[pangram]

Not free, but I would suspect that paying electronically is at least a magnitude less impactful on the environment. That checkbook had to be produced, shipped to the bank, mailed to you, and then the individual check has to get moved around as well.

[dinkumthinkum]

That wasn't my claim but I don't think the online payments are as low energy as you may believe. In order to allow the Internet to exist such that online payments are so efficient, we must necessarily have all the servers, cables, routers, all the infrastructure, on all the time or otherwise not even a single online payment would go through. That's a lot of air conditioning, alone. So, fine but let's not think online payments use magnitudes less energy by using simplistic calculations.