ASA Non-broadcast Adjudication: Renewable Energy Systems Ltd

Complaint

Objection to a circular, headlined "Den Brook to do its bit for the planet? The Proposal for Wind Turbines at Den Brook", that described the benefits of a proposed wind farm in Devon. The circular stated " ... The Den Brook Proposal We have begun work on a number of studies to inform our proposal, such as wind monitoring, ecology, archeology [sic], hydrology, visual impact and access surveys. However, we have started to think about what kind of wind farm might be suitable there and some options are described below: About 10 large turbines (eg 2.3 MW with 60m towers and 40m blades) OR about 19 smaller turbines (eg 1.3 MW with 49m tower and 31m blades) on land around the railway line, south east of North Tawton. Such a project would generate green electricity equivalent to the annual needs of over 12,900 homes ... It would reduce CO²missions by over 1.3 million tonnes over its lifetime ... please take time to reflect on some of the hard facts about wind power: A typical turbine in the UK, rated at 1 MW, produces 2.63 million units of electricity each year. This means generating enough power to meet the yearly needs of 560 families ... A 'tower of coal', with a similar radius to a turbine, would have to be over 11km high to produce the same amount of electricity!". A page of text, headlined "Fact, Fiction or Rumours? Some frequently-asked questions answered" stated " ... Will property prices be adversely affected once a wind farm is operating in the area? There is currently no evidence in the UK showing that wind farms impact house prices. According to the Royal Institution of Chartered Surveyors, there are no studies that suggest an effect either way ...". The complainant challenged the claims:

1. "Such a project would generate green electricity equivalent to the annual needs of over 12,900 homes", because he believed the calculation on which it was based used either an exaggerated capacity factor or an underestimated annual domestic consumption figure;

2. "It would reduce CO²missions by over 1.3 million tonnes over its lifetime", because he believed the advertisers had used an exaggerated emissions factor in their calculation of the quoted figure;

3. "A typical turbine in the UK, rated at 1 MW, produces 2.63 million units of electricity each year. This means generating enough power to meet the yearly needs of 560 families", because he believed the calculation on which it was based used either an exaggerated capacity factor or an underestimated annual domestic consumption figure;

4. "A 'tower of coal', with a similar radius to a turbine, would have to be over 11km high to produce the same amount of electricity!" and

5. "There is currently no evidence in the UK showing that wind farms impact house prices. According to the Royal Institution of Chartered Surveyors, there are no studies that suggest an effect either way", because the results of The Royal Institute of Chartered Surveyors (RICS) survey October 2004 suggested that wind farm developments reduced property values.

CAP Code

Adjudication

REVISED ADJUDICATION:

This adjudication replaces that published on 3 August 2005. The decision on Complaint 2 has been reversed, making the complaint 'upheld'.

Renewable Energy Systems Ltd (RES) said the circular was withdrawn in November 2004 and they had no plans to use it again.

1. Complaint not upheld

RES arrived at the figure of 12,900 homes by dividing the predicted energy yield of the proposed Den Brook wind farm by the average UK household electricity consumption figure.

They explained that, when calculating the predicted energy yield of the proposed Den Brook wind farm, they used specific data that related to the wind speed and climatic conditions at the site, not a standard capacity factor. To predict the site's long-term mean wind speed they used a meso-scale prediction model, which was a numerical weather model that was capable of simulating the complete physics of the atmosphere. They sent details of the data and method used in the prediction.

RES used an annual domestic consumption figure of 4700 kWh per household per year, which was the figure used by the British Wind Energy Association (BWEA); they asserted that that was the most recent and accurate consumption figure available. They explained that it was based on a domestic consumption figure of 115.3 TWh from the Department of Trade and Industry's Digest of UK Energy Statistics (DUKES) 2002 and a figure of 24.48 million households from the 2001 Census. They were aware of an alternative consumption figure of 3300 kWh per household per year but said using that figure in their calculation would result in a higher number of homes and could therefore make their claim seem exaggerated.

The Authority took expert advice. The expert advised that it was reasonable, and in line with wind energy industry practice, for RES to base their estimate of the proposed wind farm's energy yield on meso-scale modelling techniques. He advised that, when tested against historic wind measurement data in a variety of locations, RES's model had demonstrated a standard error of 10% or less; the expert considered that such a low error was remarkable. He advised that RES had provided rigorous, published documentary evidence of the accuracy and validity of the model's results.

The Authority considered that RES had provided sufficient documentary evidence to substantiate their prediction of the energy yield of the proposed Den Brook wind farm. It did not object on that point.

The Authority noted the domestic electricity consumption figure currently recommended by Energywatch and recognised by the industry was 3300 kWh per household per year and considered that that would have been a reasonable figure for RES to use in their calculation. It also noted, however, the lower the annual domestic consumption figure used in the calculation, the higher the number of homes RES could claim would be powered by their project. It considered that, by using a consumption figure of 4700 instead of 3300 kWh per household per year, RES had made their claim more conservative. Given that, the Authority did not object to the use of the 4700 kWh consumption figure in the calculation. The Authority concluded that the claim was not misleading.

2. Complaint upheld

RES explained that they used an emissions factor of 860 g carbon dioxide (CO²)/kWh, which were the typical emissions of a coal-burning power plant. They argued that that figure was widely used in the energy industry and endorsed by the House of Commons Environmental Audit Committee in 2001. They said electricity from wind turbines replaced the output of coal-fired power stations because the coal plant was the most flexible plant on the system, the output from which could be most easily adjusted to meet electricity demand; they said that was demonstrated in the National Grid Transco's Seven Year Statement 2004 and was also endorsed by the Environmental Audit Committee. RES also pointed out that the British Wind Energy Association (BWEA) recommended an emissions factor of 860 g CO²/kWh.

The Authority took expert advice. The expert advised that the 860 g CO²/kWh figure was widely used in the industry, although some confusion existed in official government documents about the appropriate emissions factor for wind-generated electricity. The expert advised further that the National Grid Transco's Seven Year Statement 2004 supported the theory that wind power currently displaced high-emitting coal and indicated that an appropriate CO²missions factor for electricity generated by wind should be higher than that of the year average UK mix of generating fuels (43O g CO²/kWh) and in the region of 860 g CO²/kWh. The expert also advised 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 cannot be known accurately. The Authority considered that, although an emissions factor of 860g CO²/kWh might have been a reasonable figure for RES to use to calculate the reduction of CO²missions at the present time, it was not a reasonable figure to use for calculating the reduction over a period of as long as 25 years without some qualification to indicate the uncertainties about future fuel generating mix. It asked the advertisers not to publish the results of similar calculations in the future without such a qualification.

3. Complaint not upheld

RES used a capacity factor of 0.3 in their calculation. They asserted that a typical UK wind turbine had a capacity factor of 30% and pointed out that the BWEA used a capacity factor of 30%. They sent data to show that the average capacity factor of their 16 UK wind farms was above 0.3.

The Authority took expert advice. The expert advised that the average capacity factor of RES's turbines was not undermined by the lower capacity factors published in DUKES, because DUKES covered good and bad turbine efficiencies, sites and maintenance, whereas the RES turbines were efficient, well-managed and on favourable sites, so were likely to achieve capacity factors that were above the average.

The Authority accepted that RES's turbines achieved an average capacity factor of above 0.3. It noted, however, the claim referred specifically to "a typical turbine in the UK", not to RES's turbines. The Authority considered that DUKES was therefore an appropriate source from which to derive the average capacity factor of a typical UK turbine. It noted DUKES published a capacity factor of 0.29 for the year 2002 and 0.24 for the year 2003; accompanying text in DUKES stated that two factors had contributed to the lower capacity factor for wind in 2003: first, a capacity of 110 MWe was installed late in the year and had little opportunity to contribute towards generation, and second, it was likely that the long hot summer of 2003 was less windy than previous years, although meteorological data was not yet available to substantiate that. The Authority noted the capacity factor for the year 2004 had not yet been published. It noted the capacity factor was 0.28 for 1999 and 2000, and 0.26 for 2001. It considered that, although the capacity factor of 0.24 for 2003 seemed unusually low, the capacity factor of 0.29 for 2002 seemed unusually high. The Authority understood that the higher the capacity factor used in RES's calculation, the greater the number of homes RES could claim were served by a typical UK turbine. It noted RES had used the highest capacity factor published in DUKES in the past five years in their calculation. The Authority considered that, when making claims about the number of homes to which power needs could be met by wind farms, the most appropriate capacity factor to use was either the average capacity factor from DUKES from the past few years, or the capacity factor most recently published in DUKES, if that figure was representative of average capacity factors.

The Authority noted, however, RES had again used an annual domestic consumption figure of 4700 kWh per household per year in the calculation on which the claim was based. Although that was not the figure recommended by Energywatch, the Authority considered that using that figure made the claim more conservative than it would otherwise have been. It considered that, although RES had used an inappropriate capacity factor, they had not exaggerated the number of families whose yearly needs were met by a typical UK turbine, because any benefit derived from using a capacity factor of 0.3 was far outweighed by the conservative effect on the claim of using a consumption figure of 4700 kWh. The Authority concluded that the claim was not misleading.

4. Complaint not upheld

RES said wind farms were often criticized because of the large size of a wind turbine in relation to its electrical output; they believed it would be useful to convey to readers the typical amount of coal that would have to be mined and burned to generate the same amount of electricity as produced by a wind turbine over its life span. They explained that the calculation involved a number of variables that could affect its result; there were, for example, different types of wind turbines with different combinations of power ratings and tower dimensions, different types and grades of coal with different calorific values and packing densities and varying efficiencies of coal-fired power stations. RES used the dimensions and power ratings of the turbines in the planned Den Brook project to calculate the height of the tower of coal. They asserted that they erred on the side of caution and were conservative in their assumptions to avoid exaggeration, for example, they used the maximum tower radius at the base, which gave a shorter tower of coal than if they had used the minimum radius. They said their calculation also accounted for the fact that turbine towers were tapered. They said the volume of coal related to the dimensions of the turbine tower, not to the turbine blades or rotor. They explained their calculation in detail.

The Authority took expert advice. The expert advised that, when calculating the energy that would be produced by a Den Brook wind turbine over a 25-year life-time, RES had used a capacity factor of 0.3. He advised that the values RES had used for the calorific value and packing density of coal and the efficiency of a coal-fired power station were all reasonable and within accepted ranges of variation. He also advised that, to calculate the volume of the tower of coal, RES had used the formula for the volume of a cone. He explained that, if RES had instead interpreted the tower of coal as cylindrical, the calculation would have resulted in a tower one-third the height of the conical tower; he considered, however, that the shape of a coal heap was better approximated as conical than cylindrical.

The Authority noted RES had used a capacity factor of 0.3 in their calculation and understood that if they had instead used an average capacity factor from DUKES from the past few years, the height of the tower of coal would have been approximately 10.5 km. The Authority considered, however, that the difference between 10.5 km and "over 11 km" was not significant enough to render the claim misleading. It considered further that readers would realise that a tower of coal with a height of 11 km was a concept, not a real structure, and that RES were merely providing an illustrative example of the typical amount of coal that would have to be mined and burned to generate the same amount of electricity as produced by a wind turbine over its life span. It did not object on that point.

5. Complaint not upheld

RES said the claim was correct at the time of publication. They explained that the circular was written and printed in October 2004 and distributed to homes on 3 November 2004; RICS released the results of their October 2004 survey on 4 November 2004.

The Authority considered that, because the RICS survey October 2004 was issued after the circular was printed and distributed, the claim was not misleading at the time of publication. It noted, however, the RICS survey October 2004 suggested that wind farm developments reduced property values. It told RES not to use the claim in future.