3 ms·

> 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 330k

> 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

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.