Not enough reliable wind?
Pöyry’s ‘North European Wind and Solar Intermittency Study’ (NEWSIS) has found that “The creation of an offshore ‘super grid’ and a major upgrade of energy interconnections are not the silver bullet solutions to Europe’s energy needs”. It says that the introduction of improved connectivity would only partially alleviate the volatility of increased renewable energy generation. Basically it claims that “Wind and solar output will be highly variable and will not ‘average out’”, even over wide areas- it looks at the NW of Europe- England, Wales , Scotland (but oddly not Ireland, North or South), France, Belgium, Luxembourg, Austria, Poland, Germany, the Czech Republic, Switzerland, Denmark, the Netherlands, Sweden and Norway.
It assumes existing wind and solar expansion plans go ahead, but says that, as result, “by 2030, wholesale market prices in some countries will have become highly volatile and driven by short term weather patterns”. although it adds “countries with large amounts of hydro - in particular the Nordics - are much less affected by increased price volatility.”
Crucially it says that “heavy reinforcement of interconnection doesn’t appear to offset the need for very much backup plant, however. This surprising observation comes from the fact that weather systems - in particular high pressure ‘cold and calm’ periods in winter - can extend for 1000 miles, so that periods of low wind generation are often correlated across Europe. Hence interconnection helps when it is windy in one country and still in another, but when it is calm across many countries together, interconnection is much less helpful”.
So it concludes “interconnectors are not a complete solution.’ But actually no one said that interconnectors were ‘a complete solution’ - there would also be a need for backup, storage, and demand side management, plus inputs from other renewables. The report does say that “in many ways ‘demand-side’ solutions are most suited to matching the needs of intermittency” and it looks at key aspects of ‘Flexible demand’ e.g. flexibility from non-heat sources (such as washing machines, tumble dryers etc.) and optimised charging of electric vehicles, including for example “the speed of response, the timescales for being turned off, speed of deployment and likely behavioural characteristics”. But it claims that, while ‘demand-side’ involvement may be attractive, “the wide range of likely deployment patterns and technological developments will further complicate investment decisions- and quite possibly slow deployment”. www.poyry.com/linked/en/press/NEWSIS.pdf
Overall then a pretty negative vision, coming to very different conclusions to those from most other studies- apart from those from the UK Renewable Energy Foundation (who loved it!) and some anti-wind utilities (who helped with it). For example, a new Germany academic study, published in Recent Advances in Energy and Environment, concluded that pan-EU supergrid links could halve the need for backup: www.wseas.us/e-library/conferences/2010/Cambridge/EE/EE-29.pdf
An earlier EWEA Tradewind study found that, for the 2020 medium scenario (200 GW, 12% wind penetration), aggregating wind energy production from multiple countries strongly increased the capacity credit, the amount of capacity that can be relied on to meet peak demand, almost doubled it to 14%, which they say corresponds to approximately 27 GW of firm power in the system. www.trade-wind.eu
And the EREC /Greenpeace’s Energy [R]evolution ‘24/7’ report concluded that “during the last 30 years, the potential power production from wind during winter time throughout Europe in the Energy [R]evolution scenario would have only dropped below 50GW 0.4% of the time, equivalent to once a year if the average duration of the event is 12 hours”. See: www.energyblueprint.info/ and for the full report: www.erec.org/fileadmin/erec_docs/ Documents/Publications/global%20energy%20grid%20scenario.pdf
But then, unlike Pöyry, they were all looking across the whole of Europe, North and South- a wider footprint- and in some cases (e.g. Gregor Czich’s seminal supergrid work) the windy east and North Africa as well, with a full supergrid network linking in wind, solar, biomass, geothermal, hydro and other renewables.
Czich’s study is soon to published by the IET. The pan -EU grid balancing issue is followed up in more detail in a recent report from Greenpeace: www.greenpeace.org/international/Global/international/publications/climate/2011/battle of the grids.pdf
No one is suggesting that there will not be a need to balance wind variations, or that at times there will relatively little wind in many places, but most studies seem to agree that this problem can be dealt with at low cost. Those who are basically hostile to significant reliance on wind power, tend to make much of this issue, often focusing just on one country, and on what they see as the hopelessly low on-land wind turbine load factors. For example, Scottish environmental charity, the John Muir Trust (JMT), recently released a report produced by Stuart Young Consultancy claiming that, rather than the 30% load factor often cited, between Nov. 2008 to Dec 2010 UK on-land wind farms operated below 20% of capacity more than half the time and below 10% of capacity over one third of the time. Overall they achieved 24% average. In 2009 it was 27.18%, in 2010 21.14%.
Average wind speeds have certainly fallen in recent years, but this may just be a short-term climate variation. The JMT report however saw the recent low average load factors as fundamental, and challenged industry claims that periods of widespread low wind were ‘infrequent’. The JMT report claimed that the average frequency and duration of a ‘low wind event’ was once every 6.38 days for 4.93 hours- and the analysis found that there were 124 times when winds dropped so much that just 4% of expected output was generated.
The report noted: ‘Very low wind events are not confined to periods of high pressure in winter. They can occur at any time of the year.’ During each of the four highest peak demands of 2010, wind output reached just 4.72%, 5.51%, 2.59% and 2.51% of capacity, according to the analysis. It concluded wind behaves in a “quite different manner” from that suggested by average output figures or wind speed records.
The report concluded: ‘It is clear from this analysis that wind cannot be relied upon to provide any significant level of generation at any defined time in the future. There is an urgent need to re-evaluate the implications of reliance on wind for any significant proportion of our energy requirement.’
Dr Lee Moroney, the Renewable Energy Foundation’s planning director, said: ‘Experience is teaching us that wind power is not only highly variable over short timescales, but also from year to year and even in regions which have previously performed well. This finding has important economic implications for the conventional generators acting in the support role for wind. These face radical uncertainty about income from one year to the next.’
However, Jenny Hogan, director of policy for Scottish Renewables, said ‘We have no confidence in these unofficial figures. Last time Stuart Young completed research on wind farm output an independent analysis showed serious discrepancies. He claimed the load factor for wind for the period of November 2009 to November 2010 was 22%, however GL Garrad Hassan, an independent consultancy firm, found on average it was in fact 24.8%. We recognise this is lower than the 30% average load factor. However, this was anticipated as it had been an exceptionally calm year.’
She added: ‘Yet again the John Muir Trust has commissioned an anti-wind farm campaigner to produce a report about UK onshore wind energy output. It could be argued the trust is acting irresponsibly given their expertise lies in protecting our wild lands and yet they seem to be going to great lengths to undermine renewable energy which is widely recognised as one of the biggest solutions to tackling climate change - the single biggest threat to our natural heritage’.
Stuart Young, the JMT report’s author, is, it seems the chairman of the Caithness Windfarm Information Forum - described on its website as ‘group of people concerned about the proliferation of windfarms in Scotland’.
‘Analysis of UK Wind Generation’ is at www.jmt.org/assets/pdf/wind-report.pdf
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