ASA Adjudication on Your Energy Ltd

Ad

A circular, distributed by Your Energy, was headlined "WEST WIGHT WIND FARM SUMMER 2006". Introductory text stated "… Sometimes information in the public domain is misleading or incorrect. Here are some answers to questions we frequently get asked and some other useful facts and figures". The body copy then continued "How much electricity will the wind farm produce? The wind farm will generate, on average, 30 million units (kilowatt hours) of clean electricity each year. This is equivalent to the needs of 6,500 homes - or around 10% of the Island's residences. It will amount to two-thirds of the region's renewable energy targets. How will the wind farm help combat climate change? It will displace around 25,000 tonnes of CO2 and other greenhouse gases from entering the atmosphere every year (1), which in broad terms is equivalent to the CO2 emissions from approximately 10,000 cars (2)". Text in smaller print, in a separate column, stated “(1) emission savings calculations are based on the current generating capacity mix in the UK and the plant dispatch methodology. Any extrapolation of these annual emissions savings over the 25 year life of the wind farm may vary up or down. (2) based on calculations from DfT and FOE.” Text under the sub-heading "Why Wind?" stated "Did you know… … Noise levels from wind farms are low enough to hold a normal conversation at the base" and, under the sub-heading "Are the wind turbines noisy?", text stated "… There are strict guidelines that we have to adhere to that make sure noise from turbines will not be a nuisance".

Issue

The Wight Against Rural Turbines (ThWART) challenged the claims:

1.  "The wind farm will generate, on average, 30 million units ... of clean electricity each year" and "This is equivalent to the needs of 6,500 homes - or around 10% of the Islands residences", because they believed Your Energy had used an incorrect load factor and annual domestic consumption figure in their calculation of the quoted figures;

2.  "it will amount to two-thirds of the regions renewable energy targets", because they believed it over-estimated the wind farms likely capability;

3.  "It will displace around 25,000 tonnes of CO2 ... which in broad terms is equivalent to the CO2 emissions from approximately 10,000 cars", because they believed the calculation on which it was based used an incorrect conversion rate; and

4.  "Noise levels from wind farms are low enough to hold a normal conversation at the base" and "There are strict guidelines that we have to adhere to that make sure noise from turbines will not be a nuisance", because they believed the proposed turbines would breach the limits for noise for properties in close proximity of them.

CAP Code (Edition 11)

Response

1.  Your Energy (YE) explained that they had commissioned an independent report from a world renowned wind energy consultancy, which calculated the projected energy output of the proposed farm based on the collation of wind speed data at the site over a period of approximately two years.  They explained that they had calculated the predicted energy output to be 30,800,000 kWh per year and the capacity or load factor to be 35.5%.  They sent excerpts from their Environmental Statement (ES), a document prepared to accompany a planning application for the wind farm, and a copy of the independent report which showed how the figures were deduced.

The ES stated that the average UK electricity consumption per household was 4.7 MWh per year and explained that the British Wind Energy Association (BWEA) had calculated that approximate figure based on statistics from the Digest of UK Energy Statistics (DUKES) 2002.  YE explained that, using the annual power output figure of 30,800 MWh and the annual average electricity consumption per household figure from the BWEA, the wind farm was expected to supply approximately 6,500 homes.  They added that the census predicted an Isle of Wight population in 2004 of approximately 138,400 and the average occupancy rates from the 2001 census were 2.25 per dwelling; this equated to approximately 61,500 dwellings and the West Wight Wind Farm would, therefore, produce enough electricity to power approximately 10% of the islands residences.

2.  YE referred to the Isle of Wight Council's Renewable Energy Strategy document "Powering the Island through Renewable Energy", which, they pointed out, had been in circulation since 2002.  The document showed that the contribution to the amount of electricity needed by the island, which on-shore wind energy was predicted to supply by 2010, ranged between 12 MW and 18 MW.  YE said they had taken an average of the two extremes, 15 MW, and with the installed capacity of 9.9 MW [6 x 1.65 MW turbines], the proposed West Wight wind farm would meet two-thirds of that target.

3.  YE said the displacement figure of 25,000 tonnes of CO2 was based on a capacity factor of 35.5% and a conversion rate of 860 tonnes of CO2 per million units.  They explained that that equated to 26,488 tonnes, which they had rounded down to 25,000 tonnes in their marketing.

They pointed out that a previous ASA adjudication stipulated that 860 g CO2/kWh was an appropriate emissions displacement factor to use, providing that qualification was given about the uncertainties of future fuel generating mix in the UK.  

4.  YE explained that they had commissioned consultants to undertake noise studies on the site.  They said the results of the consultation showed that noise levels at each of the locations tested were below the limits set out by ETSU-R-97, a 1997 report by the Energy Technology Support Unit (ETSU) for the Department of Trade and Industry, which laid out the noise levels with which planned turbine sites were expected to comply.  

Assessment

1.  Not upheld

The ASA understood that the claims were based on energy output calculations deduced by an independent third party, using wind readings taken from the proposed turbine site, not on a generic UK-wide load factor.  

We noted the energy output had been calculated using the annual mean readings of the wind speed taken from the site over approximately two years, taking into account factors such as the rated power of the proposed farm, the site's topographic effects, the site's wake effects (which referred to how much the turbines shielded each other from the wind), an assumption of the availability, or reliability of the turbines and the estimated rate of blade degradation.  

We considered that it was appropriate to base the claims, which referred to a particular proposed wind farm in West Wight, on site specific data.  We consulted an expert to assess the reliability of the data.  He reported that, using the wind speed measurements carried out at 40 metres above ground level at the wind farm site, adjusted to the turbine hub heights, together with the wind speed power curve for the proposed turbine, estimates of the electricity that would be produced annually by the six wind turbines at the wind farm were calculated.  In addition, to act as an approximate check, calculated estimates of annual electricity production were also made using the Rayleigh mathematical probability distribution in combination with annual mean wind speed data measured at the site and also derived from three wind speed atlases for the UK: the NOABL wind speed database, the Moore wind speed map and the European Wind Atlas.  

The expert found that his calculated estimates of annual energy production were consistent with those submitted by YE with divergences of less than 10%; in most cases the divergence was less than 6%.  He explained that the divergence was small and could be because of the different methods used to take account of wind speeds or different computer modelling methods employed.  Regardless, he believed 30.8 GWh per year was a feasible value, given the turbine specified and wind speed data supplied.  He pointed out, however, that the figure relied on the optimum performance of the wind farm, keeping any reduction in availability and performance and efficiency losses to a minimum.  

The expert explained that the load or capacity factor, which was an alternative way of illustrating the annual electricity production, was derived after the electricity output was calculated in this case. He explained that an assumed capacity factor was sometimes used to estimate the likely electricity production but pointed out that that could give only approximate figures; YE's method was more appropriate.

We considered that readers were likely to expect that the "30 million units ..." claim was an approximate, not a precise, figure. We considered that the level of divergence between YE's and the expert's calculations was low and also noted the expert's comment that 30.8 GWh per year was a feasible value.  We considered that it was acceptable for YE to claim that the wind farm would generate, on average, 30 million units of electricity each year.

We noted the domestic electricity consumption figure currently recommended by Energywatch and recognised by the industry was 3,300 kWh per household per year and considered that that would have been a reasonable figure for YE to use in their calculation.  We also noted, however, the lower the annual domestic consumption figure used in the calculation, the higher the number of homes YE could claim would be powered by their project.  By using a consumption figure of 4,700 instead of 3,300 kWh per household per year, YE had made their claim more conservative.  We therefore did not object to the use of the 4,700 kWh consumption figure in the calculation.

We noted, taking the projected annual output figure of 30,800 MWh and the average UK electricity consumption figure of 4,700 kWh per household per year, the number of homes expected to be powered by the farm was 6,553.  We considered, therefore, that the quoted figure of 6,500 homes was a reasonable estimation.  In addition, taking the number of homes expected to be powered as 6,500, and using population census figures, we noted YE had calculated that the number of dwellings on the Isle of Wight was 61,500.  We noted the ad stated that the wind farm's energy output would be equivalent to the needs of "around" 10% of the island's residences, which, we considered, made clear that the percentage was approximate, not precise.  We also noted 6,500 was more than 10% of 61,500.  We considered that the "around 10%" claim was acceptable.

Because YE had shown that the projected energy output figure of approximately 30 million units was realistically achievable, and also that the quoted number of the island's homes they expected to be powered by the farm was viable, we considered that the claims "The wind farm will generate, on average, 30 million units ... of clean electricity each year" and "This is equivalent to the needs of 6,500 homes - or around 10% of the island's residences" were unlikely to mislead.  

On this point, we investigated the ad under CAP Code clauses 3.1 (Substantiation) and 7.1 (Truthfulness) but did not find it in breach.

2.  Upheld

We considered that the word "region" was likely to be seen to refer to the Isle of Wight.  We noted YE's argument that the wind farm would meet two-thirds of the average of the output figures quoted in the Isle of Wight Council's Renewable Energy Strategy document.  We also noted, however, the average figure calculated by YE related to the expected output of on-shore wind only, whereas a contribution to the renewable energy requirements of the region was expected from other sources, for example, off-shore wind and biomass methods. We considered that 9.9 MW would, therefore, constitute two-thirds of the renewable energy target for on-shore wind only, not two-thirds of the overall renewable energy target as implied.

On this point, the ad breached CAP Code clauses 3.1 (Substantiation) and 7.1 (Truthfulness).

3.  Not upheld

We noted YE had used a conversion rate of 860 g CO2/kWh, which was the recorded typical emissions rate of a coal-burning power plant, and understood that they believed that to be acceptable following a previous ASA adjudication.  Having taken expert advice on the rate of 860 g CO2/kWh on that previous occasion, we understood that the figure was widely used but could vary over the life of the proposed farm because of the evolution of the profile of the UK's future generating mix.  We noted YE had included a disclaimer, which they believed was in line with the previous adjudication, and which clarified that the calculation was based on the current generating capacity mix in the UK and that the figure could vary over the 25-year life of the wind farm.  We understood that, based on a conversion rate of 860 g CO2/kWh, the rated power output of the farm at 9.9 MW and a capacity factor of 35%, the CO2 emissions reductions could be calculated to be 26,103 tonnes.

We noted the conversion rate that the complainants believed to be more appropriate, which they understood was the conversion rate used by the Department for Environment, Food and Rural Affairs (Defra), the Carbon Trust and the Office of Gas and Electricity Markets (Ofgem), and which we understood was also the figure currently quoted by the Energy Savings Trust, was 430 g CO2/kWh and was used for calculating the offsetting of conventional mains electricity.  Using that figure in the calculation instead of 860 g CO2/kWh, the amount of carbon dioxide displaced by the wind farm would be 12,900 tonnes, which was much less than the quoted figure of 25,000 tonnes.

We understood, therefore, that the displacement figure would be greater if wind displaced coal, rather than other power sources, in emissions displacement calculations.  We noted from expert advice given in the previous case in 2005, however, that an appropriate CO2 emissions factor for electricity generated by wind should be higher than that of the year average UK mix of generating fuels (430 g CO2/kWh) and, at that time, was in the region of 860 g CO2/kWh.  We also understood that the evolution of the actual profile of the UK's future fuel generating mix (and therefore grid average emission factor) over the course of the next 25 years could not be predicted accurately.  We noted the previous ASA adjudication YE had referred to indicated that it was reasonable to use an emissions factor of 860 g CO2/kWh to calculate the reduction of CO2 emissions at the present time but that was not a reasonable figure to use for calculating the reduction over a period as long as 25 years unless there was some qualification to indicate the uncertainties about future fuel generating mix.

We recognised that YE had included a disclaimer to reflect the likely fact that the UK generating mix would vary over time and appreciated their efforts to clarify that the displacement figure could vary.  Because they had used the most up-to-date ASA guidance available to them at the time they published their ad, we considered that YE had not breached the Code on this point.  

However, following the publication of the ad in this case, an ASA adjudication established that a disclaimer that implied the amount of CO2 displaced might increase or decrease over time was not acceptable, because we understood it was likely only to decrease over time.  In addition, the adjudication established that a claim in the body copy, which suggested a CO2 tonnage displacement was achievable every year throughout the life of the proposed wind farm, was contradicted, rather than qualified, by a disclaimer which clarified that that was unlikely to be the case.  That adjudication concluded that this type of claim, which stated an achievable annual displacement figure, even with a disclaimer, was likely to mislead.  We therefore considered that, were YEs circular to be published now, it would be in breach of the new, refined guidelines, because the claim in the body copy, "It will displace around 25,000 tonnes of CO2 and other greenhouse gases from entering the atmosphere every year (1), which in broad terms is equivalent to the CO2 emissions from approximately 10,000 cars (2)", implied that tonnage displacement was achievable every year throughout the life of the proposed wind farm, but was contradicted, rather than qualified, by the disclaimer, which clarified that that was unlikely to be the case.  The disclaimer "Any extrapolation of these annual emissions savings over the 25 year life of the wind farm may vary up or down" also misleadingly implied the amount of CO2 displaced might increase or decrease, whereas we understood it was likely only to decrease over time.

In addition to this, at the time the ad appeared, summer 2006, the conversion rate of 860 g CO2/kWh was broadly accepted by the ASA for use in CO2 displacement calculations and we acknowledged that YE had used the figure in good faith.  However, a recent ASA adjudication established that, because of the flux of the UK electricity generating mix, the 860 g CO2/kWh figure was no longer representative as the rate of displacement and should not be used in marketing as the basis of carbon saving claims.

On this point, we investigated the ad under CAP Code clauses 3.1 (Substantiation), 7.1 (Truthfulness) and 49.1 (Environmental claims) but did not find it in breach.

4.  Not upheld

We acknowledged that recorded noise levels at the residences in closest proximity to the proposed site were below the limits set out in the ETSU report and considered that the claim are strict guidelines that we have to adhere to that make sure noise from turbines will not be a nuisance" was acceptable.  We noted the ETSU report did not contain information about noise levels at the base of turbines.  

We understood that the sound level recorded in the ETSU report as being representational of a conversation was 60 dB and, very generally, noise levels decreased at a rate of 6 dB with every doubling of distance from a turbine in accordance with the theory of spherical propagation.  We also understood that, with advances in modern turbine technology, sound levels emitted from a turbine and recorded at the nearest receptors and noise levels realised at the base of a turbine would fall below the 60 dB guideline conversation limit.      

We noted however that, although readers might expect the base of a turbine to be the noisiest location, it was sometimes possible to recognize small increases in sound at a short distance from it, because some noise was emitted from the turbine hub and carried by the wind.  Despite this effect, we understood that the noise increases would not be so significant as to make normal conversation problematic.

We considered that, by using the claim "Noise levels from wind farms are low enough to hold a normal conversation at the base", YE had intended to allay fears about noise emissions emanated from wind farms in general.  We also considered that, given that sound levels at the base of a turbine would allow for a normal conversation and any increases in noise were noticeable only close to the base of a turbine, away from residences, and those increases would not be sufficient to overbear a conversational noise level, the claim levels from wind farms are low enough to hold a normal conversation at the base", was unlikely to mislead readers about noise levels at the base of a turbine or about the overall noise levels emitted from wind farms.

On this point, we investigated the ad under CAP Code clauses 7.1 (Truthfulness) and 49.1 (Environmental claims) but did not find it in breach.  

Action

We told YE to ensure any future claims relating to the region's renewable energy targets were accurate so that the benefit of the proposed wind farm was not exaggerated, to remove from future ads the implication that the amount of CO2 that could be offset by the wind farm would be the same for every year of its operation and to base future carbon savings claims on a more representative and rigorous carbon emissions factor.

Adjudication of the ASA Council (Non-broadcast)