Monday, September 27, 2004

The N Word

I was a little disappointed in the 20/20 item on Nuclear power. It came across as a technical case for nuclear power (pushed by a small number of "experts") counterbalanced by an emotional case against (well presented by Rob Donald). In fact, a more balanced polling of technical experts in the New Zealand electricity industry would have revealed a more sceptical view of nuclear energy - at least for New Zealand. It's not that there isn't an urgent need to reduce (or at least hold) CO2 emissions or that replacing fossil fuel power stations by nuclear power won't do that. Expanding or at least retaining nuclear power in the USA, Japan, France and Britain may be a good idea (at least in the short term) but introducing it to New Zealand makes much less sense.

The risk of a Chernobyl accident is not the main issue. Nuclear power plants can be made safe enough (at a price). The waste problem is more serious - humanity simply has no precedent for safeguarding dangerous materials for the millenia required. At the very least it is a substantial external cost which has yet to be paid. The real problem for NZ, however, is one of scale. We simply don't justify the technological infrastructural overheads that are required to establish a nuclear industry.

New Zealand already generates about 1/3 of its electricity by burning fossil fuels. We should certainly not increase our greenhouse gas emissions from this source and we probably need to reduce them over the next decade or two but we do not need to reduce them to zero. There should be little objection to maintaining fossil fuel stations (we already have plenty - or would if the national grid had sufficient capacity) as reserve power for dry years. Not all fossil fuels are equal - coal produces roughly twice as much CO2 per MJoule as oil while natural gas produces about 20% less CO2 than oil.

New Zealand can meet its near-term requirements for electricity by expanding wind power (already happening), energy conservation and biomass. None of this requires any new technology but we might have to review our power pricing objectives to make them all happen. Electricity prices in NZ are only about 60% of the OECD average. This distorts the market so as to inhibit uptake of a number of technologies (heat pumps, solar water heating, wood-fired space heating, double glazing, high-efficiency light bulbs, etc) which have the capacity to replace electricity or otherwise reduce electricity consumption.

The 20/20 programme raised the longer-term prospect for replacing motor fuels with hydrogen (from electrolysis) and suggested that even if we could meet our ordinary needs we couldn't do this without going nuclear. However, if we replace fossil fuels with hydrogen produced by electricity generated from fossil fuel we do not materially increase our overal emissions. Further, hydrogen production provides a new form of energy storage and would let us generate a larger proportion of our power from wind (or other intermittent sources).

We shouldn't get too hung up on long-term power needs. It is likely that additional technologies will come onstream in the next 20 years. Photovoltaics can already produce solar electricity at about four times the standard price. If this price can be brought down we have an effectively unlimited supply of clean renewable energy. The current price of photovoltaics includes the cost of batteries. This cost component largely disapears if surplus power can be fed back to the national grid. Then (the real bolter) someone might crack the problem of controlled nuclear fusion. Or find a way of permanently sequestering the CO2 from burning coal. Whatever happens we may get our planning wrong and we may wind up burning more fossil fuel than we hoped and paying a Carbon Tax - or we might incur an unplanned cost in some other way. But that won't melt the polar ice cap and in an imperfect world we're always likely to pay something for past planning errors.

New Zealand is Nuclear-Free for a good reason. We don't like nuclear weapons and we don't like the hazardous technologies that go with them. Nuclear power shares the same tecnologies and provides a dangerously easy route to nuclear weapons proliferation (India, Pakistan, Iran, North Korea). The world would be a safer place if these technologies were confined to the industrial powers that already have them. We allow the use of other nuclear technologies such as radio-isotopes and particle accelerators because they do not share the technologies needed to make nuclear weapons and do not require us to adopt any such technologies to support them.

If we did have a nuclear power station we'd have to import the fuel here and export the spent fuel (or reactor core) overseas (to Japan?). This leaves us open to environmental (or terrorist) disaster. We'd still need facilities for short-term storage of high level waste until it cooled down sufficiently to be exported. Finally the World's reserves of high-grade uranium ores are quite limited. Without breeder technology, less than 1% of natural uranium can be "burned" and this makes it uneconomical to mine low-grade reserves. Better to leave the world's dwindling stock of naturally fissionable uranium to be burned by those nations who have already sunk the costs and risks of developing a nuclear industry.

SageNZ has pointed out (comments below) that an article in the SST which suggests that there would only be about 3 years supply of Uranium in the World if all electricity were produced by nuclear power. Like Rich, I suspect there probably is somewhat more Uranium available than that but it IS quite limited if we use non-breeding technologies. This is because you need quite high-grade ores (or easily concentratable ores) to get a net (never mind cost-effective)energy gain if you are using non-breeder reactors (and therefore burn only 0.7% of the Uranium). Uranium is quite an abundant element but high-grade ores are scarce.
Breeder reactors burn all the Uranium which means
(1) the high grade ores give 140 times more power per tonne of uranium (so SST 3 years becomes 140)
(2) low grade ores (which are abundant) become economic making the resource very large (millions of years)
Unfortunately this is an expensive technology and poses huge proliferation and security risk. If the World generates a significant fraction of it's power by this cycle then it will be awash with more weapons-grade fissile material (Plutonium) than Kazhakstan has ever dreamed of.

This technology can give us all the energy we could ever use - at a price. But so do renewables. NZ's total current electricity production could be met by photovoltaic panels covering less than 0.02% of our land area using existing technology.


Blogger span said...

thanks for this GreyShade, it is much better than my attempt! :-)

28 September 2004 at 6:15 PM  
Blogger Rich said...

I don't believe that there is any nuclear power station anywhere (including the USA and France) which would be economical on a basis of strict accounting for decommissioning costs and public liability insurance. The UK government tried to privatise part of their nuclear industry, and it promptly went bust for this very reason.

The nuclear power plant was primarily invented because:
1. various nations wanted to make a Plutonium (Pu) bomb
2. making Pu requires an atomic reactor, which produces lots of heat
3. you might as well use the heat energy to generate electricity
4. it makes these huge industrial installations appear to have a peaceful purpose rather than just being part of a bomb factory

Since we don't want a New Zealand atomic bomb, we don't really have any reason to build nuclear reactors.

30 September 2004 at 2:47 PM  
Blogger Greyshade said...

I agree with your assessment of nuclear power costs. Given that a lot of these costs are now sunk I'm willing to concede that there may be an economic case for prolonging the life of nuclear power in countries that already have them. It all depends on what price we put on CO2 emmissions, etc. But there's no way it will ever make sense here.

30 September 2004 at 6:57 PM  
Blogger sagenz said...

Most interestingly is the aside I read in sunday times that if the world electricity supply came from Uranium there would only be 3 years known reserves. Hardly a long term solution. Acceptable for 2-3% of world supply

4 October 2004 at 6:13 AM  
Blogger Rich said...

Highly unlikely that the Sunday Times is right, except in the narrowest sense. I've found a reference that gives Uranium as 0.00018% of the earths crust, which equates to 4x10^13 cubic metres, an immense amount!

I suspect that the Uranium mining industry has only *identified* enough U for 3 years world electricity consumption - there is an awful lot more around!

5 October 2004 at 2:22 PM  
Blogger Weekend_Viking said...

Actually, there's a fair amount of uranium in NZ, in the blacksand deposits on the West Coast. While the bulk of the blacksands are ilmenite, titanomagnetite and magnetite, a significant proportion of them are monazite, zircon, and a few other obscure granite sourced uranium minerals. Mining them is easy - you just run the sands through a dredge with a gravity concentrator, pull out the iron minerals with a magnetic separator, and you are left with your radioactives. I recollect that a bulk sampling project to test feasibility of mining the ironsands on the 'Coast fell through because although the iron and titanium ore was fine, the waste sand out the back of the plant was several hundred times WHO radiation limits, and they weren't allowed to sell it overseas because of the anti-nuke policy.

I reckon some of the Chinese pebble bed reactors would be excellent.


5 October 2004 at 9:18 PM  
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