Nuclear CHP as a solution

GreatApe

Sizewell B was built in 8 years and for £5.3 billion (in todays money) and that is a 3.5GW thermal reactor. So sizewell B cost £1,500 per KW thermal. But a heat only reactor would be a lot cheaper and quicker to build for obvious reasons. Let's say half the price since it's less than half the size and would be built quicker than 8 years.

£750/KW with 55% CF 60 year life 2.5% interest gives a capital cost of 0.5p/KWh
The fuel assembly cost is about 0.1p/KWh

For staff if we use HPC it's meant to employ 900 staff for the deal reactors which are 9GW thermal so 100 staff per GW. However that is an electricity generation plant so let's say half the workers so 50 staff per GW therefore 100GW of heat reactors will need something like 5,000 staff. Pay them £40k let's up it to £50k per worker once employer national insurance is paid so staff bill of £250 million per year which adds 0.05p/KWh

So 0.65p per kWh of heat for staff wages, fuel cost, and capital cost. There will also be maintenance and upkeep beyond wages but these won't be huge costs. Let's say another 0.1p so 0.75p/KWh of load following heat

That is about half the price of natural gas!

Sure you need to build a distributed heat grid but natural gas costs 3.5p retail and realistically customers pay over 5p for natural gas heat (3.5p natural gas 85% efficient and about 1p a unit in capital cost for the boiler makes over 5p per unit of heat). So plenty of headroom.

unforeseen

Have you studied Manhattan's system?

zeupater

unforeseen wrote: »

Have you studied Manhattan's system?

Hi

Don't know whether that was directed at my previous post or not, but I looked at it in detail when researching heat-main distribution systems as part of a friend's multi-property heating project (which was actually done!) a few years back .... also seen it in person, but took little more than a passing interest at the time ...

If you look at my posts on this thread from yesterday there's reference to the New York CHP setup alongside a link to a detailed description of the system and future plans by the heat-network operator which I read at the time ... as mentioned, it makes good reading, but it'll take a few mugs of coffee to wade through it in detail! ...

HTH
Z

GreatApe

zeupater wrote: »

Hi

I see the source as being related to distribution of heat as opposed to it's initial creation as that's where the major cost & disruption lies.

If we're following the thread title & talking CHP, the major nuclear generation provision will continue to be located exactly where it currently is and if the nuclear fleet needs expansion it would almost certainly be on current sites & previously decommissioned ones.

This provides access to a pretty easy basic calculation of average transmission distance because we know the potential sites and their distance to major population centres ... for example Sizewell to central London would be ~120miles and Dungeness being ~80miles and elsewhere Wylfa to Liverpool would be ~80 miles, with Manchester being ~120 & Birmingham ~150... it must now be noted that all of these locations are just examples of distances to major population centres and that heat delivery from network branching would require significantly more miles of transport.

So, let's take 180km (~110miles) as being the typical requirement for backbone network heat delivery to a customer ... that's 360km of pipework including the return line and this carries just 500MW of heat which represents ~0.25% of peak demand .... So the total heat transmission backbone pipe requirement based purely on 10bar delivery in 750mm diameter pipes scales up to ~150000km ... whichever way you look at it, this represents a significant investment prior to entering the branch network (delivery to street) & individual property connections.

On individual connections, there's a pretty good case study on a reasonably sized CHP development in Chichester which would provide an example of what's involved ... Graylingwell Park ... works out at about £10k/connected property for the local heatmain piping plus property connections, but that doesn't include the cost & disruption of digging up existing roadways, paths, driveways etc & making good afterwards as it's a total development project involving disused buildings and new build ... looks pretty expensive to me even in a relatively high density development (9 properties/acre), not much change from £500billion on that level of density, so wait until you get to a semi-rural level of population density ....

As you say, Fukushima was a steam pressure event and planning for that kind of failure is exactly why reactors are built well away from population centres and it is this safety consideration that creates the requirement for massive investment in heat transmission, which is why it's effectively unaffordable as a solution ...

By the way, did I mention the energy required to pump 500MW of heat at 10bar in a 750mm pipeline is approx 5MW for the first 2km with an additional O.5MW being required every additional 2km ... this represents about 100MW per 360km return, so around 40GW of electricity in total ... odd really, isn't that pretty much the same as we currently use? ... oh well, I suppose that the ongoing & incidental costs of maintaining 10 bar pressure & high flow rates would have been a consideration in the theoretical stage, so I doubt that it would be overlooked for some reason, mind though - the idea of doubling current generation capacity just to save doubling generation capacity would be interesting to some ...

HTH
Z

Do you do this on purpose? I think so!

Why would you use sizewell to feed London when Bradwell is so much closer (30 miles to the M25)?

I'm not sure the rest of your post is even worth commenting on when you do crap like that!

I will say peak heating demand for the UK is closer to 100GW in January not your suggested 200GW.

And try as you might to paint pumping water around as impossible, people will instinctively know you are full of manure by the fact that they have tap water pipes into their homes at quantities and flows that is more than a district heating grid would require

The cold water in and sewerage out and then cleaning that all up has a book value of about £50 billion there is no Reason to suggest a district heating grid would cost more than that. Certainly not magnitudes more like you try to paint

And the backbone pipes they don't need to be burried have them overground with hedgerows hiding it to make it look not ugly.

I'm not saying this would be easy but it would definitely be possible and would likely be more affordable than the current system. I reckon sub 1p per unit for the heat and sub 2p per unit for the distribution to give about 3p a unit heat. The current system of natural gas boilers is closer to 5p per unit of heat (3.5p natural gas @ 85% efficiency and about 1p a unit for upkeep and depreciation of the gas boiler)

GreatApe

zeupater wrote: »

.. looks pretty expensive to me even in a relatively high density development (9 properties/acre), not much change from £500billion on that level of density, so wait until you get to a semi-rural level of population density ....

1. You don't need to connect every single house to this grid.
Natural gas is connected to 85% of homes you would be looking at something similar 85-90% of buildings

2. A significant number of homes are apartments so one connection to sometimes a block of 100 flats

3. Large buildings also use heat very significant quantities of heat. For example offices or shopping centres or hospitals again that's just one connection to a building using perhaps 1,000,000+ KWh of heat (therefore the connection cost per unit of heat is much lower (

4. Your figure of £500 ++ billion is another figure out of your bum. The cold water grid (which is cold water in sewerage out and cleaning all of that., Has a book value of around £50 billion. This isn't going to cost 10-50x that which is what you are trying to suggest

As you say, Fukushima was a steam pressure event and planning for that kind of failure is exactly why reactors are built well away from population centres and it is this safety consideration that creates the requirement for massive investment in heat transmission, which is why it's effectively unaffordable as a solution ...

Oh brother

A heat only reactor can be submerged in water and be designed such that 7% of its rated heat can be lost through the reactor walls. This would mean in the event of total loss of coiling through the reactor, as per Fukushima, the system would be fine.

Normal electricity reactors are not designed this way because you don't want to waste 7% of your heat you want to convert it to electricity. But as a heat only reactor it's not wasted as you want to generate heat.

By the way, did I mention the energy required to pump 500MW of heat at 10bar in a 750mm pipeline is approx 5MW for the first 2km with an additional O.5MW being required every additional 2km ... this represents about 100MW per 360km return, so around 40GW of electricity in total ... odd really, isn't that pretty much the same as we currently use? ... oh well, I suppose that the ongoing & incidental costs of maintaining 10 bar pressure & high flow rates would have been a consideration in the theoretical stage, so I doubt that it would be overlooked for some reason, mind though - the idea of doubling current generation capacity just to save doubling generation capacity would be interesting to some ...

Z

Cold water is pumped at nowhere near that energy cost and so can hot water be.

Zed

GreatApe

Only the government could do it

I would give the heat away for free to homes a national heating service NHS for short. Would even save the original NHS money in fewer deaths fewer colds fewer sickness as homes would be heated more by the poor and old

Limited to perhaps 10,000 units of heat for free per property

35 million homes 32 million connected to this grid. 250TWh of heating for free. Charge for the other 150TWh or so (shops offices etc)

Free will win public support might actually cost £10 billion a year in interest and upkeep and fuel and wages but the government can get that back by charging a little more in tax elsewhere the population can afford it as they are not paying £10B a year for heating. Maybe add 1.5p to VAT to cover it.

This is great for the poor in two ways. 1st heating is 'free' and maybe even more importantly no more boilers breaking down requiring £1-2k to replace which would be very difficult for a poor household

Saves lives and fewer sick days as the old pensioners and poor no longer need to ration so much
The actual marginal cost once built would be something in the order of 0.2p/kWh so let's not force the poor or the old to ration below 10,000 units. Although I think a lot of homes above 10,000 units today would see it as a challenge to get below 10,000 units

ABrass

Energy too cheap to meter has long been the tag line for nuclear power. It has spectacularly failed to deliver. As a rule of thumb if you think you've found a perpetual motion machine or a free money tree you're generally wrong.

You're consistently ignoring the maintenance costs of all of your piping. You used the example of tap water to say it can be done. The running costs for the water system are in the region of £10 Billion per annum. I don't see why this would be any cheaper.

zeupater

ABrass wrote: »

... You're consistently ignoring the maintenance costs of all of your piping. You used the example of tap water to say it can be done. The running costs for the water system are in the region of £10 Billion per annum. I don't see why this would be any cheaper.

Hi

The issue between tap water and a CHP heat-main is that only a small proportion of taps are running at any one time, with most being only partially open whereas when it's cold & heat is required a good majority of connections are fully open potentially creating a downstream flow deficit on the supply side main ... it's a little like the difference between the flow rate & heating up time through radiators in the home in a pumped wet system - even if the flow is well balanced, the ones nearest to the pump operate at a higher pressure/flow rate than those at the end of the feed/return circuit.

The difference to tap water is that it operates as an open flow circuit with limited and occasional flow ... there's no return circuit & there's no heat to lose on a standing storage basis, so there's little need to maintain a fast flow rate, therefore both maintenance & operating costs are low ...

For example, as previously mentioned, the energy input required to maintain an average 1m/s flow rate in any particular diameter pipe would be raised by approx 8x for each doubling of flow rate ...

v1 = 1 = 1
v2 = 1x8^1 = 8
v4 = 1x8^2 = 64
v8 = 1x8^3 = 512

... however, as flow rate increases so does resistance between the fluid & the pipe wall material which effects the laminar element of the flow (ie pressure drop), which effectively acts to reduce flow & efficiency at the pump, which requires additional downstream pumping provision ...

Flow rates at showers likely represents the most common time related high usage flow of household water water these days which may be around 22litres/minute (0.3litres/second), so we're back to where we started a few days ago, 2m of flow per second (0.3*6.9) in a 15mm od tube being fed by ~0.9m of flow per second (0.3x 3.1) from a typical 25mm household water supply pipe ... importantly, this creates content and pressure loss in the piping system, but the effect manifests through inducing an additional flow of ~18mm/second in a 150mm id main in the street, but only while the shower is running, after which the flow (if any) reduces by 18mm/second .... all this happening by maintaining ~7m of static head through raised reservoirs or variable speed pumps ....

In winter when there's little water draw-off (demand), there's little requirement for energy input into a mains water system, however, this is not the case with a fully pumped heat-main supply, especially ones driving tonnes of hot water per second through equivalent sized conduits, so yes, the running & maintenance costs for a heat-main system are bound to be considerably higher ...

HTH
Z

GreatApe

ABrass wrote: »

Energy too cheap to meter has long been the tag line for nuclear power. It has spectacularly failed to deliver

Which nuclear company has ever quoted officially energy too cheap to meter?
It's just one of those sayings that people bring up I doubt it was any companies official offering
My best guess is it was some journalist clip not anything to do with a nuclear vendor
So what's the value in people brining up this non statement that was never the quote of any nuclear vendor?

I suppose some engineers might have assumed the cost of the nuclear fuel, aka the uranium is a trivial part of the cost of Nuclear power. That is roughly true as uranium costs about 1/20th of what natural gas costs

And nowhere did I suggest this would be energy too cheap to meter, I in fact tried to estimate the cost about and came up with 0.75p/KWh out of the heat only nukes including wages fuel maintenance and capital repayments over 60 years.

You're consistently ignoring the maintenance costs of all of your piping. You used the example of tap water to say it can be done. The running costs for the water system are in the region of £10 Billion per annum. I don't see why this would be any cheaper.

I actually thought the upkeep cost would be roughly around that mark.
£10 billion is a lot of money but spread over 450TWh it's only 2.2p/KWh which is okay.

Nuclear heat would cost around 0.75p so add the two together and you are at around 3p/KWh

Consider the overhead of electricity where wholesale is about 5p a unit but retail is about 16p a unit

Going back to that £10 billion figure
Compare that to the upkeep of boilers in homes shops etc
Say 40 million boilers if they last 15 years and cost £1.5k to replace that's £4 billion a year to just upkeep the gas boiler infrastructure actually more as you have servicing and gas safety inspections etc. Likewise if heat pumps cost £5k and last 20 years and we need 40 million of them that's £10 billion a year upkeep for them

Heating costs a lot of money irrespective of the method chosen

Heating with electricity and mass offshore wind will cost more than today
Heating with nuclear heat only reactors and district heating would cost I think roughly the same or less than today
With the nuclear you can do 100% with load following nuclear heat reactors
With the heat pumps and resistance heaters you can get upto maybe 70% but beyond that need to imagine up mass hydrogen/synthetic-fuels petrochemical industries to try and store excess wind to use it when the wind don't blow.

GreatApe

zeupater wrote: »

Hi

The issue between tap water and a CHP heat-main is that only a small proportion of taps are running at any one time, with most being only partially open whereas when it's cold & heat is required a good majority of connections are fully open potentially creating a downstream flow deficit on the supply side main ... it's a little like the difference between the flow rate & heating up time through radiators in the home in a pumped wet system - even if the flow is well balanced, the ones nearest to the pump operate at a higher pressure/flow rate than those at the end of the feed/return circuit.

The difference to tap water is that it operates as an open flow circuit with limited and occasional flow ... there's no return circuit & there's no heat to lose on a standing storage basis, so there's little need to maintain a fast flow rate, therefore both maintenance & operating costs are low ...

For example, as previously mentioned, the energy input required to maintain an average 1m/s flow rate in any particular diameter pipe would be raised by approx 8x for each doubling of flow rate ...

v1 = 1 = 1
v2 = 1x8^1 = 8
v4 = 1x8^2 = 64
v8 = 1x8^3 = 512


... however, as flow rate increases so does resistance between the fluid & the pipe wall material which effects the laminar element of the flow, which effectively acts to reduce flow & efficiency at the pump, which requires additional downstream pumping provision ...

Flow rates at showers likely represents the most common time related high usage flow of household water water these days which may be around 22litres/minute (0.3litres/second), so we're back to where we started a few days ago, 2m of flow per second (0.3*6.9) in a 15mm od tube being fed by ~0.9m of flow per second (0.3x 3.1) from a typical 25mm household water supply pipe ... importantly, this creates content and pressure loss in the piping system, but the effect is effectively inducing an additional flow of ~18mm/second in a 150mm id main in the street, but only while the shower is running, after which the flow (if any) reduces by 18mm/second .... all this happening by maintaining ~7m of static head through raised reservoirs or variable speed pumps ....

In winter when there's little water draw-off (demand), there's little requirement for energy input into a mains water system, however, this is not the case with a fully pumped heat-main supply, especially ones driving tonnes of hot water per second through equivalent sized conduits, so yes, the running & maintenance costs for a heat-main system are bound to be considerably higher ...

HTH
Z

Erm....if you do the calculations you find that the average home would need about 200 tons of hot water (not consumed just circulated) per year for heating which is not far off the demand of cold water which is about 150 tons per year

Returning warm water would be less of a problem then returning sewerage filled with !!!! and chemicals that need cleaning. What's easier piping warm water back or cleaning up used water with a thousand chemicals in it so it can be used for drinking again?

Your argument for cold water useage being easier to deliver is probably false.
Cold water peaks more (showers toilets) while hot water can be supplied over many hours for heating. So the peak flow rates for heating would be lower. In fact you wouldn't use this water for showers you'd use the cold water system and a heat exchanger. So this district heating water would not be consumed it would be recycled over and over and over again

I've done the calculation for energy use to pump the water it comes out as less than 1% used for pumping both ways and assuming the heat source is 100km away. Summer months this falls towards 0.1% pumping energy (since flow rate and pressure can be reduced in the summer months) so that is another mistake myth fake news by you