Thread by @berrill_peter

Low-carbon electricity, deep electrification-focused renovations, and smaller, electric new homes are part of decarbonization pathways for the US residential sector. Our new paper out in @NatureClimate with @EdgarHertwich @NREL rdcu.be/cSWD6 doi.org/10.1038/s41558…

@NatureClimate @EdgarHertwich @NREL Clean electricity and renovations are the two big strategies with biggest impact at a national level.

But further reductions come from building electric, smaller new homes.

@NatureClimate @EdgarHertwich @NREL Speeding up the demolition and construction of housing increases emissions (despite more efficient new homes), due to embodied emissions in construction and new single-family homes being a lot larger than old ones (curbing the efficiency benefits of new homes)

@NatureClimate @EdgarHertwich @NREL So, with the majority of the building stock that will exist by mid-century already standing, the most important action for old less-efficient homes is to renovate, and electricify rdcu.be/cSWA3
doi.org/10.1038/s41558…

First most urgent action? Speed up the decarbonization of electricity. The Senate’s Inflation Reduction Act will help.

https://twitter.com/JesseJenkins/status/1554444864904994824?s=20&t=k9HpjHxcHMXlIeNtfQm-jQ

But carbon-free electricity by 2035 would require truly impressive increases in renewables, averaging 120 GW/yr of new capacity

Second, increase the rate and depth of residential renovations focused on improved insulation, less air leakage, and heat pumps. This has greatest impacts in the Northeast, where the grid is quite clean, heating needs are large, and many houses are old and run on oil/gas.

Potential of strategies varies a lot by location. Here we show the difference in cumulative GHG reductions 2020-2060 from extensive renovation only vs one of our grid scenarios only (LREC) - which enables substantial reductions through the center and southeast in particular

For new homes, build smaller, more multifamily, and 100% electric new homes. These options have biggest impact in regions with high housing demand, and already clean electricity, such as CA. #housingtwitter

Do our projection achieve the necessary target of net-zero emissions in 2050? No, even our most ambitious scenarios have ~85 MTCO2/yr in 2050. To get to 0, we will need greater attention on low-carbon construction, and stronger action on lower floor area.

Due to continued slow decline of household sizes, and because new single-family homes are so much bigger than old homes, our housing stock scenario (smaller homes, and more multifamily) with lowest growth of residential floorspace basically keeps current levels of ~60m2/cap.

Moving US floor area in the direction of #sufficiency levels 30-40 m2/cap would require action on existing homes, which we did not model in this analysis. That could involve conversions of underutilised large homes into multiple housing units, or increasing household sharing.

See more details in my blog post …inabilitycommunity.springernature.com/posts/pathways…, and in the paper itself!

Missed out the figure on one of the tweets above, relating to geographical variation of potential reductions from deep renovation and clean electricity. What we show here is % reduction in cumulative 2020-2060 emissions from individual strategies by state