By Dave Elliott
British Pugwash has produced a report looking at three possible 2050 UK energy scenarios – high nuclear, high renewables and an intermediate scenario. They were all run through the DECC Pathways analysis software to see how they stood up.
Pugwash has been working as an international body since 1955 to diminish the role of nuclear arms in international politics and towards nuclear disarmament, but it seems has no specific view on civil nuclear, apart perhaps from general background sympathy for the post WWII ‘Atoms for Peace’ position, given that many of its members were of that generation. But some of the younger members may have anti civil nuclear views-including those in the UK.
The UK Pugwash group enlisted support from some external experts to help produce the report. I was asked to produce the ‘maximum renewables’ section. It was a challenge. But, working with Dr David Finney, who helped with the modeling, I found that it does seem that, assuming a sensible commitment to reducing energy waste (an eventual 40% reduction), it would be possible to match supply and (reduced) demand with almost 100% renewables by 2050, with off shore wind, wave and tidal power playing major roles, along with PV solar, for electricity supply, and some of this electricity being used, together with biomass and solar, for heating, and, along with biofuels, for transport.
With 76GW of offshore wind and 30GW of on land wind, the High Renewables scenario supplies electricity for direct use, and for heating and transport, but that leaves plenty for export. Indeed exports of excess wind derived electricity would earn around £15 billion per annum, by 2050. There is also heat from biomass and solar, but no biofuel or biomass imports. Hydro, geothermal, biomass CHP, some stored electricity and some stored green gas, along with interconnectors (up to 15GW) and demand management, balance the variable renewables.
The DECC calculator indicated that, with the balancing provisions, by 2050 there would no need for extra fossil backup capacity. Even when energy demand was high and the input from wind and the other variable renewables was low, it met demand and indeed, most of the time, oversupplied, leading to a significant potential for net power exports. It also easily achieved the DECC emission reduction target.
To get to a full 100% renewables, while being able to balance the system when wind was low, we wanted to make use of some of the excess wind derived electricity to make hydrogen and store it ready to meet demand and replace the residual fossil input. The DECC software would not allow for that, or for all the fossil fuel transport input to be removed, so the scenario we tested did not reach 100%, but were confident that this would be possible.
Looking ahead to 2050 is hard, so as a guide I used existing scenarios where I could. For the electricity side, I used the contributions outlined in the ‘Max’ 2050 electricity scenario produced by Poyry in 2011. That actually now looks quite conservative, given for example the capacity gains PV solar has made recently- DECC now says PV might supply 22GW by 2020. And also the 9.5 GW of geothermal power that REA/SKM say are possible. The only adventurous element on the electricity supply side was the assumption that floating offshore wind systems would be available for deep-sea use. But to be cautious I cut the Poyry offshore wind allocation in half.
On the heat side however I was a bit more adventurous. In addition to the idea of producing green gas, using excess wind derived electricity, I made use of some the emerging ideas about solar and biomass fed district heating and heat stores, including possibly interseasonal heat stores. But DECC now seems to have rccognised these as possibilities. The land-use implications of biomass requirement might be more problematic (10% of UK land) , but if that proved to be major issue then some biomass could be imported e.g. wood chips from Canada.
Given the novel boundary-crossing options, it was not easy to run it on the DECC software- as noted above that won’t let you replace all the fossil oil and gas with syngas from wind ! But nuclear was easy to remove. It was just not needed. The Pugwash ‘maximum nuclear’ scenario by contrast saw it as essential, supplying over 74% of electricity by 2050. I will leave that to you to decide if that is realistic or needed.
I have avoided scenario writing in the past since I felt that all that did was allow you the project unrealistic normative and technical assumptions into the future and give a spurious sense of legitimacy to them. However maybe it is useful to test the technical viability of specific policies and have assumptions played out for all to see! Even so I still have my doubts. Prof. David Mackay has sensibly made much of the need for quantification and for ‘the sums to add up’, but unfortunately, at this stage, given the open-ended nature of the emerging system, it is hard to come up with reliable data to feed into the DECC model and the model itself has problems. So perhaps, for now, we still have to fall back on what Mackay depicts as ‘Hot Air’, that is, more general strategic assessments.
Although I did include some detailed technical rationales, perhaps inevitably, I also found it necessary to make some policy points. For example I argued that ‘There are longer term advantages from focusing on renewables, not least the fact that the energy sources will never be exhausted and the conversion technology is likely to continue to become more economic. It is sometimes argued that, while that may be true, the UK should wait until the technology has developed (presumably mostly elsewhere) before deploying it widely. But that argument ignores ‘first mover’ commercial and technological advantages. It might be wise for the UK to focus on it strengths, which currently are in the marine renewables field, but more generally, as Barak Obama put it eloquently ‘the country that harnesses the power of the clean, renewable energy will lead the 21st century’.
The UK may not be able to lead in all areas, but it can be a major player, whereas it stands little chance of leading in nuclear or CCS. Given that the UK has probably has the worlds best renewable resources, as well as established technological expertise, particularly in offshore engineering and marine technology, there is a strong strategic case for focusing on renewables.’ Certainly of its is diversity you want, then renewables offer a range of options at various scales.
My venture into modeling confirmed that renewables really can help us attain a sustainable energy future and by 2050, if we so wished. Several studies have suggested that while some of the initial investment costs might be higher than for some conventional technologies, longer term the overall cost would be similar if not less- since we would no longer have to import expensive fossil fuel or deal with the extra cost of nuclear power. And, interestingly, on the basis of DECC’s Calculator, the Pugwash High Renewables Pathway did turn out to be slightly cheaper than the nuclear/CCS based pathways also looked at in the report.
The Pugwash report is at: www.britishpugwash.org/