by Will Lockett | Medium
An untapped near-limitless carbon neutral energy source lies dormant off the shore of Japan.
Amongst the hustle and bustle of Tokyo city you’d be forgiven for forgetting the raw natural power that exists in Japan. For just offshore, deep in the ocean, lies a monster with ungodly strength. It has remained untouched and undisturbed for millennia. But now scientists want to harness this power to save Japan. Don’t worry, I’m not talking about Godzilla, though he may still be down there somewhere. Instead, I’m talking about deep sea turbines, as Japan is the first country to try and harness the potential of ocean currents. But why has Japan turned to the sea for power? What are the benefits? And what are the risks? Could this be an energy revolution?
Geologically speaking, Japan is one of the most fascinating countries in the world. With extensive mountain ranges, geothermal springs, volcanoes, fault lines and near-shore deep sea trenches. However, their incredible landscape has made solar farms and offshore wind turbines challenging as there isn’t the available space or suitable seabed near where energy is needed. This is also why Japanese cities are so famously cramped — the landscape boxes them in.
So, when Japan started to transition away from fossil fuel and towards renewables, they mainly went nuclear. However, since the Fukushima disaster, they have been trying to find alternatives, and recently landed on ocean currents as their carbon neutral energy of choice. You may have never heard of ocean currents as an energy source and that is because no one else has tried to harness it. Which is a shame, as it has the potential to be the ultimate climate-friendly energy supply because of how ocean currents work.
Ocean currents are powered by salinity (how salty water is). In the Poles ocean water freezes, and because ice can’t contain salt, the water around the Poles becomes saltier and therefore denser which makes it sink to the sea floor. This water is then pushed/pulled towards the equator as more water sinks in the poles and wind system around the tropic cause upwellings. Once at the surface, the water is then sucked back towards the Poles as more cold water sinks, causing this now warm water to rush in to take its place. This rotating process is known as thermohaline circulation.
These forces create giant rivers in our ocean that are way more extensive than any we have on land. Take the Kuroshio current off the East Coast of Japan. It is the ocean’s largest current and can travel at a rate of 75 miles per day and carry the equivalent water volume as 6,000 large rivers.
But, as thermohaline currents don’t rely on temperamental weather systems like wind or a clear sky, they flow with consistent power, making them an ideal energy source. What’s more, due to the nature of marine ecosystems, we can build structures within the flow of currents without causing habitat loss. In fact these structures will act as artificial reefs and have the ability to boost marine biomass and biodiversity.