“We decided to install a hydrogen system on board Race for Water. It’s a very light gas that’s derived from sea water, and we can store it in high-pressure tanks. It gives us the option of a clean, on-demand energy source,” explains Race for Water Foundation manager Pascal Goulpié.
When the batteries are full and the solar panels are still producing energy, or the kite is up, the electric motors turn into generators. We use the excess energy to produce hydrogen through sea water electrolysis. Goulpié, who has a PhD in technical sciences, explains, “We break down the sea water molecule (H2O), after first desalinating and deionizing it. That leaves us with oxygen (O) that we release into the atmosphere, and hydrogen (H2), that we store.”
The hydrogen is then compressed to 350 bar (5,076 psi) and bottled; that allows us to store more hydrogen in less space. An additional advantage is that we can store hydrogen for long periods of time without it losing any of its fuel power.
“When we need extra power on board Race for Water, we combine the stored hydrogen with oxygen from the atmosphere, then funnel it into the fuel cell. Through a physical and chemical reaction guided by the fuel cell’s high-tech semi-permeable membranes, we combine the hydrogen (H2) with oxygen (O) to create water (H2O). That reaction is 50% efficient, and produces an electric current that we can use,” says Goulpié.
And that reaction produces electricity, with only water as a byproduct.
Technical specifications for the on board system:
- Twenty-five 350-bar hydrogen tanks
- Two 30kW fuel cells
- Two 5kW electrolyzers
- The complete system can store 2,600 kWh