The hydrogen fuel cell is a technology more often associated with cars than with houses, but it could be about to make its way into our homes and businesses. Japanese electrical manufacturer Panasonic has now entered the domestic green energy market and is pioneering the first major commercial use of the household fuel cell.
This article is going to have a look at this technology and its potential to reduce carbon emissions and save energy. It will describe how the household fuel cell works and how it may achieve these environmental gains.
What is a fuel cell?
To put it very basically and avoid confusing chemical equations; fuel cells are energy creating devices that turn oxygen and hydrogen into electricity. This is done by a reverse method of the electrolysis of water in which hydrogen and oxygen are created when a voltage is applied to water – an experiment I’m sure we all did in school. In a fuel cell oxygen is added to hydrogen and the result is the creation of an electrical current, and a little bit of water.
How can this be used in a house?
My initial thoughts on this were concerning the supply of hydrogen to houses. In order to supply hydrogen for a household fuel cell an infrastructure akin to that which currently supplies gas to our houses would need to be built. Failing that, some kind of hydrogen delivery system would have to be devised. While I am a proponent of the hydrogen economy [1], I am also under no illusions as to how challenging it is to supply houses with hydrogen, which has to be either compressed or liquidised. But of course, the Japanese being…well…the Japanese, have come up with a technologically brilliant idea.
One way of creating hydrogen is via the steam reforming of natural gas, which is available through the existing infrastructure. Steam reforming is essentially a process where natural gas (methane) and steam are combined in a catalyst to produce hydrogen. Unfortunately the process also produces carbon monoxide, which then has to be converted into carbon dioxide, but this is a perfectly safe procedure and is all undertaken within the fuel cell itself. When operating, the fuel cell will heat water and supply electricity, converting natural gas into heat and electricity without the need for combustion.
While not as green as a traditional fuel cell, which emits nothing but water, the manufacturers of these devices still claim they are environmentally friendly, in so much as they will reduce primary energy consumption. i.e. coal, oil, gas, etc.
Environmental benefits
It must be highlighted here that installing a fuel cell such as this will raise gas consumption quite significantly (about 1.7 times as much). However, in terms of overall energy usage Panasonic claim that an average family of four swapping a gas water heater for a household fuel cell could save 4502 kilowatt hours (kWh) of primary energy, equating to 1465 kg of carbon [2] and approximately £550 [see below]. This is due to the better efficiency of the fuel cell at converting primary energy compared to the power stations supplying the energy.
The supplied figures say that 4502 kWh of primary energy are saved, with 3308 kWh of these being electricity.
Assuming an electricity price of 14p/kWh and a gas price of 7p/kWh the savings can be worked out as below:
1194 kWh gas @ 7p = £83.58
3308 kWh electricity @ 14p = £463.12
Total saving = £546.70
Although more gas is consumed when using this technology, the overall energy savings are nonetheless significant. Obviously the above figures are dependent on numerous variables and are only supplied as an example.
Ironically though, the increased gas consumption of the house introduces an inverse anomaly into the equation. What I mean by this is that with most green/renewable technologies, primary energy consumption will drop once the systems are installed. The bonus being that as the price of energy increases, the payback time decreases. This would not be the case with a household fuel cell running on gas as the owner would be acutely susceptible to gas price rises.
Additionally, it must be remembered that this is not a renewable energy source, it is simply an energy saving device. A very large, expensive energy saving device. Saying that however, one advantage the fuel cell does have over the more traditional green technologies, such as wind or solar, is that it doesn’t rely on the elements and is therefore more predictable.
The cost
To buy one of these little beauties will cost you £20,000 plus, with a payback time of around 10 years. Considering this is a reasonably complicated bit of kit that hasn’t been trialled for anywhere near that amount of time, I can’t see the household fuel cell taking off any time soon.
Because the system is a micro combined heat and power source (microCHP) it may actually qualify for the feed-in tariff, which would also make it more affordable (I say may qualify).
In Japan the government will currently pick up half the cost of a fuel cell, and consequently around 5000 have already been installed [3].
In summary then…
Although not yet truly sequestered within the commercial market place, there could be a future for household fuel cells, especially as they are soon to become available in Europe. The fact that they ultimately save energy and carbon emissions will make them popular, plus, if the price can be lowered through economies of scale, then they will also save money. Of course the most beneficial way of using a household fuel cell would be for it to actually run off hydrogen as opposed to gas, but this is some way off yet.
One instance where I envisage it being successful is as a compliment to a house that is running a number of solar installations; solar thermal for hot water and solar PV for electricity. When the sun is in short supply during the dark winter months, a household fuel cell could step in to take up the slack. But, at the risk of repeating myself, this will not be feasible until they become more affordable.
In all honesty though, I’m not sure how I feel about this technology. Yes it does save energy, yes it will function all year round no matter the weather conditions and yes, it is utilising a technology that could help us overcome our energy problems in the future. Nevertheless, it does consume a fossil fuel and it is very expensive. I still believe that we should really be focusing our efforts on clean forms of energy production that truly fit within the remit of sustainable development.
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