A lot depends on your state rebates and how your electric supplier pays.
In Illinois the rebate is pretty good and my supplier trades my production for the power they provide up to a break even point. They won’t pay me for any extra I produce.

Bottom line is after all rebates mine cost me about $1.05 per kw. Depreciation will lower this cost some what.

Works out to be about a 4-5 year pay off at current electric rates.

Mine is free standing.