HOW
Here’s how the dollar on the Energy Standard works:
Energy use multiplied by the inverse in the increase in energy efficiency. That’s how we calculate increases in the money supply.
The FED has their own methodology. We map the FEDs moves to the Energy Standard.

WHY
Here’s why:
Energy use tracks growth. Of course we need to adjust for increases in efficiency.

COOL UNINTENDED CONSEQUENCE:
Energy efficiency gains are like productivity gains.
Energy efficiency gains improve relative currency valuations, which make the purchase of energy less expensive as purchasing power has increased. So, the most efficient economies have the lowest imported energy cost.

The same is true of any commodity which we would choose to use as standard of value for a currency. If the dollar was on the fresh water standard we would have a similar effect.