It seems that 2014 has been the year to knock wind energy, with detractors trying to take a swipe at the technology, the health issues, planning, or any one of a number of perceived ills. We take a look at the reality behind the scare stories.
This year has seen yet more negativity on wind power, and proposals to cut support for on -land wind, despite this being the cheapest of the major new renewables. While overall public support for the use of wind energy remains high, in practice many new on-land projects are now opposed: two thirds of applications have been turned down in the last year. Much of this has been about visual intrusion, ‘Not In My Back Yard’ concerns relating to treasured views and, more prosaically, possible impacts on house prices. There have been conflicting reports on the latter.
A study for RenewableUK by the Centre for Economics and Business Research concluded that, on the basis of an analysis of 82,000 transactions at seven sites in England and Wales over the past 10 years, wind farms don’t have negative impacts on property prices within a 5km radius, and can even push up house prices in some areas. But an LSE study, using a different methodology, said prices within a 2km radius can fall by up to 12%!
Another issue sometimes raised is noise and in particular infrasound. While audible noise, even at very low levels, can be annoying, so that siting is a key issue, the claim that there have been significant heath effects from ultrasound seems to have been roundly disproved: http://barnardonwind.com/2013/02/20/humans-evolved-with-infrasound-is-there-any-truth-to-health-concerns-about-it/
Wider economic and strategic arguments have also come to the fore. For example in April, in a leader entitled ‘An Ill Wind’, the Times said ‘Britain’s wind power boom is based on assumptions that have proved wrong and subsidies that are unsustainable.’ It went on ‘Britain has pledged to produce 30% of its electricity from renewable sources by 2020. Assuming this target is met and all commitments to wind turbine operators are honoured by this and future governments, the cumulative cost to British consumers could reach a staggering £160bn by 2040’.
It concluded ‘Wind power is the most practical form of renewable energy available, but subsidies have allowed the industry to delay technological advances to bring down costs. Wind has a place in the energy supply of any economy in search of a sustainable future, but not on these unsustainable terms’.
The debate over relative levels of subsidy for renewables and nuclear will no doubt continue, but in terms of technical viability, there has been much made of the problems of relying on ‘intermittent’ wind. However, the Royal Academy of Engineering’s new study ‘Wind energy: implications of large-scale deployment on the GB electricity system’, does not see major grid integration problems with wind power up to around a 20% contribution: ‘With a wind fleet of 26GW (as expected in 2020 or soon thereafter) and using a de-rating factor of 0.17, the equivalent firm capacity would be 4.4GW.
On occasions of negligible output from wind, this would mean a potential shortfall of 4.4GW which should still be manageable assuming a healthy overall capacity margin.’ Although it said that ‘additional unexpected events such as a generating plant outage could compound the situation,’ it felt that ‘the probability of this happening would be low enough to constitute an acceptable level of risk.’ But it warned ‘The de-rating factor is likely to fall as wind capacity rises, since a de-rating factor of 0.17 and a wind fleet of 50GW, as suggested for 2030, would produce a potential shortfall of 8.5GW which would present problems for security of supply on its own’.
The implications are that there would have be more extensive grid balancing measures available to cope with wind at this level, and the RAe looks at some, including smart grid demand management, interconnection and storage. Certainly smart grids can help time shift demand away from peaks when wind is low, and the local variability of wind means that there will also be options for converting excess wind-derived electricity into hydrogen gas by electrolysis and then storing it for later use when wind is low, or exporting excess electricity via supergrid links to other regions where demand there is high, but wind low.
That must surely be better than just dumping the excess electricity, or curtailing wind plant operation regularly.
The RAe however see this possible surplus as a problem rather than an opportunity: ‘Considering 2020 and a wind fleet of 26GW, if minimum demand is still around 20GW it is unlikely, but possible on rare occasions, that wind could be producing almost as much electricity as the system requires. This might therefore be a level of penetration of wind energy when issues could start to occur that could have knock-on effects for other types of generation and overall system security. By 2030 and with a wind fleet of 50GW, the situation would be much more extreme. Output from wind could easily exceed demand and the system would need to find ways to manage the situation’.
Wouldn’t export be one option? The RAe evidently doesn’t think so. Balancing via supergrid imports is also apparently not very viable. While it accepts that ‘higher levels of interconnection with other systems and the full range of generation that they offer will afford greater levels of flexibility’, it says that the geographical and time correlations between wind availability and demand are not that good across the EU.
A bit debatable, that – it depends how wide the footprint is set. They only look at correlations between the UK, Denmark and Germany. Southern, Eastern, Northern and Western Europe do not necessarily share the same weather patterns (for sun as well as wind). Although it may be true that, as the RAe asserts, ‘low wind output in one region is unlikely to ever guarantee high wind output in another.’
So they conclude ‘the UK system must still be designed to cope with periods of low contribution from wind energy, regardless of where it is from’. Even so ‘in the future, assuming higher degrees of interconnection, it will be important to consider the UK grid as part of the larger EU grid with a detailed analysis of various mixes of generation required on a European basis’.
The energy storage option is looked at in detail in a parallel report from the Institution of Mechanical Engineers (IMechE). It claims that, without storage, consumers will be faced by increasingly bills for constraint/curtailment payments to wind generators. The report ‘Energy Storage: The missing link in the UK’s energy commitments’, highlights energy storage technologies such as those based on cryogenics (liquid air), flywheels, and graphene super-capacitors. It’s a useful report, but while storage clearly has a role, it’s expensive and, as the RAe note, there are other grid balancing options which could help us to use large amounts of wind power more effectively.
What next? Will wind meet the planned targets? The UK has around 10GW of on-land and offshore wind generation capacity in place at present, and Gary Dolphin, National Grid’s Market Outlook Manager, says, to meet our targets ‘we need to reach a combined wind capacity of 26 GW by 2020, so the scale of the challenge is readily apparent’. He points out that National Grid’s Gone Green scenario ‘requires three hundred 5 MW turbines to be connected offshore every year from 2017 to 2020 – a rate that is close to one [turbine] a day.
During 2012, there were a total of 234 turbines connected offshore’. That’s only 0.64/day. With some new proposal having been withdrawn and on land projects also meeting opposition, it’s going to be a race! It can still be done, given the political will, but as Dolphin says ‘the next one to two years will be pivotal’.
