20,000 megawatts under the sea: Oceanic steam engines
"IF ANY energy source is worthy of the name "steampunk", it is surely ocean thermal energy conversion. Victorian-era science fiction? Check: Jules Verne mused about its potential in Twenty Thousand Leagues Under the Sea in 1870. Mechanical, vaguely 19th-century technology? Check. Compelling candidate for renewable energy in a post-apocalyptic future? Tick that box as well.
Claims for it have certainly been grandiose. In theory, ocean thermal energy conversion (OTEC) could provide 4000 times the world’s energy needs in any given year, with neither pollution nor greenhouse gases to show for it. In the real world, however, it has long been written off as impractical.
This year, a surprising number of projects are getting under way around the world, helmed not by quixotic visionaries but by hard-nosed pragmatists such as those at aerospace giant Lockheed Martin.”