Eli5 if electric vehicles are better for the environment than fossil fuel, why isn’t there any emphasis on heating homes with electricity rather gas or oil?
In: Physics
A simplified rule of thumb: if you convert heat to motion or electricity, you unavoidably waste about 2/3 of it: only 1/3 gets converted into useful energy. Every other common form of energy conversion is nearly 100% efficient. (These numbers aren’t exact, of course.)
A car turns heat into motion, wasting 2/3 of it as hot exhaust: only 1/3 goes to power the car. A fossil fuel power plant turns heat into electricity, wasting 2/3 of it. If the electricity is used to run an electric car (near 100% efficient) you can see the two are roughly equal. (The electric car comes out ahead because cars are a bit worse than 2/3 and power plants a bit better, and electric cars have access to carbon-free energy.)
But if heat is the goal, it’s different. Burning fuel in a home furnace releases almost 100% of its energy to heat the house. But if we turn it into electricity, 2/3 of the energy is lost at the power plant, and only 1/3 can be used in the home. What a waste!!! This is why electric resistance heat is so expensive.
Where it gets really interesting is heat pumps, which use electricity to push heat into the home from outdoors. These flip the script on the “2/3 rule”: while the power plant uses 3 units of heat to make 1 unit of electricity, the heat pump uses 1 unit of electricity to push at least 3 units of heat — often 5 or 6 or more — into the house. So even if you’re not using green energy sources, heat pumps are a big win.
I think it depends on country. Here there is increasing pressure and subsidies to use electricity to heat up homes.
There is. California is requiring new houses to use electrical appliances, not gas (stoves, ovens, clothes dryers, etc)
Also, gas furnaces are now running over 95% efficient. They are extracting almost ALL of the heat from the fuel they consume. The exhaust can be run through a PVC pipe because it’s so cold. Yes, it creates more carbon, but electrical heating is less efficient, especially considering line transmission loss.
There is a lot of work on electrifying large parts of the economy going on in conjunction with cleaning up the supply of electricity.
One examples is the progress being made to make heat pumps work in colder and colder places.
So yes electrification is being discussed.
70% of the gas you burn in your car is lost as heat energy, it doesn’t actually help your wheels turn. This is very *inefficient*. Gas burners are not this inefficient so there’s not really a big benefit to using electricity to heat homes.
Depend where you are. In Quebec, the vast majority of available electricity is generated through hydro power and is really cheap compare to the rest of US and some other provinces. Therefore, most houses are heated through resistive heaters. It’s also convenient as you have no central « furnace » and you can easily control temperature on an individual room basis. Also, all appliances are typically electrically powered.
> why isn’t there any emphasis on heating homes with electricity rather gas or oil?
2 big reasons:
1 – Cost effectiveness
2 – Efficiency
Cost Effectiveness:
It is cheaper to burn gas than it is to use electricity. There wouldn’t need to be any social pressures if everyone was acting selfishly and doing what’s cheapest. Gas just happens to be significantly cheaper. By about 50%.
Generally if something is cheaper, it means there are fewer resources used to do it, which means a smaller carbon footprint. Generally the price of something relates to all the things that had to be done to get that product to market.
I.E. Electric cars are more expensive because more industrial activity goes into making them. Off the assembly line, they’re worse for the environment than gas vehicles. Electric vehicles then play catch up, because electricity is generated more efficiently at a powerplant than a gas engine in a car can propel itself, and they eventually in their lifetimes pass gas vehicles for efficiency.
Efficiency:
If your goal is to make heat, the most efficient way of doing that is to directly make heat. Heat is the reason why everything else is not efficient, because some is always lost as heat. If you’re only making heat, ta da, you’re done.
So for your home, if you directly burn natural gas to make heat, it goes like this:
1 – Burn gas in furnace, 2 – House is warm.
But if you heat with electricity, it goes like this:
1 – Burn gas in powerplant to generate electricity (60% efficient). 2 – Transmit power to house (98% efficient). 3 – Run electric heaters. 4 – House is warm.
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One additional thing that tips the balance towards electric are “Heat Pumps”. Heat pumps are air conditioners that work backwards. They take advantage of compression to create a heat difference from the ambient temperature, and are more than 100% efficient (not in terms of physics, but they get “free” energy by taking it from the “free” ambient temperature). This is effective when moderate amounts of heat difference are needed, (it doesn’t accomplish much in Canadian winters for example, but Kansas winters would see gains), and in worst case is only as bad as only having an electric heater without a heat pump.
Another consideration is that electricity is as clean as it’s generated. If it’s from solar or hydro, then no gas or oil is being burned. It’s still not cost effective though, which means it’s still net-negative for the environment (until solar power is cheaper, some combination of it requiring resources to have those panels is worse than just burning gas). Solar panels have nearly bottomed out in terms of theoretical maximums for scientific improvements, so there is no change on the horizon there, but they haven’t bottomed out for manufacturing efficiency yet, so there’s still room for improvements to be made.
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In the DIY EV scene, because batteries are so expensive (and, by extension, bad for the environment), guys who need heat will install a small diesel heater under the hood instead of wasting precious battery reserves to make heat. It’s amazing how little fuel is needed for heat compared to how mammoth an impact electric heat has on your range.
It’s kinda funny because here it’s mostly all heated with electricity. We have big dams that provide plenty of it, so anyone here heating with gas or oil is the odd one out.
I converted my old house to heat pump a couple years ago, and with my new house I’m planning to install solar panels *and* switch to heat pumps. Eventually, I’ll disconnect the gas line completely.
I also built a small cottage in the back. That was all electric from the start.
My neighbor next door switched to all electric and installed solar panels. Now the power company pays *him* $7000/year.
It’s easier to build an all electric house than to convert an existing house.
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