Renewable energy, particularly solar energy, was one of the best-performing industries in 2020 -- with the Invesco Solar exchange-traded fund (ETF) (NYSEMKT: TAN) rising over 233% that year while the energy sector fell over 36%. In short, renewables remain a growth industry that is vulnerable to a weakening economy, high inflation, and rising interest rates. On top of that, many solar and wind energy stocks rocketed higher too far, too fast in 2020, which left them a lot of room to fall in 2021 and 2022 given the headwinds discussed and valuation concerns.