Wind farms – myths & truths. Global context. In 2008 Ernst & Young identified climate change as the number one risk to the insurance industry worldwide . In 2012 Fatih Birol , IEA chief economist said: ‘We have 5 years to change the energy system – or have it changed [for us].’.
Wind farms – myths & truths
In 2008 Ernst & Young identified climate change as the number one risk to the insurance industry worldwide.
In 2012 FatihBirol, IEA chief economist said: ‘We have 5 years to change the energy system – or have it changed [for us].’
Climate change – ‘well established science’
The Royal Society regards man-made climate change as well established science.
Each decade since the 1970s has been clearly warmer than the one immediately preceding it.
Local temperatures are a poor guide to global conditions.
Various lines of evidence point strongly to human activity being the main reason for the recent increase.
Wide consensus, but continuing debate
If we stopped our CO2 emissions today, it would still take several millennia for concentrations to return to preindustrial levels.
Impact of volcanic eruptions – ‘largest effects last only a few years’.
Emissions from the sun – ‘natural forcing [from] the sun over the past 150 years is estimated to be small – about 0.12 Wm2’.
Effect of other greenhouse gases resulting from human activity, e.g. carbon monoxide.
Changes in water vapour levels.
Areas of substantial uncertainty
The impact of known tipping points – major climate forcing events, such as ice caps melting, rainforests dying out, tundra drying out, sea-bed gas release.
Not uncertainty over whether these will have an effect; instead over how large the impact and how much global warming will surge as a result.
These tipping points have largely not been factored into climate models.
What’s the ‘safe’ level of climate change?
Currently a general consensus that climate change must be kept below 2oC.
2oC will lead to additional rises in global temperatures – because impacts will provoke further climate forcing events.
Global agreement of need to reduce CO2 emissions by 80% by 2050 – but no formal treaty.
BUT – increasing evidence that global warming is happening faster than predicted.
Prime Minister of Greenland said in 2012 that Greenland is already struggling to adapt to climate change, because warming has been much faster than predicted.
How long do we have to adapt?
Growing consensus that staying below 2°C is impossible.
The International Energy Association (IEA) view is that the world is on track for a 3.5°C rise by 2040.
There is a widespread view that a 4°C future is incompatible with an organised global community – beyond adaptation.
Widespread fear that 4°C may lead to run away climate change.
Increasing fear among climate scientists that a 2°C rise could do this.
74% of the world’s greenhouse gas emissions come from energy production.
Britain, a key player in the Industrial Revolution and the carbon-based economic growth, should play a leading role in mitigating the impacts.
In 2012 FatihBirol, IEA chief economist said: ‘We have 5 years to change the energy system – or have it changed [for us].’
Why do we need wind farms?
Whatever happens, we’ll need new power stations.
Over 25% of our electricity capacity needs to be replaced in the next few years because it’s too old or polluting.
All major political parties have supported both the Climate Change Act which includes a legally binding reduction in CO2 emissions of 80% by 2050, and our renewable energy target of 15% total energy from renewable sources by 2020.
Together these ambitions mean that the great majority of our new electricity generation has to come from low carbon or renewable sources.
No-one’s suggesting wind farms will provide all of our energy in the future - we need a multi-source approach to electricity supply, especially because demand is likely to increase significantly.
Wind is competitive in price terms
In terms of renewables onshore wind is easily the most competitive in price terms. As shown in this recent comparison of levelised costs made by the LSE.
The government is also determined to develop shale gas.
Coal CCS & nuclear are more helpful options in my view, but both come with significant risks.
If you don’t like wind farms…
I probably can’t convince you otherwise.
But 2/3rds of British public consistently support wind energy.
And renewable energy capacity (much of it from wind) is set to overtake nuclear energy by 2018, if current rates of growth continue.
By 2015 we expect renewables to provide enough power for one in ten British homes.
Engagement in the planning process often results in developers amending proposals, to reflect local concerns.
Impact on Britain’s landscape
Myths about wind farms
Mostly perpetuated byclimate sceptic elements of the press, and anti-wind organisations, such as the REF, who use selective and often misleading data.
Others are concerned that wind farms will change the landscape they live in.
But, climate change will change the landscape more, and probably sooner than we think.
Despite vociferous opponents of wind energy – the majority of people in the UK support it.
Only about 1 in 20 are strongly against wind energy.
A recent poll showed 67% would rather live next to a wind turbine, than a shale gas development.
Not surprisingly, community ownership increases support.
Wind energy is one of the safest forms of electricity generation.
All deaths are regrettable, but since 1975 there have been only 76 deaths worldwide among people building, maintaining or taking down turbines.
In addition, eight members of the public have been killed in accidents world-wide since 1975 – none of them were simply passers by:
A parachutist in Denmark.
Acrop duster in the US hit a guy-wire on a meteorological mast.
Two traffic accidents in the UK and Ireland involving turbine transporters.
A man on a college campus who became unconscious while climbing a turbine tower on a tour.
A child in Canada was killed whilst playing around a residential turbine under repair.
One person killed during a high school prank.
One man was killed when his snowmobile collided with a fence around a turbine construction site.
Records across the energy sector from 1975 – 2010 show:
Wind energy 0.054 deaths per Gigawatt year; Natural gas: 0.197; Coal: 6.921; and LPG: 15.058
Only nuclear has better record, 0.048, but this fails to account for accidents such as Chernobyl and Fukishima.
The UK HSE has calculated the risk of being killed by a wind turbine is about the same as being killed by lightening.
Despite this, Wiltshire Council is trying to ban wind farms on safety grounds.
UK government has rejected separation distances.
Government guidance recognises that the ‘minimum desirable distance between wind turbines and occupied buildings calculated on the basis of expected noise levels and visual impact will often be greater than that necessary to meet safety requirements.’
The safe distance between turbines and buildings is generally considered to be the ‘fall-over distance’. The height of the turbine to the tip of the blade) plus 10% is often used as a safe separation distance.
In Scotland, where there is much lower population density, there is a flexible recommended separation distance of 2km, based largely on visual impact.
Wales also has a guide separation distance of 500m.
The UK National Planning Policy Framework states that wind farms should be assessed on a case-by-case basis. Flexibility is built-in to the framework.
Planners are ‘required to design their policies to maximise renewable and low carbon energy development while ensuring that adverse impacts are addressed satisfactorily, including cumulative landscape and visual impacts.’
Blade-throw and ice-throw
Blade-throw occurs when a blade comes loose, and is thrown a distance away from the turbine due to its momentum.
No reliable data evidence exists.
A recent study for the UK HSEestimated that, at a distance of twice the turbine’s height, the risk that a thrown blade would directly strike someone causing a fatality is 1 in 100 million.
Ice-throw is not a major issue in the UK’s milder climate. In most cases, ice falls within a distance from the turbine equal to the tower height.
It is very seldom that ice reaches a distance of twice the total height of the turbine.
The most modern turbines have blades that heat up so that ice does not gather.
Efficiency of wind turbines
Wind turbines start operating at wind speeds of 4 -5 metres per second (around 10 miles an hour)
They reach maximum power output at around 15 m/s(33mph).
At very high wind speeds, i.e. gale force winds, 25 metres/second (50+ mph), wind turbines shut down.
The most modern turbines can operate at up to 76mph.
One 1.8 MW wind turbine at a decent site could supply enough electricity for 1,000 households.
Wind turbines generate electricity for 75% - 85% of the time, but the output varies with the wind.
But, they don’t always operate at full power.
The electricity delivered annually to the grid is around 25% - 35% of what would be generated if they worked at full tilt continuously.
Energy infrastructure is very expensive, and governments in all countries find ways to support development.
British Gas, nuclear and coal all benefitted from enormous up-front tax-payer investment.
Nuclear legacy costs us 72% of DECC’s budget in 2010/11 (£1.9bn of £2.7bn budget).
Renewables, including wind, get no up-front support – nothing for capital costs or R&D.
Only when wind farms are actually generating electricity do they receive financial support – through Renewable Obligations Certificates.
Support from electricity users
Taxes are not used to subsidise ROCs – instead they’re traded by electricity companies, and so ultimately funded by their customers.
People who use electricity help fund the development of cleaner energy.
Ofgem figures show renewable energy accounts for just under 2% of a total combined average household energy bill of £1,174. (May 2012)
RenewableUK estimates that in 2010/11 wind energy added £7.74 to bills – or about 0.7% of a £1174 bill.
Other energy also gets government subsidy. For example, the ‘Contracts for Difference’ the government will award the nuclear industry could mean a subsidy of £2bn/year to just one operator, EDF.
In the long term, renewables should bring down consumers’ bills because they will free us from dependence on imported energy.
Other factors will also affect energy costs in the future, such as the likely introduction of global carbon tax.
GWPF says each MW generated by wind must be backed conventionally.
DECC says this isn’t correct – backup is needed anyway to cover demand surges – e.g. a World Cup penalty shootout can create a demand spike of around 2-3GW.
We need to see the system as a whole, to recognise that wind plays a key role.
The flicker effect
‘Shadow flicker’ is caused when the rotating blades of a wind turbine cast a shadow on an observer.
It is quantifiable.
Large commercial turbines can create a flicker effect at frequencies up to 2 Hz – well below the threshold that can cause photo-epileptic seizures (3-30 Hz)
Wind turbines do create some noise.
A motor moves turbine blades into the wind; blades swish in the air; there can be low mechanical noise.
Planning Guidance says day- and night-time levels should be set at 5 dB(A) above background ambient noise, with a fixed limit of 43 dB(A) at night, or 45 dB(A) for a dwelling that derives a direct economic benefit.
Wind Turbine Syndrome
This concept has been publicised by the press, but essentially dismissed by the NHS.
Alleged condition proposed by pediatrician Dr Nina Pierpoint, an anti-wind campaigner in North America.
She cites a whole range of physical sensations (e.g. tinnitus, headache etc.) and effects (sleeplessness, anxiety etc.), based on a series of interviews from a study group of 10 self-selected families.
The NHS described said, ‘study design was weak, the study was small and there was no comparison group.’
It was self-published and has not been reproduced in a single peer-reviewed journal.
Also rejected by Massachusetts Deptof Public Health, and Dept of Environmental Protection.
UK cats catch 55m birds each year.
It’s reckoned that for every bird killed by a turbine, 5,820, on average, are killed striking buildings, typically windows.
RSPB‘supports significant growth in offshore and onshore wind power generation in the UK.’
Turbines should be carefully located so birds aren’t disturbed during construction or operation.
The Bat Conservation Trust ‘supports the development of sustainable energy’.
If turbines are sited close to foraging routes, collision might be possible.
Natural England recommends 50m between turbines & foraging routes.
Developers help ensure bats are led away from the turbines, e.g. by planting new hedgerows.
Bats are much more active when wind speeds are low.
If identified on a site, great care would need to be taken to ensure the turbines posed no risk.
No evidence of detrimental impact on house prices when wind farms are operational.
Studies have shown anticipation ‘stigma’, during the construction period.
This transitory drop in house prices, quickly reverses when these negative effects fail to materialise post-construction.
Previous predictions by estate agents have been found to be inaccurate, compared with actual transaction data and the views of the buyers themselves.
There is also evidence that wind farms can have a positive impact on tourism.
Getting something back
There is an increasing view that affected communities should gain direct benefit.
People with a direct stake in the ownership or profits of a wind farm are better inclined towards them.
It’s important that benefits are not compensation for a poorly designed wind farm and must not be seen as a bribe.
Communities can benefit in different ways – by sharing ownership; – through reduced electricity prices; – through funds that invest directly in community projects.
In Germany almost two-thirds of renewable energy capacity is individually or community owned.
Electricity demand will grow.
We need to update our power supplies.
Climate Change Act includes a legally binding CO2reduction of 80% by 2050.
Renewables will supply 15% of our energy by 2020.
Future energy needs will be met by a combination of low carbon and renewable sources.
Large power station model replaced with a patchwork of micro and industrial-scale energy sources.
Wind farms do not provide all the answers.
But they do deliver efficient, clean, affordable energy to the National Grid.
for your time
Sceptic myth 1: It’s the sun
Yes, the sun has a strong influence on climate.
But The Royal Society says there is wide consensus that natural forcing from the sun over the past 150 years is about 0.12 Wm2.
A comparison of sun and climate over the past 1150 years found temperatures closely match solar activity – but over the last 35 years sun and climate have been moving in opposite directions.
In fact, a number of independent measurements of solar activity indicate the sun has shown a slight cooling trend since 1960, over the same period that global temperatures have been warming.
An analysis of solar trends concluded that the sun has actually contributed a slight cooling influence in recent decades.
Sceptic myth 2: Broken hockey stick
Sceptics have tried to convince people that the famous hockey stick graph, used by Al Gore, is 'broken'.
The hockey stick paper was produced in 1998 by University of Massachusetts.
It showed the 20thC to be the warmest in the last 1000 years.
And showed warming was most dramatic after 1920.
Since the original research a number of proxy studies have confirmed the original hockey stick conclusion.
They have included analysis a variety of different sources including corals, stalagmites, tree rings, boreholes and ice cores.
Hockey stick remodel
An independent assessment of Mann's hockey stick was conducted by the National Center for Atmospheric Research (Wahl 2007). They reconstructed temperatures employing a variety of statistical techniques. Their results found slightly different temperatures in the early 15th Century, but confirmed the principal results.
Consistent research: Bore holes
Changes in surface temperature send thermal waves underground, cooling or warming the subterranean rock. Underground temperature measurements were examined from over 350 bore holes in North America, Europe, Southern Africa and Australia (Huang 2000).
Image shows global surface temperature change over the last five centuries from boreholes (thick red line). Shading represents uncertainty.
Consistent research: Stalagmites
Stalagmites are formed from groundwater within underground caverns. As they're annually banded, the thickness of the layers can be used as climate proxies.
Image shows northern Hemisphere annual temperature reconstruction from stalagmite reconstructions shown with 2 standard error (shaded area).
Consistent research: Glacier length
Historical records of glacier length can be used as a proxy for temperature.
Image shows global mean temperature calculated from glaciers. The red vertical lines indicate uncertainty.
Sceptic myth 3: Antarctica is gaining ice
Ignores the difference between land & sea ice.
Antarctica is gaining sea ice but losing land ice at an accelerating rate, which has implications for sea level rise.
In Antarctica, sea ice grows during winter but nearly melts during the summer.
Arctic sea ice lasts all the year round – it increases during winter and decreases during summer – but ice cover remains in the North.
Arctic sea ice is more important for the earth's energy balance because when it melts, more sunlight is absorbed by the oceans.
Whereas Antarctic sea ice normally melts each summer leaving the earth's energy balance largely unchanged.
Care must be taken when interpreting trends in Antarctic sea ice.
Antarctic sea ice is gaining for many reasons.
These are two accepted recent explanations:
A – Ozone levels over Antarctica have dropped causing stratospheric cooling and increasing winds which lead to more areas of open water that can be frozen.
B – The Southern Ocean is freshening because of increased rain, glacial run-off and snowfall. Fresh water freezes more quickly than salt water. Changes in the composition of the ocean are causing less mixing between warm and cold layers and thus less melted sea ice.
Sea ice talk aside, it is quite clear that really when it comes to Antarctic ice overall, sea ice is not the most important thing to measure.
In Antarctica, the most important ice mass is the land ice sitting on the West Antarctic Ice Sheet and the East Antarctic Ice Sheet.
Image - Observed and modelled Arctic sea-ice extent, completed for the IPCC for December 2009 UN climate conference in Copenhagen. (Copenhagen Diagnosis, 2009)
Intergovernmental Panel on Climate Change
Sceptics accuse the IPCC of over-stating the case for man-made climate change.
But many times the IPCChas understated the case.
CO2 output from fossil fuels – emissions close to IPCC’s worst-case projections.
Sea-level rise is faster than predicted.
Arctic sea ice is melting faster than predicted too – On 27 August 2012, Arctic sea ice shrank to its smallest extent ever recorded: 3.5m sq km – less than half the area four decades ago (around 8m sq km at this time of year). The previous record low in 2007 was 4.17m sq km
Didcot and Kingsnorth power stations
Hydraulic fracturing for shale gas
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