No, I'm not talking about net metering, which has nothing to do with the cost per peak watt.
You're right that you do need energy storage, though. Even sensible-heat thermal energy storage is completely adequate for this purpose, and it's very cheap, on the order of US$2–3/kWh. See the sand-battery outline I wrote yesterday in https://news.ycombinator.com/item?id=45690085. Electric night storage heaters are widely available off the shelf in many countries already, though not in the US.
For some other kinds of energy storage, it's debatable whether utility-scale storage or household-scale storage is more efficient; you're trading off economies of scale against transmission and distribution losses and transaction costs. But low-grade thermal energy storage is clearly better at household or neighborhood scale; my design outline linked above comes to a price per kWh that's 3% of the price of the batteries needed for BESS, and maybe 15% of the optimistic cost estimates for sodium-ion. You have to reduce the energy to low-grade heat up front to store it so cheaply, but that makes it hard to redistribute later—to redistribute low-grade stored heat from a central energy storage facility, you need something like New York's steam district heating systems. It's far cheaper to store the thermal energy at the point of use.
This is not a new idea. It's the idea behind adobe walls, Russian stoves, rocket mass heaters, electric night storage heaters, dol beds, kachelofens, kangs, earth-bermed walls, Trombe walls, and ondols. People have been doing this for 7000 years, without an electrical grid or, for that matter, electrical power at all. It definitely doesn't rely on net metering!
This looks like something that needs to be done before the house is built, under the foundation / slab? Or did I read it incorrectly? Either way, I had to really push on my contractor just to do a heat pump. (And there are two large areas of sand under my house, one under my garage and the other under my sunroom.) I don't know how I could get someone to build that where I live.
I also couldn't tell if this is something that warms up throughout the year, or if this is something that warms up during the day and cools at night? Where I live, the days are very short in December / January, so I'm not sure if would work if it's day-to-day instead of seasonal.
You're right that you do need energy storage, though. Even sensible-heat thermal energy storage is completely adequate for this purpose, and it's very cheap, on the order of US$2–3/kWh. See the sand-battery outline I wrote yesterday in https://news.ycombinator.com/item?id=45690085. Electric night storage heaters are widely available off the shelf in many countries already, though not in the US.
For some other kinds of energy storage, it's debatable whether utility-scale storage or household-scale storage is more efficient; you're trading off economies of scale against transmission and distribution losses and transaction costs. But low-grade thermal energy storage is clearly better at household or neighborhood scale; my design outline linked above comes to a price per kWh that's 3% of the price of the batteries needed for BESS, and maybe 15% of the optimistic cost estimates for sodium-ion. You have to reduce the energy to low-grade heat up front to store it so cheaply, but that makes it hard to redistribute later—to redistribute low-grade stored heat from a central energy storage facility, you need something like New York's steam district heating systems. It's far cheaper to store the thermal energy at the point of use.
This is not a new idea. It's the idea behind adobe walls, Russian stoves, rocket mass heaters, electric night storage heaters, dol beds, kachelofens, kangs, earth-bermed walls, Trombe walls, and ondols. People have been doing this for 7000 years, without an electrical grid or, for that matter, electrical power at all. It definitely doesn't rely on net metering!