Why is 1099-MISC income treated as self-employment? This was a credit I received for solar panels from the electric company.

The income you mention should not be considered self-employment income. You should enter the form in the Income and Expenses section, then Other Common Income, then Income from Form 1099-Misc. You should enter the amount in box 3 of the Let's get the info from your 1099-MISC screen. You will see a screen that says Did the Other income involve work that's like (you name) main Job? You need to answer "no" to that question. You also need to answer that you only got the income in 2021 when asked. You also need to answer that your activity does not involve an intent to earn money. Then, the income will not show as self-employment income on your tax return.