tax explained

Illustration: Aïda Amer/Axios

There is now legislative language behind the push to tax American billionaires on unrealized capital gains, as Sen. Ron Wyden last night released his 107-page plan.

Why it matters: This would be a sea change in U.S. tax policy, which has only applied to realized gains (otherwise known as income).