11 FEBRUARY 2004

Dr Brenda Boardman and Mr Graham Sinden

  Q127  Chairman: Good afternoon. Thank you very much for coming to see us. May we begin, please. I have to say at the beginning that you should be aware that these proceedings are public, on the record and are being broadcast live as a web cast. I wonder if I could ask you if you would introduce yourselves in turn, simply to say who you are and what you do.

  Dr Boardman: Thank you very much. We are delighted to be here.

  Q128  Chairman: Could I also ask everyone to speak up because the acoustics in this room are very bad. If you see me doing that, it means I cannot hear you.

  Dr Boardman: Good afternoon, everybody. We are delighted to be here. My name is Brenda Boardman. I am from the Environmental Change Institute, which is part of the University of Oxford. I lead a group called Lower Carbon Futures. May I introduce Graham Sinden, who is one of our researchers.

  Q129  Chairman: Thank you very much. We have alerted you to a number of questions that we might wish to ask you. We may not be able to reach all of those this afternoon but perhaps if we do not reach any we might be able to do those by correspondence afterwards. Your submission describes really what is a considerable research effort and explores various scenarios for electricity generation from renewable sources and the management of intermittency. Could you give us an initial overview of your research and your results?

  Dr Boardman: I am going to ask Graham to answer most of the questions because it is his research that we are reporting on, so it is better if it comes from him.

  Mr Sinden: Thank you very much. The basis of the research was to look at the question of intermittency to try and quantify what was happening with intermittency in wind and solar energy and domestic combined heat and power systems. In summary, we took a large body of wind speed data from around England and Wales. We used 13 different sites from around England and Wales with 21 years of hourly wind speed data at each. We used hourly solar radiation data for London and we used temperature data for London to infer domestic combined heat and power output. We were able to construct a model which on an hourly basis balanced what would be coming from wind farms at different locations, what would be coming from solar power and what would be coming from dCHP against what the electricity demand was in that hour, so that model was then run for the 21 years of data that we had. The objective was to find a mix of renewable technologies and sites where those technologies would be used that provided the best match between intermittent electricity supply and the demand patterns that we see currently.

  Q130  Chairman: The output of models is all very well but you have to have a fair amount of reality in them. Did you choose as the locations for your wind generation the sites which have already been identified by the Government as places where they would like to see this? How did you choose them?

  Mr Sinden: The 13 wind sites that we used were the first round offshore wind sites that were licensed by the Government. That formed the basis of the wind power aspect of it. For solar and CHP we just used London as a single site for the generation of those electricity supplies.

  Q131  Chairman: Thank you very much. Did you do your analysis by hour or by day of wind power?

  Mr Sinden: It is average hourly wind speed for every hour between 1980-2000.

  Q132  Chairman: Did you compare your analysis with the output of other bodies who have done similar things, like the Oxera group, for example, based in Oxford too?

  Mr Sinden: The wind data that the Oxera report was based around was some work that I did for Oxera.

  Q133  Chairman: It is not surprising that they agreed.

  Mr Sinden: I am not familiar with the model that they ran afterwards but I am familiar with the data that they fed into it at the start. Broadly our results are consistent with a number of studies in this field. I think one of the defining differences with our work is that we do treat the data on an hour by hour basis rather than aggregating the data and looking at probabilities. With the approach we have used we are able to identify what is the worst case scenario, the worst hour where intermittent supply is low and demand is high.

  Q134  Chairman: If I remember rightly, I think Oxera recognises a figure of something like eight hours during the year when zero wind production or minimum wind production corresponds to maximum demand or something of that kind. That is simply for wind.

  Mr Sinden: That is simply for wind. It is in that order, I cannot remember the specific numbers.

  Q135  Lord Young of Graffham: Last autumn we went over to Denmark, it was a rather windy day I remember, to see the Horns Rev field. The operators told us that on occasion the output could drop by 100 megawatts in a matter of a few minutes. Do you have the confidence that if we were to expand wind power substantially in the way that you foresee that we would still have a system which could keep the wind going?

  Mr Sinden: Yes, I believe so. What you are describing there is something that you would expect to see where you have a lot of wind turbines in one place because all those wind turbines are experiencing the same wind, or in the case of changing output they are experiencing the same change in wind at the same time. If you use a geographically distributed system where you have wind farms in quite distant locations around the country these are going to be experiencing different winds at the same time and, therefore, you will not be seeing all turbines responding the same way at the same time. Across the portfolio that you have, you will have a far more reliable wind electricity supply than what you have seen just at one wind farm.

  Q136  Lord Young of Graffham: Did your statistics, looking back over the last 20-odd years, show any periods when we were high pressure and we had no winds for two or three days?

  Mr Sinden: It is an interesting question because it does get raised a fair bit but in essence, no. We have looked at that 21 year period and the longest consecutive time of calm across England and Wales—we are not including Scotland—was 11 hours and that 11 hours was overnight in summer, so there was quite a low electricity demand at that time.

  Q137  Lord Tombs: I am interested in this question of diversity, and it is obvious there will be diversity, but how consistent is it likely to be between the chosen sites? Are you able to say, for example, the worse case we will encounter will be 40 per cent generation or something? The diversity must vary between nothing and another figure.

  Mr Sinden: Even with a highly diverse system you will get quite a range of outputs. The data that we have looked at shows that the more diversity you have within the system, and particularly with distance, so if you have a wind farm located in the South of England and you have a wind farm located in the North of Scotland, the difference in wind patterns is quite large so the movement of electricity output from those different wind farms is very different. The further you can separate your wind farms and the greater the geographic representation you have within your wind farms, the more reliable your output is going to be. That is not to say that it will be constant, there will be high points and there will be low points, but it will be more consistent as you bring more sites in and you separate them further across the country.

  Q138  Lord Tombs: There will be quite a range of diversity. Wind farms generally offshore will be placed in the most favourable areas. Is there a link between that and the behaviour of the wind, in terms of reliability?

  Mr Sinden: With the work that we have done we have been looking at the offshore wind sites in terms of how well they contribute electricity at certain times rather than their absolute ability to produce electricity. We see the ability to produce electricity when electricity is needed as being fundamental to overcoming problems with intermittency and to guarantee supply at the times of peak demand. We have not really addressed the question in terms of whether these offshore sites are absolutely the largest contributors of electricity.

  Lord Tombs: Let us hope they will be otherwise they will not pay.

  Q139  Baroness Platt of Writtle: What about a stationary anticyclone in the middle of winter over the British Isles?

  Mr Sinden: We have looked at that occurring in the wind data and the wind data does not show it.