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Discussion > Do Wind Turbines Reduce CO2 emissions?

As it's gone a little quiet, and we have quite a few engineers commenting on here, I thought I'd ask if anyone has a handle on the net effect on CO2 emissions of wind turbines. I notice that wind is currently producing about 5.5% of our electricity generation in the UK - maybe 3% of our total energy requirements? A few thoughts occur to me regarding whether or not wind turbines actually reduce CO2 emissions overall:

1. CO2 emitted in mining raw materials used in their manufacture;
2. CO2 emitted in transporting said raw materials to the point of manufacture;
3. CO2 emitted in the manufacturing process;
4. CO2 emitted in the manufacturing of the huge amounts of concrete poured into their foundations;
5. CO2 emitted in transporting the manufactured parts, and concrete, to site;
6. CO2 emitted in driving roads through to the site (different considerations apply to offshore turbines, of course, though the process there may be even more CO2-intensive?);
7. CO2 emitted by the destruction of peat bogs etc when turbines are installed in peat bog locations, especially in the Scottish highlands;
8. CO2 emitted on the eventual removal (one hopes) of said turbines (and one hopes but suspects not, the removal of the concrete foundations) at the end of the turbines' life (including transportation of redundant parts, scrapping thereof etc);
9. Extra CO2 emitted by conventional power stations being on back-up (rather than running efficiently) to cover the intermittency of power generated by turbines;
10. Extra CO2 emitted by exporting our manufacturing to places like China and India (due to the high cost of our electricity), taking into account not only the lower environmental standards of such countries, but also the CO2 emitted in transporting said manufactured products from China/India to the UK.
11. CO2 emitted in staff travelling to site to maintain the turbines, and CO2 emitted during said maintenance process.

There may well be a number of CO2 emitting stages that I have missed. My uninformed guess is that all of the above adds up to more CO2 emissions than the savings generated during the limited life-span and limited utility of wind turbines. Of all the thousands of papers published each year to try to tell us that global warming is a crisis and we need to act, I am unaware of a single paper considering this issue. If such a paper exists I'd like to be alerted to its existence.

One of my big problems with climate alarmism is that even if one accepts its central premise, the policy prescriptions which follow from the climate alarmists seem to me, by their own lights, often to be counter-productive. Any thoughts?

PS First frost of the winter in Cumbria today. Our local wind turbines are at a standstill...

Oct 24, 2016 at 9:09 AM | Unregistered CommenterMark Hodgson

Mark - I have never managed to find an estimate of the total lifetime reduction in emitted CO2 resulting from the construction, operation and eventual replacement of a wind turbine. The fact that such a figure has not been publicised incessantly strongly suggests to me that it has a negative value.

Oct 24, 2016 at 9:16 AM | Registered CommenterMartin A

#9 is a killer point. The back-up needed is appalling.

Oct 24, 2016 at 9:31 AM | Unregistered Commenterkim

You could add the CO2 required to build all the new transmission lines such as Beauly-Denny which also require steel and concrete and cross peat bogs and require access tracks when being constructed.
Building access tracks across Peat Bogs isn't particularly good for them.
I've never seen, I've not looked in depth, information on disposing of turbine blades.

As Martin A says information is sparse.

Oct 24, 2016 at 9:54 AM | Unregistered CommenterSandyS

#9 - try Googling the 'Intermittency Myth' and 'The Merit Order Effect'

Oct 24, 2016 at 11:22 AM | Unregistered CommenterPhil Clarke

Interesting question. You're basically talking about the Levelised Cost, which will have a fairly linear relationship with CO2 emissions

The levelised cost of energy (LCOE) measures the overall life cycle costs of a technology per unit of electricity produced. It is calculated as the sum of the discounted costs over the generator’s lifetime, spread across the discounted units of energy produced over the lifetime. This requires future costs to be expressed in ‘present value’ terms by discounting.

A quick Google turned up these

This study by Scotland's Climate Exchange, includes a review of the admittedly sparse literature and found

The life cycle carbon emissions from both on- and offshore wind are very low at 15 and 12 gCO2eq/kWh, respectively;

And for comparison:

Electricity generated by long term marginal plant results in average emissions of 430gCO2/kWh of electricity generated (DEFRA environmental reporting guidelines – April 2008).

4,380,000 kWh of clean energy displacing electricity generated from this generation mix will result in the displacement of 1,880 tonnes of CO2 ((4,380,000 x 430)/1,000,000) per 2MW wind turbine over a year.

Oct 24, 2016 at 11:46 AM | Unregistered CommenterPhil Clarke

Anyone every seen a proper cost benefit analysis for wind or solar ?
No of course not ..cos wind/solar are rubbish

That's why PC has to try and divert the talk to "You're basically talking about the Levelised Cost"

Oct 24, 2016 at 11:59 AM | Registered Commenterstewgreen

Mark Hodgson, having done a bit of sailing, I am a great "fan" of windpower. Small wind generators and solar panels are brilliant ways of keeping batteries topped up, to cope with the increasing dependence on electrical and electronic systems, and reduce the amount of time spent burning diesel to generate electrical power.

They are great for remote islands and communities, to reduce the need for fuel for generators.

Solar/wind packpack portable systems are ideal for disaster relief in remote areas, especially when a water purifier/desalinator is included (850psi reverse osmosis)

Pretending that they reduce CO2, and are dependable, is total rubbish. The Dutch, Danes and Germans are now counting the cost of this fallacy.

Oct 24, 2016 at 1:54 PM | Unregistered Commentergolf charlie

Stewie - levelised cost is the total lifecycle cost of whatever plant you're assessing, utterley Germane to the question.

GC - According to the ,a href="">Fraunhoffer Institute, the German economy benefited from wind power to the tune of 5 billion euros in 2006 alone.

Oct 24, 2016 at 2:00 PM | Unregistered CommenterPhil Clarke

Heh, Energiewiende unwinds, disastrously.

Oct 24, 2016 at 2:09 PM | Unregistered Commenterkim on 10/23, the thrill is gone.

Oct 24, 2016 at 4:00 PM | Unregistered Commenterkim

Phil Clarke, Mark Hodgson said ...I thought I'd ask if anyone has a handle on the net effect on CO2 emissions of wind turbines.

Wikipedia says...
The levelized cost of electricity (...) t is an economic assessment of the average total cost to build and operate a power-generating asset over its lifetime divided by the total energy output of the asset over that lifetime.

So its units are (for example) £/kWh

You're basically talking about the Levelised Cost, which will have a fairly linear relationship with CO2 emissions
Oct 24, 2016 at 11:46 AM | Unregistered CommenterPhil Clarke

Phil Clarke - I'm not sure what you mean by that. Taking your words literally could mean that you mean that the levelised cost of electricity is proportional to [ "has a (...) linear relationship with"] the mass of CO2 emitted per unit of energy generated, with about the same constant of proportionality for all methods of generating electric power.

But that is obviously not so. So would you like to spell out what you actually do mean and explain how looking at the Levelised Cost will answer Mark's question?

Oct 24, 2016 at 4:09 PM | Registered CommenterMartin A

Phil Clarke, if what you refer to is true, then why are the Germans now sick and tired of wind energy? I am someone who respects German efficiency, especially when it involves engineering. If the Germans can't make wind work for them as a country, it is not for lack of trying, or ingenuity, or efficiency, or even self discipline.

The German Green movement is kaputt. The EU's will follow shortly, and obediently.

Oct 24, 2016 at 4:42 PM | Unregistered Commentergolf charlie

I'm sure Mark can figure it out - he seems a smart cookie.

Not quite sure where this is going; wind power 12-15g of CO2 (equiv) per KW/h vs 430g for fossils. Most estimates I've seen say the CO2 emitted during a turbine's lifecycle is paid back in a few months of operation.

Or 45 days on Orkney

I'm no expert but here are some links I found in a few minutes Googling

Oct 24, 2016 at 5:35 PM | Unregistered CommenterPhil Clarke

Here is a site that says that it takes about one year* for a wind turbine to generate the electrical energy that could have been generated by the coal used to make the concrete and steel used in its construction. It quotes a the life of a wind turbine as being 15 years.

* 10 months is the figure actually estimated but obviously there is a large tolerance on that.

Oct 24, 2016 at 7:46 PM | Registered CommenterMartin A

Thanks for all the comments. I'm working through them at the moment. Just some food for thought - currently (c 8pm) wind is contributing 2.2% of our electricity requirements, while we are importing 6% via the Cross-Channel and Britned interconnectors. Wind turbines aren't looking so useful as I type.

Oct 24, 2016 at 8:03 PM | Unregistered CommenterMark Hodgson

721 million tons of coal per 1,400 million tons of steel. Let’s just say 1 ton of coal per ton of steel.


Now a coal-fired plant has a capacity factor of ~87% and a typical wind turbine only manages ~25%. So it takes about 3.5 MW of wind power to generate as much electricity as 1 MW of coal power, assuming the wind blows.

More hmmmmm....

Not sure I trust those numbers ...

Oct 24, 2016 at 8:05 PM | Unregistered CommenterPhil Clarke

'The wind is not blowing right now therefore wind is no good' is a particularly feeble argument.

2015 was a record-breaking year for the British wind industry, with onshore and offshore farms providing a larger-than-ever share of the UK's electricity, according to new data released today by National Grid.

2015 was a record-breaking year for the British wind industry, with onshore and offshore farms providing a larger-than-ever share of the UK's electricity, according to new data released today by National Grid.

In the three months between October and December 2015, 13 per cent of the UK's electricity demand was met by wind, beating the previous 12 per cent record set in the first quarter of 2015. Meanwhile, December also saw a new monthly record set, with wind supplying 17 per cent of Britain's electricity demand - beating the previous monthly record of 14 per cent set in January 2015. A particularly windy Christmas week also set a new seven-day wind generation record in December, with wind meeting 20 per cent of the UK's electricity demand.

From <>

Oct 24, 2016 at 8:24 PM | Unregistered CommenterPhil Clarke

Phil C

Thanks very much for introducing me to the Levelised Cost of Energy - a new concept to me. I'm learning all the time. I'm still getting to grips with this, but may I point out what look like (at least to me) some inconsistencies in what you posted?

As suggested, I googled the "Intermittency Myth", but am not sure what I found meets the point about conventional power stations being less efficient (and therefore emitting more CO2 than they otherwise would have done) when being run on back-up, to cope with falls in renewable energy. Furthermore, you linked to a Climate xchange article, which I have now read, and said article has this to say on the subject:

"Another key issue of debate is the extent to which onshore wind farms achieve a net carbon emissions reduction
over their lifetime. The carbon emissions reduction of wind power cannot simply be estimated as equal to the
carbon emissions of conventional coal- or gas-fired generation that it displaces: firstly, wind power generation is
not zero carbon, as greenhouse gases are emitted during installation, maintenance and decommissioning;
secondly, wind power will not replace all forms of conventional generation equally. The true carbon emissions
displacement will therefore depend upon a combination of factors including:
 the types of power generation being replaced;
 any decrease in efficiency of conventional plant operating at part load; and
 the impact of any increase in frequency of start-up and shut-down of conventional plant.
There may also be longer-term impacts associated with the installation of new conventional plant to back up an
increase in installed wind capacity. "

The last bullet point and succeeding sentence seem to me to acknowledge the very real existence of the issue. Indeed, later in the paper, the authors say this:

"There are also efficiency penalties associated with operating these power stations at reduced outputs, which causes the carbon emissions intensity of these generators to increase as a result of the presence of wind generation on the network. This effect has led to some reports that wind power generation actually results in an increase in carbon emissions (Lea, 2012; Udo, 2011)"

In fairness, they try to debunk the last claim by continuing: "but these are based on flawed analysis (see the deconstruction of one such analysis (le Pair, 2011) in the Appendices to the main reports): while the carbon emissions per unit of energy output (emissions intensity) of thermal generators does increase at part load, overall the total emissions still fall as their output decreases, so that the effect of the efficiency penalties is to decrease the magnitude of the emissions savings from wind, but not completely negate them. This has been demonstrated by a number of studies of the marginal emissions of networks around the world (Kaffine et al., 2011; Siler-Evans et al., 2012; Thomson, 2015; Voorspools and D'Haeseleer, 2000)."

Nevertheless, the point remains that running conventional power stations inefficiently to accommodate the unreliability and unpredictability of wind turbines is a real issue, and not without controversy, or at least differing viewpoints. Also, it is at least arguable that Climate xchange is not a completely disinterested organisation - in the "about us" section of their website they say:

"We provide independent advice, research and analysis to support the Scottish Government as it develops and implements policies on adapting to the changing climate and the transition to a low carbon society. Our members provide wide-ranging expertise on how we can reduce the greenhouse gas emissions that cause climate change, how different sectors can adapt to Scotland's changing climate, and how to create climate change policies that are fair and make the most of Scotland's assets."

An unimpeachable statement, perhaps, to true believers, but begging a few questions to a sceptic.

You also quote Climate xchange as saying "The life cycle carbon emissions from both on- and offshore wind are very low at 15 and 12 gCO2eq/kWh, respectively". However, having downloaded and read the paper, I found them saying this in the "key messages" section at page 16:

" Credible estimates of the carbon emissions for onshore wind range from 3 to 45 g CO2eq/kWh, but
when farms are constructed on forested peatlands these increase to 62 to 106g CO2 eq/kWh.
 Credible estimates of the carbon emissions for offshore wind range from 7 to 23g CO2eq/kWh."

And at the end of page 17: "The carbon payback period is the time for the carbon emissions displaced by wind power to equal the life cycle carbon footprint of the wind farm. In order to achieve a net reduction in GHG emissions, this should be significantly shorter than the intended lifetime of the wind farm. At current marginal displacement rates carbon payback is typically around 6 months to a year, although this can be several years for onshore farms built on
peatlands where no effort has been made to mitigate the effects of wind farm construction."

Indeed, they go further on the next page:

"Both the average and marginal emissions of electricity generation are likely to reduce over time, as the most
polluting power stations are replaced with lower carbon alternatives (Hawkes, 2010; Voorspools and D'Haeseleer,
2000). As such, the emissions displaced by a given wind farm will tend to decline over time, so that farms built
further into the future will take longer to pay back. Pay back will be achieved as long as lifetime average emissions
reduction factor exceeds the carbon footprint (Smith et al., 2015). Based on the most recent DECC forecasts (DECC,
2013) for future grid emissions, Figure 11 shows the lifetime average payback threshold for wind farms with a design life of 20 years, constructed between 2010 and 2050. It can be seen that the vast majority of carbon footprint estimates for onshore farms fall below this line and will achieve carbon payback; however, the highest three, which correspond to onshore wind farms constructed on forested peat lands, will not achieve carbon payback if they are constructed after the mid-2020s. This is significant for wind farms currently being planned and highlights the importance of ensuring that undegraded peatlands are disturbed as little as possible"

Also, bear in mind that while the paper does try hard to include many relevant phases of CO2 emissions related to wind turbine manufacture, installation, use and maintenance, and ultimate decommissioning, no effort is made to include the effects of my (admittedly subjective, but I would submit relevant) point number 10. If that is taken into account, fully and impartially, I suggest their conclusions might be radically different (and worse for supporters of wind turbines).

Oct 24, 2016 at 8:38 PM | Unregistered CommenterMark Hodgson

Phil C at 8.24pm:

In your own words, "More hmmmmm....

Not sure I trust those numbers ..."

According to DECC’s latest energy trends, wind, solar and hydro added up to only 2.4% of primary energy consumption last year. Strip out hydro's 0.3% contribution, and you're left with 2.1% from wind & solar. Don't believe, believe the DECC (before it was abolished):

Oct 24, 2016 at 8:48 PM | Unregistered CommenterMark Hodgson

@Golf suggested they are good for remote locations ..that's the idea but in practice tribal people just get a generator that way you get power when you want/NEED it
(topping up backup lights is a small use)

@Mark Hodgson I see PC still hasn't simply given you a proper cost benefit analysis for a project.
You'd expect something like theis project costs £X and will save this much CO2 so i costs £Y per tonne of CO2 saved

Oct 24, 2016 at 8:54 PM | Registered Commenterstewgreen

Perhaps I should have been more explicit

Researchers have carried out an environmental lifecycle assessment of 2-megawatt wind turbines mooted for a large wind farm in the U.S. Pacific Northwest. They conclude that in terms of cumulative energy payback, or the time to produce the amount of energy required of production and installation, a wind turbine with a working life of 20 years will offer a net benefit within five to eight months of being brought online.

Paper is paywalled, but abstract is here

As to offshoring emissions to China this has been quantified although I would contend that cheaper labour is a much larger factor than cheaper energy.

Even on the most pessimistic assumptions, the differential between wind and fossil means the answer to the question has to be Yes.

Oct 24, 2016 at 9:30 PM | Unregistered CommenterPhil Clarke

According to DECC’s latest energy trends, wind, solar and hydro added up to only 2.4% of primary energy consumption last year. Strip out hydro's 0.3% contribution, and you're left with 2.1% from wind & solar. Don't believe, believe the DECC (before it was abolished)

You seem to be confusing total energy with electricity, which makes up about 20% of energy consumption,

Oct 24, 2016 at 9:35 PM | Unregistered CommenterPhil Clarke

I noticed also, from the DECC paper table 1.1 that wind, hydro and solar have increased 250% in just 4 years from 1.86 to 4.66 million barrels equivalent - while all other sources other than bio- have gone the other way.

Oct 24, 2016 at 9:43 PM | Unregistered CommenterPhil Clarke

Phil Clarke, what percentage of your linked articles are reliable? Your past record is not good, and it would be foolish to rely on your accuracy improving any quicker than the reliability of wind power.

Oct 25, 2016 at 7:11 AM | Unregistered Commentergolf charlie