Holochain, Holo's underlying technology, uses vastly less electricity than blockchain-based systems. Your HoloPort will use as much electricity as a light-bulb.

Holochain, as compared to blockchain, eliminates the need for all nodes to be synchronized with each other in global consensus. By using more intelligent and adaptable ways to manage cooperation between parties and agreement around data, Holochain cuts down the energy use of traditional blockchain systems drastically while simultaneously being many times faster and more scalable. Blockchain uses huge amounts of electricity on mining for the purpose of creating consensus. With Holochain, we've realized consensus isn't even the best way to collaborate in these systems, and we've done away with it.

HoloPorts use very little electricity. Here's a breakdown of their approximate energy use, and cost based on the average U.S. electricity cost ($0.12/kWh).

Energy usage
Monthly cost
HoloPort Nano
1 LED bulb
1 incandescent light-bulb
1 incandescent light-bulb

As you can see, your HoloPort will use about as much electricity as a light-bulb. If you're concerned about your HoloPort costing you more on your electricity bill, simply be a bit more vigilant about turning off unused lights, and you'll already have more than cancelled out its electricity usage.