midas March 5, 2019 12:45 PM 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 March 5, 2019 01:18 PM I think a combination of solar panels, batteries, and heat pumps would be a more effective solution. guzmanchinky March 5, 2019 03:11 PM 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 March 5, 2019 04:33 PM @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 March 5, 2019 06:35 PM 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 March 5, 2019 07:56 PM Who does want a hydrogen bomb on the front lawn or in the basement. Wombat56 March 5, 2019 08:38 PM 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 March 5, 2019 10:17 PM @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 March 6, 2019 04:22 AM 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 March 6, 2019 11:50 AM 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.