this post was submitted on 11 Mar 2024
321 points (99.1% liked)

Climate - truthful information about climate, related activism and politics.

5197 readers
663 users here now

Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world. About 1C of total warming. Second chart: about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability. Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases. About 0.5C of cooling with large error bars from SO2.

Recommended actions to cut greenhouse gas emissions in the near future:

Anti-science, inactivism, and unsupported conspiracy theories are not ok here.

founded 1 year ago
MODERATORS
[email protected]
321
Yes, heat pumps slash emissions even if powered by a dirty grid | Installing a heat pump now is better for the climate, even on U.S. electricity generated mostly by fossil fuels. Here’s why (www.canarymedia.com)
submitted 8 months ago by [email protected] to c/[email protected]
60 comments fedilink hide all child comments
 

The article doesn't go into it, but a key advantage they have is that heat pumps move heat, rather then trying to generate it. So they can move a lot more heat into your house than would be generated by running the electricity they use through a resistor. This makes them effectively more than 100% efficient (the exact amount depends on temperature) as compared with burning a fuel or resistive heat.

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 11 points 8 months ago* (last edited 8 months ago) (1 children)

It is really not hard. Heat pump coefficients of efficiency floor at 1, but typically range between ~2.5 and 7. That is, for every joule of energy they consume, they pump 2.5 to 7 joules of heat into the conditioned space.

So you have to just look at efficiencies involved.

  • The electric heat pump (theoretically ~250-700% efficient at warming a space)
  • The efficiency of energy transmission on the electrical grid (maybe around 90% ish? Depends on a lot of factors)
  • The fossil fuel furnace (theoretically something like 90-100% efficient)
  • The efficiency of the residential fossil fuel delivery system (last I read, something around 5% of natural gas ends up just leaking)
  • The efficiency at conversion of chemical to electrical energy by fossil production plants (and this one is rough -- I see numbers like 40-60% efficient)

Still, we're just summing stuff. And while I won't pretend any napkin math here is the same as a formal research project, we can plainly see that the HUGE energy efficiency of heat pumps can easily eclipse the inefficiency of fossil electrical production, all else being equal. Of course, whether it actually WILL be better than a fossil furnace will depend on local factors, but these places are increasingly becoming edge cases. And then, on top of that, you unlock future potential to seamlessly switch fuel sources from fossils to renewables, which becomes very important in lifecycle cost analysis.

[–] [email protected] 5 points 8 months ago* (last edited 8 months ago) (1 children)

This is the same reason electric cars beats ICE (gas driven) cars even when charged on coal power. Big coal plants and the distribution grid are more efficient than small scale car engines.

You need combustion engines to be BIG to get past 30-40% efficiency ranges, but the really big power plants can just perform efficient burns and heat water to drive efficient turbines, which is impossible in cars. And the rest of losses in electric cars are either minimal or equivalent, so you get a big net benefit.

Even better than that is an electric bus and other public transit!

[–] [email protected] 1 points 8 months ago

Even better when your busses/transit are powered by a pantograph.