21 June, 2006

Are we running out of Uranium?

I’ve just seen this post over at Bunsen Burner which discusses the case for new nuclear build, and which I heartily agree with (mainly because I’ve come to the same conclusions, albeit in a less concise manner). Whilst it’s always nice to see people agreeing with me, I was interested by the following sentence:

There is only so much uranium in the world and even with reprocessing this power source will run-out at some point. So wouldn't the money better be spent on something a bit more long term?

Which got this comment in response:

There is a significant body of work that disputes your conclusions about the global uranium supply.

Does this mean that somebody somewhere is seriously arguing that uranium supplies are renewable? Entertaining as that would be, it would seem not. Instead, the the link in the above comment is a post responding to claims (in a Guardian article which I missed) that the uranium supply is already on the verge of being exhausted. So, whilst the comment is a slight over-reaction in the context of this particular post, it does raise an interesting issue. So what are the facts?

A recently published IAEA report (home page here - except for the one exception listed below all the figures I use come from here) estimates the known inventory of uranium extractable at current market prices to be about 4.7 million tonnes, and total estimated reserves to be about 35 million tonnes. An estimate from what could be regarded as the other side of the fence is provided by van Leeuwen and Smith, whose work I’ve referred to before, and who estimate 4.3 million tonnes of ‘useful’ reserves with little hope of new major ore bodies being discovered (Chapter 2 from here). So a lower limit of about 4.5 million tonnes seems well-supported; estimating an upper limit is fraught with the usual difficulties you get when guessing how much you haven’t discovered yet, but we could probably take 35 million tonnes as an optimistic upper bound (I’m not sure how these figures would be affected by economic considerations, but it looks like it includes stuff which cannot be profitably extracted at current prices).

Production and Usage:
The IAE report says that mining produced 40 000 tonnes of Uranium in 2004. About 67 000 tonnes was actually used in nuclear power stations, with the shortfall coming from ‘secondary sources’ (stockpiles, reclamation from decommissioned nuclear weapons, some reprocessing). These secondary sources are being depleted, so we’re going to rely more and more on primary production in the future.

Doing the sums, if it’s all coming from primary sources the supply will last 65-500 years at the present rate of consumption. But demand is expected to increase to as much as 100 000 tonnes/year by 2025 (based on proposed new build, which probably doesn’t include any hypothetical new UK stations), reducing the supply lifespan to 45-350 years. That is, if we can actually supply 100 000 tonnes/year; by 2010, up to 30 000 tonnes/year may be added by mines currently being or planned to be developed. This still leaves a bit of a shortfall, but we’d have 15 years to address it.

So, on current trends it would appear that there’s no real supply problem, at least not in the lifetime of the next generation of power stations. But the key phrase is ‘on current trends’, because the whole point is that there’s a lot of debate (and hence uncertainty) over the future of nuclear power. For example, if we embark on a massive nuclear building program to replace fossil fuels, all these sums get skewed towards rather lower supply lifetimes. This would be a concern, but not an insurmountable one; my chief objections have always been, and remain, the questionable effectiveness of the nuclear option in solving the problems of greenhouse gas emissions and energy security.


Lab Lemming said...

How do the current projections account for unproven reserves and economically marginal deposits? The avialable uranium depends strongly on how much you are willing to pay to acquire it. If it has to be as cheap to mine as coal, then obviously the reserves will be limited. If, on the other hand, you want to know all uranium that is energy-effective to mine (the extraction energy required is less than the fission output), then the projected supplies are probably very large indeed.

Above all, one must remember that uranium exploration has been virtually dormant since the end of the cold war, since flat demand, stringent regulations, and weapon conversions gave very little incentive to find new deposits.

IanH said...

Like every other metal commodity, as the high-grade, easily mined deposits get worked out, the price will increase and thus lower and lower grade deposits will become economically viable. Can't see us running out any time soon.

CJR said...

Lab Lemming: as I said in the post, it's not entirely clear how the total reserves were estimated (and, given all the uncertainties, I'm not sure any method would be particularly robust).

I agree with you both that in terms of absolute supply, there's almost certainly enough to be getting along with - economic (whether it's profitable to extract) and infrastructure (developing new mines fast enough to meet rising demands) issues notwithstanding.

Anonymous said...

Interesting point from the global warming perspective. Right now nuclear makes up less than 20% of global electricity production, so we can ask if it is realistic to try to replace a lot of the rest with nuclear. If the low estimate of reserves is correct (65 years at current demand) then using nuclear to displace a lot of fossil production would leave us with not a lot of supply. If (extreme case) nuclear were to become 60% of world energy supply we would be looking at not much more than 20 years of uranium supply, and this is without counting growth in demand. Of course if the high estimates are right it looks more like 160-180 years, but at what price does that become feasible to extract?

CJ said...

Another consideration is the time it takes to develop a uranium mine. Recently someone quoted to me the figure of ten years before they are able to produce. This estimate was based on extracting high grade material so it's fair to assume that timeframes would lengthen for lower-grade/difficult to access material. This presents a definite time crunch for the 60% scenario mentioned above.

Also, when projecting demand increases it’s important to remember that 28% of North America’s energy usage comes from transport. As plug-in hybrids and electric vehicles gain in prominence the demand on the electric grid will increase. Similarly, the developing world has a thirst for cars, and, as gasoline becomes increasingly disadvantaged as a fuel, the likelihood that China and India will adopt electric cars will increase. Much of the resistance to electric cars in North America and Europe stems from a car culture which is used to having the freedom to travel hundreds of mile without a stop. The developing world, for the most part, doesn’t have this history and therefore can be expected to show less reluctance to electric cars.