Researchers from Paderborn University in Germany have developed a model to deploy residential rooftop PV in combination with batteries for short-term storage and hydrogen for long-term storage.
“The system design has modeled on a residential building but it can also be used for other buildings if the load curves for electricity and heating are known,” researcher Stefan Krauter told pv magazine.”It can provide autonomy for electricity over the whole year.”
The decentralized energy system is designed to cover a household's main power demand via photovoltaics, even during winter, by including sufficient storage capacity.
“The aim is to minimize the grid load by achieving low or even zero grid interaction, which is realized by the use of decentralized long-term energy storage,” the scientists explained.
The system utilizes a 6.8kW PV array and a 5kW electrolyzer powered by surplus solar power to produce hydrogen, which is then stored in a hydrogen tank via a compressor. In periods of high energy demand, when PV generation is not sufficient, the green fuel is used to produce electricity via a 1.24kW fuel cell system. Lithium-ion batteries are part of the proposed system configuration in order to react to too rapid load changes, which the hydrogen system would not be able to handle.
The heat waste generated by the fuel cell and the electrolyzer is transferred via heat exchangers to a hot water tank, which supplies hot water to the household. The remaining demand is covered by a heat pump.
The academics tried to identify the kind and size of components required under different scenarios. They also aimed to assess the conditions under which a system could compete with conventional power systems in terms of price and costs. The model was simulated in Simulink (MATLAB) to analyze when and how the PV system is fully able to cover the energy needs of a household.
The scientists also used HOMER software, which was developed by the US National Renewable Energy Laboratory (NREL), in order to verify the results. Measurements were taken with a time resolution of 15 minutes and a total time frame of one year.
The German group estimated that the electrolyzer used 4283.55kWh of surplus solar power to produce 80.50 kg of hydrogen in one year, while the fuel cell was able to return 1009.86kWh energy by burning 73.52 kg of hydrogen.
“The compression of hydrogen required a yearly energy demand of 268.14kWh, while the heating demand was 1208.66kWh,” the scientists explained. “The heating demand was reduced by 643.69kWh by using the waste heat produced within the electrolyzer and the fuel cell.”
They said their simulation via Simulink showed that household heating demand expands the required amount of decentralized stored hydrogen when aiming for energy-independent operations.
“Future research has to focus on optimizing the control system and on analyzing which component dimensioning under which scenarios is preferable in terms of energy and resource efficiency and in terms of lifetime increase,” they said.
The scientists described the system design in “Hybrid Energy System Model in Matlab/Simulink Based on Solar Energy, Lithium-Ion Battery and Hydrogen,” which was recently published in Energies.
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This is exactly what we homeowners could use. It is considerably more complex than my gas powered generator, but I love the use of H2 to power the electric generator.
In another scenario, assume H2 is available in tanks from a supplier and my generator uses that canister to power my house when the grid goes down.
This is good stuff to come.
I’m wondering if H2 is better than Biogas. If PV and thermal solar are used to use a digester with intermittent use of sour gas Genset, couldn’t that be far easier to produce year-round on demand home energy? Just at a thought 🤔
What happens with the oxygen from the electrolyser.?
Is it separated from the hydrogen in the electrolyzer, then fed to the fuel cell
by a different route?
Bellingen NSW, Australia.
O2 and H2 are kept separate in the electrolyser stacks thanks to grioves on the bipolar plates and use of membranes, non porous to gas in between. The O2 will be typically vented and not used in a decentralised production unit like this one.
PS: this solution is interesting but in my opinion its way way to complex for houses (many equipments, high capex and maintenance cost)
It doesn’t do a single thing a battery alone will do. And it does it at multiple times the cost.
Anyone foolish enough to pay for a system like this deserves to be parted from their money.
What (if)about economies of scale coupled with circular economy?
In Germany you need five times larger PV array to cover january electricity needs vs. july, and five times larger battery array. When ju heat with electricity, seasonal discreapenicies are even larger. So that s the reason for testing H2
Great design, the one who develops modular syatem for single-family houses, will achieve great success. The only unsolved problem here – H2O source.
I don’t think there’s anything new here, is there? Only new analysis that such systems are practical. Hydrogen is the only viable way, currently, of storing excess summer energy through until late winter. I’d like to see more work on catalysing methanol synthesis so energy could be stored as ambient liquid rather than 3000psi gas!
Philip, o2 is released to air. Niko, h2o is freely available
Owning an EV, can help with seasonal changes in energy requirements, and production. During spring and fall, when home energy needs are lowest, use excess energy to charge your vehicle. During hot summer days, or cold winter days, where energy needs are high, use a public fast charger to charge your vehicle, and save the energy for home use. Bidirectional EV charging is even better.
Hi Dear ,
Being specialist in the production of gas especially air seapration units and electrolizers , I think the worth solution is not not to generalize home electrolizer , this will be paracticly difficult to manage , the appropriate is to invest in large electrolizer to produce high power for homes .
the best is to supply hydrogen electolizer from solar field and to create Hydrogen power plant to supply your energy .
focusing on equipement in one area make sense than spreading all over the areas .
If you want to shorten your EV battery life by using an expensive battery that is designed for transportation, then go ahead! There are studies showing that the battery life can be shorten by 40 to 60% if the charging-decharging cycles in the home requirement are not well studied and performed. I have an EV but I prefer to use the battery for what was designed : moving my car and not charge my refrigerator!
Real progress towards nett zero. Neat combination of fuels to use solar excess in summer to power via fuel cell in winter. I question the safety of storing domestic hydrogen in tanks, but applaud the principle nevertheless. What are the next steps ?
How much would this proposed set cost?
Wish the diagram factor in V2H/V2G (whether it’s EV or Fuelcell car) integration also.
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