Question on prioritizing interventions (related to full lifecycle impact, and how close a technology is to its ceiling)

[sbutler-gh]

This question came to mind while thinking about a very specific example. To be clear, this example is going beyond the scope of 'gap technologies', to thinking about how to prioritize interventions in general (now that we have more than 7 pages ...)

Intuitively, I think it would be preferable to invest in home/building insulation before solar panels (assuming emissions reductions and ROI are equal.)

Two reasons are coming to mind:

1. Adding insulation to homes and buildings seems like it would have a lower cradle-to-grave impact than building solar panels

2. Home insulation seems like its closer to maximum efficiency than solar panels -- so if you invest in home insulation now, and wait for solar panel efficiency to improve, in the long-term you will likely have higher emissions reductions

Reason 1 would implicitly be addressed in the framework, although I wonder if there is an additional principle buried in that. Something like -- it's preferable to patch an existing hole (e.g. the literal holes in a home/building) before constructing something new.

Maybe this is already addressed with our statement on full life-cycle considerations, but I just wanted to float it to the group.

Reason 2 does not seem to be addressed in the framework, although I do believe related conversations came up during our work.

When it comes to R&D, you probably want to prioritize technologies which are farther from their emissions reductions ceiling -- to help those technologies reach their ceilings faster.

But when it comes to deployment, given limited resources, you would probably want to prioritize technologies which are closest to their emissions reductions ceiling, in order to give other technologies a chance to improve their efficiency prior to deploying/scaling them.

Would love to hear the group's thoughts on this