Published on December 27th, 2015 | by Glenn Meyers


Phi Suea Solar Homes Store Excess Energy As Hydrogen

December 27th, 2015 by  

Four Phi Suea solar homes being developed in Chiang Mai, Thailand, will convert excess energy into hydrogen and store it in fuel cells.


Here is how the energy system functions: During daytime, excess solar power from PV panels is directed to run electrolyzers and produce hydrogen. Said hydrogen can then be transformed back into electricity using a fuel cell storage system at night.

Some 114 kW of photovoltaic panels will be capable of generating around 441 kWh of daily electricity. Excess electricity will be stored in two 2,000-Ah lead-acid battery banks. Electrolyzers will then convert additional excess power into hydrogen gas by applying an electrical current to water. The hydrogen will then be stored until it is needed, typically at night, at which point it will be changed back into electricity using fuel cells.

According to the US Department of Energy, “Hydrogen can be stored physically as either a gas or a liquid. Storage of hydrogen as a gas typically requires high-pressure tanks (350–700 bar [5,000–10,000 psi] tank pressure). Storage of hydrogen as a liquid requires cryogenic temperatures because the boiling point of hydrogen at one atmosphere pressure is −252.8°C. Hydrogen can also be stored on the surfaces of solids (by adsorption) or within solids (by absorption).”

An electrolyzer is an electrochemical apparatus designed to perform electrolysis: splitting a solution into the atoms from which it is made by passing electricity through it. Electrolysis was pioneered in the 18th century by British chemist Sir Humphry Davy (1778–1829).

Phi Suea system 10325692_1564572803816731_5521884907813350615_n“It’s a dream to have 24-hour access to the power of the sun. With our renewable power system and hydrogen energy storage, we have fulfilled this dream,” said Sebastian-Justus Schmidt, initiator of the Phi Suea House project.

According to the developer, the first phase of the development has been completed and the energy system has entered the testing phase with the first three buildings. The system, states Thailand-based CNX Construction, is expected to be 100% operational when construction is completed at the end of 2015.

“The technology behind this system is still very new. There are some systems already running in labs at leading universities worldwide and small numbers of similar hydrogen energy storages have been deployed as backup power systems for telecommunications in remote areas, but the Phi Suea House is the first project worldwide where this ground-breaking technology is being used as the main energy storage for a multi-house residential development.”

CNX says the energy conversion process is entirely clean, with oxygen and water being its only byproducts.

When fully up and running, the system will reportedly be able to produce hydrogen at a maximum rate of 2,000 l (440 gal) every hour and will be able to store up to 90,000 l (19,800 gal). The daily demand for electricity is expected be around 200 kWh. The fuel cells will be able to produce 120 kWh at full storage, which should be adequate for nighttime use.

Related: Adding Energy Storage To Home Solar: Does It Make Sense?

Images via CNX Construction

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About the Author

is a writer, producer, and director. Meyers was editor and site director of Green Building Elements, a contributing writer for CleanTechnica, and is founder of Green Streets MediaTrain, a communications connection and eLearning hub. As an independent producer, he's been involved in the development, production and distribution of television and distance learning programs for both the education industry and corporate sector. He also is an avid gardener and loves sustainable innovation.

  • UseYourBrainDummy

    Millions of homes with highly combustible Hydrogen tanks sitting outside. A terrorist’s wet dream. Compressed air or a flow battery sounds alot better.

    • One-Of-A-Kind

      What a ridiculous thing to say. Almost every gas station in the country has a cage of propane tanks sitting outside, meanwhile, thousands of gallons of gasoline to go with it. Why would a terrorist care to blow up a house?

      This is typical FUD (Fear, Uncertainty, and Doubt) – It’s been proven that when leaked, hydrogen is much safer than a hydro-carbon gas that pools up at ground level.

  • “…and store it in fuel cells…”

    Not sure what to make of that. Either I or the author lacks some critical knowledge. Fuel cells are the components that convert hydrogen into electricity. They are not for storage.

    • T.S.Seshadri

      With CAES electricity can be regenerated through electrical heater, small air turbine, and then an alternator. This is similar to generation of electricity from wind turbine.I am converting the potential energy–CAES into electrical energy ( 65% Conversion efficiency) whereas for fuel cell use first hydrogen has to be produced through electricity either from natural gas or water electrolysis. Then it is reacted with oxygen in the air and finally the chemical energy is converted to electrical energy in fuel cells. Air is freely available everywhere and only it has to be compressed using solar power. CAES technology is best suited for generation of electricity from solar to all countries 24×7 and also all road transport vehicles can be run with it. This is perfectly a renewable energy source and it will last as long as the earth and sun exists.

  • T.S.Seshadri

    Instead of hydrogen, compressed air energy storage –CAES can be used. During non solar hours the compressed air will turn an alternator and electricity can be generated.this is safer and cheaper. More details 919642434597 T.S.Seshadri, Hyderabad India

    • Bob_Wallace

      Unless you have a way to either store or sell on the heat during compression CAES is likely to be non-competitive. Too lossy = too expensive.

      • T.S.Seshadri

        In Germany Compressed air is stored and used in Huntorf plant for better grid management and in Mclntosh plant Alabama state USA for storing excess electricity. This is practically used in non solar and non renewable sources applications. My idea is to use CAES for solar and wind applications. CAES efficieny declared is 65% in Germany and US plants. In Germany and US natural gas is used for heating CAES and I am heating the CAES with an electrical heater with electricity drawn from the regenerated solar electricity or wind electricity. Of course this is not possible during the initial runs. I have a paper published on CAES and I am interested to send you the same by mail. Please give your mail ID. Also CAES electric car is than the Hydrogen fuel cell car. This is safer and can be run both day and night similar to fuel cell car. My technology can be used as long as the earth and sun exists. T.S.Seshadri, Hyderabad, India

        • Bob_Wallace

          You need to solve the efficiency problem. Adding more energy at the output, be it gas or electricity, decreases overall efficiency.

          One company that has an interesting (I’m not sure how promising) approach is Light Sail. They spray water into the compression cylinder to absorb the heat and then store the water separately from the air. Then the stored heat is used to reheat and expand the air when it’s used.

          • T.S.Seshadri

            Storing and spraying hot water can be used only at the source of electricity generation. My concept is to generate solar and wind electricity in all countries 24×7 and take the stored CAES in cylinders where solar energy is deficient. Here the water spraying technique will not work. The efficiency declared is 65% and the hydrogen fuel cell has an efficiency of 70%. Platinum electrodes are scarce and non renewable and I am using iron and copper in CAES technology wherein it is renewable. Full details will be sent as attachment provided sir your mail id is given.

          • Bob_Wallace

            Good luck. Sounds like you’ve got all the answers….

          • T.S.Seshadri

            I thank you very much sir. Your Mail ID please so that I can give my full idea for the benefit of the entire world. My mail ID is 919642434597.T.S. Seshadri,Hyderabad India

          • mike_dyke

            This site has a worldwide audience and you’ve already shown your idea to the world in your comments. Although Bob has been the only one to respond, there’s a lot of people reading your posts/comments. FYI Bob’s in the USA and I’m in the UK.

            One thing that we don’t do on this site is ask for or give out email IDs – there’s no need as all comments go to everyone. The moderators know your posting address and that’s all they need to know. If you keep asking for the IDs, you start to sound like a troll which we don’t like/tolerate.

            One thing you can do though here is post a link to your paper – you say it’s been published – has it been peer reviewed? and if anyone is interested in finding out more about the subject, they can read it at their leisure. However given the number of potential systems/ideas around, we are more interested in reading about systems which have at least got a prototype working as ideas can and do change over time.

            Good luck with your idea – I hope you succeed in making it work especially with all the difficulties with storage/efficiency that others have found when working in the compressed gasses field.

          • T.S.Seshadri

            Many thanks for your mail and for correcting my approach.Hot compressed air from electrical heater which I am using will double the efficiency of conversion. No prototype making is desired by me since CAES technology has been successfully used in Germany and US for electricity generation in non solar and non renewable sources application.Only for the vehicles I am making a prototype which is an improvement of fuel cells technology.

  • vensonata

    Wow. Thailand is out on the cutting edge. I will offer a few conjectures. The battery banks is 2×2000 amphours at 48 volts (probably). = about 200kwh storage. But lead acid so 50% available = 100 kwh actual storage. The houses use 50 kwh per day each total 200 kwh (lots of air con) and they require night time about half…total of 100kwh of storage. So the battery bank will cover it as long as they don’t get several cloudy days. The cloudy days are going to be covered by the hydrogen. I suspect it will not be high pressure storage nor cryogenic but low pressure storage in large propane tanks. Efficiency losses round trip will be about 50% at least. But there you have it… not bad, and not too pricey.

    • Matt

      The in/out loss on the electric-H2-electric is likely much higher that 50%. Even at lower pressure storage you would still have to run a compressor.
      In Thailand, I would storing cold and extra batteries would be a cheaper, more efficient path. From the picture and story it is not clear that they are off grid, and the H2-electric is only enough for night time use. So wild guess, week with no sun is handled by grid.

      • Glenn Meyers

        Good observation. While the idea sounds admirable, cost-effective execution is probably going to present serious difficulties, as will sunless days, unless the panels are extraordinary performers.

      • vensonata

        They probably are off grid. The land price might be exceptionally low and justify the cost of the off grid system. The spokesman seems to have a German name so that is where the hydrogen idea came from. You may well be right about the round trip hydrogen being only 30% efficient, but at some point batteries simply are not good for the last 3% storage. Either they need natural gas generators or hydrogen fuel cell…looks like they made the choice…hydrogen won.

        • Bob_Wallace

          Or methane fueled generators.

          • jeffhre

            Yes. Would make more sense at a farm, or by an urban dump than within an isolated vacation house though.

          • Bob_Wallace

            Yes, but not necessarily for a year round off the grid house. A biodigester hooked up to the septic system might do the deal. You’d need to compress and store but you’d have to do that with hydrogen.

            And methane is easier to store. Looks like it would take about 25% as much tank space.

          • vensonata

            Hmm, I have 2000 gallon septic tank. Methane…I will have to do some more research. Could be interesting.

        • Robert Pollock

          Careful with your assumptions. You can find all sorts of aberrations in the developing world. Costa Rica has had buried fiber for over a decade, fast internet, better than here.
          Ocean proximity land is normally not for sale, it varies by country. The Maritime zone of lease available land in Mexico is from high tide to a kilometer inland, while in Costa Rica it’s 200 meters. Thailand could be anything. Prices vary accordingly.

      • Robert Pollock

        Why don’t they just pump water, using a multi-speed, brushless motor up into a tank?

  • Jenny Sommer

    What “homes” need 200kWh/day? All four of them together? How many inhabitants?
    114kW PV? Round trip efficiency of the fuel cell storage system? Cost?

  • kvleeuwen

    So, is the hydrogen stored onder high pressure or at cryogenic temperatures? Neither is energy-efficient 🙂

    Which explains the conventional battery banks (the Ah rating is meaningless without knowing the system voltage btw).

    • Robert Pollock

      I don’t understand why there is so much interest in using hydrogen to generate or store electricity. It’s one of the most elusive elements.

      • Bob_Wallace

        There are a number of ideas including thorium reactors and vertical axis wind vanes that have significant popular support like hydrogen but, like hydrogen, aren’t finding success in the real world.

        I think one reason is that the ideas are well presented to people who don’t look past the story and ask for data.

        Some of the support may go back in time to when wind, solar, and batteries were a lot less viable. A lot more expensive. Perhaps people bought into those solutions back then and haven’t kept up.

  • omar

    Good idea but will be more convenient if the build it at a utility scale, as maintenance should be an issue with such complex electronic control system.

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