The case for nuclear is clear!

andy80085

Are they commercially available yet?

owain.davies

On the assumption that mech has picked himself up from the floor... (thank you constructive debate by the way)

All I can say to that is "rofl". 20 years would be wildly optimistic. The government hopes to generate 20% of electricity by renewables by 2020. Nuclear's share is about 19% and will go down before it goes up again - unlikely to be much different from now in 2018. So 60% of electricity will still be fossil fuelled. Crucially, much of this will be during the evening peak that microCHP could contribute to.

Possibly true, but it's too soon to call either way. Power from micro-CHP is realtively cabon intensive, and it doesn'et take a large drop in grid carbon, which could be from nuclear, but more likely from renewables, carbon capture and carbon reduction to make it higher in carbon than the grid.

They're generating the electricity practically for free as a side benefit. Why do people find this so difficult to understand? You have a gas boiler that generates some electricity, direct gas heat heats the house, the waste heat from using the electricity in appliances also heats the house. You heat the house with gas, but you got some electricity along the way.

You say practically for free, but that doesn't take in to account the massive capital cost, which isn't liekly to reduce, as almost all the major companies have decided not to support the technology. British Gas is currently the only one looking seriously at commerical trial, and i believe that E.On/Whispergen are not currently proceeding at any sort of commerical pace (although I stand to be corrected)

I can't fathom why you think centralised CHP is better. It needs to be able to be shoehorned in to a neighbourhood so that it's close enough to homes and then all the roads need to be dug up to lay insulated hot water pipes (which will inevitably lose some heat between the power station and the homes). It also needs a totally different metering/billing system. Installation doesn't sound as cheap as microCHP to me

Of course, disruption can be an issue during installation of the system, but for new build, macro-CHP is far far cheaper to install than micro-CHP. As for retrofit, several demonstration projects, like Barkantine Heat and Power (which is about to expand because it has been a real success) prove that it can be done retrofit.

Tidal, wave, biomas, hydro, storage. But your strawman ignores the fact that the weather is never the same over the entire British mainland.

All good points, I grant you, but you often get the same prevailing conditions over large areas, and a quick bit of research would show you that we don't have (and probably will never have) sufficient interconnector resource to move the power from the north of Scotland to Brighton (think of the huge power losses on the way, even if the capacity was available)

Nuclear needs tens of thousands of tons of rock to be pulverised per year per reactor and that's before you actually get the fuel out of it.

Absolutely true - as do minerals such as cadmium telluride, copper indium gallium selenide, amorphous silicon etc. which are required for the manufacture of photo voltaic panels. You'll have to excuse me, because it was a couple of years since my geology degree (focusing on mineral and energy resource), but at the time, the figures were that we had less than 1% of the required minerals to power the world by solar, but more 80% of the Uranium to do the same. I would have to get my old lecture notes out for more info!

Carbon wise, many renewable installations take far more carbon to produce than they ever save!
Such as?

Such as small wind installations. I've seen the life cycle analysis, and they emit more carbon (and by far more greenhouse gas total) in manufacture, shipping and installation, than they ever return from offsetting grid.

Nuclear can't vary throughout the day. Gas can only realistically be replaced with biomass.

Partially agree with that, but it still remains that nuclear needs to play a large part in baseload. Biomass has come a long way, but we are decades off a sustainable biomass solution, although I have seen some very interesting work with algae cross my desk, which has some promise.

My general conclusion is that the UK needs a mix of technologies - probably more nuclear than now (50-60% IMHO), renewables (around 20%) and the remainder in the highly reactive fossil fuels.

MarkyMarkD

Slightly away from the way this thread has developed, but back to an earlier post.

I was involved in the Coal Review in the 1990s. The argument put forward by the NUM was that coal was cheap compared to nuclear. But that argument was false and the argument was lost, because the issue wasn't about total costs but marginal costs.

NUM wanted the government to close down the older nuclear power stations and use coal instead. But the marginal cost of electricity from even the older nuclear power stations was minuscule; far, far lower than the cost of using coal.

Nuclear generation inherently has huge fixed costs, both capital and decommissioning, and very low variable costs. The waste disposal costs relating to the station itself (fixed) are far higher than those relating to the fuel (variable).

The outcome of the Coal Review was that the older nuclear power stations were kept open, where they could be, and indeed their lives were extended quite significantly in a number of cases which made economic, as well as environmental, sense.

mech_2

andy80085 wrote: »

Are they commercially available yet?

No. Not in practice (though there are some Whispergens that were installed for trials).

But the technology has been demonstrated, the designs have been built and tested, and more than one company is aiming for mass production within a year, so I think it's safe to speculate about what is possible on this basis.

mech_2

owain.davies wrote: »

Possibly true, but it's too soon to call either way.

Not really. How many new nuclear plants do you think can be online by 2018? The current aim is to close down three existing plants before then, and to have the first new one running in 2017. Renewables generate, what, 4.5% of our electricity?

[/quote] Power from micro-CHP is realtively cabon intensive, and it doesn'et take a large drop in grid carbon, which could be from nuclear, but more likely from renewables, carbon capture and carbon reduction to make it higher in carbon than the grid.[/quote]We're going around in circles here. It's effectively carbon-free. I explained why.

You say practically for free, but that doesn't take in to account the massive capital cost, which isn't liekly to reduce, as almost all the major companies have decided not to support the technology.

You've lost the thread and are talking at cross-purposes. You said they were high-carbon. I'm saying they aren't as the gas is being burnt anyway. They are effectively carbon-free unless you have a plan for heating the UK's housing that manages to sidestep both carbon and capital costs?

Privatised power companies will drag their heels to invest in microCHP because it would mean spending money to damage their business model. That is why an initiative would have to come from government.

Of course, disruption can be an issue during installation of the system, but for new build, macro-CHP is far far cheaper to install than micro-CHP. As for retrofit, several demonstration projects, like Barkantine Heat and Power (which is about to expand because it has been a real success) prove that it can be done retrofit.

I can't find enough information on the Barkantine Heat and Power project to compare costs vs benefits.

I suspect a large chunk of the saving with new build is in the elimination of the requirement for connection to a gas supply. But as I keep saying, new build isn't the problem. Existing housing stock is.

Absolutely true - as do minerals such as cadmium telluride, copper indium gallium selenide, amorphous silicon etc. which are required for the manufacture of photo voltaic panels.

Well there's no shortage of silicon... I suspect the comparison picks and chooses which solar technology to compare. Solar energy doesn't require those materials, but nuclear fission certainly requires uranium.

You'll have to excuse me, because it was a couple of years since my geology degree (focusing on mineral and energy resource), but at the time, the figures were that we had less than 1% of the required minerals to power the world by solar, but more 80% of the Uranium to do the same. I would have to get my old lecture notes out for more info!

You'll have to be clearer on what you mean by "power the world". Uranium is a fuel, but solar panels have a one-time mineral cost in construction (and therefore could be recycled). Once uranium is fissioned it's gone forever. Forget breeders. They promised us those half a century ago and there's still no chance of any appearing in the next 30 years.

Does "power the world" mean all energy requirements or just electricity?

Let's have a look at meeting world electricity supply with nuclear: annual uranium requirement is approx 68,000 tons of natural uranium or equivalent (about 40% of this is currently from dwindling stockpiles). This supplies 16% of world electricity according to the OECD. The most optimistic estimates of world uranium reserves seem to be around 5 million tons. Let's say the uranium could be mined at whatever rate we could use it. If we turned off all the world's current nuclear power stations tomorrow and, with a wave of the magic wand, met all the world's electricity requirements with state-of-the art reactors which use 25% less uranium the world uranium supply would last about 5000000/(68000*0.75) = 16 years. Are you seriously suggesting solar can do worse than that?

Such as small wind installations. I've seen the life cycle analysis, and they emit more carbon (and by far more greenhouse gas total) in manufacture, shipping and installation, than they ever return from offsetting grid.

OK, fair enough. I'm with you there.

owain.davies

It's effectively carbon-free. I explained why

Just because people currently burn it, doesn't make it carbon free. Heat pumps from low carbon electricity are more efficient, more reliable and quite accessible. Far better to install these than micro-CHP - and they are currently about the same price! You don't need ground space, there are some very good air source units coming on the the market, and this just needs an outside wall to bolt to. When replacing equipment, you can't assume previous emmissions to be the base level - you should start at zero, and in this case, for the same price, you can get either a heat pump which could be powered from low carbon electricity sources, or a gas boiler, which is a major CO2 contributor. It doesn't seem like a difficult choice.

I suspect a large chunk of the saving with new build is in the elimination of the requirement for connection to a gas supply

Not really, the saving is in not buying gas boilers!

Well there's no shortage of silicon

Isn't there? All mineral resources are finite, and as for the specific minerals chosen - they are used in all commercial PV applications and of course, unless you want to artificially synthesise them, at great expense and energy usage, these compund are limited application. You could of course use solar thermal to generate, as that requires less specialist minerals (but a lot a metals and concrete), but the applicaitons for 'power towers' etc is very very limited in the UK

Uranium is a fuel, but solar panels have a one-time mineral cost in construction (and therefore could be recycled). Once uranium is fissioned it's gone forever.

Apart from the fact that only 1% of the uranium is actually used during fissioning, and reprocessing can return 99% of the material to a usable state. For various reasons, the government is not in favour of reprocessing, but that makes it one of the most recyclable products in the world/universe!

mech_2

owain.davies wrote: »

Just because people currently burn it, doesn't make it carbon free.

The gas isn't carbon free, the electricity is.

Heat pumps from low carbon electricity are more efficient, more reliable and quite accessible.

I covered the efficiency - they are roughly equivalent with current technology. Reliability shouldn't be any more of an issue in one case than the other. After all, a Stirling engine is just a heat pump in reverse: You create a temperature difference and a working medium pushed pistons turn a generator to make electricity. A heat pump is a working medium squeezed by pistons driven by a motor by electricity to make a temperature difference. The difference is the fuel. Gas is a primary energy source, electricity isn't. This is why I liked the gas-powered heat pump, but it was only a research project, not a product.

Far better to install these than micro-CHP - and they are currently about the same price!

If you say so. I've only heard of vast sums. Regardless, the heat pump costs more to run and may require new radiators. It also exacerbates the problems of meeting electricity demand in the UK; the CHP unit helps with that.

When replacing equipment, you can't assume previous emmissions to be the base level - you should start at zero,

Erm? You work with what you've got. CHP reduces emissions without major infrastructure or heating system changes. That means it's good.

and in this case, for the same price, you can get either a heat pump which could be powered from low carbon electricity sources,

We don't have low carbon electricity. A "green" tariff makes no difference, the energy mix is still not green.

or a gas boiler, which is a major CO2 contributor. It doesn't seem like a difficult choice.

I did the sums. Show me where they're wrong.

Not really, the saving is in not buying gas boilers!

I'm not sure it is. Connecting a house to a gas main can cost thousands/tens of thousands. A gas boiler is about £500 quid.

Isn't there?

You're the geologist. Presumably the worldwide sand shortage passed me by.

All mineral resources are finite, and as for the specific minerals chosen - they are used in all commercial PV applications

But not all solar applications.

and of course, unless you want to artificially synthesise them, at great expense and energy usage, these compund are limited application. You could of course use solar thermal to generate, as that requires less specialist minerals (but a lot a metals and concrete), but the applicaitons for 'power towers' etc is very very limited in the UK

Again, you've forgotten what we were discussing. You were talking about "powering the world". The UK isn't the world.

Apart from the fact that only 1% of the uranium is actually used during fissioning, and reprocessing can return 99% of the material to a usable state. For various reasons, the government is not in favour of reprocessing, but that makes it one of the most recyclable products in the world/universe!

I'm afraid this is getting rofl-worthy again. You just don't understand the limitations of the technology. You get about 22% extra energy from uranium by reprocessing the spent fuel (both uranium and plutonium). It's tricky as it means rendering highly radioactive waste into a volatile liquid form (if the cooling system failed, it would be a disaster 40 times the magnitude of Chernobyl). The UK has had to reprocess fuel because the Magnox fuel demanded it. But when the last of the Magnox reactors are closed down, Sellafield's Purex plant will close too. It's a loss-making enterprise.

With more advanced fuel formulations you can increase the "burn-up" in the first pass through a reactor. Generation 3 reactor designs are meant to be able to take this further than is possible with current reactors, but they would only get 15% more thermal energy per unit of fuel than currently. And then the fuel is less viable for reprocessing. It's not magic. There's no free lunch.

A_fiend_for_life

Scargill and Monbiot look set for some debate

http://www.guardian.co.uk/commentisfree/2008/aug/08/nuclearpower.fossilfuels