Berkeley National Laboratory (USA) estimates that these days solar PV has an average energy payback period of 0.5 to 2 years, meaning that about 6-24 months worth of its energy collection is used across the lifecycle for fabrication + transportation + construction + maintenance + deconstruction + recycling. If a panel nominally rated for 100W produces a daily average of 0.5kWh, then across a year that’s 0.5 * 365 = ~180kWh, and across an estimated 25-year panel life it's 180 kWh * 25 = 4.5 MWh. With current retail electricity costs in China of approximately $0.084/kWh on average (
source), the embedded energy cost is at most around $0.084/kWh * 180 kWh/year * 1 year typical energy payback / 100W nominal = ~$0.15/W embedded energy cost, approximately 15% of the entire current $1/W cost of solar. Even if going carbon neutral doubles this energy cost to 30%, that's still only a 15% increase, equivalent to a single year of overall solar PV cost decline.
Let's look at it another way. I see various estimates that
solar has embedded CO2 equivalent of roughly 1 ton CO2e/MWh. Carbon offset credits cost on the order of $10/ton. With unsubsidized all-in solar costs today of about $30/MWh in Western nations with favorable insolation (like USA, Australia & NZ), carbon offsets would drive up cost by 25% to $40/MWh. Again, only for now because eventually solar energy will be used to make more solar energy and all the logistics and construction and all that will be going renewable too, dropping the CO2e/MWh to vastly less than it is today.
I am terrible
But at least I don’t sell much
