I've thought the same, specifically for green energy. The "logical" way would be to allocate some money to one of the green mutual funds -- but those are typica

I've thought the same, specifically for green energy. The "logical" way would be to allocate some money to one of the green mutual funds -- but those are typical pretty high ER. And I'm not sure be desire to try to be green-ish overcomes that. A customizable ETF/mutual fund would awesome. But I wonder what the hurdles are technically/legally...