The following is in reply to Robert Wilson specifically and some of the other blogs more generally (see Carbon Counter)
1. Robert suggests the term power station is commonly understood to refer to the number of reactors on site; hence he proposes the capacity (GW) figure I used should be doubled.
The question about stations, reactors or sites may certainly be open to interpretation; however the question posed by Jim Al-Khalili was: “the amount of energy produced by one modern nuclear power station – how may wind turbines would that need?”
Given the Radio 4 programme was aimed at the lay public, I am unsure as to whether the typical interested rather than expert listener, or indeed the presenter, would have understood “one modern nuclear power station” to have meant ‘as many reactors as you can fit on a site’. But perhaps that is what they thought. Only asking the presenter and polling listeners could give an answer to this.
2. Robert suggests 6MW should be a high estimate of future wind turbine capacity (I’m unclear as to the timeframe of his comment)
Despite various comments and suggestions, I remain of the view that 6MW by 2020 is completely reasonable – if not conservative; please note the 2020 date! Are those that disagree, suggesting 6MW turbines are unlikely to succeed – or that this is some threshold of capacity – there are certainly turbine manufacturers that think differently. Again, please note I was and am talking about 2020.
3. Robert suggests “talking in terms of turbines is not a good idea, instead we should be talking in terms of watts per square metre.”
I’m very unsure about watts per square metre as being a useful measure. But if it is to be used I think it would need a time dimension and include all the fuel phase for options being compared, and, from an LCA perspective, the construction, decommissioning and waste phases too. So the exploration, extraction, enrichment, land transport, ports, ships etc, would need to be factored in, along with any space used in relation to the waste. Then this would need to be considered over time – to give a watts per square metre-year. As I say, I think this is unhelpful – but I certainly have no idea how the numbers would pan out – or how waste storage over decades to centuries should be factored in. In addition, some estimate of the frequency and severity of nuclear & wind accidents would need to be assessed and any changes in use of areas impacted considered – again measured in square metre-years. Personally, I’d stick with number of turbines being a least-worst proxy – after all, such figures are just a guide.
Two final points.
A) I get a sense (which I acknowledge may be incorrect) – that those arguing against my numbers are unreasonably favouring nuclear over wind in terms of load factors, capacities and operating dates. I took the view from the start that a new nuclear plant could be operating in the UK by 2020 at 85% load factor and assuming one of the three designs outlined. Similarly, I took the view that the 6MW wind turbines now being installed could be typical by 2020, and quite possibly could have reached 10MW. Moreover, that a 40% capacity factor was not unreasonable to assume for well sited arrays of large offshore turbines by 2020. For both nuclear and wind I took what I continue to hold to be a positive and achievable view of the future. However, I find it difficult to understand how the repeated disregard, by some bloggers, of the 2020 date along with their dismissal of both the 6MW capacities and the 40% capacity factor (as viable norms for 2020), can be said to represent a balanced contribution.
B) Finally, on reflection I recognise that the tone of my original comment could have been construed as unnecessarily critical of Sue Ion. This was not my intention – rather I was and remain committed to trying to analyse and compare all energy options fairly, with the relative merits and drawbacks considered openly and honestly. So whilst I hold to the conclusion of my initial response to the Sue Ion interview, I wish to assure her, should she be following any of this, that my observations were not personal, but about the substance of her comments on the numbers of turbines and informing the media.