39 ms·

Isn't that because we're using fossil fuels for the base load? What happens when all we have is renewables?

pfdietz 7y ago
Fossil fuel baseload is also incompatible with renewables, although not as badly because more of its costs are variable. This is one of the reasons coal is hurting. Think carefully about the economics. Suppose we want to use nuclear to cover the (say) 20% of the time renewables + short term storage might not cover. Nuclear's cost of power would be greatly inflated over what it would be if it were baseload. The effective CO2 tax to make that cheaper than (say) gas turbines burning natural gas would be outrageous, over $1000/ton. A vast array of CO2-reducing changes would occur before that. It would also likely be cheaper to use renewable hydrogen (from electrolysis, stored underground) in gas turbines for that last bit. The round trip efficiency would be lousy, but it would still be cheaper than using nuclear there. View it another way: if we have really cheap power most of the time, insisting we use nuclear then, just so nuclear would be available in that other 20%, would incur a huge opportunity cost. That cost should properly be assigned to the place nuclear is being depended on (that 20%).
- StavrosK 7y ago
  That makes sense, although I don't know enough to refute it. However, renewables covering 80% sounds very high to me without some large-scale energy storage solutions.
  - pfdietz 7y ago
    Solar is getting so cheap that the first thing one would do is over-install and curtail it. In some places, the solar gets installed at near-vertical angles to maximize output in winter. The next is diurnal storage. The final 20% or so is seasonal and rare long outages due to weather. Dispatchable demand is also a big possibility, especially if it can exploit the times the curtailed output is almost free. There was a study in Minnesota that solar and wind could get to 70% of the market there before storage would make sense. The crossover point depends on economic details.
- acidburnNSA 7y ago
  I'm sure you're aware that nuclear heat and electricity could be stored and/or distributed just like renewable stuff in the vast energy storage system of the future. I still would like an answer from you on EROI
  - pfdietz 7y ago
    There is no point charging batteries with expensive nuclear energy when cheap renewable energy can be used. And the operator of a battery can shift when they are charged, making nuclear even less likely to be the cheapest source available at any time. So this doesn't save nuclear. Heat is difficult to transport any great distance, and the reactors we have today produce only moderate grade heat, which isn't very valuable. And if PV becomes a bit cheaper, then the cost per joule of its power will become comparable to the cost per thermal joule of natural gas. In that situation, consumers will shift to resistive heat, and be able to bank that heat in large thermal stores. This will provide enormous cheap storage capacity for that solar energy. EROI of renewables is just fine, some horribly flawed claims to the opposite notwithstanding. In particular, the EROI of PV was estimated to be about 8 in Europe -- but that assumes one puts the solar-powered PV factories IN EUROPE, rather than in a location with more sun. The real issue there is that energy-intensive industry will flee Europe in a solar-powered world.

Fossil fuel baseload is also incompatible with renewables, although not as badly because more of its costs are variable. This is one of the reasons coal is hurting. Think carefully about the economics. Suppose we want to use nuclear to cover the (say) 20% of the time renewables + short term storage might not cover. Nuclear's cost of power would be greatly inflated over what it would be if it were baseload. The effective CO2 tax to make that cheaper than (say) gas turbines burning natural gas would be outrageous, over $1000/ton. A vast array of CO2-reducing changes would occur before that. It would also likely be cheaper to use renewable hydrogen (from electrolysis, stored underground) in gas turbines for that last bit. The round trip efficiency would be lousy, but it would still be cheaper than using nuclear there. View it another way: if we have really cheap power most of the time, insisting we use nuclear then, just so nuclear would be available in that other 20%, would incur a huge opportunity cost. That cost should properly be assigned to the place nuclear is being depended on (that 20%).

StavrosK 7y ago
That makes sense, although I don't know enough to refute it. However, renewables covering 80% sounds very high to me without some large-scale energy storage solutions.
- pfdietz 7y ago
  Solar is getting so cheap that the first thing one would do is over-install and curtail it. In some places, the solar gets installed at near-vertical angles to maximize output in winter. The next is diurnal storage. The final 20% or so is seasonal and rare long outages due to weather. Dispatchable demand is also a big possibility, especially if it can exploit the times the curtailed output is almost free. There was a study in Minnesota that solar and wind could get to 70% of the market there before storage would make sense. The crossover point depends on economic details.
acidburnNSA 7y ago
I'm sure you're aware that nuclear heat and electricity could be stored and/or distributed just like renewable stuff in the vast energy storage system of the future. I still would like an answer from you on EROI
- pfdietz 7y ago
  There is no point charging batteries with expensive nuclear energy when cheap renewable energy can be used. And the operator of a battery can shift when they are charged, making nuclear even less likely to be the cheapest source available at any time. So this doesn't save nuclear. Heat is difficult to transport any great distance, and the reactors we have today produce only moderate grade heat, which isn't very valuable. And if PV becomes a bit cheaper, then the cost per joule of its power will become comparable to the cost per thermal joule of natural gas. In that situation, consumers will shift to resistive heat, and be able to bank that heat in large thermal stores. This will provide enormous cheap storage capacity for that solar energy. EROI of renewables is just fine, some horribly flawed claims to the opposite notwithstanding. In particular, the EROI of PV was estimated to be about 8 in Europe -- but that assumes one puts the solar-powered PV factories IN EUROPE, rather than in a location with more sun. The real issue there is that energy-intensive industry will flee Europe in a solar-powered world.