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| the dark side of cobalt |
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| tom66:
--- Quote from: TimFox on July 16, 2023, 10:25:15 pm ---A government report from 2018 estimated a range of about 1 to 8 million USD per mile for HVDC transmission lines. https://www.eia.gov/analysis/studies/electricity/hvdctransmission/pdf/transmission.pdf --- End quote --- So taking the high side figure of that... $8mn per mile or $5mn per km. $5 billion to build a 5000km line. If it transmitted the same power as the Chinese line - 12GW - and had 75% availability - it would move 78.9 TWh per year. So over a 100 year lifespan about 15c/kWh. A bit more than I expected, but if the line costs closer to the low end at larger scales, it makes a lot more sense. |
| nctnico:
100 years is rather optimistic. 50 years maybe but there will need to be maintenance like changing isolators and so on. As a reference: sea cables have a life span around 25 to 30 years. Additionally, the cable alone will not be enough. Storage will need to be added ass well. |
| Siwastaja:
--- Quote from: nctnico on July 17, 2023, 02:37:41 pm ---Additionally, the cable alone will not be enough. Storage will need to be added ass well. --- End quote --- Storage as in energy storage? The whole point is that better transmission can reduce the need for storage. There are situations in today's Europe some countries run at negative prices with excess generation while others run their fossils full blast and spot prices skyrocket, at the same minute. There are two completely orthogonal mitigations: storage or transmission. Third is, adding more production, and fourth is, accept the amount of fossils being burned. I see tomorrow's energy systems as combining all four as mentioned. Adding more PV and wind is possible and helps, but it has a limit because the price of each produced kWh starts going up when dimensioned multiple times over the peak demand. Thus, transmission helps: when it's windy and sunny in X, but cloudy and still in Y, transfer excess from X to Y, X gets money from Y and Y needs to pay less than when producing using back-up measures. Also, storage helps: store when excess is available, use when needed. Finally, even if you do all of this, there will be situations when it's super cold everywhere in Europe and wind is totally standstill for two weeks straight over the whole continent, and your new fancy HVDC link from Africa can't simply supply enough. Then you apply the Fourth principle above, and happily burn fossil fuels in your storage, because it simply does not matter in the big picture. It is especially this fourth point which is so difficult to accept for the purists. All-or-nothing approach is devastating. |
| TimFox:
All of these approaches have been shown to work. In a specific application, the cost accountants and engineers must work together to evaluate the choice to include scientific, engineering, and economic considerations (including the interest rate on capital and taxation). (Politicians would rather wave hands and pontificate than do the math.) |
| Siwastaja:
That 5 billion specifically sounds like a small sum of money, Finland can easily pay for it and much more, and we don't except anything in return. |
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