9 ms·

Power supply already doesn't follow demand. Large scale power plants (coal, nuclear, even gas to some extent) run at a very steady output. It's a big system to

Power supply already doesn't follow demand. Large scale power plants (coal, nuclear, even gas to some extent) run at a very steady output. It's a big system to get started & stopped, you need to get every part of the system to the proper temperature for quality steam, there are a bunch of lossy startup processes, etc. You can't just throttle them up and down at will. The timeline is longer than a day for most of them. Because of that they sell electricity at a discount at night. Large industrial users will schedule their entire operations around this. For example ski mountains do their snowmaking at night because the power is the greatest expense (even more than labor) and the discount is enormous. I also believe that aluminum and steel foundries do some form of this. The renewables change this dynamic a bit, but there are many loads that can be time shifted. I could imagine an electric car connected to the internet and plugged in all night at home and all day at work could optimize its charging cycle to match the lowest energy prices of the day. Of course this requires major changes to metering and billing, but there is no technical reason why it couldn't happen, it is all a business and infrastructure problem.

bjz_ 12y ago
> Large scale power plants (coal, nuclear, even gas to some extent) run at a very steady output I wonder if we could do the same with legacy power plants as they do with solar thermal - shove some of the excess heat into molten salt heat storage when renewables are reaching their maximum output, then use that as a finer throttling mechanism. That would mean you wouldn't have to run the coal plants as heavily non-stop. It could buy us some time as we figure out how best to store the energy from photovoltaics and wind (it's pretty much solved for solar thermal).
- thrownaway2424 12y ago
  Isn't it solved for any prime generator, by way of hydroelectric storage? It's quite efficient and hills are common.
  - jimmcslim 12y ago
    Hills might be common, but suitable geography for creating a dam out of them is probably less so. Not to mention that such geography frequently tends to cover farmland and rural communities who are less than likely to want their land flooded.. they may also tend to vote on the conservative-side of the spectrum which cares less for renewable generation such as hydro. The construction cost of dams isn't insignificant either!
    - markvdb 12y ago
      In Japan, and soon in Belgium too, "energy islands" are built in the sea to store wind energy. http://rt.com/news/belgium-battery-island-renewable-319/ http://rt.com/news/belgium-battery-island-renewable-319/ (P.S. I couldn't immediately find any more reputable English speaking news source for this. Oh well, on this sort of fairly neutral subject, rt.con seem to do quite well.)
  - deleted 12y ago
    [deleted]
  - hellgas00 12y ago
    It just takes a lot of water and space to make any meaningful dent in the power supply. There are hydroelectric storage facilities near Niagara falls but they produce something like 50MW for a very limited time. If you take for instance an elevation of 100m, to produce 1000MW of electricity it would take about 1000m^3 of water per second (before losses). In other words a pipe of a diameter of 6ft would need to need to move 20.8ft of water through it per second, which would be enough water to fill an Olympic sized swimming pool in about 2.5sec. That's 5760 pools for 4hrs of 1000MWh of electricity, not an insignificant amount of space.
    - thrownaway2424 12y ago
      I think you should read up. There are multiple such facilities in the US with power over 1GW and capacity of several hours. They were built decades ago with decades-ago technology.
jessaustin 12y ago
...ski mountains do their snowmaking at night because the power is the greatest expense... Well, also, it's usually colder at night, which also helps the snowmaking. b^)
- wiredfool 12y ago
  And their paying users are more likely to be on the slopes in the daytime. Snow guns are loud and unpleasant to be around.
crdoconnor 12y ago
>Of course this requires major changes to metering and billing, but there is no technical reason why it couldn't happen, it is all a business and infrastructure problem. It is mainly a political problem. Utilities want you to be their customers not suppliers - if you're a supplier you're destroying their profit margins. Thus any attempt to upgrade metering and billing capabilities of the system and to let households sell surplus electricity at a fair spot price will be met with resistance from the monopoly-utilities.
- vidarh 12y ago
  It doesn't even need to change to allow fair price sales. Just spot priced supply and a way to easily get the current price would allow a lot of optimisation. E.g. consider a washer-dryer or dishwasher with a "wash within X hours, or at predicted best price point" option. Most of the time I don't care when it runs when I put something in at the evening, just that it's done before I'm home from work the following day. Or aforementioned electric car with a similar option. Or water heaters with a storage tank and logic to optimise heating. Or a data centre that tries to optimise air con settings depending on predicted cost (e.g. pushing temperatures down further than necessary when the power is cheaper to allow running at lower power for a period when power is more expensive while the temperature rises again). With access to spot priced supply, there'd potentially be a massive market for adding intelligence to various devices where part of the energy usage could be time shifted.
  - crdoconnor 12y ago
    You can basically do this already. Generally your electric bill will have fixed prices throughout the day. Spot price for retail doesn't fluctuate (as far as I'm aware). It'll get more expensive during mid-summer at certain times of day, but you'll know when.

bjz_ 12y ago

> Large scale power plants (coal, nuclear, even gas to some extent) run at a very steady output I wonder if we could do the same with legacy power plants as they do with solar thermal - shove some of the excess heat into molten salt heat storage when renewables are reaching their maximum output, then use that as a finer throttling mechanism. That would mean you wouldn't have to run the coal plants as heavily non-stop. It could buy us some time as we figure out how best to store the energy from photovoltaics and wind (it's pretty much solved for solar thermal).

thrownaway2424 12y ago
Isn't it solved for any prime generator, by way of hydroelectric storage? It's quite efficient and hills are common.
- jimmcslim 12y ago
  Hills might be common, but suitable geography for creating a dam out of them is probably less so. Not to mention that such geography frequently tends to cover farmland and rural communities who are less than likely to want their land flooded.. they may also tend to vote on the conservative-side of the spectrum which cares less for renewable generation such as hydro. The construction cost of dams isn't insignificant either!
  - markvdb 12y ago
    In Japan, and soon in Belgium too, "energy islands" are built in the sea to store wind energy. http://rt.com/news/belgium-battery-island-renewable-319/ http://rt.com/news/belgium-battery-island-renewable-319/ (P.S. I couldn't immediately find any more reputable English speaking news source for this. Oh well, on this sort of fairly neutral subject, rt.con seem to do quite well.)
- deleted 12y ago
  [deleted]
- hellgas00 12y ago
  It just takes a lot of water and space to make any meaningful dent in the power supply. There are hydroelectric storage facilities near Niagara falls but they produce something like 50MW for a very limited time. If you take for instance an elevation of 100m, to produce 1000MW of electricity it would take about 1000m^3 of water per second (before losses). In other words a pipe of a diameter of 6ft would need to need to move 20.8ft of water through it per second, which would be enough water to fill an Olympic sized swimming pool in about 2.5sec. That's 5760 pools for 4hrs of 1000MWh of electricity, not an insignificant amount of space.
  - thrownaway2424 12y ago
    I think you should read up. There are multiple such facilities in the US with power over 1GW and capacity of several hours. They were built decades ago with decades-ago technology.

jessaustin 12y ago

...ski mountains do their snowmaking at night because the power is the greatest expense... Well, also, it's usually colder at night, which also helps the snowmaking. b^)

wiredfool 12y ago
And their paying users are more likely to be on the slopes in the daytime. Snow guns are loud and unpleasant to be around.

crdoconnor 12y ago

>Of course this requires major changes to metering and billing, but there is no technical reason why it couldn't happen, it is all a business and infrastructure problem. It is mainly a political problem. Utilities want you to be their customers not suppliers - if you're a supplier you're destroying their profit margins. Thus any attempt to upgrade metering and billing capabilities of the system and to let households sell surplus electricity at a fair spot price will be met with resistance from the monopoly-utilities.

vidarh 12y ago
It doesn't even need to change to allow fair price sales. Just spot priced supply and a way to easily get the current price would allow a lot of optimisation. E.g. consider a washer-dryer or dishwasher with a "wash within X hours, or at predicted best price point" option. Most of the time I don't care when it runs when I put something in at the evening, just that it's done before I'm home from work the following day. Or aforementioned electric car with a similar option. Or water heaters with a storage tank and logic to optimise heating. Or a data centre that tries to optimise air con settings depending on predicted cost (e.g. pushing temperatures down further than necessary when the power is cheaper to allow running at lower power for a period when power is more expensive while the temperature rises again). With access to spot priced supply, there'd potentially be a massive market for adding intelligence to various devices where part of the energy usage could be time shifted.
- crdoconnor 12y ago
  You can basically do this already. Generally your electric bill will have fixed prices throughout the day. Spot price for retail doesn't fluctuate (as far as I'm aware). It'll get more expensive during mid-summer at certain times of day, but you'll know when.