5 ms·

Let's Build a Global Power Grid

44 points by bpolania 11y ago

transfire 11y ago
Er... no. Just as homes and business that can should be moving to solar and wind, so too cities should be moving to next generation nuclear. Interconnected grids to provide redundancy is good, but a global super grid is unnecessary.
- brownbat 11y ago
  HVDC and long transmission is actually one of the best ways to encourage the expanded investment in solar farms, wind farms, or nuclear facilities. Usually greatest output potential is far from people, be it offshore wind, desert solar, or even nuclear near large lakes for cooling. Hydro or pumped hydro and geothermal too. If it was easier to move this power from remote regions to population centers with lower losses, clean power would boom. The megaprojects cited in the article are extreme versions of this, but we could build up to those gradually. Development of better interconnections and long transmission lines even within countries would be a start, and would encourage better siting for new plants. [0] https://en.wikipedia.org/wiki/Desertec https://en.wikipedia.org/wiki/Desertec
  - elithrar 11y ago
    > If it was easier to move this power from remote regions to population centers with lower losses Loss isn't really the motivating factor though: at about 330kV transmission losses are < 3%[1]. Building transmission towers, the land/access corridors, and dealing with the supporting infrastructure is the biggest barrier by a long shot: it just costs a lot of money to build terrestrial (power|communications) networks. [1]: http://www.e-ijaet.org/media/9I9-DETERMINATION-OF-BUS-VOLTAGES.pdf http://www.e-ijaet.org/media/9I9-DETERMINATION-OF-BUS-VOLTAG...
    - brownbat 11y ago
      Current systems emphasize short trips between generation and consumption to minimize line losses. Per your cite, Nigeria has a little over 5,000 miles of transmission lines. The US has over 450,000 miles. http://www.naruc.org/grants/Documents/Silverstein%20NCEP%20T-101%200420111.pdf http://www.naruc.org/grants/Documents/Silverstein%20NCEP%20T... Neither of these systems transmit power from one end straight to the other end, but you can do neat things if you can increase your range. The losses from AC compound rapidly with distance. There's a good bit here: http://www.tinyrevolution.com/mt/archives/003223.html http://www.tinyrevolution.com/mt/archives/003223.html "In aggregate, the example system comprised of Argonne National Laboratory plus a factory in Nebraska refining corn syrup suffers transmission losses of 785kW, or 0.52%. America is like this. The transmission efficiency looks high (losses of only 10%) because most of the power we use (normalized to capacity) travels only short distances (normalized to length). This does not mean that line losses per distance are low. Mostly it means that the lines are short - not at all adequate to carry power from North Dakota to someplace useful. So, this is a nice, simple explanation, but is it true? To test it, this site has a useful model of an electrical distribution network. There is a little bit of math ahead, which I only include because I think some readers will like it. Following the diagram and the text below it, Ohio Edison operates 5757MW of electrical power generation (let’s call it 6000MW). The source voltage is 18kV; this gives 300,000A of current in the generating facilities (rounding for convenience). The ratio of the step-up transformer to the transmission line is 350/18, which we’ll call 20. This means that the current in the transmission line is 300,000/20, or 15,000A. Current is stepped down in this manner in order to minimize transmission losses, but they cannot be eliminated. In order to calculate the transmission losses, we’ll assume that the transmission cable used for this application has a resistance of around 0.1 Ohms per km of length. This is at the low end of the range (so the loss estimate will be low) according to a couple of spec sheets I looked at. This yields (P=I^2R) 22.5MW lost power per km of length, or 0.4% per km. That’s 0.6% per mile, or 10% of the total energy lost over a transmission distance of just 18 miles. After 115 miles, only 50% of the power remains.
brownbat 11y ago
Easily missed gems: And superconducting DC cable requires even smaller rights-of-way than does HVDC with traditional cables. Some of the biggest obstacles to ensuring grid stability are rights-of-way fights. There's abundant power just north of NYC in Canada, and NYC has one of the most fragile grids in the US. A major project to implement the obvious solution was tanked because of NIMBY fights all along the corridor. The compromise was to try to build a buried line (under a lake!) at about a tenth the capacity (essentially not helping) at about ten times the cost. Now Albany is fighting against the buried line plan too. HVDC doesn't make these problems disappear, but when you finally get anyone to agree to one thin line, at least you can transmit a lot of power over it. * * * Although [supercooled transmission lines] do need to be cooled to liquid-nitrogen temperatures—below 77 kelvins—the losses from refrigeration and other sources are less than half those of conventional AC and DC overhead transmission lines. Moving power around the country through frozen ice lines, it's like magic in some unbelievable fantasy novel (ie, the best kind of science). * * * China, which is now the world leader in the development and deployment of grid technology, in particular HVDC. * * * The cost of the generated power with the HVDC supergrid would almost certainly be much lower than what’s available today because operators would be able to buy electricity from the least expensive source. * * * ...governments and grid operators will need to agree on the rules for free trade in electricity. Electricity trading through a wholesale market, perhaps broken up into regions, would enable the kind of efficient power flows a global supergrid would offer. While baking in strong protections against ENRON-style disasters. * * * Not mentioned: DC converting stations serve as a firewall for blackouts. Post-Fukushima, the southern part of Japan's grid was unaffected. It operates on 50 Hz, because it was mostly built on German tech, while the northern grid operates at 60 Hz, because it was mostly built up on American tech. There's a massive AC-DC-AC conversion system in the middle. Problems with balance or shortages don't infect the other part of the system. http://www.japantimes.co.jp/news/2011/07/19/reference/japans-incompatible-power-grids/ http://www.japantimes.co.jp/news/2011/07/19/reference/japans...

44 points by bpolania 11y ago

Er... no. Just as homes and business that can should be moving to solar and wind, so too cities should be moving to next generation nuclear. Interconnected grids to provide redundancy is good, but a global super grid is unnecessary.

brownbat 11y ago
HVDC and long transmission is actually one of the best ways to encourage the expanded investment in solar farms, wind farms, or nuclear facilities. Usually greatest output potential is far from people, be it offshore wind, desert solar, or even nuclear near large lakes for cooling. Hydro or pumped hydro and geothermal too. If it was easier to move this power from remote regions to population centers with lower losses, clean power would boom. The megaprojects cited in the article are extreme versions of this, but we could build up to those gradually. Development of better interconnections and long transmission lines even within countries would be a start, and would encourage better siting for new plants. [0] https://en.wikipedia.org/wiki/Desertec https://en.wikipedia.org/wiki/Desertec
- elithrar 11y ago
  > If it was easier to move this power from remote regions to population centers with lower losses Loss isn't really the motivating factor though: at about 330kV transmission losses are < 3%[1]. Building transmission towers, the land/access corridors, and dealing with the supporting infrastructure is the biggest barrier by a long shot: it just costs a lot of money to build terrestrial (power|communications) networks. [1]: http://www.e-ijaet.org/media/9I9-DETERMINATION-OF-BUS-VOLTAGES.pdf http://www.e-ijaet.org/media/9I9-DETERMINATION-OF-BUS-VOLTAG...
  - brownbat 11y ago
    Current systems emphasize short trips between generation and consumption to minimize line losses. Per your cite, Nigeria has a little over 5,000 miles of transmission lines. The US has over 450,000 miles. http://www.naruc.org/grants/Documents/Silverstein%20NCEP%20T-101%200420111.pdf http://www.naruc.org/grants/Documents/Silverstein%20NCEP%20T... Neither of these systems transmit power from one end straight to the other end, but you can do neat things if you can increase your range. The losses from AC compound rapidly with distance. There's a good bit here: http://www.tinyrevolution.com/mt/archives/003223.html http://www.tinyrevolution.com/mt/archives/003223.html "In aggregate, the example system comprised of Argonne National Laboratory plus a factory in Nebraska refining corn syrup suffers transmission losses of 785kW, or 0.52%. America is like this. The transmission efficiency looks high (losses of only 10%) because most of the power we use (normalized to capacity) travels only short distances (normalized to length). This does not mean that line losses per distance are low. Mostly it means that the lines are short - not at all adequate to carry power from North Dakota to someplace useful. So, this is a nice, simple explanation, but is it true? To test it, this site has a useful model of an electrical distribution network. There is a little bit of math ahead, which I only include because I think some readers will like it. Following the diagram and the text below it, Ohio Edison operates 5757MW of electrical power generation (let’s call it 6000MW). The source voltage is 18kV; this gives 300,000A of current in the generating facilities (rounding for convenience). The ratio of the step-up transformer to the transmission line is 350/18, which we’ll call 20. This means that the current in the transmission line is 300,000/20, or 15,000A. Current is stepped down in this manner in order to minimize transmission losses, but they cannot be eliminated. In order to calculate the transmission losses, we’ll assume that the transmission cable used for this application has a resistance of around 0.1 Ohms per km of length. This is at the low end of the range (so the loss estimate will be low) according to a couple of spec sheets I looked at. This yields (P=I^2R) 22.5MW lost power per km of length, or 0.4% per km. That’s 0.6% per mile, or 10% of the total energy lost over a transmission distance of just 18 miles. After 115 miles, only 50% of the power remains.

brownbat 11y ago

Easily missed gems: And superconducting DC cable requires even smaller rights-of-way than does HVDC with traditional cables. Some of the biggest obstacles to ensuring grid stability are rights-of-way fights. There's abundant power just north of NYC in Canada, and NYC has one of the most fragile grids in the US. A major project to implement the obvious solution was tanked because of NIMBY fights all along the corridor. The compromise was to try to build a buried line (under a lake!) at about a tenth the capacity (essentially not helping) at about ten times the cost. Now Albany is fighting against the buried line plan too. HVDC doesn't make these problems disappear, but when you finally get anyone to agree to one thin line, at least you can transmit a lot of power over it. * * * Although [supercooled transmission lines] do need to be cooled to liquid-nitrogen temperatures—below 77 kelvins—the losses from refrigeration and other sources are less than half those of conventional AC and DC overhead transmission lines. Moving power around the country through frozen ice lines, it's like magic in some unbelievable fantasy novel (ie, the best kind of science). * * * China, which is now the world leader in the development and deployment of grid technology, in particular HVDC. * * * The cost of the generated power with the HVDC supergrid would almost certainly be much lower than what’s available today because operators would be able to buy electricity from the least expensive source. * * * ...governments and grid operators will need to agree on the rules for free trade in electricity. Electricity trading through a wholesale market, perhaps broken up into regions, would enable the kind of efficient power flows a global supergrid would offer. While baking in strong protections against ENRON-style disasters. * * * Not mentioned: DC converting stations serve as a firewall for blackouts. Post-Fukushima, the southern part of Japan's grid was unaffected. It operates on 50 Hz, because it was mostly built on German tech, while the northern grid operates at 60 Hz, because it was mostly built up on American tech. There's a massive AC-DC-AC conversion system in the middle. Problems with balance or shortages don't infect the other part of the system. http://www.japantimes.co.jp/news/2011/07/19/reference/japans-incompatible-power-grids/ http://www.japantimes.co.jp/news/2011/07/19/reference/japans...