Yeah something like fuel is definitely good for the economy, as is any other money(nic)-sink. It keeps inflation in check and I fully expect the Energy System to be basically a big money sink. If you look at Eve, one of the most succesful virtual economies, it has tons of these, ranging from ammo to POS Fuel.

Nevertheless the Devs have to be careful about the implementation as it cannot be too tediuos. I'd rather have the big corps carry most of the sinks than the little guy having to grind half hour every day to keep his bot fueled.