Answer first: Shore power, the industry also calls it cold ironing, lets a docked cruise ship shut down its diesel generators and run everything from the landside electrical grid. PortMiami built it at five cruise terminals for about $125 million, says a plugged-in ship cuts its dockside emissions by up to 98 percent, and can connect three ships at once. It's the reason Norwegian Getaway stays docked overnight in Miami on August 24, 2026, sailing at 3:00 a.m.. The port is testing the system. For passengers, plugging in mostly means a quieter, cleaner ship at the pier, and occasionally a schedule shaped around the plug.
Who This Is For
Anyone whose cruise schedule just did something odd. An overnight at the embarkation pier, a 3 a.m. departure, and wants to know why. Anyone curious what that thick cable between the hull and the dock actually does. And anyone weighing the honest environmental picture of cruising, which is neither as clean as the brochures say nor as hopeless as the critics say.
My own stake: I'm booked on the Getaway sailing that sleeps over in Miami Monday night for these tests. Monday evening I'll be aboard a ship at a pier, and I'll be paying attention to the things this article says you can notice: the hum, the haze, the quiet. The daily dispatches will say whether the theory held.
The Problem Shore Power Solves
A big cruise ship at a dock is still, in one sense, running hard. The propulsion is off, but the hotel is not: thousands of cabins of air conditioning in a Florida summer, a dozen galleys, elevators, freezers, lights, water treatment. All of that electricity has historically come from the ship's own diesel generators: engines idling at the pier for eight or ten hours, in the middle of a city, on turnaround days when the ship never moves an inch. PortMiami's own description is blunt about the scale: a docked cruise ship uses about as much electricity as a small city.
Shore power moves that load ashore. A heavy connection joins the ship to the local grid, at PortMiami, that's Florida Power & Light, and the generators shut down. The ship's lights stay on; the source changes. When the ship is ready to sail, it transfers back to its own power and unplugs.
The payoff is local and immediate. Per Miami-Dade County, switching a docked ship's engines off cuts its emissions by up to 98 percent while connected, and the county estimates the annual reduction at a single terminal equals taking 7,500 cars off the road. Those are the program's own numbers, a port promoting its investment, but the mechanism behind them is simple physics: an engine that isn't running doesn't emit.
What Miami Built
PortMiami calls itself the Cruise Capital of the World, which makes it the natural proving ground. The county's Shore Power Program wired five cruise terminals, each matched to a resident line:
| Terminal | Cruise line |
|---|---|
| AA | MSC Cruises |
| A | Royal Caribbean International |
| B | Norwegian Cruise Line |
| F | Carnival Cruise Line |
| V | Virgin Voyages |
The cost was about $125 million — roughly $25 million per terminal — with $21.7 million of it covered by grants ($19.7 million from the Florida Department of Transportation, $2 million from the EPA). The port says it can plug in three ships safely at the same time, and that in the coming year it expects 21 different ships to connect across more than 350 calls. For scale on how early-days this still is: PortMiami counts itself among roughly 35 seaports worldwide with even one shore-power cruise berth.
That last number is the honest context. Shore power is real, funded, and operating — and it is nowhere near universal. A ship that plugs in at Miami runs its generators at the next port that has no plug. Newer ships are generally built ready to connect; older ships need retrofits, which is part of why the port's 21-ship figure isn't the whole fleet that calls there.
Why a Ship Sleeps Over: the Getaway Test
Which brings us to the odd schedule that started this article. Norwegian Getaway's August 24, 2026 sailing boards on Monday, stays at the pier overnight, and departs at 3:00 a.m. Tuesday. Cruise media report the reason plainly: the ship remains docked to help PortMiami test its shore power systems — Norwegian's home is Terminal B, one of the five wired berths. (This is a separate matter from the same sailing's propulsion repairs in Nassau, which have their own article.)
Commissioning a system like this takes exactly this kind of time: a real ship, connected for real hours, under real hotel load, while engineers on both sides of the cable watch what happens. A ship that would normally cast off at 5 p.m. instead becomes the test bench for the evening. For the passengers aboard, the practical shape is a hotel night on a ship — board, unpack, have dinner, sleep at the pier, wake up somewhere in the Florida Straits.
What might you notice from a cabin during a shore-power hookup? The honest answer is: possibly nothing, and that's the point. The differences passengers do report at plugged-in ports are the absence of things — no faint engine hum through the hull, no vibration at the stern, no exhaust shimmer over the aft rail. I'll be aboard for this one, and the Monday dispatch will say what an ordinary passenger can actually perceive, rather than what the theory predicts.
What Shore Power Means for Passengers
- Nothing on your bill. There's no shore-power line item. The infrastructure was county-funded with state and federal grants; the lines are program partners. Whether energy costs eventually find their way into fares is not something any line itemizes, so no one can honestly tell you the per-passenger cost.
- A quieter ship at the pier — sometimes noticeably. If you've ever eaten breakfast on an aft deck over the low rumble of generators, the plugged-in version of that morning is stiller. Light sleepers in aft cabins have the most to gain.
- Cleaner air where the ship sits. The 98-percent figure applies while connected, at that pier. It's a genuinely large local improvement, and it says nothing about the ship's emissions at sea. Both halves of that sentence are true; marketing tends to quote only the first.
- Occasionally, a schedule shaped by the plug. Testing windows, connection time, and port electrical work can nudge departure times — the Getaway's 3 a.m. sailing being the live example. Read your itinerary emails; the reason is usually in the fine print or, failing that, in the cruise press.
Frequently Asked Questions
What is shore power on a cruise ship?
It lets a docked ship shut down its diesel generators and draw power from the landside grid — the hotel functions run on city electricity while the engines rest. PortMiami puts the emissions cut at up to 98 percent while connected.
Which PortMiami terminals have it?
Five: AA (MSC), A (Royal Caribbean), B (Norwegian), F (Carnival), and V (Virgin Voyages) — about $125 million of infrastructure, three ships connectable at once.
Why is Norwegian Getaway overnighting in Miami on August 24?
To help the port test shore power systems, per cruise media — departing 3:00 a.m. Tuesday. It works like a hotel night aboard, and it's unrelated to the ship's Nassau propulsion repairs.
Can passengers tell when a ship is plugged in?
Sometimes — mostly by absence: no engine hum, no vibration, no exhaust haze aft. Onboard life is otherwise unchanged.
Does it cost passengers anything?
No fee appears anywhere on your account. The build was grant-supported county infrastructure; any indirect cost in fares isn't itemized by the lines.
How common is this?
Roughly 35 seaports worldwide offer at least one shore-power cruise berth, per PortMiami — real momentum, far from universal. Ships still run generators at unwired ports.
Related Guides & Coverage
- Norwegian Getaway's Overnight in Nassau — the same sailing's other schedule change
- Cruise Embarkation Day: What to Expect
- Miami — port guide
- Norwegian Getaway — ship guide
- Cruise Ship Size, Explained
Sources: Miami-Dade County — PortMiami Shore Power Program (terminals, cost, grants, emissions and capacity figures); Cruise Hive (the Getaway overnight's shore-power-testing purpose). Reviewed August 22, 2026. This page carries no affiliate links.