Bitcoin has the potential to help unlock between 2 to 4 terawatts of clean, continuous and year-round baseload power — for one billion people — by harnessing the thermal energy of the oceans. The technology is Ocean Thermal Energy Conversion (OTEC), a 150-year old idea stymied by economies of scale, that turns Earth’s oceans into an enormous renewable solar battery.

It does this by combining warm tropical surface water and deep cold seawater to create a conventional heat engine.

Over one billion people live within 100 kilometers of a tropical coast, where a 25ºC temperature difference can be found between warm surface seawater and cold deep seawater, at depths of one kilometer. This differential, or delta T, is perfect for OTEC.

The diverging temperatures produce the Rankine cycle that will power a turbine and generate electricity. The result is a clean, continuous base load power that runs year round and can provide free cooling for buildings, infrastructure or mining equipment.

Nikola Tesla considered ocean thermal energy to be extremely promising and proposed optimizations to Claude’s heat engine in order to improve the logistics and economics.

Hawaii has a unique power grid that is similar to Texas in that it is completely isolated and disconnected. As an added complexity, each island has its own stranded grid. No power is connected or shared between the individual islands, nor is there any political will to interconnect the island.

It is estimated that a large-scale, 100-to-400-MW OTEC plant would produce electricity in the range of 6 cents to 20 cents per kilowatt hour. However, engineers need to build a medium-scale (5-to-10-MW) test facility — proving it can reliably maintain its cold water intake pipes to produce continuous base load power for about two-and-a-half years — before a large-scale plant can be simulated and built. The problem is that an interconnected, medium-scale plant would cost about $200 million to $300 million and produce electricity in the range of 50 cents to $1 per kilowatt hour. Nobody on the grid will buy energy at that price.

Moving from Hawaii (which has a 20ºC annual mean delta T) to the equator (which has a 28ºC annual mean delta T) can turn a 5-MW facility into a 10-MW facility.

Harmon contends that his team can bring stranded, medium-scale OTEC down to 11 cents per kilowatt hour. Combined with free cooling and overclocked mining rigs, the test facility would be able to sell its stranded energy to a symbiotic and highly-optimized co-located buyer: Bitcoin mining.

The first steps for Harmon and his team will be to refactor Makai’s Kailua-Kona 100-kW plant, on the Big Island, with S9 Bitcoin miners. The plant is too small to make money, but it will demonstrate the integrated cooling technology from OTEC. Next, the team wants to work on the medium-scale demonstration using a grazing containerized platform.

Before Bitcoin, a 10 MW OTEC plant was too expensive and the Innovation Valley of Death too wide.

For the first time, the opportunity to economically harness planetary power is within our grasp.