You’re clutching at straws here. At a degradation rate of 0.4% per annum, after 20 years your 4kW array is (drumroll please)... a 3.7 kW array.
Look at it this way: the carbon intensity of coal-fired power is some 2,000-8,000% higher than that of solar, and you’re quibbling over details that will change it by maybe 20-30%. This is a non-argument. On a CO2-per-kWh basis, wind and solar beat fossil fuels by better than an order of magnitude. That’s a simple fact.
