13 ms·

There's nothing wrong with solar per-se, but it's just not sufficiently power dense if you're talking national scale power usage. https://www.finder.com/uk/sola

There's nothing wrong with solar per-se, but it's just not sufficiently power dense if you're talking national scale power usage. https://www.finder.com/uk/solar-power-potential https://www.finder.com/uk/solar-power-potential seems to think that countries like the UK would need more than 10% of their area covering with solar panels to cover their energy needs. I think you'd need to be talking about an order of magnitude improvement in efficiency to really start making it look really feasible as a significant way to change our fossil fuel usage, no?

godelski 7y ago
We also need batteries. But that's why solar is only part of the solution. No single source will solve all the problems in all the areas. I'm a big proponent of nuclear but it's only part. Solar is also what I want to see. But more than the other two I want batteries.
- plufz 7y ago
  From what I heard from people in the solar business battery is generally not a good idea. Better to invest in a good grid where we can transfer electricity from one place to another (there’s always windy somewhere). And have some sort of backup power plants on the lowest days (like natural gas, biofuel, etc, not co2 free but they wouldn’t be used very often from what I understand). Or alternative “batteries” like pumping up a lot of water in some dam.
  - Gibbon1 7y ago
    I like to point out the efficiency gains and load shifting will also reduce off peek demand somewhat. Industrial users will chase lowest cost if possible. If electricity costs 3X at 1am the price at 11am, no ones going to be running an electric furnace at 1am. Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. So it's slightly pointless argue as some do that lack of current solutions is a reason not to move forward with renewables. Worst comes to worst we already have peaking plants that could substitute for baseload power.
    - deleted 7y ago
      [deleted]
    - godelski 7y ago
      I think there's miscommunication. > lack of current solutions is a reason not to move forward with renewables No one is saying we shouldn't move forward with renewables. Well maybe a certain canine news network, but not anyone here. > Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. What people are saying is there isn't good enough technology yet. So that means that we need to continue funding research. Not being solved means that just building won't be the solution. That we need to spend some serious money researching. That's what people mean by "battery tech isn't there yet". It isn't a defeatist attitude, it is a "continuing and doubling down on research is an important part of the equation" type of attitude. This is typically because that kind of research isn't done by the private sector, but rather government. DOE does a lot of this funding, and even funds a lot of the research being done in the private sector. So being vocal about this means we care and hopefully those in control of allocating that money (probably not by Rick Perry) will spend more on fixing that part of the equation while the private sector does the building out part.
  - sfifs 7y ago
    There's significant power loss in transmission on grid and to avoid power loss, you need fairly expensive equipment to convert to and from high voltage. If you are adding wind to the mix and working on an AC grid as normal, phase sync is also tricky. Electricity supply on grid has to be very closely matched to demand and the problem will likely become fairly complex with lots variable sources. A lot of problems potentially go away if you push renewable to significant battery storage first and you also get a much more resilient grid to natural disasters (see Puerto Rico's situation)
    - godelski 7y ago
      For an interesting graphic along these lines see [0]. The parent of this comment is talking about increasing the efficiency (reducing rejected energy) and the gp is talking about just increasing the total amount of energy. Both are solutions. But I wouldn't say it is a good thing we reject more than half the energy we create. [0] https://flowcharts.llnl.gov/content/assets/images/energy/us/Energy_US_2018.png https://flowcharts.llnl.gov/content/assets/images/energy/us/...
      - sfifs 7y ago
        As an addendum - explanation of the electricity distribution losses on grid: https://electrical-engineering-portal.com/total-losses-in-power-distribution-and-transmission-lines-1 https://electrical-engineering-portal.com/total-losses-in-po...
        godelski 7y ago
        Because there's confusion I'm adding an addendum to the addendum. Here's an LLNL scientist explaining the graph. Which he does talk about the rejected energy [0] [0] https://www.youtube.com/watch?v=G6dlvECRfcI https://www.youtube.com/watch?v=G6dlvECRfcI
      - strainer 7y ago
        > But I wouldn't say it is a good thing we reject more than half the energy we create. The meaning of "Rejected Energy" in that graphic is obscure but it certainly doesn't relate to energy which has been created and rejected. It may relate to excess capacity of fossil fuel plants (how much more they could produce if ordered to burn more fuel). The US is thankfully not "rejecting" twice as much energy as it is producing as those figures of 68.5 vs 32.7 lead you to believe. Curtailment of wind and solar generation in the US is recently around 2-4% [1] https://blog.ucsusa.org/mark-specht/renewable-energy-curtailment-101 https://blog.ucsusa.org/mark-specht/renewable-energy-curtail...
  - greglindahl 7y ago
    The battery business is a great idea today for grid stabilization, is getting there for peak demand shaving for customers, and the cost is falling.
  - rickycook 7y ago
    from what i understand (and i could be wrong), you could make biofuels using atmospheric co2, alguae, heat from the grid during low demand... when you burn it, it releases that co2, but when you’re not it acts as a big carbon sink could be totally off base, or very much a “not yet industrialised” process... but the idea is super cool none the less
    - imtringued 7y ago
      The efficiency is too low for day to day storage but for month to month storage it might work.
- cortesoft 7y ago
  Or other forms of energy storage.
ben_w 7y ago
Your own link says that about 6% of the UK has been built over; although I am unclear exactly what that means [1], this is an achievable level. Of course, I would still agree that it’s good to have a mixture, for example the British Isles have a lot wind power (I’ve heard, but can’t find a reference for the claim, that it could supply most of the European continent). [1] the percentage sounds high enough that I assume it includes all gardens and roads not just the buildings themselves
- goodcanadian 7y ago
  Here's a good link for you: http://gridwatch.co.uk/ http://gridwatch.co.uk/ It shows current UK grid demand and generation sources as well as historical data.
  - ben_w 7y ago
    Thank you, though — while interesting — that doesn’t tell me how much wind power the British Isles could produce if UK and Ireland built the wind farms necessary to exploit it.
    - deleted 7y ago
      [deleted]
llukas 7y ago
Methodology is flawed. If you switch from burning oil in ice engines to electric you use at least 50% total energy less. So they overestimate area needed.
- gtirloni 7y ago
  What's that due to? Less energy lost to dissipation?
  - Gibbon1 7y ago
    Thermodynamic cycles and engineering constraints. ICE engines are about 30% efficient at best. Operationally they're usually a lot worse. Where modern combined cycle power plants are pushing towards 60%. A big part of the difference is that stationary plants use multiple stages to wring the last bit of energy out of the fuel. Where piston engines use one stage. They also suffer from mechanical and thermal losses due to their small size. Small size means higher internal surface area to volume and higher operating speeds. Contributes to higher friction and thermal losses. Friction in an ICE is actually significant.
  - llukas 7y ago
    Carnot cycle limiting maximum ICE efficiency to ~40% (can be obtained if you're big electric power plant) vs 95% electric engine efficiency. For practical purposes, ICE has way lower efficiency than 40% and electrics lose some due to the transmission and battery recharge.
  - Robotbeat 7y ago
    For the same kind of reason solar panels only access about 15-20% of the energy that hits them.
    - Robotbeat 7y ago
      I was serious. Solar cells are like solid state heat engines in that they’re fundamentally limited by Carnot Efficiency (which is theoretically high for solar cells as the effective temperature of sunlight is high). If we’re going to use “primary energy” and not useful electrical or mechanical energy, then we’d need to include the energy of sunlight falling on the solar panels, which is about 5 times the useful electrical energy produced. And just like actual heat engines, solar cells are improving. The best cells have achieved 47% efficiency in the lab, comparable to a high performance combined cycle natural gas plant (note that thermal power plants often cheat a bit by listing the efficiency in terms of the low heating value of a fuel, ie the heat produced not counting condensing the water vapor out).
NeedMoreTea 7y ago
UK would do best supplementing wind with solar, rather than going wholly solar. UK is famous for many things, consistent reliable sun isn't one of them. Maybe in 20 years we'll have a more Spanish climate, though I would hope not. Adding solar on every roof that's suitable should be plenty for starters. There's probably dozens of spots around the UK suitable for Dinorwig 10 GWh pumped storage style solutions. NIMBYs permitting. If the UK fully built out offshore wind it would probably have enough to power the whole of Europe. Same goes for Ireland.
- roryisok 7y ago
  Actually the estimates are that the Irish coast alone has enough potential wind energy to power all of the planet, during peak seasonal wind, and at least all of Europe during the less windy summer season. Building the infrastructure to transmit that power would be a massive undertaking though. Ireland and France are currently cooperating to build an undersea power cable which is going to cost $1Bn, take 5 years, run 575km and have an annual transmission capacity of 6.1 TWh. Annual global energy usage in 2013 was 19,504 TWh, or 3,197 times that.
GlennS 7y ago
Here is a source which says otherwise, and includes references: https://withouthotair.com/c18/page_103.shtml https://withouthotair.com/c18/page_103.shtml Warning this book is quite old now. While the discussion of theoretical limits should probably still hold up, all the economics has been turned upside down since then. Solar and wind costs dropped faster and further than most people's best case estimates, while nuclear costs and timescales just keep going up.
imtringued 7y ago
The problem with solar isn't that it isn't power dense. The problem is that the capacity factor compared to something like wind energy is very low. I'm skeptical of that 10% area claim. They probably made a very basic mistake of replacing all chemical energy with the electricity generated by solar power plants. This completely ignores that we can only turn that chemical energy into heat and then have to convert it to electricity. Depending on the size of the engine the efficiency of this step can range from anywhere between 25% to 50%. So you need 2 to 4 times more primary energy than if your power source generated electricity from the start. Take a look at this chart [0]. As you can see, renewables produce barely any primary energy at all with the exception of biomass, because they don't need to. [1] If we really did increase our renewable deployment 8 fold then Germany would be at 400% renewables at current consumption rates which clearly isn't necessary even if every single car is electric and all industry switched away from fossil fuels. There will still be some processes that depend on fossil fuels as input material but those do not burn the fuels to obtain their energy. Oil products like plastic will most likely dumped in the oce- I mean in landfills. [0] https://www.cleanenergywire.org/sites/default/files/styles/paragraph_text_image/public/paragraphs/images/fig10-germany-energy-mix-energy-sources-share-primary-energy-consumption-2018.png?itok=DHJj3zQy https://www.cleanenergywire.org/sites/default/files/styles/p... [1] https://www.cleanenergywire.org/sites/default/files/styles/paragraph_text_image/public/fig1_installed_net_power_generation_capacity_in_germany_2002_2018.png?itok=dpkm8Ja9 https://www.cleanenergywire.org/sites/default/files/styles/p...

godelski 7y ago

We also need batteries. But that's why solar is only part of the solution. No single source will solve all the problems in all the areas. I'm a big proponent of nuclear but it's only part. Solar is also what I want to see. But more than the other two I want batteries.

plufz 7y ago
From what I heard from people in the solar business battery is generally not a good idea. Better to invest in a good grid where we can transfer electricity from one place to another (there’s always windy somewhere). And have some sort of backup power plants on the lowest days (like natural gas, biofuel, etc, not co2 free but they wouldn’t be used very often from what I understand). Or alternative “batteries” like pumping up a lot of water in some dam.
- Gibbon1 7y ago
  I like to point out the efficiency gains and load shifting will also reduce off peek demand somewhat. Industrial users will chase lowest cost if possible. If electricity costs 3X at 1am the price at 11am, no ones going to be running an electric furnace at 1am. Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. So it's slightly pointless argue as some do that lack of current solutions is a reason not to move forward with renewables. Worst comes to worst we already have peaking plants that could substitute for baseload power.
  - deleted 7y ago
    [deleted]
  - godelski 7y ago
    I think there's miscommunication. > lack of current solutions is a reason not to move forward with renewables No one is saying we shouldn't move forward with renewables. Well maybe a certain canine news network, but not anyone here. > Either way I'm actually rather confident that the whole storage thing is more or less solvable. Since there are a host of technologies that are workable. What people are saying is there isn't good enough technology yet. So that means that we need to continue funding research. Not being solved means that just building won't be the solution. That we need to spend some serious money researching. That's what people mean by "battery tech isn't there yet". It isn't a defeatist attitude, it is a "continuing and doubling down on research is an important part of the equation" type of attitude. This is typically because that kind of research isn't done by the private sector, but rather government. DOE does a lot of this funding, and even funds a lot of the research being done in the private sector. So being vocal about this means we care and hopefully those in control of allocating that money (probably not by Rick Perry) will spend more on fixing that part of the equation while the private sector does the building out part.
- sfifs 7y ago
  There's significant power loss in transmission on grid and to avoid power loss, you need fairly expensive equipment to convert to and from high voltage. If you are adding wind to the mix and working on an AC grid as normal, phase sync is also tricky. Electricity supply on grid has to be very closely matched to demand and the problem will likely become fairly complex with lots variable sources. A lot of problems potentially go away if you push renewable to significant battery storage first and you also get a much more resilient grid to natural disasters (see Puerto Rico's situation)
  - godelski 7y ago
    For an interesting graphic along these lines see [0]. The parent of this comment is talking about increasing the efficiency (reducing rejected energy) and the gp is talking about just increasing the total amount of energy. Both are solutions. But I wouldn't say it is a good thing we reject more than half the energy we create. [0] https://flowcharts.llnl.gov/content/assets/images/energy/us/Energy_US_2018.png https://flowcharts.llnl.gov/content/assets/images/energy/us/...
    - sfifs 7y ago
      As an addendum - explanation of the electricity distribution losses on grid: https://electrical-engineering-portal.com/total-losses-in-power-distribution-and-transmission-lines-1 https://electrical-engineering-portal.com/total-losses-in-po...
      - godelski 7y ago
        Because there's confusion I'm adding an addendum to the addendum. Here's an LLNL scientist explaining the graph. Which he does talk about the rejected energy [0] [0] https://www.youtube.com/watch?v=G6dlvECRfcI https://www.youtube.com/watch?v=G6dlvECRfcI
    - strainer 7y ago
      > But I wouldn't say it is a good thing we reject more than half the energy we create. The meaning of "Rejected Energy" in that graphic is obscure but it certainly doesn't relate to energy which has been created and rejected. It may relate to excess capacity of fossil fuel plants (how much more they could produce if ordered to burn more fuel). The US is thankfully not "rejecting" twice as much energy as it is producing as those figures of 68.5 vs 32.7 lead you to believe. Curtailment of wind and solar generation in the US is recently around 2-4% [1] https://blog.ucsusa.org/mark-specht/renewable-energy-curtailment-101 https://blog.ucsusa.org/mark-specht/renewable-energy-curtail...
- greglindahl 7y ago
  The battery business is a great idea today for grid stabilization, is getting there for peak demand shaving for customers, and the cost is falling.
- rickycook 7y ago
  from what i understand (and i could be wrong), you could make biofuels using atmospheric co2, alguae, heat from the grid during low demand... when you burn it, it releases that co2, but when you’re not it acts as a big carbon sink could be totally off base, or very much a “not yet industrialised” process... but the idea is super cool none the less
  - imtringued 7y ago
    The efficiency is too low for day to day storage but for month to month storage it might work.
cortesoft 7y ago
Or other forms of energy storage.

ben_w 7y ago

Your own link says that about 6% of the UK has been built over; although I am unclear exactly what that means [1], this is an achievable level. Of course, I would still agree that it’s good to have a mixture, for example the British Isles have a lot wind power (I’ve heard, but can’t find a reference for the claim, that it could supply most of the European continent). [1] the percentage sounds high enough that I assume it includes all gardens and roads not just the buildings themselves

goodcanadian 7y ago
Here's a good link for you: http://gridwatch.co.uk/ http://gridwatch.co.uk/ It shows current UK grid demand and generation sources as well as historical data.
- ben_w 7y ago
  Thank you, though — while interesting — that doesn’t tell me how much wind power the British Isles could produce if UK and Ireland built the wind farms necessary to exploit it.
  - deleted 7y ago
    [deleted]

llukas 7y ago

Methodology is flawed. If you switch from burning oil in ice engines to electric you use at least 50% total energy less. So they overestimate area needed.

gtirloni 7y ago
What's that due to? Less energy lost to dissipation?
- Gibbon1 7y ago
  Thermodynamic cycles and engineering constraints. ICE engines are about 30% efficient at best. Operationally they're usually a lot worse. Where modern combined cycle power plants are pushing towards 60%. A big part of the difference is that stationary plants use multiple stages to wring the last bit of energy out of the fuel. Where piston engines use one stage. They also suffer from mechanical and thermal losses due to their small size. Small size means higher internal surface area to volume and higher operating speeds. Contributes to higher friction and thermal losses. Friction in an ICE is actually significant.
- llukas 7y ago
  Carnot cycle limiting maximum ICE efficiency to ~40% (can be obtained if you're big electric power plant) vs 95% electric engine efficiency. For practical purposes, ICE has way lower efficiency than 40% and electrics lose some due to the transmission and battery recharge.
- Robotbeat 7y ago
  For the same kind of reason solar panels only access about 15-20% of the energy that hits them.
  - Robotbeat 7y ago
    I was serious. Solar cells are like solid state heat engines in that they’re fundamentally limited by Carnot Efficiency (which is theoretically high for solar cells as the effective temperature of sunlight is high). If we’re going to use “primary energy” and not useful electrical or mechanical energy, then we’d need to include the energy of sunlight falling on the solar panels, which is about 5 times the useful electrical energy produced. And just like actual heat engines, solar cells are improving. The best cells have achieved 47% efficiency in the lab, comparable to a high performance combined cycle natural gas plant (note that thermal power plants often cheat a bit by listing the efficiency in terms of the low heating value of a fuel, ie the heat produced not counting condensing the water vapor out).

NeedMoreTea 7y ago

UK would do best supplementing wind with solar, rather than going wholly solar. UK is famous for many things, consistent reliable sun isn't one of them. Maybe in 20 years we'll have a more Spanish climate, though I would hope not. Adding solar on every roof that's suitable should be plenty for starters. There's probably dozens of spots around the UK suitable for Dinorwig 10 GWh pumped storage style solutions. NIMBYs permitting. If the UK fully built out offshore wind it would probably have enough to power the whole of Europe. Same goes for Ireland.

roryisok 7y ago
Actually the estimates are that the Irish coast alone has enough potential wind energy to power all of the planet, during peak seasonal wind, and at least all of Europe during the less windy summer season. Building the infrastructure to transmit that power would be a massive undertaking though. Ireland and France are currently cooperating to build an undersea power cable which is going to cost $1Bn, take 5 years, run 575km and have an annual transmission capacity of 6.1 TWh. Annual global energy usage in 2013 was 19,504 TWh, or 3,197 times that.

GlennS 7y ago

Here is a source which says otherwise, and includes references: https://withouthotair.com/c18/page_103.shtml https://withouthotair.com/c18/page_103.shtml Warning this book is quite old now. While the discussion of theoretical limits should probably still hold up, all the economics has been turned upside down since then. Solar and wind costs dropped faster and further than most people's best case estimates, while nuclear costs and timescales just keep going up.

imtringued 7y ago

The problem with solar isn't that it isn't power dense. The problem is that the capacity factor compared to something like wind energy is very low. I'm skeptical of that 10% area claim. They probably made a very basic mistake of replacing all chemical energy with the electricity generated by solar power plants. This completely ignores that we can only turn that chemical energy into heat and then have to convert it to electricity. Depending on the size of the engine the efficiency of this step can range from anywhere between 25% to 50%. So you need 2 to 4 times more primary energy than if your power source generated electricity from the start. Take a look at this chart [0]. As you can see, renewables produce barely any primary energy at all with the exception of biomass, because they don't need to. [1] If we really did increase our renewable deployment 8 fold then Germany would be at 400% renewables at current consumption rates which clearly isn't necessary even if every single car is electric and all industry switched away from fossil fuels. There will still be some processes that depend on fossil fuels as input material but those do not burn the fuels to obtain their energy. Oil products like plastic will most likely dumped in the oce- I mean in landfills. [0] https://www.cleanenergywire.org/sites/default/files/styles/paragraph_text_image/public/paragraphs/images/fig10-germany-energy-mix-energy-sources-share-primary-energy-consumption-2018.png?itok=DHJj3zQy https://www.cleanenergywire.org/sites/default/files/styles/p... [1] https://www.cleanenergywire.org/sites/default/files/styles/paragraph_text_image/public/fig1_installed_net_power_generation_capacity_in_germany_2002_2018.png?itok=dpkm8Ja9 https://www.cleanenergywire.org/sites/default/files/styles/p...