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> Unlike solar or wind or even a battery system of any reasonable size, it can be run when needed and turned off when needed Wind is available at night. Solar

> Unlike solar or wind or even a battery system of any reasonable size, it can be run when needed and turned off when needed Wind is available at night. Solar + battery is available whenever. Battery storage can replace gas peaker plants > keep everything working reliably under adverse conditions What adverse conditions are you imagining? > So surely the article should talk about the economics (to the grid operator and to the rate-payers) Are renewables + storage not cheaper than gas plants? > shiny new heat pump in a place that can get very cold https://www.wired.com/story/myth-heat-pumps-cold-weather-freezing-subzero/ https://www.wired.com/story/myth-heat-pumps-cold-weather-fre...

amluto 2y ago
>> shiny new heat pump in a place that can get very cold > https://www.wired.com/story/https://www.wired.com/story/myth-heat-pumps-cold-weather-freezing-subzero/ https://www.wired.com/story/https://www.wired.com/story/myth... Which doesn't invalidate the point. If the desired indoor-outdoor temperature difference doubles (say 68F indoors, 30F outdoors changes to 68F indoors, -8F outdoors), then a gas furnace uses gas at about twice the rate (as the heat loss in a house is roughly proportional to temperature difference). And natural gas is easy to store. But a heat pump needs twice the output and its COP drops, so maybe you need 3-4x as much electric power, and electric power is not easy to store. But you can still store gas, and you can connect a peaker plant to the grid, and it all works out, and you might not even need to run that peaker plant very much.
- nielsbot 2y ago
  What’s so important about ease of storage? You worried the solar + battery grid will suddenly fail? You know what else connects to the grid? Renewables and storage. Confused by your reply.
  - amluto 2y ago
    The grid needs several nines of reliability even on that cold night, and more nines are needed in places where extreme cold weather happens and people use electric heat. To achieve any reliability at all, there needs to be enough capacity for these extreme temperature events. With heat pumps, on a cold night, 3-4x normal usage from all the heat pumps is possible, even likely. Maybe worse in places that get really cold and push the limits of the heat pumps (where COP can get quite close to 1). So the grid needs overprovisioned capacity. One could hook up a lot of renewables, a lot of storage and a lot of inverter capacity to that storage, which is expensive. But this is expensive: batteries are approaching reasonable prices if the get used heavily, but there aren’t extra-cheap batteries for systems that only get used on rare occasions. But there are extra cheap power plants that make economic sense even if rarely used: these are peaker plants. Yes, it would be nice to have a non-emitting peaker plant, and someone will surely figure this out eventually. But it wouldn’t be shocking if the eventual solution is an ordinary methane-fired plant (or maybe methanol?) where the fuel is synthetic. After all, even with renewable sources, if you actually want to store a whole lot of energy, chemical storage is pretty effective.

amluto 2y ago

>> shiny new heat pump in a place that can get very cold > https://www.wired.com/story/https://www.wired.com/story/myth-heat-pumps-cold-weather-freezing-subzero/ https://www.wired.com/story/https://www.wired.com/story/myth... Which doesn't invalidate the point. If the desired indoor-outdoor temperature difference doubles (say 68F indoors, 30F outdoors changes to 68F indoors, -8F outdoors), then a gas furnace uses gas at about twice the rate (as the heat loss in a house is roughly proportional to temperature difference). And natural gas is easy to store. But a heat pump needs twice the output and its COP drops, so maybe you need 3-4x as much electric power, and electric power is not easy to store. But you can still store gas, and you can connect a peaker plant to the grid, and it all works out, and you might not even need to run that peaker plant very much.

nielsbot 2y ago
What’s so important about ease of storage? You worried the solar + battery grid will suddenly fail? You know what else connects to the grid? Renewables and storage. Confused by your reply.
- amluto 2y ago
  The grid needs several nines of reliability even on that cold night, and more nines are needed in places where extreme cold weather happens and people use electric heat. To achieve any reliability at all, there needs to be enough capacity for these extreme temperature events. With heat pumps, on a cold night, 3-4x normal usage from all the heat pumps is possible, even likely. Maybe worse in places that get really cold and push the limits of the heat pumps (where COP can get quite close to 1). So the grid needs overprovisioned capacity. One could hook up a lot of renewables, a lot of storage and a lot of inverter capacity to that storage, which is expensive. But this is expensive: batteries are approaching reasonable prices if the get used heavily, but there aren’t extra-cheap batteries for systems that only get used on rare occasions. But there are extra cheap power plants that make economic sense even if rarely used: these are peaker plants. Yes, it would be nice to have a non-emitting peaker plant, and someone will surely figure this out eventually. But it wouldn’t be shocking if the eventual solution is an ordinary methane-fired plant (or maybe methanol?) where the fuel is synthetic. After all, even with renewable sources, if you actually want to store a whole lot of energy, chemical storage is pretty effective.