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Wind farms 'repay lost C02 in 3 years'



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Published Date: 01 July 2008
By Jenny Haworth
IT TAKES just three years for a wind farm to pay back the carbon dioxide released from peat land damaged during construction, according to a new report.
There have been concerns that draining peat land to build wind farms causes irreversible damage, releasing huge quantities of C02 that has been stored there.

Struan Stevenson, MEP, has called for a moratorium on building wind farms on peat land, w
hich he calls Scotland's rain forests because of their importance for storing damaging C02.

Now research for the Scottish Government has found that, with good practice, the benefits of building a wind farm will overtake the carbon lost from peat in between 1.8 and 2.6 years.

Jason Ormiston, the chief executive of Scottish Renewables, said the research discredits the "myth" that wind farms cannot be built on peat land without releasing carbon. He added: "This research shows that by using good practice we can responsibly develop on peat soils and still slash the emissions that cause climate change.

"Calls for a blanket moratorium on all peat-land areas have now been shown to be misguided and are blocking effective action on climate change."

However, Mr Stevenson hit back, saying it was "fatuous" to think the damage can be reversed within three years. He added: "For anyone to suggest that beggars belief."

At a seminar of experts earlier this year, Mr Stevenson said all agreed that wind farms should not be built on peat land.

The report, "Calculating carbon savings from wind farms on Scottish peat lands – A new approach", was produced by the Macaulay Institute and Aberdeen University for the Scottish Government.





The full article contains 279 words and appears in The Scotsman newspaper.
Page 1 of 1

 
1

Schot,

01/07/2008 00:13:06
Surely good environmental practice means leaving peat-land alone. Don't dig it, don't build there, go elsewhere.

Scottish Renewables is a trade organistion with financial interest in skewing the science. I'd prefer a link to the report so that I could read it myself.

We know building on peat releases more carbon than building elsewhere. We have plenty of non-peat land for wind-farms, so we could build there first. The cheapest land however happens to be peat-land.

Never trust a Green in a suit.
2

Nomada,

01/07/2008 07:37:30
I think a little digging will reveal that the pay-back calculation includes the assumption that any energy generated from the turbines *replaces* in full equivalent generation from carbon-based fuels.

This assumption is invalid.

Therefore, as any conclusions based on a flawed assumption, any figure arrived at in that way is itself invalid.

Schot #1 says 'Never trust a Green in a suit'. I would say: 'never trust anything anyone says in praise of the economics or carbon benefits of wind turbines'. The vision of a licence to print money tends to warp their judgement.
3

Unimpressed one,

01/07/2008 08:43:58
But how long will it take for the windmill operators to repay the huge public subsidies they get? Answer: they never will. The 'emperor's new clothes' syndrome that is 'climate change', will suck dry EU taxpayers. Meanwhile, the rest of the more sensible parts of the world, i.e. the developing Asian economies, will never buy into this green farce and will laugh all the way to the bank.
4

JUSmith,

University of Aberdeen 01/07/2008 10:48:09
Nomada 01/07/2008 07:37:30 comments that a little digging would reveal that the pay-back calculation includes the assumption that any energy generated from the turbines replaces in full equivalent generation from carbon-based fuels. If Nomada had in fact done a little digging (ie read the report - to be found on the Scottish website), it would have been clear that this is not the case. This assumption would certainly be invalid, which is why the calculation DOES NOT USE THIS ASSUMPTION, but instead accounts for CO2 emissions due to backup generation, as well as losses of C from the peat, from plants, and from production, operation, dismantling of the turbines.

Schot 01/07/2008 00:13:06 comments that good environmental practice means leaving peatland alone. There are many good reasons why we should leave peatlands alone - such as habitat preservation, amenity resources, and risks of C losses. This report shows that good management practices can result in C losses from peatlands that are very much less than the potential savings in fossil fuels. However, poor management practice can result in C losses that are very much greater than the potential savings from fossil fuels. If the planning process ensures the management of peatlands is good, we can indeed reduce CO2 emissions even when windfarms are sited on peatlands. However, the risks of losses with poor management are much higher than they would be on a mineral soil. Therefore, it is safer to site windfarms on mineral soils rather than peatlands if at all possible.

5

Nomada,

01/07/2008 12:27:11
I am grateful for the clarification, JU Smith #4. Can you provide the URL for the report, please?

My comment was based on previous assessments by organisations which really should have known better, and who explicitly followed the non-logic I described to come to a not very different conclusion. I am glad to hear that this study is different in that respect, and will certainly be interested to read the full report.
6

Neil,

Glasgow 01/07/2008 12:29:15
"to pay back the carbon dioxide released from peat land damaged during construction"

The story is clearly misleading since this is only a fraction of its "carbon footprint". The main stuff is the manufacturing of the thing, putting it in place, pouring in 1,000 tons of cncrete etc. I suspect the figure given does not cover digging roads to it & cables away. That sort of fraud being the case it would be unwise to trust the basic figure either in ways such as Nomad mentions.
7

Saoghal Beag,

01/07/2008 13:04:09
Neil, that would be the same way the nuclear energy ignores the embedded carbon in its construction, the minimng, refining and transporting of fuel, the transport and management of spent fuel, the excavation of an underground repository and its management. ANother fine example of fraud.
8

japananne,

Edinburgh 01/07/2008 13:25:53
The report is available on the Scottish Government website here:
http://www.scotland.gov.uk/Publications/2008/06/25114657/18
9

nabodican,

Rural Scotland 01/07/2008 13:36:03
It is a pity that Struan Stevenson did not call for a moratorium on all windfarms, not just those on peatlands. We can all ignore Jason Ormiston's opinion as he is just a jumped up journalist who represents the wind industry and knows little or nothing about electricity generation and even less about peat bogs,
I doubt if he would recognise a peat bog even if he fell flat on his face in one.
Any report commisioned by the Scottish government has to be distrusted and this one is no exception as it is plain wrong.I would suggest they read a rather excellent publication by one of their own bodies, the SNH on "The ecology of Bogs & Ombrotrophic mires" they may learn something.
They are simply dancing to the tune of the wind industry with this report as they previously did with two reports on the public attitude to windfarms.
The first by "System 3" they were forced to withdraw due to being wrong and the second by Mori was proved to be a total con in which they scaled the results in such a manner that the closer you lived to a windfarm the less your opinion counted.
The bottom line is that wind turbines will never repay their carbon costs as they do not cause any less coal to be burned at Longannet of Cockenzie. Indeed even more coal has been burned this last year.
It really is time to stop this windfarm madness especially now that the Holyrood lunatics are granting permission for 450ft high onshore turbines such as at Barrhill. These turbines need nearly 3000 tonnes of reinforced concrete per base.
10

Colin, Glasgow,

01/07/2008 14:21:47
At the risk of stating the patently obvious, the wind turbines will never “pay back” the carbon emissions of the peat if they are used to displace nuclear power, which is the stated policy of the Scottish Executive.

They can only pay back if we keep the nuclear, and replace the fossil fuel with wind.

11

JUSmith,

University of Aberdeen 01/07/2008 14:25:40
Neil,Glasgow 01/07/2008 12:29:15 says the story is misleading since only a fraction of the "carbon footprint" is accounted for, the main part being accounted for by manufacturing. Neil suspects the figure given does not cover digging for roads & cables. As you can read in the report (at the website given above by japananne,Edinburgh 01/07/2008 13:25:53), manufacturing carbon costs are all factored in and the digging of roads and pylons are explicity described.

Nabodican, Rural Scotland 01/07/2008 13:36:03 says any report commisioned by the Scottish government has to be distrusted and this one is no exception as it is plain wrong. Please read the report and be more explicit as to where you believe it has gone wrong - then we can have a more meaningful discussion.
12

JUSmith,

University of Aberdeen 01/07/2008 14:40:41
Colin, Glasgow,01/07/2008 14:21:47 suggests that wind turbines will never “pay back” the carbon emissions of the peat if they are used to displace nuclear power. However, it is not likely that nuclear power will be replaced by wind energy. Data published by The National Grid Company (National Grid Transco, 2004), describing the distribution of energy generation in the UK power system, demonstrate that in the day-to-day running of the national grid, coal plants tend to be taken off load when additional base load plants, such as nuclear or renewables, start to generate. It is also suggested (BWEA, 2005) that, in the long-term, as older coal plants become uneconomic, these will tend to be replaced by the new energy plants. Clearly the proportion of the national grid generation displaced from the different energy sources depends on complex economic drivers, but it is the thermal plants (coal, gas and oil) that are currently used for grid balancing.
13

Colin, Glasgow,

01/07/2008 15:24:53
#12 JUSmith, I know wind is unlikely to replace nuclear. I know the BWEA say this too. It is the Scottish Government that needs to be persuaded.

What will take the place of the nuclear powerstations if they are not replaced with more nuclear? In all probability they would be replaced with fossil fuel.

Replacing nuclear with fossil fuel, and then using wind to displace some of that fossil fuel, will not save any carbon emissions in real terms.

14

Schot,

01/07/2008 15:28:42
Grid balancing could be achieve by more energy storage schemes, pumping water between lochs, or even in electric vehicles. Scotland could be totally non-nuclear if it chose to be, but it would require major tidal schemes too, plus more turbines than Denmark currently has.

My quibble is sites are chosen primarily for maximum profit rather than maximum environmental benefit.

Preserving our peat lands is so vital to fighting climate change that it sends out the wrong message.
15

Nomada,

01/07/2008 16:10:20
Having now read the report (although not every word on the 83 pages, and handicapped by the poor resolution of some of the pdf graphics), I conclude that the headline '"Wind farms 'repay lost C02 in 3 years'" is a piece of spin on the behalf of the notorious Mr Ormiston. The paper describes a *method* and uses one case study (which I assume gives the figure of 3y, although that is where the resolution of the graphics makes reading impossible) where it is acknowledged that 'the very short payback time [is] due to good practice in the use of floating roads and the large area of habitat improvement'.

I don't see anything that implies that it will always be as short as 3y, since the payback time is acknowledged as being affected by a large number of factors, many of them site-specific and dependent on the implementation of best practice. It will be interesting to see what the method returns for some other actual cases.

It is a very thorough piece of work, though, and should be a useful contribution to the issue.
16

nabodican,

Rural Scotland 01/07/2008 16:25:48
Unfortunately I am unable to download the above mentioned report at the moment, however I notice that J U Smith of the "Dept of Plant & Soil Science" at Aberdeen University along with The "Macaulay Institute" were actually funded by the Scottish Executive to produce a result that had clearly been pre-determined.
This off course was because they were desperate to approve the Lewis windfarm and only rejected it because of European legislation.
Mr Smith also fails to understand the difference between taking generating plant offline and switching off the boilers.
I doubt if Mr Smith has ever looked at the size of hole required for a turbine base, the amount of concrete and steel that is dumped in it, the devastation caused to hillsides as they drive roads through.
Has he ever heard of Derrybrien where the whole hillside came down causing utter devastation.
No Mr Smith, you are dancing to the tune that your paymasters are calling.
17

JUSmith,

University of Aberdeen 01/07/2008 17:59:10
#13 Colin, Glasgow,01/07/2008 15:24:53 "Replacing nuclear with fossil fuel, and then using wind to displace some of that fossil fuel, will not save any carbon emissions in real terms."

This is a very good point. Current energy production in Scotland is 40% from nuclear power and 11% from renewable sources. The Scottish Government target for renewable energy production is 50% by 2020. If energy production from nuclear sources was reduced to 0% by 2020, and this was replaced by fossil fuels, then fossil fuel energy production would increase by 40% by 2020. The increase in renewables given by the Scottish Government target (an increase from the present day (11%) to 2020 (50%)) is (50-11)% = 39%. Therefore, in the extreme case where all nuclear plants were to shut down by 2020, fossil fuel production would be reduced by 39% due to increased use of renewables, but would be up by 40% due to loss of nuclear production: overall an increase of 1%.

In reality, the percentage energy from nuclear power will be higher than 0% in 2020. However, any reduction in nuclear power will increase CO2 emissions. We can claim a carbon saving associated with windfarms, and this may go some way to compensating for the increased emissions associated with any nuclear decommissioning that may occur.
18

nabodican,

Rural Scotland 01/07/2008 18:18:16
J U Smith, I would suggest you stick to soil science because your arithmetic is pretty poor.
50% renewables,ie windpower minus the 11% for hydro etc leaves 39% "installed capacity" which will only give 30% max production and not necessarily when it is required, therefore to claim a 39% reduction in fossil fuel generation is nonsense.
Added to which the coal is still being burned even when the turbines are off line.
19

JUSmith,

University of Aberdeen 01/07/2008 18:18:48
#15 Nomada,01/07/2008 16:10:20 - "I conclude that the headline '"Wind farms 'repay lost C02 in 3 years'" is a piece of spin."

This is the work of the Scotsman journalist who had opportunity to read the report but decided to quote an example calculation for a particular well-managed wind farm in central Scotland as the headline. The report certainly does not imply carbon payback time will always be 3 years. If management practices had been poor, carbon payback time for the same site would have been significantly increased. The risks associated with bad management practice are much higher on peatlands than on mineral soils. So although low carbon payback times are possible with good management, it is likely to be a less risky strategy to build windfarms on mineral soils.

20

JUSmith,

01/07/2008 18:41:15
#18 Nabodican - Rural Scotland 01/07/2008 18:18:16
"50% renewables,ie windpower minus the 11% for hydro etc leaves 39% "installed capacity" which will only give 30% max production and not necessarily when it is required, therefore to claim a 39% reduction in fossil fuel generation is nonsense."

The target is 50% renewable electricity production by 2020 - not 50% installed capacity (quote from Scottish Government website "Ministers want 50% of the demand for Scottish electricity to be supplied from renewable sources by 2020, with an interim milestone of 31% by 2011" (http://www.scotland.gov.uk/Topics/Business-Industry/Energy/19185/17612)).

Therefore to multiply the target by a 30% capacity factor of the turbines is wrong as it is the actual electricity production that is the target, not the installed capacity. If it were achieved, the target of 50% electricity production by renewables would infact mean 39% reduction in fossil fuels as stated earlier.
21

Nomada,

01/07/2008 18:43:50
Thanks #19. I realised, of course, that the headline did not derive from the reporting team, but we are used in these threads to an apparent deficit of understanding and balance from the sub-eds at the Scotsman!
22

nabodican,

Rural Scotland 01/07/2008 19:04:35
#20 Don't be daft, 50% of electricity production would be never ending.
Joke McConnel once stated that the target would be a percentage of energy used in Scotland.
Besides, most of our politicians are too thick to understand.
23

Colin, Glasgow,

01/07/2008 20:29:26
JUSmith, frustratingly, the graphics in the pdf document make the important figures unreadable. Out of curiosity, if you have access to the original document, can you tell me how much more lifecycle CO2-equivalent is produced by a turbine built on peat, compared to one built elsewhere? I mean, just roughly. Is it 50% more? Is it twice as much? (If you have figures stated as g CO2/kWh so much the better.)
24

JUSmith,

01/07/2008 23:36:29
#23 Colin, Glasgow,01/07/2008 20:29:26 "how much more lifecycle CO2-equivalent is produced by a turbine built on peat, compared to one built elsewhere? I mean, just roughly. Is it 50% more? Is it twice as much"

The report concerned windfarms built on peatlands only. Therefore, even if you could read the figures they would not provide the numbers you want. Furthermore, the answer depends on the particular site being considered and the management practices used. However, for the EXAMPLE windfarm discussed in the report (well managed, using floating roads and substantial habitat improvement, on level ground, so the extent of drainage around each constructed feature is not excessive), the carbon payback time using fossil-fuel mix as the counterfactual was only 29 months. If good management practices had not been used (excavated roads constructed instead of floating roads, habitat improvements not used), and the site selection had been poor, resulting in a much greater extent of drainage, the carbon payback time increased to 434 months (36 years). Since the anticipated lifetime of the windfarm is 25 years, this represents a net carbon cost.

If this soil had been a mineral soil, because most mineral soils are already aerobic, the impact of drainage on C losses from the soil is reduced. Therefore C losses from the soil on construction of the windfarm would be very low, infact soil carbon stocks might actually increase, and the potential for C sequestration by habitat improvement is much lower. Losses associated with the windfarm construction on a mineral soil using good management practices would be in the region of 17 months (very similar to the peatland), but in contrast to the peatland, if the good management practices were abandoned, carbon payback time would increase to only 20 months.

This calculation was for an example windfarm. A different site layout would give a completely different result, but the calculation demonstrates that C emissions from windfarm
25

JUSmith,

01/07/2008 23:45:59
...continued from above

...but the calculation demonstrates that C emissions from windfarms are more likely to increase with poor management on peatlands than on mineral soils. If windfarms are to be sited on peatlands, good management practice and careful site selection are essential.
26

Colin, Glasgow,

02/07/2008 00:04:02
JUSmith #24+25, thanks for the detail. Forgive my lack of soil science knowledge, but would most locations that are not peatlands be characterised as “mineral soil”?

So are you saying that, all else being equal and assuming well-managed remediation, the same windfarm would produce 29/17 times as much CO2-equivalent if it was built on peatland compared to a non-peat site? i.e. About 70% more CO2 equivalent.

That being the case, I don’t see a big problem with using the peatland, at least from a carbon point of view. There is a lot more than 70% variation in the other aspects of lifecycle emissions from wind. It is still significantly better than fossil fuel (or most other renewables for that matter).
27

RCro,

Edinburgh 02/07/2008 09:25:33
#22 nabodican,Rural Scotland 01/07/2008 19:04:35 "Don't be daft, 50% of electricity production would be never ending."

And your point is? I think everyone is aware that electricity demand grows each year. Installed capacity is only importent from a system security perspective, i.e. instantaneous demand. Over longer periods such as a year for instance, total power output from renewables can be fairly accurately predicted. As you negatively comment on every renewables story which appears in the Scotsman without fail, you will no doubt have been told this before but chosen to ignore it.
28

JUSmith,

University of Aberdeen 02/07/2008 10:30:36
#26 Colin, Glasgow,02/07/2008 00:04:02
"would most locations that are not peatlands be characterised as “mineral soil”?"

No - there is the whole range of soil types from mineral through highly organic to peatlands. But the key issue is drainage. Organic matter in peatlands decomposes very slowly, either because the soil is too acidic, because it is flooded, or both. Soil organic matter decomposition under acidic and anaerobic conditions is usually much slower than under neutral or aerobic conditions. If plant inputs of organic matter exceed losses due to decomposition then organic matter accumulates in the soil, and this is often the case in an active peatland. Highly organic to mineral soils are usually less anaerobic, so decomposition is more rapid. With stable management conditions, losses of C from the soil eventually balance C inputs. So in mineral to highly organic soils, carbon does not usually accumulate indefinitely, whereas in many peatlands it does.

If you drain the peat, the soil becomes aerobic for longer periods in the year, and so decomposition increases. Often plant inputs will be removed as well. This means that decomposition starts to exceed plant inputs and the carbon stocks of the soil fall. Losses can be very rapid, because there is alot of carbon in the peat, and it is not protected by association with clay minerals. If the peat is not restored following decomissioning, it is possible that most of the carbon from the peat will be lost, and catastrophic landslides may occur due to subsidence as the carbon "burns off".

Mineral or highly organic soils usually do not need the same degree of drainage, and if the soil does need to be extensively drained for the development, losses are usually much lower than from peats due to the lower C content of the soil and protection of the soil organic matter by association with clay minerals.

Having said all that, as Colin of Glasgow points out, for the example given with good management practic
29

JUSmith,

02/07/2008 10:42:50
...continued from above (Im obviously going on too much!)

Having said all that, as Colin of Glasgow points out, for the example given with good management practices "the same windfarm would produce 29/17 times as much CO2-equivalent if it was built on peatland compared to a non-peat site" "i.e. About 70% more CO2 equivalent." - no problem from a C perspective, although the need for preservation of sensitive habitats might present a different problem.

However, with bad management practices, the same windfarm would produce 434/20 times as much CO2-equivalent if it was built on peatland compared to a non-peat site i.e. about 2070% more CO2 equivalent! The risks of C losses with bad management and poor site selection are much greater on peatlands than on mineral soils. So if windfarms are to be constructed on peatlands, the developers will need to take a very active and serious view of habitat restoration, good site design and site restoration.
30

Weatherman,

Borders 02/07/2008 10:44:52
We have read a lot here about 'best practice' etc. But absolutely nothing about the amount of concrete (and the associated carbon burden) in constructing turbines into up to 12m of wet peat, as at Lochgoin Moor (Whitelee).

I remember reading about the massively deep foundations that were needed at Bowbeat (Peebles) some years ago to overcome similar peat problems.

In both cases engineers boasted of the heroic scale of the excavations and concrete pour that was needed in order to build the things.
31

Schot,

02/07/2008 16:51:02
I love it when experts drop by with figures and facts.

"However, for the EXAMPLE windfarm ...the carbon payback time using fossil-fuel mix as the counterfactual was only 29 months. If good management practices had not been used ... 434 months (36 years). Since the anticipated lifetime of the windfarm is 25 years, "

So badly managed windfarms are carbon negative ? Is 25 years the mean time to failure of the example turbines, and if so, couldn't that be improved on ? Which existing wind-farms in Scotland most closely match the example 29 months and which are least well managed ? Are the rules on good management being applied in your opinion ?
32

JUSmith,

University of Aberdeen 02/07/2008 18:19:23
#31 Schot,02/07/2008 16:51:02 "So badly managed windfarms are carbon negative ?"
Badly managed windfarms can in some instances be carbon negative. In this example on peatland, very bad management would have resulted in a net carbon cost - ie carbon negative. Whereas, if good management had been used, there would have been a significant carbon benefit. If this had been on a mineral soil, there would have been a carbon benefit, even with very poor management. Whether this applies at other sites depends on the site layout and the nature of the peatland.

"Is 25 years the mean time to failure of the example turbines, and if so, couldn't that be improved on ?"
For this example, the anticipated lifetime of the wind farm given in the environmental statement was 25 years, but the technology is improving all the time.

"Which existing wind-farms in Scotland most closely match the example 29 months and which are least well managed? Are the rules on good management being applied in your opinion ?"
This example exactley matches a particular wind farm in Scotland, as it is a real example. However, the name of the wind farm cannot be given without the developers permission. We are currently doing a survey of practices and calculating C payback time for existing and proposed wind farms across Scotland both on mineral and peatland soils. This will be completed later this year and will provide an answer to this important question.
33

Schot,

02/07/2008 18:32:19
Thanks for the answers. I'd appreciate it if you could try to publish at least a summary of your results either in the paper or on the comments section. Preferably with pie-charts and graphs for the non academics like me.
34

JUSmith,

02/07/2008 18:35:17
#33 Definitely - there is no point in doing it if we dont publish!

 

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