Water scarcity could define the next century. Around two billion people lack secure access to water, on top of the one billion who have no access to electricity.
The green revolution is barely worthy of the name if it leaves those people behind. That’s where London-based start-up Hydro Wind Energy comes in.
It’s developing a range of ocean-based systems designed to provide low-cost, dispatchable energy, and end water scarcity. SubSea RO Wind is aimed
at providing low-cost fresh water from seawater – and lowering the price of expensive, energy-intensive and fossil-fuel-powered desalination systems that are currently in use.
The technology uses offshore kites at high altitudes, combined with reverse-osmosis membranes and subsea pressure to eliminate the need for fossil fuels and reduce desalination costs by up to 90%. The most energy-intensive part of traditional desalination is pressurising seawater to 5,500kPa to pass it through a reverse-osmosis membrane. By moving this process 600m underwater, SubSea RO harnesses the pressure of the ocean to reduce the amount of energy required – with wind-powered kites used to lift the desalinated water to the surface.
Those kites form the company’s other product – OceanHydro Wind, an innovative technology that harnesses offshore altitude wind using kites, stores the energy subsea in pressure vessels and releases it on-demand as electrical energy. The technology is a combination of wind power and pumped hydro storage – but using sea depth and pressure instead of height to achieve the same results.
It could open up more of the ocean to energy generation. Wind turbines are limited to shallow waters and – like existing kite-based systems – are only 30% efficient at converting wind into electrical energy, with peaks and troughs in supply. Instead of this approach, OceanHydro Wind uses the kites not to generate electricity directly, but to provide mechanical power to lift and alter the buoyancy of a submerged pressure vessel. Water flooding into the vessel at pressure is used to generate electricity – providing an efficiency of 90%, and on-demand power.
Vision of the future
The company is raising funds to build prototypes, which it hopes to have completed by the end of 2021, with commercialisation planned for 2023. “Hydro Wind Energy has huge plans for 2021, and our crowdfunding campaign will provide the foundations for future success and growth,” says CEO Lee King. “Our vision is to play a major role in the global transition to renewables in the 21st century and beyond.”
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