One of the biggest problems with solar energy is that it is available only intermittently at any one place on Earth. However, solar energy is always available at some (large) surface on Earth. Another thread asks about (literally) shipping that energy from one place to another, but the more natural question to ask is whether long distance transmission grids can achieve that purpose. If not, what are the (technological/engineering) constraints?
Considering that we already ship large quantities of power long distances (for example see the Paciific intertie), I’d say there’s no reason we couldn’t do it with solar power. The main problem with doing this is that there’s a certain amount of loss. But that’s a problem no matter how the power was produced.
What’s the distance over which that power is being transmitted? It isn’t on the page, but I think I’m asking about distances at least an order of magnitude higher than the one covered by the Intertie. And the advantage with non solar sources is that you can locate them (mostly) arbitrarily. You cannot control where the sun is shining at any point in time.
I’m assuming you will have read about the possibility of a superconducting grid as described on this Wiki page?
When and if we build such a supergrid connecting the various power production locations and consumers of this planet, then power produced on one side of the world will be shippable to the other side with relative ease.
A few caveats, however; the existence of a worldwide energy grid would be very difficult to achieve politically, and the infrastructure would be vulnerable to terrorism. Also, having large scale power distribution shouldn’t prevent local energy production and consumption, which should also become commonplace, and would not remove the need to make all power consumption more efficient.
1360 km, which is somewhere around 850 miles. I doubt if you need a whole lot more distance than that. And note that the longer the distance, the more losses you have. The ideal place for solar power is in the cities where the power is consumed. The roofs of large suburban lowrises should be the first place they put large solar panels.
That particular line carries hydro power from the northwest to LA. Hydro dams can’t be placed just anywhere, which is why they have to have the Intertie.
AIUI, most renewable energy (windmills and solar) feed the local grid of wherever they’re at first, thus avoiding transmission losses. When there’s more power generated than the nearby towns can use, then they transmit it to cities further away.
A superconducting grid is just science fiction at this point though. I want to know what are the current constraints that we face. What are the technological factors stopping us from running cables from India to the US to ensure that both countries can get solar power 24 hours a day? Would the heat losses be too high? Would it be impossible to lay cables over that distance?
I’m not sure you understand my question.
The losses would be enormous. You’d be much better off using excess solar in the day to electrolyse water to hydrogen or pump water uphill into holding reservoirs and then use that power during the night.
At what length do the losses become too enormous? The pacific intertie linked above runs ~1500 kms, so we know that’s possible. How long would be too long? 2k? 3k? 10k?
Well, you didn’t say you wanted to ship the power halfway around the world. But as coremelt said, that would be wasteful. Really, it’s best to consume power locally and not suffer the transmission losses.
If you try to cross an ocean, the costs soar well up into the ridiculous range pretty quickly.
If you look at the U.S., most of the country has plenty of power. The only problem areas are the northeast and southwest. The Pacific intertie is designed to help with the southwest side of things. It’s not a question of how far can you ship the power before the losses get too big, although that does factor into the costs of things. It’s more a question of where do you have power and where do you need power.
It’s technically possible, I suppose, to run a high voltage transmission line from Washington State to Kansas, but it wouldn’t make any sense to do so. There’s not that much spare power in Washington State and there’s no huge demand in Kansas. There’s very few places where it makes any economic sense at all to run a transmission line as long as the Pacific intertie.
Adding solar plants with long transmission lines doesn’t solve much. There’s only a few hours time difference between the east coast and west coast of the U.S. so the daylight difference doesn’t buy you much. It’s not like it’s high noon in New York while it’s midnight in Los Angeles.
You’ve also got the problem that solar only works when it’s sunny. The only consistently sunny parts of the U.S. are the southwestern desert areas. Not surprisingly, the largest solar plants in the U.S. (and the world, for that matter) are located in the Mojave Desert. A solar plant in Seattle isn’t going to work so well.
A single nuke or coal plant can easily supply 1500 MW of power, which is an order of magnitude larger than all but the world’s largest solar arrays. If you want to solve the U.S. power problems, add more nuke and coal plants. Nobody wants one of those in their back yard though, which is why we have things like the Pacific intertie instead. People also don’t want to shell out the money for a new power plant, since it takes decades for the plant to recoup it’s construction costs. This is why we have the problems that we do.
Where do you propose adding solar plants that would help with the northeast/southwest power problems in the U.S.?
I don’t really care about the U.S’s power problems(What gave you the impression that I did?). I’m trying to understand if long distance transmission of power is a possible solution to the intermittency of solar availability, and since it is likely not, what are the technological constraints in the way. Is it cost/transmission losses/etc.
How big a factor are transmission losses? Is it even theoretically possible (without going into science fiction realm) to transmit power halfway across the globe?
Also, you mention that cables cannot be laid across oceans because the cost would be prohibitive. Would a power cable be significantly different from the fiber pipes that we currently lay down?
I did. It’s in my OP.
Long-distance transmission isn’t really the answer to solar power’s intermittency. Even taken world-wide, I don’t think you have a very stable pattern of usable sunlight, especially not a pattern that matches very well with global electric usage patterns, and it gets worse if you’re restricted to land areas that are at all feasible.
And, in most places you don’t really need to go that far to get a decent spot to generate solar; certainly not whole continents away. The problem with solar isn’t where it’s generated; it’s when it’s generated.
So what solar really needs is a good way to store energy for medium terms (days to weeks). There’s no clear winner yet, though people are of course working on it.
Read the wiki page on high voltage direct current and it pretty much answers all of the above.
Losses for hvdc are 3.5 percent per 1000 km. assuming that’s applied compounding you’re going to lose almost 50 percent of the power with a theoretical 10’000 km hvdc line going halfway round the world.
If you use wire of the same thickness for 10,000 km as you do for 1000 km, that would probably be true. Is there any reason that is essential? Since resistance decreases by the square of thickness, and increases only linearly in length, it might be possible to reduce that.
I am not an electrical engineer but your costs per Km go up with thicker wire and at some point it just doesn’t make economic sense. The longest hvdc link at the moment is 2000km.
It seems like it would be theoretically possible to build a 20,000 km hvdc link but why? It just doesn’t make any sense from economic or power efficiency points of view.
I think I understand what the OP is getting at. He’s possibly imagining a future time where perhaps we have 1% of the entire surface of the Earth covered with solar panels, and they are fairly randomly distributed in such a way that at any one time the combined total of all the panels is enough to power all energy demands of the planet. Of course the problem with this is that on the side of the planet that’s dark, all the power would have to be transmitted from the side of the planet in sunlight. In this scenario you don’t have to worry about storing energy locally, or anything else, power is just sent where it is needed whenever it is needed from wherever it is being generated. I think that may be what he’s getting at. Obviously we’re a long way from that, but it is an intriguing possibility.
Yes, pretty much something like this. I thought I’d made it clear, but apparently I was wrong.
There are definitely people working on it.
Like; Solar storage below $100/kWh - with the help of a steam engine | RenewEconomy
Though I don’t know if that works for ‘medium terms’.
Yes but it’s not feasible as been explained at least four times above. Unless you build your global power link from super conductors it will always be more efficient in terms of energy losses to store power by other methods rather than sending it from the other side of the world.