ASA Adjudication on E.ON UK plc

Ad

A leaflet, for a proposed wind farm, stated " ... There are many myths about wind energy. Below are the facts: ... Myth: Wind farms are inefficient, they are only operational 30% of the time Fact: A modern wind turbine produces electricity 70-85% of the time, but it generates different outputs dependent on wind speed. Over the course of a year, it will generate about 30% of the theoretical maximum output. This is known as its load factor. The load factor of conventional power stations is on average 50%. A single modern wind turbine will generate enough to meet the electricity demands of more than a [sic] 1,000 homes over the course of a year ... ".

Issue

The complainant, who understood that the Department of Trade and Industry figures for 2005 showed the overall system load factor for UK power stations was 66%, challenged whether the claim "The load factor of conventional power stations is on average 50%" was misleading.

CAP Code (Edition 11)

Response

E.ON UK (E.ON) believed the comparison of 30% and 50% load factor figures for wind and conventional power generation did not mislead.  They explained that the figures represented the average generation output expressed as a percentage of the theoretical maximum of wind or conventional energy generation.  They said the Department of Trade and Industry (DTI) Digest of UK energy statistics (DUKES) figures were not the source of their figures but explained that they had used a different data set, source and time period from DUKES.  They further explained that DUKES was based on information for the whole of the UK in 2005 but, as E.ON operated in Great Britain, they had access to an up to date centralised data source of plant capacity and generation for the national grid.  They also explained that they had not used DUKES "all plant" classification because it included nuclear and pumped storage and they had defined conventional generation to be based on forms of thermal combustion only.  They submitted their calculations in support of their claim and pointed out that their data were almost identical to the DUKES data for the "all plant" classification, which was 53.6%.  They therefore believed that, although they had not used the DUKES data, their data did not contradict those figures and the figures quoted in the ad were an accurate representation of the actual output obtained from wind power and conventional power as a percentage of the theoretical maximum.

Assessment

Not upheld

The ASA understood from the DTI that the average plant load factor was a suitable measure for a comparison of power generation.  We also considered that the method used by E.ON to calculate the average plant load factor for conventional combustion power stations to produce the figure of 50% quoted in the ad was appropriate, given the reference to "conventional power stations", and noted there was little difference between their figure and the DUKES "all plant" load factor.  We understood that the system load factor compared the average hourly quantity of electricity available with the maximum demand placed on the system during the year and was a measure of demand on the whole system. We therefore considered that it was not comparable with load factors of individual generating plant, or all generating plant taken together, as described in the ad.  We concluded that E.ON had substantiated the claim and that it did not mislead.

We investigated the ad under CAP Code clauses 3.1 (Substantiation), 7.1 (Truthfulness), 8.1 (Opinion) and 19.1 (Fair comparison) but did not find it in breach.

Action

No further action necessary.

Adjudication of the ASA Council (Non-broadcast)