4 ms·

The example is clearly hypothetical only. We're never going to cover one third of the continental US with wind turbines. The more important information to me i

The example is clearly hypothetical only. We're never going to cover one third of the continental US with wind turbines. The more important information to me is that neither wind nor solar have the power density that has been claimed. For wind, we found that the average power density — meaning the rate of energy generation divided by the encompassing area of the wind plant — was up to 100 times lower than estimates by some leading energy experts ... For solar energy, the average power density (measured in watts per meter squared) is 10 times higher than wind power, but also much lower than estimates by leading energy experts. Then you have the separate problem that the wind doesn't always blow and the sun doesn't always shine, so you need a huge storage infrastructure (batteries, presumably) alongside the wind and solar generating infrastructure. IMO nuclear is the only realistic alternative to coal to provide reliable, zero-emission "base load" power generation. Wind and solar could make sense in some use cases but not in general.

bilbo0s 8y ago
>IMO nuclear is the only realistic alternative to coal to provide reliable, zero-emission "base load" power generation... Yeah, but no one wants to pay for it. Which is why you'll see more wind and solar with hydro-storage, and even more geo-thermal energy plants in the future. Even with all the extra infrastructure, it still comes in at less than 2 or 3 cents a kwh long term. Whereas even if you take a very optimistic long term view on nuclear, it's just REALLY hard to get down below 3 cents. So for nuclear sources to get higher in the dispatch stack, government must take on more of the costs. But then, of course, if government is taking on more of the costs, then you're still paying more than 3 cents. Probably a lot more. You'd just pay it in extra taxes instead of a utility bill. So, yeah, I guess that's why energy is a hard problem. No easy solutions really. Just hard to balance pros and cons to every known technology at this point. (Maybe someday someone will figure out this whole fusion thing and we'll be able to consign all these other, less refined, technologies to history's dust bin?)
- u320 8y ago
  You're not going to be anywhere close to 3 cents in a 100% renewable system without hydro. Cheapest solar price in the US is 2.3 cents but that is in one of the sunniest places in the world, subsidised, and no storage.
- benjaminjackman 8y ago
  Whether or not fusion is possible (it seems like it is, just incredibly difficult and meticulous, unless the MIT-ARC project works out). There is always the eventual option to harvest solar energy in space The primary limiting factor at the moment is obviously the insane price of rocketing stuff into space. Perhaps even before that solar power could be harvested in the upper atmosphere on massive scale by being tethered to balloons, it might even have the benefit of counter-acting some of the effects of global heating.
  - tremon 8y ago
    The primary limiting factor at the moment is obviously the insane price of rocketing stuff into space. The people who are opposed to nuclear power because of the military proliferation risk might have something to say about the capability to transmit large amounts of power from space to the surface of this planet.
    - bilbo0s 8y ago
      And you'd have to add to that objection the people who oppose nuclear power because of the costs. Those people would definitely be opposed to these ideas barring some new technological development that made space-based infrastructure several orders of magnitude less expensive.
- beat 8y ago
  Time to build also matters. How long does it take to build a storage mechanism for a solar/wind farm, vs the time to build a nuclear plant? What are the reasonable regulatory requirements? (Lest anyone be complaining about the ignorant treehuggers stopping nuclear plants, I think we can all agree that a nuclear plant is potentially more hazardous than pile of batteries, and should be regulated proportionally.) What are the up-front capital requirements of nuclear vs solar/wind + storage? Another thing people need to keep in mind is we don't need enough storage to run the entire grid indefinitely. We just need enough to smooth the curve out to four nines or whatever number is deemed necessary. And while "the sun isn't always shining and the wind isn't always blowing", the wind is always blowing somewhere.
  - bilbo0s 8y ago
    You wouldn't use batteries generally though. For example, if you had hydro-storage, you'd use the power from the wind or solar to pump water into giant reservoirs. When wind or solar is unavailable, power is drawn from the hydro reservoirs by letting the stored water flow through turbines. (So a dam, basically.) So, yeah, building reservoirs is pretty well defined. And would certainly take much less time than building a nuclear plant. (The cost would be orders of magnitude lower as well.) Still has regulatory issues, just not nearly as many as dead batteries or nuclear power plants do.
    - pjc50 8y ago
      There's not many geologically good locations for pumped storage, they tend to be a bit environmentally sensitive, and they're not that quick to build - the one nearest me, Cruachan, took 6 years to build in the 1950s at the reduced safety standards of the time.
      - bilbo0s 8y ago
        That's only one way that you would do hydro-storage these days though. Think, for example, if you drill a hole deep into the ground, lower a cylinder into it, poke a hole in the bottom of the cylinder, then fill that cylinder with water. If I put a platform with a giant weight on top of it, the platform will press all of the water in the cylinder down through the hole in the bottom. That water will travel through a tube to the top of the cylinder and pour back into the cylinder on top of the weighted platform. In that tube, is where you capture the stored energy with turbines. Then, when the wind picks back up, or the sun comes out, or power is just cheap even from the coal plant, you use that power to lift the platform back up and suck all the water back into the bottom of the cylinder. Benefits of this are, as the HN User "beat" implied below, it's so cheap and simple to build that even a single, say, shopping mall might invest in it to lower their power draw from the grid. They would build one that only serves their mall for instance. You start to build out a truly distributed power storage infrastructure.
frgewut 8y ago
I have started to view "baseload" generation more in a negative sense (as in "can't be easily turned on/off"). Also the daytime/nighttime power consumption differs almost twice, so almost any solar added only smoothens out the difference. Also the new offshore wind turbines (>10MW) offer some extraordinary capacity factors (~60%). Makes me wonder what these capacity factors could be if we could get to 20MW turbines.
- beat 8y ago
  Traditional "baseload" plants are a product of cost and engineering. Nuclear and baseload coal plants are designed to deliver maximum power for minimum cost. Due to engineering constraints, this means that it's hard to scale the output up or down to meet changes in demand (hours? days?). So short-term demand is dealt with by "peaker" plants, which are very expensive. They're less efficient, and they aren't always in use, which means tying up capital in something you don't always need. I think of solar/wind as a sort of weird baseload, with a wide variance in output that is not controllable and not always predictable in the short term. Where I think we have a real opportunity is the application of modern software to this unpredictable power grid, by pricing power dynamically at a rate that matches the fluctuations in both supply and demand. At this point, building storage to stabilize the grid is arbitrage, a market imperative. Independent storage systems can buy power from the grid when it's cheap (sunny, windy days), and sell it when it's expensive (cloudy days with no wind and high demand). Then it's just a numbers game, and the market itself will provide the right amount of storage. This gets more fun as electric cars become more and more common. Every electric car is just a big battery, right? Plug it into this smart grid, and you can make a few bucks using the same arbitrage as big power companies. Sell the power in your car!
beat 8y ago
Why is nuclear capacity easier or less expensive to build than storage capacity for wind/solar? Be sure you're not starting with a conclusion and working backwards to the data required to support it.
KineticLensman 8y ago
> so you need a huge storage infrastructure (batteries, presumably) The approach in the UK is to build Combined Cycle Gas Turbine [0] stations rather than storage infrastructure, as CCGT can be spun up quickly if renewables aren't cooperating. When I checked this awesome dashboard [1] just now, 48% of the UK's power was CCGT compared with approx 12% wind solar, presumably partly today has been still foggy. On good days solar and wind get to 30%. [0] https://en.wikipedia.org/wiki/Combined_cycle https://en.wikipedia.org/wiki/Combined_cycle [1] http://www.gridwatch.templar.co.uk/index.php http://www.gridwatch.templar.co.uk/index.php
westurner 8y ago
> IMO nuclear is the only realistic alternative to coal to provide reliable, zero-emission "base load" power generation. Wind and solar could make sense in some use cases but not in general. How much heat energy does a reactor with n meters of concrete around it, located on a water supply in order to use water in an open closed loop, protected with national security resources, waste into the environment? I'd be interested to see which power sources the authors of this study would choose as a control for these just sensational stats. From https://news.ycombinator.com/item?id=17806589 https://news.ycombinator.com/item?id=17806589 : > Canada (2030), France (2021), and the UK (2025) are all working to entirely phase out coal-fired power plants for very good reasons (such as neonatal health). Would you burn a charcoal grill in an enclosed space like a garage? No.

bilbo0s 8y ago

>IMO nuclear is the only realistic alternative to coal to provide reliable, zero-emission "base load" power generation... Yeah, but no one wants to pay for it. Which is why you'll see more wind and solar with hydro-storage, and even more geo-thermal energy plants in the future. Even with all the extra infrastructure, it still comes in at less than 2 or 3 cents a kwh long term. Whereas even if you take a very optimistic long term view on nuclear, it's just REALLY hard to get down below 3 cents. So for nuclear sources to get higher in the dispatch stack, government must take on more of the costs. But then, of course, if government is taking on more of the costs, then you're still paying more than 3 cents. Probably a lot more. You'd just pay it in extra taxes instead of a utility bill. So, yeah, I guess that's why energy is a hard problem. No easy solutions really. Just hard to balance pros and cons to every known technology at this point. (Maybe someday someone will figure out this whole fusion thing and we'll be able to consign all these other, less refined, technologies to history's dust bin?)

u320 8y ago
You're not going to be anywhere close to 3 cents in a 100% renewable system without hydro. Cheapest solar price in the US is 2.3 cents but that is in one of the sunniest places in the world, subsidised, and no storage.
benjaminjackman 8y ago
Whether or not fusion is possible (it seems like it is, just incredibly difficult and meticulous, unless the MIT-ARC project works out). There is always the eventual option to harvest solar energy in space The primary limiting factor at the moment is obviously the insane price of rocketing stuff into space. Perhaps even before that solar power could be harvested in the upper atmosphere on massive scale by being tethered to balloons, it might even have the benefit of counter-acting some of the effects of global heating.
- tremon 8y ago
  The primary limiting factor at the moment is obviously the insane price of rocketing stuff into space. The people who are opposed to nuclear power because of the military proliferation risk might have something to say about the capability to transmit large amounts of power from space to the surface of this planet.
  - bilbo0s 8y ago
    And you'd have to add to that objection the people who oppose nuclear power because of the costs. Those people would definitely be opposed to these ideas barring some new technological development that made space-based infrastructure several orders of magnitude less expensive.
beat 8y ago
Time to build also matters. How long does it take to build a storage mechanism for a solar/wind farm, vs the time to build a nuclear plant? What are the reasonable regulatory requirements? (Lest anyone be complaining about the ignorant treehuggers stopping nuclear plants, I think we can all agree that a nuclear plant is potentially more hazardous than pile of batteries, and should be regulated proportionally.) What are the up-front capital requirements of nuclear vs solar/wind + storage? Another thing people need to keep in mind is we don't need enough storage to run the entire grid indefinitely. We just need enough to smooth the curve out to four nines or whatever number is deemed necessary. And while "the sun isn't always shining and the wind isn't always blowing", the wind is always blowing somewhere.
- bilbo0s 8y ago
  You wouldn't use batteries generally though. For example, if you had hydro-storage, you'd use the power from the wind or solar to pump water into giant reservoirs. When wind or solar is unavailable, power is drawn from the hydro reservoirs by letting the stored water flow through turbines. (So a dam, basically.) So, yeah, building reservoirs is pretty well defined. And would certainly take much less time than building a nuclear plant. (The cost would be orders of magnitude lower as well.) Still has regulatory issues, just not nearly as many as dead batteries or nuclear power plants do.
  - pjc50 8y ago
    There's not many geologically good locations for pumped storage, they tend to be a bit environmentally sensitive, and they're not that quick to build - the one nearest me, Cruachan, took 6 years to build in the 1950s at the reduced safety standards of the time.
    - bilbo0s 8y ago
      That's only one way that you would do hydro-storage these days though. Think, for example, if you drill a hole deep into the ground, lower a cylinder into it, poke a hole in the bottom of the cylinder, then fill that cylinder with water. If I put a platform with a giant weight on top of it, the platform will press all of the water in the cylinder down through the hole in the bottom. That water will travel through a tube to the top of the cylinder and pour back into the cylinder on top of the weighted platform. In that tube, is where you capture the stored energy with turbines. Then, when the wind picks back up, or the sun comes out, or power is just cheap even from the coal plant, you use that power to lift the platform back up and suck all the water back into the bottom of the cylinder. Benefits of this are, as the HN User "beat" implied below, it's so cheap and simple to build that even a single, say, shopping mall might invest in it to lower their power draw from the grid. They would build one that only serves their mall for instance. You start to build out a truly distributed power storage infrastructure.

frgewut 8y ago

I have started to view "baseload" generation more in a negative sense (as in "can't be easily turned on/off"). Also the daytime/nighttime power consumption differs almost twice, so almost any solar added only smoothens out the difference. Also the new offshore wind turbines (>10MW) offer some extraordinary capacity factors (~60%). Makes me wonder what these capacity factors could be if we could get to 20MW turbines.

beat 8y ago
Traditional "baseload" plants are a product of cost and engineering. Nuclear and baseload coal plants are designed to deliver maximum power for minimum cost. Due to engineering constraints, this means that it's hard to scale the output up or down to meet changes in demand (hours? days?). So short-term demand is dealt with by "peaker" plants, which are very expensive. They're less efficient, and they aren't always in use, which means tying up capital in something you don't always need. I think of solar/wind as a sort of weird baseload, with a wide variance in output that is not controllable and not always predictable in the short term. Where I think we have a real opportunity is the application of modern software to this unpredictable power grid, by pricing power dynamically at a rate that matches the fluctuations in both supply and demand. At this point, building storage to stabilize the grid is arbitrage, a market imperative. Independent storage systems can buy power from the grid when it's cheap (sunny, windy days), and sell it when it's expensive (cloudy days with no wind and high demand). Then it's just a numbers game, and the market itself will provide the right amount of storage. This gets more fun as electric cars become more and more common. Every electric car is just a big battery, right? Plug it into this smart grid, and you can make a few bucks using the same arbitrage as big power companies. Sell the power in your car!

beat 8y ago

Why is nuclear capacity easier or less expensive to build than storage capacity for wind/solar? Be sure you're not starting with a conclusion and working backwards to the data required to support it.

KineticLensman 8y ago

> so you need a huge storage infrastructure (batteries, presumably) The approach in the UK is to build Combined Cycle Gas Turbine [0] stations rather than storage infrastructure, as CCGT can be spun up quickly if renewables aren't cooperating. When I checked this awesome dashboard [1] just now, 48% of the UK's power was CCGT compared with approx 12% wind solar, presumably partly today has been still foggy. On good days solar and wind get to 30%. [0] https://en.wikipedia.org/wiki/Combined_cycle https://en.wikipedia.org/wiki/Combined_cycle [1] http://www.gridwatch.templar.co.uk/index.php http://www.gridwatch.templar.co.uk/index.php

westurner 8y ago

> IMO nuclear is the only realistic alternative to coal to provide reliable, zero-emission "base load" power generation. Wind and solar could make sense in some use cases but not in general. How much heat energy does a reactor with n meters of concrete around it, located on a water supply in order to use water in an open closed loop, protected with national security resources, waste into the environment? I'd be interested to see which power sources the authors of this study would choose as a control for these just sensational stats. From https://news.ycombinator.com/item?id=17806589 https://news.ycombinator.com/item?id=17806589 : > Canada (2030), France (2021), and the UK (2025) are all working to entirely phase out coal-fired power plants for very good reasons (such as neonatal health). Would you burn a charcoal grill in an enclosed space like a garage? No.