Emergency power rental is a diesel generator on a trailer or a skid, delivered while the utility is down or the building's own set has failed. Fleets run roughly 25 to 500 kW, and a 25 to 60 kW towable is about $150 to $400 a day before fuel and cable. The call is fast; the sizing is what decides whether it works when it arrives.
Size the load, not the building
Add up what actually has to run: refrigeration, a server room, a lift, life safety, a few circuits of lighting. That number in kilowatts is what you rent, plus headroom for the surge when a motor starts, which can be several times its running draw. A set sized off the main breaker will be far bigger and far more expensive than the job needs.
Voltage and connection are the delay
A generator is useless until it is tied in. Ask what voltage and phase the panel wants, whether a manual transfer switch or a camlock tail already exists, and whether an electrician is needed to land the cable. On buildings with no prepared connection, that electrician, not the machine, is what sets the time to power.
Fuel is a separate contract
A towable set carries a base tank measured in hours at load, commonly eight to twenty-four. Beyond that somebody has to refuel, and yards either sell that as a fuel service or leave it to you. Multi-day outages are where fuel quietly becomes the largest line, so agree the refuelling arrangement when you book, not on day two.
What to say on the first call
Kilowatts needed, voltage and phase, single largest motor, the connection you have, the site access for a trailer, and how long you expect to need it. Six answers gets a machine dispatched. Starting with a price question gets a quote for the wrong set.
Questions people ask about emergency power rental
What size generator runs a small commercial building?
For essential loads only, many small buildings sit between 25 and 60 kW. Running everything, including electric heat or full air conditioning, moves it into the hundreds. Price both, because the essential-loads set is usually available faster and costs a fraction to fuel.
How fast can one arrive?
In a normal week, hours. In a regional storm or a wide outage, the mobile fleet in a metro is committed early and the answer becomes days. Sites that cannot lose power should have a supplier and a connection agreed before the season, not during it.
Do I need an electrician?
If there is no transfer switch or camlock connection already installed, yes. Back-feeding a panel through an outlet is dangerous to line workers and to you, and no rental yard will support it.