Single day record for solar energy use, Germany:

Well, that's nice. What's the percentage on a dark winter day?

Originally posted by KazetNagorra
Well, that's nice. What's the percentage on a dark winter day?

probably not much but, depending on the wind, much of the electricity could come from wind power.

Originally posted by KazetNagorra
Well, that's nice. What's the percentage on a dark winter day?

http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/data-nivc-/electricity-production-from-solar-and-wind-in-germany-2014.pdf

Page 36

The minimal daily production was 0.006 TWh at 21.01.2014

Originally posted by twhitehead
http://www.ise.fraunhofer.de/en/downloads-englisch/pdf-files-englisch/data-nivc-/electricity-production-from-solar-and-wind-in-germany-2014.pdf

Page 36

The minimal daily production was 0.006 TWh at 21.01.2014

Just looking at that chart I can see an immediate way of cutting their CO2 emissions.

They underutilise their installed gas energy production vs coal [probably because coal is
cheaper.]

If there was a carbon tax that would up the price of coal relative to gas and the market
would off-line coal power generation instead of gas.


The downside currently is that the gas comes largely from Russia.

I put this here rather than start a new thread on it:

http://phys.org/news/2014-06-greater-potential-solar-power.html
"...
Research shows greater potential for solar power

Concentrating solar power (CSP) could supply a large fraction of the power supply in a decarbonized energy system, shows a new study of the technology and its potential practical application.

Concentrating solar power (CSP) could supply a substantial amount of current energy demand, according to the study published in the journal Nature Climate Change. In the Mediterranean region, for example, the study shows that a connected CSP system could provide 70-80% of current electricity demand, at no extra cost compared to gas-fired power plants. That percentage is similar to what a standard energy production plant, such as a nuclear plant, can provide.

"Solar energy systems can satisfy much more of our hunger for electricity, at not much more cost than what we currently have," says Stefan Pfenninger, who led the study while working at IIASA. He is now a Research Postgraduate at the Grantham Institute at Imperial College London.
The study was the first to examine the potential of CSP as a large-scale energy production system, in four regions around the world. "In order to address climate change we need to greatly expand our use of renewable energy systems," says IIASA researcher Fabian Wagner, who also worked on the study. "The key question, though, is how much energy renewable systems can actually deliver."

One problem with deploying solar energy on a large scale is that the sun doesn't shine all the time. That means that energy must be stored in some way. For photovoltaic (PV) cells, which convert sunlight directly to electricity, this is especially difficult to overcome, because electricity is difficult to store.

Unlike photovoltaic (PV) cells, CSP uses the sun's energy to heat up a liquid that drives turbines. This means that the collected energy can be stored as heat, and converted to electricity only when needed. But even with CSP, if the sun doesn't shine for long periods of time, the system may not be able to support large-scale energy needs.

One way to solve this problem is to build a large, connected network of CSP. Until now, however, nobody had explored the details and feasibility of such a plan. In the new study, the researchers simulated the construction and operation of CSP systems in four regions around the world, taking into account weather variations, plant locations, electricity demand, and costs.

"Our study is the first to look closely at whether it's possible to build a power system based primarily on solar energy, and still provide reliable electricity to consumers around the clock, every day of the year. We find this to be possible in two world regions, the Mediterranean basin and the Kalahari Desert of Southern Africa," says study co-author Anthony Patt, Professor of Human-Environment Systems, ETH Zurich Department of Environmental Systems Science, and an IIASA guest research scholar.
..."

Although the link doesn't mention this, I assume, for this plan to work, some kind of supergrid will have to be made? if so, I wonder if they factored in the cost of building such a supergrid in their study? if they haven't, that could mean their conclusion is too optimistic because making such a supergrid doesn't come cheap!

Originally posted by humy
Although the link doesn't mention this, I assume, for this plan to work, some kind of supergrid will have to be made?

Why? Why do solar power plants need a 'super grid' but other power plants do not? I am sure the countries in question have electricity grids already.
Now if we were talking about putting the power plants in the Sahara and using the power all over Europe, then you might have a point, but simply using CSP in Italy, Spain, Greece etc would not require a supergrid. It also wouldn't be required here in SA. We already have a variety of power plants around the country, which provide varying amounts of power which gets switched around without failures. Why would Solar be different?

Originally posted by twhitehead
Why? Why do solar power plants need a 'super grid' but other power plants do not? I am sure the countries in question have electricity grids already.
Now if we were talking about putting the power plants in the Sahara and using the power all over Europe, then you might have a point, but simply using CSP in Italy, Spain, Greece etc would not require a sup ...[text shortened]... ying amounts of power which gets switched around without failures. Why would Solar be different?

Why do solar power plants need a 'super grid' but other power plants do not?

No, you misunderstand; I wasn't referring to those solar power stations but rather the particular scheme of combining their power output (and I assume when they are greatly spaced apart across a large area encompassing several completely different countries) in the way disused in that link. That is why I said “...for this plan to work...“ as in the plan proposed in that link and not “...for these power plants to work...” and said that directly below the link quotes to indicate it was in the context of that link. I hope I have made that clear now.

Originally posted by humy
No, you misunderstand; I wasn't referring to those solar power stations but rather the particular scheme of combining their power output (and I assume when they are greatly spaced apart across a large area encompassing several completely different countries) in the way disused in that link. That is why I said “...for this [b]plan to work...“ as in th ...[text shortened]... e link quotes to indicate it was in the context of that link. I hope I have made that clear now.[/b]

But I strongly suspect that the countries in question already share a grid capable of handling this. Why must it be a 'super grid'? What is 'super' about it?

Originally posted by twhitehead
But I strongly suspect that the countries in question already share a grid capable of handling this. Why must it be a 'super grid'? What is 'super' about it?

Current long distance grid connections between countries tend to be very lossy.

A 'super grid' would be designed to more large amounts of power with significantly lower losses.

Originally posted by twhitehead
But I strongly suspect that the countries in question already share a grid capable of handling this. Why must it be a 'super grid'? What is 'super' about it?

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

-and as googlefudge said.

A super grid may also use superconductors to reduce loss over huge distances of transmission in which case it would be very easy to see why it may be called 'super grid' although a super grid need not use superconductors to be defined as such.

Originally posted by humy
http://en.wikipedia.org/wiki/Super_grid

-and as googlefudge said.

A super grid may also use superconductors to reduce loss over huge distances of transmission in which case it would be very easy to see why it may be called 'super grid' although a super grid need not use superconductors to be defined as such.

What superconductors? There are no superconductors which can feasibly be used for energy transmission in a national power grid. They work at liquid nitrogen temperatures, and room temperature superconductors are years away even if such a thing is possible. For a power transmission grid you'd need something that can cope with getting hot, so the superconducting transition would have to be above say 70 degrees Celcius.

Originally posted by DeepThought
What superconductors? There are no superconductors which can feasibly be used for energy transmission in a national power grid. They work at liquid nitrogen temperatures, and room temperature superconductors are years away [b]even if such a thing is possible. For a power transmission grid you'd need something that can cope with getting hot, so the superconducting transition would have to be above say 70 degrees Celcius.[/b]

There are no superconductors which can feasibly be used for energy transmission in a national power grid.

If that is currently true, that doesn't mean it will ALWAYS be true. Even if room temperature superconductors are impossible, there might eventually be discovered a suitable superconductor that needs sufficiently less cooling to make it cost effective in the long run.
Anyway, a super grid doesn't HAVE to have superconductors so this is pretty academic I think.

Originally posted by googlefudge
Current long distance grid connections between countries tend to be very lossy.

A 'super grid' would be designed to more large amounts of power with significantly lower losses.

Better electricity grids with lower loss, are of course desirable whatever power stations are in use. I am, however, not convinced that they would be required for CSP to be successful in the mediterranean region.

Originally posted by humy

There are no superconductors which can feasibly be used for energy transmission in a national power grid.

If that is currently true, that doesn't mean it will ALWAYS be true. Even if room temperature superconductors are impossible, there might eventually be discovered a suitable superconductor that needs sufficiently less cooling to make ...[text shortened]... .
Anyway, a super grid doesn't HAVE to have superconductors so this is pretty academic I think.

First it is not clear there will ever be room temperature superconductors. Second, even if there can be room temperature superconductors they are sufficiently far in the future that they cannot be included in the assessment of the viability of a super-grid - which is what you were trying to do. In any case these things are basically up and running using good old copper cables with DC transmission for long distances.

Maglev trains are a different thing, containing liquid nitrogen isn't so hard and the superconductor only has to be in the train, so you can feasibly do it. There it would be reasonable to include the possibility in your assessment, as it doesn't change whether the whole thing is possible or not.

The key to transmitting power, for example between Scotland and Northern Ireland is to use DC, as there are no radiative losses and you don't blow the smaller of the two grids with phase differences.

Originally posted by DeepThought
What superconductors? There are no superconductors which can feasibly be used for energy transmission in a national power grid. They work at liquid nitrogen temperatures, and room temperature superconductors are years away [b]even if such a thing is possible. For a power transmission grid you'd need something that can cope with getting hot, so the superconducting transition would have to be above say 70 degrees Celcius.[/b]

I was thinking of long distance DC lines myself, until and unless we invent room temp
superconductors that are both strong and cheap enough to replace current cables, or
their successors, cost effectively then superconductors are just too expensive and
unreliable. We can't have a power grid that breaks down in warm weather, like [say]
whenever it gets over 80 Kelvin in the shade...