Worse than that, rather than using 100KWh of natural gas power to generate, you buy from abroad, from a less efficient producer who uses 150kWh of coal fired power, and then use another 100kWh of oil power to transport it.

With gas being 1 "badness" per 100KWh, oil being 2 and coal being 3, this would mean avoiding 1 unit locally, but getting importing 5 units.

The beauty of a carbon tax is that it satisfies those on both the environmental side ("the left") and the localism side ("the right"). The only ones not liking it are globalists that don't care about the environment.