4 ms·

So the thing about the earth is that it's big. If you have a big enough grid, it will be sunny and windy over a fairly consistent portion of that area.

HPsquared 5y ago
We don't have a planetary grid (yet, at least). If there's a high pressure system across Europe, the whole continent can have low wind. This usually comes with either very high temperatures (in summer) or very low temperatures (in winter) which further stresses the system.
BenoitP 5y ago
With the current technology, you can't transport electricity more than ~1000 km with acceptable losses. Atmospheric depressions are bigger than than, and the distance for solar are much bigger as well (other than cloudy, there's day and night).
- adgjlsfhk1 5y ago
  What do you consider acceptable? https://en.wikipedia.org/wiki/High-voltage_direct_current#Advantages https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad... puts the loss for HVDC at 3.5% per 1000km. That would imply 4000km with 15% loss, which is pretty good considering that wind and solar are significantly more than 15% cheaper than nuclear. Specifically, https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#/media/File:20201019_Levelized_Cost_of_Energy_(LCOE,_Lazard)_-_renewable_energy.svg https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#... puts the cost of wind/solar at roughly 1/3rd the cost of nuclear, so it's more (cost) efficient to spend as much on transmission as you do on generation and build a really well connected massive grid than to use nuclear.
- jacquesm 5y ago
  https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current
- midjji 5y ago
  We can transport it a fair bit further than that, but only under ideal circumstances that are rarely met, and its very rare the grid is built for it, its never been needed after all. For instance, regulatory issues usually mean that every country border crossed tends to have a transformer station, which makes minor changes at a 10% or so efficiency loss.
  - diordiderot 5y ago
    Europe. Same grid. 8% losses
pzo 5y ago
transmitting energy from other half of the earth (where is daylight when you are sleeping) is probably not best idea (not sure if even economically or technically possible). Also would be wise to turn off nuclear energy once you have this 'big enough grid'.
- flor1s 5y ago
  Is day and night really the problem here? Because I thought demand usually peaks at certain times of the day (e.g. early in the evening in California: https://www.pge.com/en_US/residential/rate-plans/rate-plan-options/time-of-use-base-plan/time-of-use-plan.page#:~:text=Peak%20(highest%20price)%20%E2%80%93%205,on%20weekends%20and%20most%20holidays https://www.pge.com/en_US/residential/rate-plans/rate-plan-o...), and actually bottoms out during the night. You would mostly use an interconnected grid (and storage) to compensate for this. Also there is wind energy which doesn't care about whether the sun shines or not (actually it generates more energy when the sun isn't shining: https://www.scientificamerican.com/article/wind-power-turbine-storage-electricity-appliances/ https://www.scientificamerican.com/article/wind-power-turbin...).
  - pzo 5y ago
    In most of the Europe the biggest use of energy for family will be heating except summer. In the future probably also charging electric car. This kind of power demand you need mostly at night when sleeping - during the day you are probsbly in the office. Transmitting power also consumes energy - you cannot have a electric wire across pacific to transmit power from US to EU without transformers - electric power line is not a fiber optic that transmit just signal. I also doubt we have enough rare earth minerals to make all those magnets for wind turbine and and electric car enough for whole planet. Remember also you have to decomission those windturbine after some years which is expensive
    - flor1s 5y ago
      At least in The Netherlands we mostly use centralised (gas-powered) heating, so nuclear energy is a tangential factor. Also there seems to be room for improvement in insulation and centralised thermal storage (warmtenet in Dutch). Electric cars seem both like both a problem and an opportunity, because you could charge them while being at the office and partly use their batteries for powering your home at night (in case you don't need a full charge to get to work in the morning). Regarding rare earths, we will need them regardless of using nuclear or renewables for electric cars, so that seems partly tangential. For wind turbines their reliance on rare earths seems troublesome. It's geopolitically ironic that we (Western Europeans) get our gas from Russia and our rare earths from China.
midjji 5y ago
It does not work that way. Long distance extreme high voltage transfer loses about 5% per 1000km, with the transformers adding another 10%, under ideal circumstances. In practice its higher, and thats on land. Sea cables lose 100x per km around 50% per 100km, again under ideal circumstances. In practice double the losses per distance, and if using existing grids, double it again, because most places dont build top end voltage grids. Looking at maps for power prices with large hydropower dams you can easily see how most countries grids dont transfer more than around 1000km, and often quite a bit shorter. In practice this is the point where it becomes more cost effective to build new powerplants, than bigger infrastructure for transfer. We could build grids designed for this, but never across oceans, and we are talking about an absolutely gargantuan investment, and its generally not considered as a solution for the unreliability of solar and wind. Its also why no one ever suggests to use the big empty oceans for truly large scale wind or solar etc, its always places very close to land. Its also worth pointing out that superconductors cannot solve this, even if price and the gargantuan cooling energy requirements are ignored. This is because while superconductors transfer power without loss, they can only do so up to a limited effect, as the power interferes with the superconducting ability after that, essentially breaking it.
- diordiderot 5y ago
  So you keep 70% of electricity piped from Morocco to the UK. That sounds bloody swell. I'd pay for that in a heart beat.
  - midjji 5y ago
    The oceans kill it completely, remember two oceans of 100km reduce transfer by 0.75, and thats ignoring all the other problems with the grids on the way.
    - adgjlsfhk1 5y ago
      this is not true with hvdc http://www.diva-portal.org/smash/get/diva2:1187920/FULLTEXT01.pdf http://www.diva-portal.org/smash/get/diva2:1187920/FULLTEXT0... has an analysis showing single digit percent loss for 500km.

HPsquared 5y ago

We don't have a planetary grid (yet, at least). If there's a high pressure system across Europe, the whole continent can have low wind. This usually comes with either very high temperatures (in summer) or very low temperatures (in winter) which further stresses the system.

BenoitP 5y ago

With the current technology, you can't transport electricity more than ~1000 km with acceptable losses. Atmospheric depressions are bigger than than, and the distance for solar are much bigger as well (other than cloudy, there's day and night).

adgjlsfhk1 5y ago
What do you consider acceptable? https://en.wikipedia.org/wiki/High-voltage_direct_current#Advantages https://en.wikipedia.org/wiki/High-voltage_direct_current#Ad... puts the loss for HVDC at 3.5% per 1000km. That would imply 4000km with 15% loss, which is pretty good considering that wind and solar are significantly more than 15% cheaper than nuclear. Specifically, https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#/media/File:20201019_Levelized_Cost_of_Energy_(LCOE,_Lazard)_-_renewable_energy.svg https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#... puts the cost of wind/solar at roughly 1/3rd the cost of nuclear, so it's more (cost) efficient to spend as much on transmission as you do on generation and build a really well connected massive grid than to use nuclear.
jacquesm 5y ago
https://en.wikipedia.org/wiki/High-voltage_direct_current https://en.wikipedia.org/wiki/High-voltage_direct_current
midjji 5y ago
We can transport it a fair bit further than that, but only under ideal circumstances that are rarely met, and its very rare the grid is built for it, its never been needed after all. For instance, regulatory issues usually mean that every country border crossed tends to have a transformer station, which makes minor changes at a 10% or so efficiency loss.
- diordiderot 5y ago
  Europe. Same grid. 8% losses

pzo 5y ago

transmitting energy from other half of the earth (where is daylight when you are sleeping) is probably not best idea (not sure if even economically or technically possible). Also would be wise to turn off nuclear energy once you have this 'big enough grid'.

flor1s 5y ago
Is day and night really the problem here? Because I thought demand usually peaks at certain times of the day (e.g. early in the evening in California: https://www.pge.com/en_US/residential/rate-plans/rate-plan-options/time-of-use-base-plan/time-of-use-plan.page#:~:text=Peak%20(highest%20price)%20%E2%80%93%205,on%20weekends%20and%20most%20holidays https://www.pge.com/en_US/residential/rate-plans/rate-plan-o...), and actually bottoms out during the night. You would mostly use an interconnected grid (and storage) to compensate for this. Also there is wind energy which doesn't care about whether the sun shines or not (actually it generates more energy when the sun isn't shining: https://www.scientificamerican.com/article/wind-power-turbine-storage-electricity-appliances/ https://www.scientificamerican.com/article/wind-power-turbin...).
- pzo 5y ago
  In most of the Europe the biggest use of energy for family will be heating except summer. In the future probably also charging electric car. This kind of power demand you need mostly at night when sleeping - during the day you are probsbly in the office. Transmitting power also consumes energy - you cannot have a electric wire across pacific to transmit power from US to EU without transformers - electric power line is not a fiber optic that transmit just signal. I also doubt we have enough rare earth minerals to make all those magnets for wind turbine and and electric car enough for whole planet. Remember also you have to decomission those windturbine after some years which is expensive
  - flor1s 5y ago
    At least in The Netherlands we mostly use centralised (gas-powered) heating, so nuclear energy is a tangential factor. Also there seems to be room for improvement in insulation and centralised thermal storage (warmtenet in Dutch). Electric cars seem both like both a problem and an opportunity, because you could charge them while being at the office and partly use their batteries for powering your home at night (in case you don't need a full charge to get to work in the morning). Regarding rare earths, we will need them regardless of using nuclear or renewables for electric cars, so that seems partly tangential. For wind turbines their reliance on rare earths seems troublesome. It's geopolitically ironic that we (Western Europeans) get our gas from Russia and our rare earths from China.

midjji 5y ago

It does not work that way. Long distance extreme high voltage transfer loses about 5% per 1000km, with the transformers adding another 10%, under ideal circumstances. In practice its higher, and thats on land. Sea cables lose 100x per km around 50% per 100km, again under ideal circumstances. In practice double the losses per distance, and if using existing grids, double it again, because most places dont build top end voltage grids. Looking at maps for power prices with large hydropower dams you can easily see how most countries grids dont transfer more than around 1000km, and often quite a bit shorter. In practice this is the point where it becomes more cost effective to build new powerplants, than bigger infrastructure for transfer. We could build grids designed for this, but never across oceans, and we are talking about an absolutely gargantuan investment, and its generally not considered as a solution for the unreliability of solar and wind. Its also why no one ever suggests to use the big empty oceans for truly large scale wind or solar etc, its always places very close to land. Its also worth pointing out that superconductors cannot solve this, even if price and the gargantuan cooling energy requirements are ignored. This is because while superconductors transfer power without loss, they can only do so up to a limited effect, as the power interferes with the superconducting ability after that, essentially breaking it.

diordiderot 5y ago
So you keep 70% of electricity piped from Morocco to the UK. That sounds bloody swell. I'd pay for that in a heart beat.
- midjji 5y ago
  The oceans kill it completely, remember two oceans of 100km reduce transfer by 0.75, and thats ignoring all the other problems with the grids on the way.
  - adgjlsfhk1 5y ago
    this is not true with hvdc http://www.diva-portal.org/smash/get/diva2:1187920/FULLTEXT01.pdf http://www.diva-portal.org/smash/get/diva2:1187920/FULLTEXT0... has an analysis showing single digit percent loss for 500km.