> In addition, if Bitcoin disrupts the banking industry and a portion of wall street, we'd have to subtract their energy consumption.

Do you seriously think that? The cost of stuff like VISA's server farms or office buildings (and the rest of the financial industry) is probably globally negligible. Not to mention similar institutions would inevitably appear for cryptocurrencies (or already have, like Exchanges, etc.).

What remains is the horrendous cost for a Bitcoin transaction vs. the negligible cost for a 'normal' transaction in most trust-based systems.