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PostPosted: Jul 21, 2015 6:56 am 
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E Ireland wrote:

Seasonal heat reserves in houses would probably come out cheaper.
Giant tank of water in the basement or back garden to store heat. (Water is very cheap and we can bury tanks almost anywhere).


There are some interesting developments in seasonal heat store, just using boreholes to store the heat.

This one uses solar collectors to get high temperatures.
http://www.dlsc.ca/

Simpler might be to take a village/school/retail park etc. Use black asphalt roads and parking. Use this to heat water in the summer, pump the water into boreholes, and heat up a chunk of the ground to 20-40C. Then use a heat pump to take out this in the winter at a very high COP.

Mackay showed that if you tried to heat a typical town using GSHPs, you'd freeze the ground after a while. This is a way of avoiding that.


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PostPosted: Jul 21, 2015 7:47 am 
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I am pretty sure everyone will be happy to spend the min of 20,000 $ on the erection of such systems in advance. XD
Capital costs uf such systems have to be low since the majority of people is simply not able to afford such wealth.
Here in Germany we are pioneers in that field and it turns out that you need a really good insulation which costs 10-20,000€ including labor costs if you are not building a new house.
Then you need 80m² of solar collectors + a giant 27m³ hot water tank.

Storing thermal energy sounds easy, but it isn't. Water can store 60kwh per m³. But you need between 4000 - 30,000kwh of heat depending on your insulation.
Even very good insulated solar heated homes need a 27m³ hot water tank, which weighs sth lik 7 tons.....etc....
Storing heat as gas is the best solution.
You would be able to store at least 10 as much heat in that tank if you would fill it with gas.

Image


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PostPosted: Jul 21, 2015 8:10 am 
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Which is why the focus is on borehole heat storage. The problem there are losses, which is why it's only feasible at a community or commercial building level.

There is work on phase change materials (waxes with a melting point around 20-50C) for heat storage, and various hydrated minerals which give out heat on contact with water, and release water when heated up.


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PostPosted: Jul 21, 2015 8:18 am 
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alexterrell wrote:
Which is why the focus is on borehole heat storage. The problem there are losses, which is why it's only feasible at a community or commercial building level.

There is work on phase change materials (waxes with a melting point around 20-50C) for heat storage, and various hydrated minerals which give out heat on contact with water, and release water when heated up.


I know. Insulating homes and storing heat in such materials would be the optimum. But our world is far from that right now.


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PostPosted: Jul 21, 2015 11:04 am 
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And yet you expect people to expend vast amounts of money buying your expensive gas. (With new LNG capacity in the US coming on line the price of gas is falling, to say nothing of what will happen with Iranian exports coming on stream).

It would be cheaper to run an 1100kV DC line down to the equator and tether your systems there.
Offshore cables are improving rapidly and have reached 600kV already, new materials means 1100kV is within reach.

You could tether mass capacity in places like the Canaries if you want to avoid using african territory for obvious reasons.
(Canaries are <30 degrees North, with peak day length of roughly 14 hours and minimum of 10)

Thanks to development in deep water drilling practices and spar platforms means you could potentially anchor installations on sea mounts in the Atlantic - and wit deep water HVDC cables available it becomes a question of how far south-west you can push.
(Once we have ~1000kV DC undersea cables working we will be able to potentially exchange power with Canada, so anywhere in the Atlantic becomes fair game).


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PostPosted: Jul 21, 2015 1:11 pm 
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I don't know what the big deal is with getting power from north african countries?
Gaddafi was pretty fast passé. https://www.youtube.com/watch?v=6O8vM0-6EEE

If we had superconducting transmission lines northern countries could get their heating energy from the antarctic continent.


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PostPosted: Jul 21, 2015 2:13 pm 
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The fact that it would be at the mercy of the despots and bandits that dominate North Africa?
They would wait for the depths of winter and then threaten to blow the converter stations unless we gave into whatever their demands were.


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PostPosted: Jul 21, 2015 2:26 pm 
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Not if the plants would belong to the 'right' people.
Goldmann Sachs, E-on, Exxon mobile, the list of the gangs of the world goes on an on.
If those people were really interested in erecting such plants no pirate would even dare to come 100 nautic miles close to them.
I wish we wouldn't depend on those people.


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PostPosted: Jul 21, 2015 2:58 pm 
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Bankers don't run things at the end of the day.
The people with guns do.

There would have to be huge armies of troops deployed to defend these facilities and that is a commitment that massively overcomes the supposed benefits of proceeding with the project.


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PostPosted: Jul 21, 2015 3:52 pm 
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cerebral wrote:
Germany uses per year 80 billion m³ of gas and has storage capabilities of over 22 billion m³.
The construction of new caverns is very cheap and easy.
Conversion of electricity to gas is very efficient and cheap.
There would be no way to heat houses electrically. Because erecting 250 additional GW transmission lines just for heating via very efficient heat pumps would be insanely expensive.
Gas ist the best solution to that since we have already the infrastructure deployed.


Well, I doubt this statement very much. The current apartment I am staying in, in the north of Germany, as well as a couple of other apartments I have stayed in before, all had electric tankless water heaters ("Durchlauferhitzer" in German). These thingies can draw a lot of power, in the range of 18-21 KW, which also shows that the gas infrastructure is not as well as deployed as you may think. German companies like Stiebel Eltron or Clage still make a good business out of these devices, although the electric rates in Germany are close to 30 Eurocents per KWh.

Other countries and/or regions use electric heating a lot, think of Sweden, where approx. 50% of detached homes already use heat pumps. Or France where electric heating is also fairly common, especially in apartments. Or places like Quebec in Canada. The transmission lines seem to cope well in those places and I doubt it is really that expensive to expand the transmission lines, especially compared to the solutions you propose.


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PostPosted: Jul 21, 2015 4:07 pm 
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well it would be great if the tripling of our current 80GW transmission network would be cheap. Nothing against it.
But most of the energy would get produced over the whole year because we need excessively more energy in the winter time.
It is the problem with inequal energy usage balance and therefore the storing. One should not forget that all the energy carriers that we use right now were stored for millions of years in the ground.
So we already use natural gas caverns.
Germany consumes 600Twh of electricity but somethng like 1200TWh of heat in winter time. You can say roughly that you need double the amount of energy in the winter half year.
Its like with the overbuilding of the electricity grid for peak demands.

22 billion m³ of gas storage means 220Twh of energy.


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PostPosted: Jul 21, 2015 4:42 pm 
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A single circuit 33kV electric transmission line costs £30-£40m per kilometre.
A single circuit 132kV electric transmission line (on wooden poles using 'Trident' supports) costs £50-80m per kilometre, but can deliver somewhere between 4 and 16 times the energy depending on the conductors.

So the transmission per kilowatt delivered costs between half and an eighth as much.

It is similar although marginally less extreme at lower voltages, in either cases uprates in the transmission/distribution system will actually reduce costs per kWh.


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PostPosted: Jul 21, 2015 4:49 pm 
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I see, i would be the last to say no to a cheap transmission network.
It just horrifies me when is see the german government spending 50-100 billion € on a few HVDC links to the south.
It isn't about the numbers, more about crazy politics that can make projects easily very expensive for no good reason.


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PostPosted: Jul 21, 2015 5:03 pm 
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As I understand it that is partially due to the obsession with undergrounding.
People don't want hundred metre tall pylons for double circuit 765-1100kV lines.

(The new compact 'T-pylons' National Grid is using in the UK for 400kV might help with this - a 765kV double circuit line fits into a similar height to a conventional double circuit 400kV line).
Just look at the likes of Hydro Quebec and Manitoba Hydro if you want to see what transmission can achieve at very low costs.


Last edited by E Ireland on Jul 22, 2015 8:05 am, edited 1 time in total.

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PostPosted: Jul 22, 2015 4:56 am 
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That is a problem. Maybe overhead power lines need just a good camouflage. Apparently it is a problem that is going to be even bigger in future since we will need more lines.
A reflective coating or maybe creating a mirage effect could help.
Or maybe even a very strong buoyant structure that would be very heavily tethered to the ground. Although this could be really risky.


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