Wind and solar PV have expanded rapidly in recent years round the world. Since solar is easier to install it has grown faster in some countries, but in countries in the north wind has been in the lead - and in the UK offshore wind now has the edge over onshore wind. That’s in part since wind speeds are generally higher and more consistent offshore (so the capacity factors are higher) and also since the machines can be much larger. That’s important because the energy output from wind turbines is proportional to the square of the blade size and the cube of the wind speed. So, put simply, big and windy is best, and so, depending on location, the cost/MWh offshore can be cheaper than onshore, despite the extra cost of installation/maintenance and undersea power transmission. Moreover, the offshore advantage may increase given the advent of floating devices, which makes it easier to install systems in deep water far out to sea where the wind regime is best.
Given that, although on shore can pay an expanding role, it seems likely that offshore wind will continue to lead all else in UK, as (usually) the lowest cost large-scale option. Certainly a study for RenewableUK by Aurora Energy Research shows that, by 2035, an electricity system mainly powered by offshore wind will be more cost-effective for consumers than alternatives such as gas or importing power from abroad through interconnectors. Other renewables, like solar, are also part of the scenario, but in the UK at least, offshore wind is likely to dominate, maybe overtaking the current 50GW by 2030 target and possibly even reaching over 250 GW by 2050 in Aurora’s highest scenario.
That view will not go down well with onshore wind enthusiasts and those who look to small/medium scale wind turbines to support decentralisation and avoid more grid links. There are many UK sites where small to medium-scale local wind is sensible, avoiding high transmission costs (Aurora’s scenarios have around 100GW by 2050), and PV solar of course too (it has over 70GW by 2050), but for local autonomy (no offshore wind power imports), to balance varying local green supply and local demand around the year, you would need a lot of long term and well as short term local storage and also a lot of local green supply over-capacity, all adding substantially to the cost.
Cutting energy waste would of course help, as can lifestyle changes, but it had been argued that, given the urgency and scale of the climate crisis, that won’t be enough. Peter Harper (CAT and then Bath University) and Stephen Peake (UNFCCC and then OU) have claimed that, ‘regrettably’, we may have to resort to ‘emergency technocentrism’. They say that ‘at first, we shared a general consensus within lay environmental circles, that the modern consumerist project is not comparable with biospheric stability; and that only a profound reorientation of lifestyles and aspirations would deliver a permanent solution. This might well have been, and indeed might still, be the case in the long term. However, in the intervening period, global-scale problems of physical sustainability have become worse, not better, and humanity appears be running out of time to avoid major physical discontinuities. We have been forced to confront the dilemma of whether to re-emphasise the need for cultural shiſts or switch to an ‘emergency’ rapid-response mode based on technology and infrastructural changes.’
The polarisation between small/local and large/central can be over-stated. There are many opportunities for energy saving at the local level, and also smart power usage ideas to avoid waste and the rebound effect. And there are also behavioural change options (e.g. fewer flights, less meat): small voluntary local lifestyle initiatives like this can add up to large central savings. But Harper and Peake say that, sadly, they won’t add up to enough savings- maybe 40% at most. So we need to engage with large scale supply technology, like offshore wind. That is not so hard since it’s now cheap and has low eco-impact. One might say why not go whole hog and buy into nuclear. But that, so far, has high costs and, arguably, high impacts- with health, safety and security issues. And it’s slow to deploy. If we can condone higher costs, then tidal stream and wave power might be better candidates, with high capacity factors and low impacts- the UK Marine Energy Council recently suggested that the UK may have 30GW of untapped tidal and wave resource.
That may be surprising, given that, as I have mentioned in an earlier post, neither wave or tidal has developed as fast as was at one time expected- with costs remaining high. But many tidal technologies have been tested, with technical progress helping tidal stream turbine systems to get cheaper and attract CfD support, and tidal lagoons and small barrages also possibly getting support. Wave is further behind, but, in addition to new ideas like mWave, there are some new versions of old wave ideas which may yet prove viable and possibly cheaper- like the Floating contour system (similar to the 1970s Cockerall raft), Weptos, the Danish duck-type wave system, and the Australian shore line OWC ‘Wave Swell’ - a bit like the UK’s ill- fated Osprey.
Perhaps rather optimistically, one of the 100% renewables scenarios produced by Finland’s LUT University for the UK and Ireland included up 27GW of wave power by 2050. Well maybe, but at least a few 10’s of GW ought to be possible from wave and tidal by then. LUT also see solar PV as doing well, even in the often cloudy UK, with around 360GW in place by 2050. But given the low capacity factor for PV, that would deliver much less power (under half) than would be produced by the 160GW of wind capacity it envisages as being in place by then. That implies a lot of storage capacity would be needed, and indeed, LUT does have 145TWh worth in use by 2050, mainly batteries along with power to gas storage for long duration backup. Finally, biomass is a storable green fuel and its combustion is actually at present a significant (and controversial) power source in the UK. It also supplies some heat. But LUT don’t see that continuing. Instead they see wind and PV powered heat pumps playing a dominant role in heating as well as for power.
All this is very speculative and some of the LUT 2050 projections seem very optimistic- PV may win overall globally, but it’s hard to see quite as much PV being installed in the UK as LUT envisage. However, 2050 is a long way off and what will matter in the end is how the various technologies develop and what decisions are made about funding for them. For now, clearly offshore wind is in the lead in the UK, and in the UK election run up (see my next post) it did well in some party Manifestoes, with Labour looking to 60GW more by 2030. But so did PV, with the Conservatives looking to 70GW by 2035. We will have to wait and see who (and which!) wins.
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