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  4. How can renewable energy farms provide 24-hour power?
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How can renewable energy farms provide 24-hour power?

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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #80 on: 21/04/2015 14:50:07 »
Careful here.

The measured wind output is 0.77 GW. That's about 1.5GW, because half is unmetered. This is coming from 12 GW of nameplate wind power.

Meanwhile Scottish Scientist called for 290GW of nameplate wind power.

So, if we had 290GW we would be getting 290/12 * 1.5 = 37 GW of power right now.

Demand is... about 33 GW (adding 0.77 to allow for the unmetered wind power).

So yes, it would be working perfectly fine right now.

Quote from: alancalverd on 21/04/2015 09:42:45
Interestingly, governments get upset and start putting emergency schemes into play when at-plant fossil fuel reserves fall below 5 days' worth. One can't help feeling that they know something about it.
And there's blazing sunshine here. By the time a system like Scottish Scientist's would be up, how many GW of solar power will be on the grid? How many GWh of electric car batteries?

Consider: it's getting to summer. In summer, you get more sunshine and less wind.
« Last Edit: 21/04/2015 16:01:57 by wolfekeeper »
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #81 on: 21/04/2015 16:31:09 »
You can't assume that metered demand is being met by unmetered input - that would be ridiculously generous of the suppliers, and anyway, as Gridwatch states, unmetered supply is already shown as a reduction in demand, so you mustn't double-count it! Furthermore it is generally the case that unmetered wind is small power for local consumption and therefore will not contribute significantly more to the grid as large windfarms are built to absorb your taxes.

Thus using conventional arithmetic, if we had 290 GW of installed wind power  right now, we would be getting  290/12 =  24.16 GW from the wind and about 10 GW from SS's reservoir. 

Except that the 100 GW-day reservoir would by now be empty, so we are going to be about 20 GW short of demand by 8 pm. No problem: just shut down half of the country, and reintroduce Victorian Values, the Paleolithic Diet, and all the other trendy non-electric goodies from the past.
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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #82 on: 21/04/2015 18:24:04 »
I didn't double count it, I added it to both the demand AND the generation sides of the equation, and doing that is quite valid.

Yes, they're individually small, but there's a lot of them.

In fact my calculation is pessimistic; some of the wind will be not grid connected, in which case it won't be reducing the grid demand; so the calculated demand would appear higher, not lower than it should be in my calculation.

All I'm really assuming is that the wind power production is representative of the unmetered production. Given that weather systems tend to cover the country, that's not an unreasonable assumption.
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #83 on: 21/04/2015 19:56:05 »
Quote from: wolfekeeper on 21/04/2015 14:50:07
By the time a system like Scottish Scientist's would be up, how many GW of solar power will be on the grid? How many GWh of electric car batteries?

You really want to have your cake and eat it! Every watt of car battery is another load on the grid, so if you want to replace road vehicles with electric ones, you will need 580 GW of installed wind power and twice the storage capacity that SS is proposing. Plus, of course, twice the grid carrying capacity and a whole lot of infrastructure to deliver the juice to the cars.

And that will still leave you with 50% of current UK fossil fuel consumption for heating, cooking and direct use in industry....
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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #84 on: 21/04/2015 20:13:21 »
We already explained to you that you that average daily mileage of cars is only 20-30 miles, and that that only needs 5 kWh per car, per day. Meanwhile the minimum electric car has a 25 kWh battery...

Please try to not repeat falsehoods that we have already pointed out. I know you don't really care about facts and truth, but it gets boring.
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #85 on: 21/04/2015 23:35:53 »
According to HM Government (or at least the Department of Energy and Climate Change), 36% of current UK energy use is for transport. If I am repeating falsehoods, they come with great authority.

If you look at domestic fuel bills you will find that the average consumption is around 50% electricity and 50% gas, oil or coal. Pretty much the same over all industries, though as UK manufacturing declines, the trend is toward more electricity and less primary heat. But then the supply companies are probably lying too.

One of the many problems with the windmill lobby is a fixation with electricity. It only accounts for a about a third of UK energy consumption, and worldwide, a lot less. Trouble is that you can't use a windmill to make anything else, so it's a very expensive fix for a small part of the problem, and replaces a cheap, reliable fuel with an expensive, unreliable one. Which is a pity. I'd love to have a wind generator, and I'd be delighted if the whole UK could be run on wind,  but it just won't do the job on the required scale. 
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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #86 on: 22/04/2015 00:41:15 »
As we have already pointed out to you, but you have pointedly 'forgotten', again, windmills and solar panels are not heat engines and the solar/wind/battery/electric motor power system is much, much, much more energy efficient than going the antiquated heat engine route.

Even with heating, it's much more energy efficient to use electrical power and run air or water source heat pumps than to use fossil fuel energy directly for heating.

So instead of using 36% of the UK's energy on transportation, try ~10% using electricity.
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #87 on: 23/04/2015 10:38:52 »
Quote from: wolfekeeper on 22/04/2015 00:41:15
solar/wind/battery/electric motor power system is much, much, much more energy efficient than going the antiquated heat engine route.


True, but vehicle aerodynamics takes no account of the power source. If you need 100 kW to shift load x at speed y with engine A, you will still need 100 kW with engine B. There is admittedly something to gain by using regenerative braking but in the words of Ettore Bugatti, "my cars are designed to go, not to stop".

And given that the energy required to make a petrol-engined car is about the same as the energy it consumes in its lifetime, how does the lifetime energy balance work out for an electric car?
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Offline Scottish Scientist

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Atlas of Solar Power from Photo-Voltaic Panels
« Reply #88 on: 23/04/2015 12:22:18 »
Quote from: jccc on 20/04/2015 17:09:50
maybe build a solar highway/belt around the equator?

Perhaps surprisingly, the equator is not the ideal location for solar power, for two reasons
- the insolation (amount of sunshine) is higher where the air is drier than the equator which gets a lot of rainfall
- the equator is hotter and photo-voltaic panels are less efficient when hot

So those two reasons explain why parts of the Himalayas and the Andes which are sunny and cold are optimal sites for PV panels. Land nearer the tropics than the equator looks to be better for solar power than land nearer the equator than the tropics.

"So nearer the equator" is not always better depending on where you start from, but starting from Scotland or Britain, most places nearer the equator are better for solar power than we are here.

Most surprisingly, according to the Atlas of Solar Power, even Antarctica (during the southern hemisphere's summer presumably) is a good spot for PV panels!

Atlas of Solar Power from Photo-Voltaic Panels


Click to view a larger image - https://scottishscientist.files.wordpress.com/2015/04/photo-voltaic-atlas.jpg

Quote from: jccc on 20/04/2015 17:09:50
floating kind?

Yes indeed, as I already suggested, mounting PV panels on artificial floating islands is a good idea. Looking at the Atlas of Solar Power, there looks to be a good place to float PV-panel platforms off the west coast of north Africa, between the Canary Islands and Cape Verde.  [8D]

Quote from: Scottish Scientist on 12/04/2015 10:50:40
I was thinking, if we are needing to use solar then let's do it right.


"Solar power in the United Kingdom"
http://en.wikipedia.org/wiki/Solar_power_in_the_United_Kingdom

What Europe needs is a whole lot of mass-arrays of solar photo-voltaic panels somewhere near the south of Spain, either on land, or if the Spanish need their land for growing grapes or whatever, how about on artificial floating islands somewhere off Gibraltar?

Maybe north Africa wants in too? There's a lot of sun in Morocco across the Gibraltar Strait. Maybe Morocco would like to sign a 50- or 100-year lease to the European Union for some land in Morocco to put solar photovoltaic arrays on? We could make it worth their while. Guarantee the deal by deploying a European military force to guard our solar PV arrays and the interconnector carrying the power back to Europe. [O8)]

So the Mediterranean or thereabouts for solar, everywhere for wind, Scotland for pumped-storage hydro.

« Last Edit: 23/04/2015 22:13:41 by Scottish Scientist »
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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #89 on: 23/04/2015 12:55:49 »
Quote from: alancalverd on 23/04/2015 10:38:52
Quote from: wolfekeeper on 22/04/2015 00:41:15
solar/wind/battery/electric motor power system is much, much, much more energy efficient than going the antiquated heat engine route.


True, but vehicle aerodynamics takes no account of the power source. If you need 100 kW to shift load x at speed y with engine A, you will still need 100 kW with engine B. There is admittedly something to gain by using regenerative braking but in the words of Ettore Bugatti, "my cars are designed to go, not to stop".
Irrelevant. A petrol car burns about 500kW or more of primary energy to get that power, and that's ignoring the energy needed to make that petrol, which is substantial, whereas the electric car is the equivalent of ~130 kW.
Quote
And given that the energy required to make a petrol-engined car is about the same as the energy it consumes in its lifetime, how does the lifetime energy balance work out for an electric car?
It seems to be significantly better, particularly if you're using solar or wind for the source of energy. They take more energy to build, but use a LOT less in operation.

Whereas virtually all of the lifecycle analyses being done right now, pretty much assume that power is more or less only being generated using fossil plants, and even they show a net win; but that isn't even what we're talking about here, we're talking about a true green grid.
« Last Edit: 23/04/2015 13:18:42 by wolfekeeper »
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Offline jccc

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Re: How can renewable energy farms provide 24-hour power?
« Reply #90 on: 23/04/2015 21:11:00 »
SS, you are so beautiful, as your science!
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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #91 on: 23/04/2015 22:31:40 »
Presumably with 290 GW of peak wind, you'd have spare energy a lot of the time. I mean the standard capacity factor is about 25-35%, so you'd be averaging more power than you actually need- it's sized for the periods when the wind is a bit anemic. So at 25% CF, that's 72GW average, whereas the normal demand is 35-55.

But that's actually probably good; things like electric cars don't usually care as much about having to have power every single day; you could potentially just set the minimum charging point for what you need day-to-day, and if there's spare electricity going because it's particularly windy, it would charge it up further and save money; also electric water heaters could be switched on.
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #92 on: 24/04/2015 01:05:58 »
Quote from: wolfekeeper on 23/04/2015 22:31:40
Presumably with 290 GW of peak wind, you'd have spare energy a lot of the time. I mean the standard capacity factor is about 25-35%,


I entered this discussion with a guesstimate that an installed capacity of 6 times average demand and 5 days' storage would do the trick, but events have shown otherwise,. My apologies.

So far this month, 20 out of 24 days the capacity factor of wind has been less than 10%, and for the last 2 days, zero. The mean capacity factor for the last 24 days has been about 14% and tomorrow isn't looking any better. So in order not to lose too many lives, destroy too much food, bring industry to a halt, or generally inconvenience the population, it seems on current evidence that you need at least to install at least 7 times average demand and one month's storage capacity.
 
And that's just to meet the present need for electricity. If you want a wholly wind-powered economy you will need a generating capacity of 20 times present electrical demand, and a month's storage capacity at 150GW, otherwise people will surely die or find themselves stranded far from home.

But here's a trick - sell electricity on a live market. When supply is low, prices are high. That will regulate demand and ensure that it is always exactly matched to supply. Because there is no significant lag between supply and consumption, and consumption can be monitored at every point of use, the unit price can be varied every second or less. The poor will have to learn to make choices instead of profligately cooking and keeping warm at the same time, and they will have to trade in their huge plasma screen TVs for neater LED models (everyone knows that the poor have ENORMOUS televisions - the Daily Mail says so). My private patients will continue to enjoy the fruits of their crimes, whilst honest peasants will be told that the waiting list for radiotherapy is due to factors beyond human control, not politics or incompetence.   
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Offline Scottish Scientist

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Off-Shore Electricity from Wind, Solar and Hydrogen Power
« Reply #93 on: 24/04/2015 02:38:39 »
On floating platforms, solar power, power-to-gas and energy storage ...

Off-shore wind-turbines generate electricity, as we all know. Now I’ll explain how off-shore solar and hydrogen can power our electricity too.

Solar at sea is easy. Simply mount photovoltaic panels on platforms isolated on their own or in the wide-open spaces between the off-shore wind turbines. Mount PV-panels high and dry but be sure to mount them below the height of the rotors of the wind turbines so as not to interfere with the wind flow.

Deep Sea Hydrogen Storage


Floating platforms can generate electricity from wind, sun or hydrogen gas, which can be stored in inflatable gas bags in deep sea water.

The diagram shows how hydrogen gas can be used to store energy from renewable-energy platforms floating at sea by sending any surplus wind and solar electrical power down a sub-sea cable to power underwater high-pressure electrolysis to make compressed hydrogen to store in underwater inflatable gas-bags.

Deeper seas are better because the water pressure is proportional to the depth allowing the hydrogen to be compressed more densely, so that more hydrogen and more energy can be stored in an inflatable gas-bag.

Later, when there is a lull in the wind or when it is dark, the hydrogen can be piped from the gas-bag up to the platform on the surface to fuel gas-fired turbine generators or hydrogen fuel cells to generate electricity on-demand in all weather conditions.

Deeper seas, which are better for storing hydrogen in, can be found from an atlas of the oceans, such as this one.

Sea Atlas - https://scottishscientist.files.wordpress.com/2015/04/6004-050-e076d00f.gif

Looking at a close-up of the map for the area of sea closest to Scotland, Britain and Western Europe –



Click to view a larger image - https://scottishscientist.files.wordpress.com/2015/04/seas_euro_n_africa-200.jpg

– this shows that deep sea water most suitable for hydrogen storage is not to be found around the coast of the British Isles but depths greater than 4,000 metres can be found in vast areas of the Atlantic beginning a few hundred miles to the south-west in the Bay of Biscay.

So one area of sea which looks suitable for both solar and hydrogen powered electricity generation appears to be just to the west and south-west of the Canary Islands and to the north of the Cape Verde Islands. Whether this area is near enough to western Europe to be the best choice to supply western Europe considering the additional costs of longer interconnection cables remains to be estimated.
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Offline wolfekeeper

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Re: How can renewable energy farms provide 24-hour power?
« Reply #94 on: 24/04/2015 03:20:38 »
Quote from: alancalverd on 24/04/2015 01:05:58
So far this month, 20 out of 24 days the capacity factor of wind has been less than 10%, and for the last 2 days, zero.
No:

https://twitter.com/ElectricMixUK/status/591194830824411136

0.37 GW out of 6 GW metered.

With 290 GW that's equivalent to 17 GW, about half the demand.

Previous day was 0.75 out of 6 GW metered:

https://twitter.com/ElectricMixUK/status/590832433391673344

That's equivalent to 36 GW, which is pretty much the average demand that day.

Previous day to that was:

https://twitter.com/ElectricMixUK/status/590470039096156160

That's equivalent, to all of the demand: 38.7 GW

After that, I got bored. But whatever else, that's not zero production; it's most of the UK demand supplied by wind, per Scottish Scientist's plan.

Anyway, so... yup... you're full of sh1t, again, sorry.
« Last Edit: 24/04/2015 03:24:03 by wolfekeeper »
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #95 on: 24/04/2015 10:45:10 »
Quote from: Scottish Scientist on 24/04/2015 02:38:39

Deep Sea Hydrogen Storage


Very sensible idea. Worth also investigating the use of the existing UK gas grid to store and distribute low-pressure hydrogen or manufactured methane, thus obviating the need for an electricity store, major construction works or any novel generating plant: use the gas to run the existing gas power stations when the wind fails, just as now.

http://www.technologyreview.com/news/510066/audi-to-make-fuel-using-solar-power/

Existing petrol-engined road vehicles can run on methane with very little conversion, or you could synthesise higher hydrocarbons for better energy density: pure synthetic diesel produces less NOx than biodiesel. And of course methane is already the preferred source of domestic and industrial heating in the UK, whilst hydrogen and oxygen are extremely useful industrial gases.   

This approach might actually make wind power economically viable and socially useful.
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Offline Scottish Scientist

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Britons being misled by the BBC on availability of new hydro-electricity sites
« Reply #96 on: 25/04/2015 02:36:11 »
"The UK has reached the limit on hydro" (paraphrased) said Andrew Neil questioning the parties' energy and climate change spokespersons on the BBC's Daily Politics, first broadcast on 20th April and rebroadcasted earlier today on BBC Parliament.

What Mr Neil meant is that even it would be nice to build more hydro-electric schemes to provide renewable power when the wind is not blowing (sun is not shining etc), regrettably there are no more suitable sites to build more hydro schemes in the UK.

Actually, I have a plan to build a new massive pumped-storage hydro scheme in Scotland which could keep the UK's lights on 24/7, in a 100% renewable energy way.

World’s biggest-ever pumped-storage hydro-scheme, for Scotland?
https://scottishscientist.wordpress.com/2015/04/15/worlds-biggest-ever-pumped-storage-hydro-scheme-for-scotland/

So Andrew Neil was wrong. The orthodoxy about "the UK has reached the limit on hydro" is wrong.

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Offline PmbPhy

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Re: How can renewable energy farms provide 24-hour power?
« Reply #97 on: 25/04/2015 13:20:44 »
Quote from: wolfekeeper
Look, none of this is rocket science; apparently it is for you,..
I'm certain that the rest of us in this forum would very much appreciate it if you'd stop using such a disrespectful tone with Alan. He's an intelligent, knowledgeable person whom many of us in the forum respect and admire. We don't like to see him insulted like this. Please stop.
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Offline RD

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Re: How can renewable energy farms provide 24-hour power?
« Reply #98 on: 25/04/2015 14:43:44 »
Quote from: Scottish Scientist on 24/04/2015 02:38:39
... Deep Sea Hydrogen Storage ...
 [ Invalid Attachment ]

How big is this gas-bag ?, and how deep will it be under the sea ? .
Do flexible materials exist to make such a bag which can withstand the buoyancy forces ?


http://en.wikipedia.org/wiki/Lifting_bag

* how big is balloon , how deep, what is it made of .jpg (42.81 kB, 419x451 - viewed 4608 times.)
« Last Edit: 25/04/2015 15:33:21 by RD »
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Offline alancalverd

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Re: How can renewable energy farms provide 24-hour power?
« Reply #99 on: 25/04/2015 17:32:19 »
It needn't be a balloon. A steel can will do quite nicely, and it doesn't need to be very deep under the ocean: the domestic gas supply pressure is only a meter of water gauge or less. The deeper it is, the more efficient, but large steel cans are very cheap and easy to make.
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