Nuclear power may not be very competitive as an electricity generation option, but a new UK National Nuclear Laboratory study looks at possible future roles for nuclear in providing not only electricity but also heat, hydrogen and synthetic fuels. On this basis, it says, the prospects look better. It has one net-zero carbon scenario with around 66GW of nuclear capacity installed by 2050, supplying a mix of heat, power and hydrogen. 13 GW of (light) water-cooled Small Modular Reactors (LWSMRs), run as co-gen/Combined Heat and Power units, supplies power and heat, for example feeding into local district heating (DH) networks, and 49 GW of Generation IV reactors supply power and hydrogen.
'Gen IV' is a catch-all category for all new large-scale nuclear designs, following on the from the various Gen III upgrades of standard large Pressurised Water /Boiling Water Reactors- the later all using conventional 'light' water, as opposed to the 'heavy' water isotropic variant used in some experimental plants. Interestingly, the report notes ‘Gen IV technologies are equally capable of combined heat & power operations for DH energisation as LWSMRs…. the technical performance & economic differences between Gen IV & LWSMR are relatively small when considering their relative merit for CHP configuration for potential DH energisation.’
That’s a little surprising. A common rationale for SMRs is that they can supply local heat loads, unlike large plants, which, for safety reasons, are usually sited remotely from urban areas. Though it’s far from clear that SMRs will be any more acceptable by local residents. The NNL report certainly seems to suggest that the technical efficiency/performance differences ‘are small when considered against the overall need for market, policy and regulation consideration of whether city scale district heat networks are to be part of the basket of technical solutions to decarbonise space heating and hot water production in larger towns and cities.’
Maybe a hint there then that nuclear, large or small, might not be welcome in or near cities. The report simply says ‘a policy decision not to deploy nuclear plants (large Gen III+, LWSMR, or Gen IV) as capable of future energisation of city scale district heating systems is likely to increase demand for hydrogen and electricity generation. Technologies contributing to this increase in installed generating capacity are likely to include wind and nuclear’. i.e. with power generated remotely and converted to and piped in as hydrogen, or used directly as electricity for heating.
Clearly there is something of a race going on the meet these needs and the NNL see new nuclear as a viable economic option, with costs predicted to fall. That’s very debatable on past experience. But its ‘higher optimism’ scenario assumes SMR costs will fall rapidly with mass production and looks to ‘an advance of the first UK operations date of a commercial AMR from 2035 to 2030 with an increase in learner effect through to 2050’. AMR is the general name for advanced modular reactor concepts like high temperature reactors. The NNL study does kook briefly at the market for high temperature industrial process heat, but it focussed on arguable easier-to-supply lower temperature hot water for urban district heating. But, whichever way it goes, it’s all based on as yet unproven technology, unlike with already developed and increasingly low-cost wind and solar.
The NNL report does not discount renewables, they are see a partnering nuclear, but you need good eyesight to see the domestic solar PV contribution in NNL’s overall UK electricity generation mix run 27 chart, even by 2050. Larger solar farms do a bit better, but they are beaten by tidal stream technology! Seems NNL doesn’t like solar much!
It will be interesting to see how things actually play out in reality. Tidal stream technology does have good prospects in the UK, but most energy scenarios see PV solar becoming dominant globally by 2050 and some even say that will be the case in the UK. Good Energy’s new Zero Carbon Britain study (see my next post) has a massive 210 GW of solar PV in use by 2050, compared to around 18 GW in one of the NNL scenarios. Interestingly, both set of scenarios were produced with help from Energy System Catapult, so this big difference feels a little odd.
On the nuclear side, it’s hard to see any more large conventional plants after the Hinkley EPR, although EDF seem keen to push the Sizewell EPR on. However, the NNL report also focuses on Light Water SMRs, of the mini-PWR type being developed by Rolls Royce and NuScale, which, although still unproven, may at some point begin to move from concept to test stage. The NNL report does mention Molten Salt Reactors in passing, but along with other novel nuclear technologies, such as the liquid sodium cooled fast reactor being developed by Terra Power, these options seem some way off, with major safety, security and economic issues to be resolved.
Overall, is does seem a bit premature to be talking in detail about heat and hydrogen supply from (very) new nuclear, but maybe the nuclear lobby does need to sustain the belief that there is a future for nuclear! Especially given the emergence of hydrogen generation from wind and PV projects and the viability of large-scale biogas, solar thermal, and geothermal heating. For example, with costs falling, IRENA looks to large industrial-scale solar thermal heating capacity to increasing from around 4 gigawatts thermal globally in 2018 to 890 GW (th) in 2030 and 1,290 GW(th) in 2050. That’s for major commercial and industrial scale heating systems, including new large urban district heating networks, and it’s in addition to the around 480 GW (th) of mostly roof-top domestic solar collector capacity that already exists globally. For comparison, total global nuclear power generation capacity at present is under 400 GW(e).
IRENA also says that, with the cost of renewable power, storage and electrolysers all falling, the cost of green hydrogen could soon beat that for fossil sourced/CCS backed ‘blue hydrogen’. Indeed, in some regions with good solar and wind resources it could already be competitive. It looks like nuclear might find it has serious rivals on all fronts.
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