It's probably academic, but if natural gas is that cheap, then I wonder about more thermodynamically-efficient uses of it.
The classic thing is cogeneration. It's a thermodynamic sin to create a large temperature difference (say, furnace combustion chamber vs. house) without running that heat through a heat engine. In the Nordic countries, in parts of Russia, and on some university campuses in the US, that's done with a "neighborhood power plant" and district heating (steam pipes). Heat engines get less efficient as they get smaller, but possibly a house-scale cogeneration setup could still make sense?
But I'm also now curious about something more interesting: In the same way that you can have, say, a propane powered refrigerator, is it also possible to have a natural gas powered heat pump? Suppose it's a cold winter day, and you're burning natural gas in a combustion chamber in an appliance in your basement. There are three temperature reservoirs: The outdoors, the house, and the combustion chamber, at temperatures T1 < T2 < T3, respectively. By harnessing heat flow (Q32) from the combustion chamber into the house, can additional heat (Q12) be pumped from the outdoors into the house? Then the house will get a total flow Q = Q32 + Q12.
From Q32, work
W = (1 - T2/T3) * Q32
is available. That can then be used to pump
Q12 = 1 / (1 - T1/T2) * W
= ((1 - T2/T3) / (1 - T1/T2)) * Q32
additional heat. And thus
Q = Q32 + Q12
= (1 + (1 - T2/T3) / (1 - T1/T2)) * Q32
= B(T1, T2, T3) * Q32 .
Here, B (a function of T1, T2, T3) is the coefficient by which the natural gas' energy is effectively multiplied, for heating purposes.
so letting T3 = 1,700 C = 1973.15 K, we get the slightly lower B(T1, T2, T3) = 6.58.
This is still fantastic.
This is also assuming a very cold day, which is when the system will have lower efficiency. If we instead assume T1 = 0 C = 273.15 K, and use the more conservative T3 = 1973.15 K assumption, then we get B(T1, T2, T3) = 12.4. That's huge.
So, assuming my math/modeling is right, a hypothetical heat-pump furnace could (using Carnot bounds) use around 1/6th - 1/12th the natural gas as a conventional one, even in a very cold place, if you keep all the other properties of the house (insulation, air exchange) constant.
The classic thing is cogeneration. It's a thermodynamic sin to create a large temperature difference (say, furnace combustion chamber vs. house) without running that heat through a heat engine. In the Nordic countries, in parts of Russia, and on some university campuses in the US, that's done with a "neighborhood power plant" and district heating (steam pipes). Heat engines get less efficient as they get smaller, but possibly a house-scale cogeneration setup could still make sense?
But I'm also now curious about something more interesting: In the same way that you can have, say, a propane powered refrigerator, is it also possible to have a natural gas powered heat pump? Suppose it's a cold winter day, and you're burning natural gas in a combustion chamber in an appliance in your basement. There are three temperature reservoirs: The outdoors, the house, and the combustion chamber, at temperatures T1 < T2 < T3, respectively. By harnessing heat flow (Q32) from the combustion chamber into the house, can additional heat (Q12) be pumped from the outdoors into the house? Then the house will get a total flow Q = Q32 + Q12.
From Q32, work
W = (1 - T2/T3) * Q32
is available. That can then be used to pump
Q12 = 1 / (1 - T1/T2) * W
= ((1 - T2/T3) / (1 - T1/T2)) * Q32
additional heat. And thus
Q = Q32 + Q12
= (1 + (1 - T2/T3) / (1 - T1/T2)) * Q32
= B(T1, T2, T3) * Q32 .
Here, B (a function of T1, T2, T3) is the coefficient by which the natural gas' energy is effectively multiplied, for heating purposes.