alt Hacker News> In that case you'd need to produce about 400TW÷20 years = 20TW/year. According to the IEA, we currently have only about 1.5TW/year of manufacturing capacity: https://www.solarplaza.com/resource/13581/article-global-sol...
So, at the current production rate, we can produce solar cells that deliver 20TW/year in about 15 years. Eventually, we’ll have to replace lots of them, but given that the rapid growth of installed panels makes the majority of panels new, I think we can mostly ignore that in this calculation.
We need to produce enough solar panels to generate net new 20TW every year; 20TW/year as a measure of energy production doesn't make sense as the Watt is a measure of energy transfer. In other words, we need to increase production by 20TW per year every year for 20 years in order to hit the 400TW that we need to be producing all the time (in this model where global energy demand is 400TW)