Power station vs generator: safety, noise, fuel and cost per kWh

Indoors, only the battery

A combustion engine produces carbon monoxide. In its press release of 26 November 2025, Santé publique France with the French health ministry states that generators must in no case be used in an enclosed space such as a home, garage, cellar or camper van, nor even placed near doors, windows or air vents. About 3,000 people in France are accidentally poisoned by carbon monoxide each year, and about a hundred die. The German Federal Office of Civil Protection (BBK) writes in its 2026 guide that generators must not be run indoors because the exhaust gases can suffocate, and recommends a well ventilated, dry place outdoors.

The Health and Safety Executive for Northern Ireland adds that a generator must not run in partially enclosed spaces such as garages, even with partial ventilation, nor near open doors and windows. The NHS lists portable generators among the sources of carbon monoxide and recommends an alarm that sounds when it is present. A power station has no exhaust, which is why the BBK names battery systems as the alternative for indoor use.

Read: LFP or NMC, which is safer?

Noise and neighbours

Honda lists its EU22i inverter generator at 71 dB(A) at the operator's position and a guaranteed sound power of 89 dB(A); its Eco Throttle adjusts engine speed to the load to save fuel and reduce noise. The BBK warns that in dense areas and blocks of flats neighbours may be disturbed, and advises choosing a quiet model. Power stations are not silent either: in the ADAC test of June 2025, all units were loud at maximum power because of their fans, and some offer a quiet mode for the night.

Fuel storage and upkeep

Fuel is regulated. In Germany, the BBK says at most 10 kg of petrol or 20 kg of diesel may be kept in suitable cans in a cellar, and gas not at all, referring to the technical rule TRGS 510. In Great Britain, the HSE allows up to 30 litres of petrol at home without notifying the enforcement authority, in plastic containers of up to 10 litres or metal ones of up to 20 litres, and not in living accommodation. Spilled fuel and hot engine parts are a fire risk, so switch the generator off and let it cool before refuelling.

An engine needs looking after. Honda ties the EU22i warranty to following the service schedule, stops the engine when the oil level is too low, and provides a fuel valve position that burns off the fuel in the carburettor to protect it from stale fuel during storage. A power station needs less, but the BBK notes that batteries discharge themselves over time, so check and recharge a stored unit regularly.

Power and run time

On paper the two can look alike. Honda gives the EU22i 1,800 W rated output, 2,200 W maximum, a 3.6 litre tank and 3.5 hours at rated load. EcoFlow gives the Delta 2 1,800 W of AC output with a 2,700 W surge, from 1,024 Wh of LFP cells. The difference is energy. The BBK notes that kettles, heaters and hot plates quickly reach 1,500 to 2,000 W each. With the factors of our runtime calculator, the Delta 2 runs a 1,500 W heater for about 35 minutes; the generator runs it for at least the 3.5 hours stated at full load, and longer each time you refuel.

Calculate the runtime for your devices

Cost per kWh: a worked example

Generator, from Honda's figures: 1,800 W for 3.5 hours is 6.3 kWh from 3.6 litres, about 0.57 litres per kWh at full load. At an assumed 1.80 euros per litre, the fuel alone costs about 1.03 euros per kWh. At smaller loads an engine uses more fuel per kWh, and Honda states run time only at rated load, so we give no figure for that. Power station: our calculator estimates about 0.9 kWh delivered from the Delta 2's 1,024 Wh. Charged from the grid at an assumed 0.30 euros per kWh, with an assumed 10 percent charging loss, each delivered kWh costs about 0.38 euros in electricity.

Then comes wear. At an assumed price of 800 euros and 3,000 cycles to 80 percent, the Delta 2 costs about 0.33 euros per stored kWh if you use all its cycles. A unit kept for power cuts may run only a few full cycles a year, and then the purchase price dominates for both machines. Compare them on what you need to run and for how long, not on the cost per kWh alone.

Read: the price per stored kWh

When a generator is still the better tool

The BBK describes battery systems as short term storage. A power station only refills from the grid, the car or the sun, while a generator keeps running as long as you have fuel. For outages of several days, or for heaters, pumps and tools that draw well over a kilowatt for hours, a generator outdoors is often the only practical option. Feeding a generator into the home's wiring is work for an electrician with a transfer switch, says the BBK, and HSENI warns that connecting one to the house without it can cause injury or death.

Both can work together: Bluetti lists a generator among the four ways to recharge its AC180. The station then runs the fridge, router and lamps quietly indoors, and the generator runs outside for a few hours to refill it.

Read: what size for power cuts?