By Dave Elliott
Nuclear and renewables continue to be seen as rivals, with, as part of the debate, studies emerging that address their problems. A study by the Energy Institute at University College London says the UK’s proposed Hinkley Point C nuclear plant will be obsolete by the time it starts up (possibly EDF says in 2025/6) since it will be in competition with cheaper low carbon options, including wind and PV solar. These sources are variable, but at times they will produce all the electricity needed, leaving no room for Hinkley unless their output is curtailed. At other times they will only make small contributions, but the UCL team calculates that only around 20GW of ‘firm’ inputs like Hinkley will be needed to operate for more than half the year by 2030 to meet the gaps and peak demand. And there are cheaper more flexible balancing options for this than Hinkley.
The UCL team says that ‘with current patterns of electricity demand in GB, the need for baseload vanishes once the GB system secures an average of around 30% of electricity generated from wind, and 10% from PV. The UK Secretary of State has indicated that the UK expects to achieve around 35% of its electricity from renewables by 2020, though this also includes controllable renewables such as biomass. National Grid’s Future Energy Scenarios (2016) span a range of projections. Their Gone Green scenario by 2030 has 28 GW of offshore wind, 18 GW of onshore wind, and 29 GW of PV, which represents 37% wind, 8% PV output, which is more than enough for the wind+solar output to sometimes exceed national electricity demand.’
Basically, they are suggesting that this 70GW of renewables can meet most demand most of the time – the UK winter peak electricity demand currently being 55GW, with the current 20GW baseload minimum being provided when needed by a range of flexible inputs. Hinkley can’t help, since, they note ‘Load-following was deliberately and explicitly excluded from the approval process for new nuclear plants, the Generic Design Assessment (GDA)’.
They conclude that ‘by 2030, around 20GW of capacity is required for less than 10% of year, to cover peak net demand, for which nuclear power is manifestly unsuitable. The dominant need in the majority of National Grid scenarios post 2030 will be for adequate responsive capacity displacing coal and gas, and more efficient approaches to balancing demand and supply’.
It’s not quite clear from what is said here if this balancing ‘10% of the time’ will be enough to meet low wind/PV situations, as well as meeting peak demand: earlier it was said to do that would need 20GW used for ‘more than half the year’. But 20GW is roughly in line with the conclusions of my IOP ebook ‘Balancing Green Power’ – although that’s for 2050, with more green power in place by then, and most of this 20GW potentially then being non-fossil and, of course, non-nuclear.
The UCL team did accept that new nuclear technology might be cheaper and more flexible, although it thought that any nuclear flexibility would come at a cost. Overall it comes down clearly on the side of renewables and flexible grid management.
That being so, then we have to address the key problems that face renewables. One is environmental impact and, in particular, visual intrusion. A new book from the US looks at ‘The Renewable Energy Landscape’ and at how renewables can blight it, but argues that we must and can preserve scenic values while shifting to a sustainable future. Edited by Dean Apostol, James Palmer, Martin Pasqualetti, Richard Smardon and Robert Sullivan, and published by Routledge, it provides a guide to understanding, assessing, avoiding, and minimizing scenic impacts as we transition to a more renewable energy future. It focuses on the unique challenges solar, wind, and geothermal energy will create for landscape protection, planning, design, and management. It says that all environments change and we can’t avoid that, but we can minimise our impacts, avoiding sensitive sites and limiting disturbance as far as possible. It looks at the situation in the US, Canada, Australia and the EU, focusing on wind onshore mainly, but also offshore wind and other renewables, including large-scale solar, with many detailed case studies.
Offshore wind might seem to be less of a problem than on-land wind and solar, but there can be impacts on sea mammals, especially if sea-bed pile drilling is needed to install foundations. However, effective amelioration of noise impacts on porpoises during foundation piling has now been achieved using bubble curtains.
And floating offshore wind systems don’t have this problem at all. Offshore wind projects also avoid bat impact issues, which have recently been reassessed. And also operational noise problems, including blade swish, which a recent study has suggested might be a significant cause of annoyance at some land-based sites.
Offshore wind may avoid some problems, but it is still a variable source and, despite analyses like that from UCL above, the variability of some renewable sources is still seen by some as a major problem. The World Energy Council (WEC) has taken a hard-headed look at this in a new report ‘Variable Renewables Integration in Electricity Systems: how to get it right’. It is quite severe in its warnings: ‘the complexity and the overall impact of variable renewables integration in national electricity systems are often underestimated both by the consumers and politicians’. And it keeps hammering home the point that ‘the weather dependency of wind and solar PV, especially when they reach a significant share of the generation capacity and energy production, may raise barriers to their smooth integration in the electrical systems which were not originally designed for this type of generation’, with examples drawn from around the world.
I will be looking at WEC’s report in my next post. However, for now, suffice it to say that, while WEC is right to point out that balancing needs attention, that is in hand and several studies have indicated that the costs need not be high, as I have reviewed in my book on Balancing Green Power. Indeed, providing better balancing of variable supply and demand using flexible systems may actually reduce overall costs by reducing waste. Some say that small modular reactors may also be able to help with grid balancing, since they might be able to meet local heat loads and ramp power up and down more easily than large nuclear plants. However, that is still uncertain, as are their costs and their safety and security implications, and hence their social acceptability, especially if sited in or near cities.
Certainly there are many arguably less problematic alternatives for system balancing and also for local power and heat production. Will anyone want a mini-nuke in their backyard? The debate goes on: renewables now supply around 25% of UK annual electricity, and with costs falling fast, they are expanding rapidly, and the 35% by 2020 expectation may well be exceeded. Balancing measures are at last also getting funded, including storage and demand management – although more is needed. But after 2020, it’s not clear what happens – there are no longer-term renewable targets. All we have is the claim last year from the then Energy Minister Baroness Neville-Rolfe that we could potentially get 30% of our electricity from nuclear by 2035.