Environment

Record-breaking device uses sunlight to produce hydrogen at 15% efficiency

Record-breaking device uses su...
The panel generates a record 250 liters (66 gal) of hydrogen per day and could be used to provide local electricity and heating on the cheap
The panel generates a record 250 liters (66 gal) of hydrogen per day and could be used to provide local electricity and heating on the cheap
View 1 Image
The panel generates a record 250 liters (66 gal) of hydrogen per day and could be used to provide local electricity and heating on the cheap
1/1
The panel generates a record 250 liters (66 gal) of hydrogen per day and could be used to provide local electricity and heating on the cheap

Scientists at KU Leuven in Belgiumhave developed a device that combines incoming solar energy and water vapor from the surrounding air to produce a record-breaking daily average of 250 liters (66 gal) of hydrogen throughout the year. According to the researchers' estimations, an array of 20 such panels paired with an underground pressurizedtank could provide the totality of a household's entire electricity and heating needs for a modest price.

Goingsolar comes with a couple of significant drawbacks, particularly whenit comes to managing your reserves. First, storing an energy bufferfor a rainy day is all but cheap: a home battery pack will run you upthousands of dollars, and its charge will keep you off the grid for a fewextra days at most. Secondly, lithium-ion batteries lose capacity withuse, and slowly self-discharge with disuse.

ProfessorJohan Martens and his team have turned to hydrogen for a cheaper,year-round green energy alternative. Their device has been under development for a decade, and can currently reach a energy conversion of 15 percent.

Commercial solar panels can easily surpass that figure, often reaching 18 or 20 percent, but the advantage of this approach is thatlarge amounts of hydrogen can be stored in an underground pressurizedtank (at a pressure of approximately 400 bar) without the inevitable losses in capacity that come with battery technology. Using fuel cells, the reserves from the tank can then be converted at will into heating, electricity, or fuel for a hydrogen-powered car with a 90 percent conversion efficiency.

Hydrogenis often produced from non-green sources such as gas and oil, and it'salso expensive to produce and store. This project aims to buck thetrend thanks to a combination of high conversion efficiency and theuse of small-scale systems designed to work at the local scale.

"Wewanted to design something sustainable that is affordable and can beused practically anywhere," says Martens. "We're using cheapraw materials and don't need precious metals or other expensivecomponents."

Theresearchers estimate that an array of 20 panels and four cubic metersof pressurized storage would meet the energy and heating needs (inBelgium) of a household throughout the year, with the assumption thatthe reserves will build up during the summer months and last throughthe winter.

Aprototype of this setup will soon begin field testing on a propertyin the rural Belgian town of Oud-Heverlee. Over the next two years, the researchers are will be focusing on testing the panels for household, agriculture and retail applications, with the eventual goal to massproduce and commercialize the system.

Source: KU Leuven

19 comments
midas
This is exciting news! I've been waiting for an efficient system that produces an appreciable amount of hydrogen from water/water vapor. This could potentially free people from the power grid! My only concern, at this point, is manufacturing greed will make parts, or all, of the components ridiculously expensive to own and maintain.
stewartm0205
I think a combination of solar panels, batteries, and heat pumps would be a more effective solution.
guzmanchinky
Is anyone else leery of a pressurized hydrogen tank? I mean this is amazing technology, but am I simply wrong about hydrogen under pressure?
ei3io
@midas, The opposite occurs from mass production in manufacturing bringing down cost as the market goes up and the cheaper the faster,, @Stewartm, hydrogen vs batteries; H2 clearly wins once mass manufacturing takes over for most every reason. Batteries are only a win being available now but their performance falls far short of what H2 fuel cells will one day provide and with solar refilling they are clearly the future.
eugah
The dimensions of the array in the photo looks like its about 4 feet by 7 feet, or 28 square feet. To get to a scale where such a device could meet the daily energy needs of an average household, the article says you need to multiply by 20. Thats 560 s
jim99
Who does want a hydrogen bomb on the front lawn or in the basement.
Wombat56
What isn't mentioned is the cost of the fuel cells, plus the extra inverters needed to convert their DC output to mains-level AC power. My bet is still on batteries.
midas
@ei3io, Good point about the mass manufacturing. I really see hydrogen fuel cell technology being a huge part of our energy source in the future.
SimonClarke
Firstly, excellent idea. a couple of comments on the article, house storage batteries are relatively cheap these days. While it is true that batteries degrade over time you will need to be looking at ten years not two for a noticeable loss. While it is true that the batteries do lose charge over time, they are in constant use so the losses are minimal. I am nervous about a lot of pressurised hydrogen too but it is no different to other compressed gasses, Propane, camping gas. Also consider the potential in Gasoline. I would like to see a unit that produces sufficient gas for me to cook. the storage tank could manage to be only a few hundred PSI.
Simon Redford
So 250 Litres/day of hydrogen which has a calorific value of 39.4 kWh/kg HCV, and a density of 0.09 kg/m**3 at atmospheric pressure – some simple maths suggest this is 887 Wh/day from a module of (roughly) 2.5m**2. OK, so we get 20 modules covering 50m**2 – that’s quite a size! So now we are getting 17.7kWh/day on average. To compress 5m**3 of hydrogen from the 20 panels to 400Bar, with optimistic compressor efficiencies, I calculate will consume around 5kWh. So already we have conversion efficiency to storage of 71% before we think of using it. Then we get the 90% conversion efficiency fuel cell – I’d like to have one of those please – 60~70% top seems to be more realistic if you don’t make use of the heat. So now we are optimistically at a turn-around efficiency of 50% (0.71 x 0.7) for electricity. Taking an optimistic 0.2kWh/mile for your electric car, the 20 panels give us the range 44 miles/per day. More realistically it could be used in a fuel cell CHP unit in the home where the conversion inefficiencies could be used for hot water (in the summer) and could be combined with heat pump output for winter heating. As with so many of these great ideas, Passivhaus building standards and limited PV stored to batteries sounds more practical and cost effective.