Tapping the power of waves for clean water

Water is one of the most important resources for human health, economic growth, and agricultural productivity.

Many people worldwide lack access to clean water, with more than one billion people without safe water to drink.

To help fill that gap innovators have stepped up to demonstrate cost-competitive desalination systems that use the power of ocean waves to provide clean drinking water.

Small, modular energy and water systems have the potential to cost-effectively serve areas where energy and clean water are expensive and challenging to produce.

This specifically could play an important role in delivering reliable sources of electricity and water worldwide for disaster recovery and remote and coastal communities.

To inspire transforming saltwater into drinking water using wave energy to power the process, the US Department of Energy launched the Waves to Water Prize in June 2019.

This five-stage competition offers intrepid competitors up to $3.3 million in cash prizes to accelerate technology innovation in wave energy powered desalination systems.

This month, Water Power Technologies Office on behalf of the US DOE selected 17 winning teams in the DESIGN Stage to share $800,000 in cash prizes for their ideas.

During the DESIGN Stage, competitors had 120 days to develop design and modeling documentation, specifically describing their systems, important technical details and plans, and any model simulation or theory accurately capturing the performance of their wave-powered desalination systems.

“Innovations from these entrepreneurial teams could help advance wave-powered desalination systems, as well as other wave energy systems,” said Scott Jenne, NREL’s principal investigator for the Waves to Water Prize. “As this competition unfolds, we’re seeing more creative solutions designed to serve water-stressed populations.”

Among the winners are six entrepreneurs who proposed the following award-winning systems:

Sam Beyenne of Ciramax won for the Aquaceano system that features a three-oscillating-buoy design.

Connected to a central hull with hydraulic pumps, the buoys’ actuating arms feed water into a pressurized reverse osmosis unit.

Mirko Previsic, who finished third in the 2016 Wave Energy Prize, developed the MetaMorph H20.

This device features an inflatable absorber float that uses a power take-off system to pressurize seawater to enter a reverse osmosis system.

Aaron Cosby of Marine Systems, along with a team of entrepreneurs from Sea Potential, Pure Marine, and Colloide Engineering Systems, designed the DUO-Powered Waves to Water system, a dual-body wave energy conversion device.

The design consists of an inflatable body that floats on the wave’s surface and is connected by a mooring chain to a sand-bagged weight on the ocean floor.

A power take-off system drives one reverse osmosis membrane on the inflatable buoy.

Developers from Wave Energy and Spectra Watermakers, a company focused on small-scale, energy-efficient desalination systems for marine applications, received two awards for their designs:

Water Duck is an innovative, easily deployable, and robust wave-driven pump with an onboard reverse osmosis desalination system.

Surge Seeker uses a double taut-moored point absorber to operate an onboard Spectra Watermaker reverse osmosis system.

Canadian firm Oneka Technologies designs autonomous desalination buoys that use wave energy to produce drinking water.

From its 10 cubic metres per day desalination buoy, Oneka down-scaled its more advanced technology using reversed osmosis and waves energy to fill the needs of emergency relief application.

Wave point absorber that once inflated, rolled out in the ocean and attached to its anchor turns waves to water mechanically.

Oneka has recently partnered with REDE (Renewable Energy Development Enterprise) which is developing projects in Chile and bringing renewable energy solutions.

It will collaborate with REDE to turn Chile’s wave energy potential into a sustainable and affordable source of drinking water.

In the next stage, ADAPT, participants will have 180 days to design flexible desalination systems to meet the specific site conditions at Jennette’s Pier on the Outer Banks of North Carolina.

Using wave energy desalination to clean nontraditional water sources offers a new pathway to generating clean water for urban settings where population growth is occurring but central energy or water systems are nearing maximum capacity.

These also include rural communities, such as tribal regions where population levels cannot accommodate the economies of scale needed to make large systems viable; for military sites in remote areas without access to central electricity and water systems; and in areas impacted by disaster when storms and other events have knocked existing energy and water systems offline.

Electricity costs account for up to half the expenses for state-of-the-art desalination plants, which have difficulty treating very-high-salinity water.

Cost-competitive desalination technologies can address water security and alleviate water stress by expanding alternative water resources, such as seawater, estuaries, brackish groundwater, and other sources.

As mentioned above, current technologies are energy intensive, with energy costs up to 10 times that of treating freshwater.

Environmental issues, such as brine disposal, also pose a challenge.

Other marine renewables such as offshore floating solar, in the form of either electricity or heat, could also help drive down costs of desalination from high-salinity sources.

As solar looks to float offshore on a commercial scale, we could also see these two technology developers teaming up in the future.

The Waves to Water Prize is a part of the previously announced Water Security Grand Challenge aiming to advance transformational technology and innovation to meet the global need for safe, secure, and affordable water.

It is led by the Office of Energy Efficiency and Renewable Energy (EERE) Water Power Technologies Office (WPTO) and administered by the National Renewable Energy Laboratory (NREL).

WPTO also pushes wave energy technology innovation which can boost ocean data collection, and contribute to the growth of the blue economy.

WPTO and NOAA recently set up the ‘Ocean Observing Prize’ competition which challenges innovators to integrate marine renewable energy with ocean observation platforms.

To this end, companies are also developing systems which use wave power to boost the evolution of the ocean internet of things.

This just shows different varieties of wave power applications as it targets to be a part of energy transition mix on a commercial scale.

Four European companies are also looking to tap into waves for both, energy source and fresh water.

The H2020 Project Wave to Energy and Water (W2EW) started in January 2019.

The joint vision of the W2EW consortium (Wavepiston, Ener.Med, Fiellberg, Vryhof) is to deliver wave powered technology solution for electricity production and desalination.

It relies on the innovative integration of wave energy and sea water desalination technologies, to produce zero-emission electricity and fresh water, with dynamic optimization of energy production and maximizing the available wave energy using fresh water as storage.

According to the project, the W2EW solution enables competitive cost of electricity and water.

The present project is critical to demonstrate the W2EW solution in a real-life environment, to reduce the risk profile of the solution and to build the market to pave the way for broad market roll-out.