The following is a response from Peter Lang to various comments made in the post “Does wind power reduce carbon emissions?“
Energy storage, at the scale required to make wind power a reliable source of dispatchable power, is uneconomic. This link provides comparative costs of energy storage technologies.
Even without energy storage wind generation is uneconomic. Wind must be mandated by governments and subsidised, otherwise it would not be built. Wind power is high cost for low value energy. It has low value because it cannot be controlled and called up on demand. It requires high cost upgrading to the grid in remote areas and requires costly systems to maintain power and frequency stability on the grid. Wind generators need $90/MWh to $140/MWh to be viable. As well, the electricity distributors and the national grid operator all incur substantial additional costs as a result of being forced (by government regulation) to buy wind energy. For comparison, the cost of new entrant baseload power is about $40/MWh.
Barry Brook will soon be posting another paper which provides insight into the amount of energy storage that would be required and just how far from being economic are intermittent, not dispatchable renewable energy generation technologies with energy storage. These technologies are not just 10% or 20%, or even 50% from being economic. Solar PV with energy storage, for example, would be some 20 times more costly than nuclear power to provide the electricity we demand. We have been researching and developing solar PV for the same time as nuclear power, and wind power for three times as long. Yet these renewables are still totally uneconomic. The advocates are making the same sorts of statements now as they were making in the early 1990s about the economics of these generation systems – “they are economic now if the government would just subsidise them and mandate them more”.
Regarding plug-in hybrid electric vehicles (PHEV’s), there are many technical and cost issues to be solved before these become economic and widely used. However, together with substantial nuclear power generation, some energy storage with PHEV’s may make sense in the future. With some 80% of electricity generated by nuclear (as in France), and the remainder from gas and renewables (mainly hydro), then PHEV’s may make sense. They could allow wind and solar to make a genuine, economic contribution to electricity generation.
The fallacy of Dr Mark Diesendorf’s “The Baseload Fallacy”
Dr Mark Diesendorf claims that “the wind is always blowing somewhere”, so, with sufficiently wide spread wind farms, wind power is dependable. Figure 1 demonstrates that this claim is wrong. Figure 1 shows the total output for wind farms in NSW, Victoria, Tasmania and South Australia for June 2009. The conclusion: wind power is unreliable, not dispatchable, and often zero when needed, no matter how large the area over which the wind farms are distributed.
Many comments on the previous thread refer to Mark Diesendorf’s paper “The Base-Load Fallacy”. For example Barry Brook in Post 7, in responding to a comment, replied as follows (the original comment is in italics and Barry Brook’s response is normal text):
“Although a single wind turbine is indeed intermittent, this is not generally true of a system of several wind farms, separated by several hundred kilometres and experiencing different wind regimes. The total output of such a system generally varies smoothly and only rarely experiences a situation where there is no wind at any site. As a result, this system can be made as reliable as a conventional base-load power station by adding a small amount of peak-load plant (say, gas turbines) that is only operated when required.”
There are no calculations here, so we must take it as a matter of faith. What does ‘rarely experiences a situation where there is no wind at any site” mean? Is that 1 day per year? 10? What about when the wind delivers power at some sites, but not others, so that capacity factor is below 10%? 10 days per year? 30? 50? How dispersed are these turbines? Spread over 100 km of coastline? 500? 1000? The area actually occupied by the turbines is quite different to this. How does this scale up, when we are no longer talking about replacing a single-coal fired power station, but a nation of them?
He does then say:
“[computer simulations show that] to maintain the reliability of the generating system at the same level as before the substitution, some additional peak-load plant may be needed. This back-up does not have to have the same capacity as the group of wind farms. For widely dispersed wind farms, the back-up capacity only has to be one-fifth to one-third of the wind capacity. In the special case when all the wind power is concentrated at a single site, the required back-up is about half the wind capacity.”
I would argue that average capacity factor is not valid for determining the amount of back-up generation capacity required. The total generation system must be able to provide peak power when there is no output from the wind turbines. When wind power is zero, or near zero, at the time of peak demand, we need sufficient conventional generator capacity to provide the peak demand. This is because electricity demand must be matched by supply at all times. In other words, wind power cannot displace much, if any, conventional generator capacity.
As already noted, the chart I have included above shows that the total power output of the major wind generators in NSW, Victoria, Tasmania and South Australia in June 2009 was zero on several occasions during the month. This demonstrates that the underlying premise of Dr. Mark Diesendorf’s paper “The Base-Load Fallacy” is false.
With wind power, we need the full capital cost of 1) the wind farms, PLUS 2) the conventional generators, PLUS 3) the transmission capacity for the full power output for each wind farm (despite the fact they produce, optimistically, just 30% of their rated power output on average), PLUS 4) the enhanced power and stability control systems. The cost of the wind generators does not offset virtually any capital cost for conventional generators in a system that has a substantial proportion of wind generation capacity.
The GHG emissions are the total of the full life cycle emissions from the wind farms, from the operation and maintenance of the wind farms and the enhanced grid, from the embedded emissions in the conventional generator systems, and from the emissions from the fuel combustion in the conventional generators operating in back up mode (which are higher per MWh than when operating at their optimum).
Short responses to the main concerns about the safety of civil nuclear energy
The risks (and perceived risks) with the safety of civil nuclear power relate to:
1. the risks of accidents (like Chernobyl)
2. nuclear waste disposal
3. accidents during the nuclear life cycle (power station and other facilities construction and decommissioning, mining, processing, waste disposal)
4. emissions and contamination from the routine running of nuclear facilities
5. production of fissile materials for making nuclear bombs
Here are a few words on each:
1. Accidents – very low probability of occurrence as demonstrated by 50 years of civil nuclear power station operation (12,700 reactor-years of operation) and only 31 people killed in a major civil nuclear accident plus an estimated 4000 probable future deaths from contamination over a period of 70 years in a population of 200 million. The risk is very small, and the consequence of an accident is much less than from the normal operation of fossil fuel power stations (see Figures to the right [from here] and below).
2. Nuclear waste disposal – the quantities to be disposed of are miniscule. There is also an unwillingness to permanently dispose of the nuclear waste because the current reactor technology has used only about 10% of the available energy. In the future it may become economic to recycle the once-used fuel. Some reactors already do so.
3. Accidents in construction, mining etc – are far lower for nuclear than for coal and renewables for several reasons: first, the amount of material mined, processed, fabricated, transported and constructed is much smaller than for fossil fuel and renewables per unit of electricity generated; second, the greater safety culture in the nuclear industry.
4. Radiation Emissions from nuclear power stations during routine operation are negligible. Even the leaks are inconsequential (except in public perception terms).
5. Use of civil nuclear power stations to produce bombs. This concern is a furphy. Fissile material for bombs is produced in dedicated military installations. The processes for producing weapons grade material are quite different from the civil processes. The relation of civil and military uses of uranium are about as unrelated as the use of oil to make plastic explosives and petrol. Civil nuclear power stations use un-enriched uranium (for Canadian reactors) or uranium enriched to 3.5%to 5% U235 for all other reactors. For bombs uranium 235 and plutonium must be enriched to over 90%. Therefore dedicated establishments (military) must be used to produce fissile materials for bombs. If we want to argue that uranium should not be used for civil nuclear power because it is also used for making nuclear weapons, then surely we should argue that oil should not be extracted because it is also used for making plastic explosives and for powering the ships and planes that drop bombs in conventional wars (like Iraq, Zimbabwe, etc). Saying we should not use nuclear power to generate electrcity because uranium is also used for nuclear weapons is an illogical and inconsistent argument.
Comparison of greenhouse gas emissions from electricity generation technologies
The following link summarises the GHG emissions from electricity generation technologies from authoritative studies. However, note that the figures for wind and solar power do not include the emissions from back-up generation.
The following link shows what is included in full life cycle analysis of the GHG emissions from nuclear energy.
Regarding life cycle emissions from nuclear power, I (Barry Brook) asked Peter the following question:
Have you been able to pin down the reasoning for Lenzen’s ISA analysis coming up with the CO2 figure of 60g/kWh for nuclear, when none of the studies you cite in Table 1 (or that I’ve seen elsewhere) come close to that. I suspect it involves placing too much weight on SLS-type ‘analyses’ and too great a focus on low-grade U ores – but I’d certainly like to get to the bottom of it. The issue was explored somewhat in the comments of this thread.
Peter’s reply was as follows:
The UK White Paper (PDF link) looked at the ISA and the Leeuwen and Smith studies in detail. Their conclusions are written up in several places in this document (e.g. 2.12, 2.13, 2.17-2.20, pp48-51).
There are several issues with the ISA study:
1. They used a ratio of 30%/70% for centrifuge to diffusion enrichment because they argued that is the ratio currently being used averaged across the world
2. They made naive assumptions about the quantity of uranium available
3. They added back end and front end emissions on top of what is already included in the LCA analyses
4. They did not use properly comparable methods for evaluating LCA emissions from wind, PV and nuclear. They were very generous to the renewables
I understand why ISA took this approach. It was a political report and all concerned wanted to minimise the opportunities for the report to be drawn into endless arguments about minor points. They wanted the report to focus on what is important, not get lost in arguments about minutiae. I feel the UMPNE is an excellent report considering the very short amount of time they had to prepare it. I also feel the commissioned EPRI report on the costs of nuclear in Australia is excellent, although the costs of all the major baseload technologies have risen substantially since it was written.