New Process Efficiently Uses Solar to Produce Hydrogen

Not long ago, we heard a great deal about the “hydrogen economy.” While the prospect of using hydrogen for vehicle fuel, as well as other energy storage functions, is not dead, it has faded into the background as a number of technical hurdles need to be overcome.

Cost is one factor, especially as battery costs continue to fall. A battery will never be able to deliver the amount of energy capacity per pound as hydrogen, though with battery-powered vehicle ranges in excess of 200 miles, that might be good enough for many applications. Heavier vehicles like trucks, trains and airplanes will likely need some other approach for which hydrogen still has great potential. But another problem facing hydrogen is where to get it in the first place.

Both of the most common methods, electrolysis and natural gas reforming, have issues. Electrolysis -- applying electric current to water to break it into its constituent parts: hydrogen and oxygen -- is straightforward and clean. However the amount of energy required for this is quite high.

Natural gas reforming, as the name implies, takes in natural gas and generally uses steam to extract hydrogen from it. As of now, natural gas is abundant and quite inexpensive. However, the process emits CO2 as a by-product -- which, to some extent, defeats the purpose of producing a clean fuel.

Now, a company called HyperSolar claims to have developed a commercially-scalable method of producing hydrogen using only sunlight and water.

The photoelectrochemical process, which HyperSolar claims was inspired by photosynthesis, uses a self-contained hydrogen generator: Water flows through, and hydrogen and oxygen are extracted at the cathode and anode, respectively, while sunlight enters from above.

If all the company did was use solar as the energy source for electrolysis, that wouldn’t be anything new. The amount of solar power required would still be cost prohibitive. But the HyperSolar system has two distinct advantages.

First, it facilitates a more complete transfer of energy into each hydrogen molecule. This provides a great deal more stored energy for each unit of energy input, which greatly reduces cost. Secondly, unlike conventional electrolysis systems, which require purified water, this system can use ocean water, waste water or just about any other water source. This is crucial as water has become as critical an issue as energy, and in some places even more so.

How is this accomplished? The HyperSolar technology is based on two breakthroughs. The company developed a nanoparticle that is designed to mimic natural photosynthesis in the way that it absorbs sunlight, as well as provide integrated anode and cathode areas that efficiently split the water and transfer electrons into the molecular hydrogen bonds. This process effectively captures far more of the sun's energy and transforms it into hydrogen than other approaches. Furthermore, each particle is encapsulated in a protective coating that allows it to be submerged under water without corrosion or short-circuiting. This allows the particles to be used in a wide range of water conditions.

The combination of these two elements provide a distinctive economic advantage. But is it enough to relaunch the hydrogen economy? Only time will tell.

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