ASA Adjudication on West Coast Energy Ltd

Ad

A brochure, about the proposed construction of a wind farm, included text that stated "The wind farm would be connected to the existing Central Networks 33 kV electricity network … Based on 5 x 2.5 MW turbines (12.5 MW installed capacity) the wind farm is projected to produce enough electricity to supply the annual domestic needs of around 7,000 homes or 16,775 people".

Issue

The complainant, who was a member of the pressure group Action Against Matlock Moor Wind Farm Proposal (AMP), challenged whether the claim that the wind farm could supply around 7,000 homes, or 16,775 people, per year was misleading, because he believed:

1. the capacity factor used was inaccurate;

2. that the electricity wind farms produced fluctuated throughout the year, as did the typical pattern of domestic usage.

CAP Code (Edition 11)

Response

1. West Coast Energy Ltd (WCE) said they had assumed a capacity factor of 0.3, which was a commonly used industry average, to calculate the number of homes the wind farm could supply.  The figure would be interpreted by the reader only as a forecast, based on expected conditions at the site, given that the leaflet contained the words "projected to" and made clear that the information related to a proposed development.  

WCE accepted that the average capacity factor across England from 2005 to 2007 was 0.23 but nevertheless believed that a capacity factor of 0.3 was a conservative estimate on which to base their calculations for the proposed site. It was recognised that wind speeds would vary at regional and local levels and 0.23 was an average figure, which meant that some areas had a higher capacity factor.  Such an average also did not account for the significant variations that could exist in the specification of each wind turbine or for the developments in technology that had improved turbines; they said the British Wind Energy Association (BWEA) argued that the average capacity factor could be expected to improve year-on-year as a result of increasing numbers of modern turbines, such as those intended for the site.   

WCE argued that wind speed data specific to each site was not usually available when brochures were issued and therefore it was acceptable to use the government NOABL wind speed forecasting data to predict the average speed for the site of a proposed turbine. Although that data was not as accurate as readings taken on the site itself, it provided a robust indication of expected conditions in a particular area and showed that the wind speed for the site, which was 7.8 metres per second at a height of 45 metres above ground level, was much greater than the average speed for England as a whole.  Although generators would inevitably operate at less than maximum output and would need to be shut down for certain periods, the availability and speed of wind was the main determinant of capacity factor. Wind speed generally increased as the height from ground level increased and the hub heights for the turbines proposed for the site were up to 80 metres therefore the figure for the site was likely to be higher than the NOABL figure suggested.  Their calculation showed that the proposed site was likely to supply 6,989 homes and it was considered sensible to round that figure up to 7,000.  WCE believed the ad was not misleading because a higher capacity factor could justifiably have been used.

WCE said that, until a few weeks before the ad was distributed when a 60 metre mast was installed, their on-site mast stood at only 10 metres high; although the readings taken from the 60-metre mast so far tended to support the NOABL wind speed figures, it would be inaccurate to base the estimate on data that did not cover a full year because that would not account for anomalies or seasonal variations. They said increasing weight could be attached to data produced by the 60 metre mast once it had been in place for a year, however, it would be prudent to collect at least two years of data to avoid results being under- or overestimated.

The 10 metre mast had recorded wind direction and wind speed at 10-minute intervals since it was erected in May 2006.  That data had been summarised into a month-by-month average, however, they had not used that data as the basis for the claim in the ad because it was not generally used to determine the capacity factor. The primary purpose of the mast was to allow the developer to understand whether there was a commercially viable wind resource and to consider the layout of the turbines.  If the mast suggested that the wind resource was sufficient to develop a commercially viable site, a taller mast would be installed as had been the case at Matlock Moor.  

They said the data produced by the 10-metre mast should be treated only as guidance and would not be used as the basis for detailed output calculations.  The site was surrounded by trees they estimated to be over 20 metres in height and therefore, due to a potential screening effect and because the turbine hub height would be 80 metres and therefore the bottom of the blades would be clear of the trees, the data might not be truly representative.  They submitted an image of the site that had been included with the planning application and showed the trees on the site.  WCE declined to provide the ASA with the data they had collected from the 10-metre mast because they said it was commercially sensitive and was irrelevant to the calculation of the capacity factor referred to in the ad. They stated, however, that the data had provided enough evidence for them to commit a significant investment to developing the site for a commercial wind farm.

2. WCE said the electricity supply industry was a system and no individual power station could guarantee to supply any particular home.  They pointed out that the ad stated "The wind farm would be connected to the existing Central Networks 33kV electricity network ... " and made no reference to 'direct supply'; that clearly informed the reader that the electricity that would be generated by the proposed wind farm would connect into the existing electricity grid.

They said the ad did not state that electricity would be supplied directly to 7,000 homes; they believed it did not imply that was the case.  The figure in the ad was clearly expressed in annual terms. It was widely recognised that, dependent on several factors but most significantly on the wind resource, the electricity produced by a wind farm would vary and the ad did not imply that energy would be produced at all times.  Equally, most people accepted that domestic electricity consumption peaked and troughed both during the average day and seasonally.  Because the scenario was constantly changing, it was impossible to state that a commercial wind farm would provide power for a certain number of homes at all times or at any given time.  The wind industry, and the electricity industry as a whole, therefore tended to express the figures in annual terms. They sent press articles to demonstrate that was the case.  WCE said the claim was based on the capacity factor, which was divided by the annual domestic household electricity value and that equalled 6,989 homes; that was sensibly rounded up to "around 7,000 homes ... per year".  They firmly believed that the general public would understand that the reference to 7,000 homes was a simple, indicative explanation expressed in annual terms and used in place of more technical, less familiar measures.

Assessment

1. Not upheld

The ASA noted WCE had based their estimate on government NOABL data, which we understood provided annual estimated mean wind speeds for each Ordinance Survey 1 km grid square in the UK based on extensive modelling of wind patterns.  We considered that NOABL data provided a robust estimate of the wind conditions expected in a particular area, although we noted it did not provide the level of accuracy associated with measurements taken on-site.  We were concerned that WCE did not provide the data generated by the 10-metre mast. However, we noted that the accuracy of that data could have been affected by trees in the vicinity that were taller than 10 metres, especially given that the proposed turbines would be up to 80 metres in height.

We noted the ad claimed that the likely amount of energy produced by the wind farm would be enough to supply the average annual energy needs of 7,000 homes if based on a capacity factor of 0.3 and an average household consumption of 4,700 kWh per year.  We noted the average household electricity consumption of 4,700 kWh per year was a generally accepted figure currently used by the industry and the NOABL figures suggested that capacity was likely to be greater than 0.3.  We therefore considered that, because the ad referred to a proposed development and included the text "is projected to ... " and "around 7,000 homes ... ", which we considered made clear that the reference to the number of homes the wind farm could supply, if it were to supply homes directly, was based on an estimate, and in the absence of accurate on-site data, the use of NOABL data to calculate the capacity factor used as the basis of the projection was acceptable.  We concluded that the capacity factor used as the basis of the calculation was not misleading.

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. Not upheld

We acknowledged the ad stated that the farm would be "connected to the existing Central Networks 33 kV electricity network ... " and considered that made sufficiently clear that any energy the wind farm produced would supply homes via the national grid (the commonly used name for the electricity transmission network)  and not directly.  We considered the claim "the wind farm is projected to produce enough electricity to supply the annual domestic needs of around 7,000 homes or 16,775 people" was likely to be understood by consumers as a projection of the equivalent number of homes the wind farm could supply energy for, expressed in annual terms.  We considered readers were also likely to understand that, due to their reliance on certain weather conditions, wind farms were unlikely to produce electricity at all times and would not therefore be able to produce enough energy to directly supply the needs of those homes throughout the year or during peaks and troughs in household usage patterns.  

Because the ad made clear that the claim related to the amount of energy the wind farm could produce being equivalent to the annual needs of 7,000 homes, we considered it was unlikely to be interpreted as suggesting that the wind farm could produce enough electricity to supply 7,000 homes directly, or 16,775 people, throughout a year.  We concluded that the ad was not misleading.  

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.

Action

No further action necessary.

Adjudication of the ASA Council (Non-broadcast)