There’s also the problem of how you switch the network to hydrogen. If you add a little bit of hydrogen things remain OK for appliances generally. Most people say up to 10% is OK but in order to get to high levels of hydrogen, as well as switching peoples appliances, you would need to switch the network and appliances instantaneously as you would not be able to use gas mixes which have near equal quantities of hydrogen/natural gas because of the way this would interact with appliances. Although the network has been switched before, the network was much smaller and we are in a very different place now socially – the last switch was more of an evolution whereas the switch to hydrogen is revolution.
In terms of gas transitions, any low-carbon gas could potentially be an important aspect and hydrogen as a concept may well be one of those things. I however am not convinced that hydrogen is a panacea to the UK’s heat problem – our addiction to gas. I was on the steering group for the recently released H2FC report and for the record although I think that research into hydrogen and potential uses for the gas grid are incredibly important I do have some concerns about the paper.
Hydrogen is one of those things, like fusion, someone is always talking about and which could at some point breakthrough to be the foundation of a new economy…..apparently. But, hydrogen is just a vector, a way a carrying energy. Admittedly potentially a good way of transporting energy but none the less a vector.
The title of the report is : The Role of Hydrogen and Fuel Cells in Providing Affordable and Secure Low-carbon heat. You can read it here: http://www.h2fcsupergen.com/whitepaper/lowcarbonheat/. As I have mentioned, I have a few concerns with the recent report which I did comment on and I hope my thoughts will push the debate further. I want to elaborate on these points.
So according to the report, hydrogen can provide secure and affordable heat. Lets tackle affordability first. The report suggests that currently the cheapest domestic hydrogen fuel cell systems are around £12,000 for a 0.75kw electrical output system. A gas boiler is around £1000 (for a good one) and that will provide probably about 24kw. There is clearly a big difference here in terms of capital costs though I do see that these could potentially come down in the future. The reports numbers for ongoing costs suggest that these will be slightly cheaper on annual basis due to the export of electricity. The report also includes the income from the FiT in its annual cost calculation and this is something which at a system level is not a benefit but a cost as this is funded through bills and ultimately paid for by consumers. I think it is an error to include this in the financial data and skews the cost results. So overall we know that at the domestic end these systems are going to be expensive to purchase and install but that using natural gas at current prices annual operating costs could be very slightly reduced.
The report also contains little on the actual costs of producing hydrogen and its sources. Much more clarity in this area would be useful to allow people to full envisage how this whole system comes together. In my mind there are two potential types of source of hydrogen and for it to be any good, it needs to come from a low-carbon source and not-a bioenergy source – the use of bioenergy for gas has its own whole host of problems namely how much is available and its life-cycle emissions. So firstly you can use excess intermittent renewable generation i.e. wind and solar to produce hydrogen. This may be at a network constraint, during a period of high supply and low-demand or a combination of both. However the TSB work released last year (Power to Gas – A UK Feasibility Study) showed that the main benefit for this was through reducing constraint payments rather than supplying a high proportion of low-carbon heat so, something good to do but not something that will solve the heat problem.
So the other potential option is using low-carbon power generation for hydrogen. Most of this will be nuclear or offshore wind which are both already expensive (say £100/MWh) and potentially unreliable and variable respectively. There are then energy losses in the conversion process (quite a lot of heat is made at the same time and wasted) and some losses in the gas networks. So the question then is why not use that valuable power for something else? A heat pump can have a performance factor of 3 effectively a 300% efficiency factor so surely that makes sense.
There is also a building stock issue in the UK that could really make fuel cells struggle. Like heat pumps, the fuel cells provide lower grade heat than a gas boiler meaning that you run them more constantly than boilers but with a lower output. The one I mentioned earlier was just 0.75kw electrical which I would expect to be around 1kw heat which is a really low output (bear in mind this was 12 grand) but even a heat pump at domestic level will be around 4 or 5 kw. In order to ensure a house gets warm enough when you use low temperature heat, the house needs to be very efficient for a heat pump and clearly even more so for a fuel cell. But we are talking really a step change from where we are to very airtight and well insulated homes. For our beloved Georgian terraces these fuel cells will not work I’m afraid.
As for the idea of using hydrogen in gas boilers although this sounds simple there is an issue with the capacity in the gas network as calorific value of a meter cubed of hydrogen is around half that of a meter cubed of natural gas. A pure hydrogen network would only be able to carry half as much energy so may need to be increased in capacity – surely you’d build more electric instead?. You would also need to replace all the steel pipes with coated pipes and remove any iron pipes. So, a pure hydrogen switch would still require a lot of work to the network – this isn’t something that could happen easily.
You may be able to tell I am clearly not convinced by the merits of hydrogen yet – yes there are benefits but, it needs to be seen as a part of the system rather than a simple fix. For heat there are no easy options. They are all difficult, expensive and a hassle for consumers. I believe that DECC’s current position to put more efficient electric and biomass in rural – areas and district heat in urban areas (the pincer movement) does seem like the most pragmatic option – despite some of the clear challenges.
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