Why I believe in Hydrogen
There are many reasons, why I believe Hydrogen is already an important energy carrier and will play a more and more massive role in the not too distant future.
Specific Energy: Hydrogen has specific energy of 40 kWh/kg. For comparison, other chemical fuels such as gasoline, LPG, and diesel are all around 12-14 kWh/kg, Natural Gas/Methane is at 15.5kWh/kg and coal is even worse at 6 kWh/kg. Electrochemical energy carriers (batteries) have much lower densities ranging from 0.05 kWh/kg (lead-acid) to 0.25 kWh/kg (lithium-ion). Specific energy density is not the only important factor in assessing an energy carrier, conversion efficiencies are obviously also important in order to actually be able to use the stored up energy. Standard commercialised electrolysers and fuel cells have already reached electrical efficiencies of over 60%, with fuel cells even exceeding 85% in cogeneration systems in which the generated heat is captured and used.
Environmental Impact: The hydrogen energy storage is 100% clean and poses zero threat to the environment. Hydrogen can be produced through electrolysis using only water and electricity from unlimited renewable resources such as the sun and wind. The only by-product of hydrogen generation through water electrolysis is oxygen. The only by-product of the reverse process of generating electricity in the fuel cell is water. It really is the ideal clean energy storage circle. Furthermore, as opposed to most battery systems, the hydrogen energy system does not pose a problem at the end of its lifetime. Most of the system and tanks consists of steel or other metals that are easily recyclable. There are no chemicals or materials harmful to the environment contained in the system.
Flexibility: Hydrogen energy storage systems consisting of electrolyser, storage tank, and fuel cell are extremely flexible and can be adapted to many different requirements. The three system parts are technically completely independent of each other. For example, it is possible to increase the size of the storage tank without any modifications to the electrolyser and fuel cell to achieve a longer system autonomy time. Similarly, it is also possible to size the electrolysers to reach the most suitable hydrogen production rate and to size the fuel cells to produce exactly the amount of power required to cover the system demand. The system components can be freely varied to find the most suitable and economical solution, in many cases resulting in significant savings compared to an equivalent battery storage.
Another advantage hydrogen has over batteries is that once hydrogen gas is produced and stored in a tank, it will stay there and will not deplete/decay/lose energy in any way. The possibility of long-time storage makes hydrogen a fantastic option for seasonal storages and backup applications. When excess power is available, hydrogen can be produced and stored in a tank, piping system, etc. It will not be lost, and even if it is only required months or years later, it will be readily available. No battery can compete in this application when we consider the low cost of a storage tank.
Safety: Hydrogen gas storage is very simple and safe. The only necessary precaution is that the storage should be set up in an open or well-ventilated space to eliminate the possibility of a build-up of gas in a trapped space. Fire regulations specifically state that while hydrogen is flammable, it poses no serious risk due to it quickly escaping in ventilated or open areas, and any hydrogen fires should be extinguished using standard firefighting methods suitable to the surroundings. On the NFPA fire diamond, Hydrogen is classified “0” for health hazard and instability/reactivity, which means it “poses no health hazard, no precautions necessary and would offer no hazard beyond that of ordinary combustible materials (e.g. wood)” and is “normally stable, even under fire exposure conditions, and is not reactive with water”. It poses less danger to health and safety than LPG, CNG, or gasoline.
All the above points are generally true advantages of hydrogen as an energy carrier, but also specifically in a stationary off-grid application such as the Phi Suea House. The following points also demonstrate the strengths of hydrogen energy systems as part of a larger energy economy.
Distribution: Hydrogen’s high specific energy density (low weight per unit of energy) means that large amounts of energy can be transported relatively easily in the form of compressed or even liquefied hydrogen. The biggest advantage, however, is the possibility of producing hydrogen from any renewable energy source anywhere. If it is not practical to produce hydrogen fuel directly on-site, it will only have to be delivered from your nearest solar or wind farm equipped with an electrolyser – transporting fuels across half the globe to fuel your car/heater/generator should seem quite ridiculous in comparison.
Storage options and grid support: Another advantage of hydrogen is the possibility of mixing it directly natural gas resources. For countries with an existing network of natural gas pipelines, storage will be a non-issue. In the short term, it will stop the nonsensical situation occurring in some places like Germany where, to prevent oversupply, wind and solar farms are taken off the grid during peak production times because temporarily shutting off coal power plants would be more expensive. This excess power could simply be converted into practically free hydrogen gas, to be used in any of its many possible applications. In the long term, the stored hydrogen gas will completely cover the energy demand during periods of low power generation from renewables and could also replace a nation’s fossil fuel energy reserves.