When evaluating backup power, many homeowners wonder: "How much will it cost to run?" The answer is very different for the two options. A portable generator burns gasoline by the hour. A battery power station costs only a few dollars of grid electricity to recharge - or nothing at all if you recharge from solar. Here's how to budget for each.
Key Takeaways
- A portable generator's running cost is the gasoline it burns - roughly a few dollars per hour depending on size and load.
- A battery power station costs only a few dollars of grid electricity per full recharge, and nothing when recharged from solar.
- A battery has no standing fuel cost and no fuel to go stale, so it's far cheaper over years of light use.
- Load management and right-sizing reduce both generator fuel use and how often a battery needs recharging.
The Big Picture: Over years of ownership, a battery power station's operating cost is minimal - it only costs money when you recharge it, and recharging is cheap. A portable generator costs nothing when idle but burns fuel whenever it runs. Match the option to how often and how long your outages last.
Portable Generator: Gasoline Cost
A portable inverter generator's running cost is the fuel it burns. Consumption depends on the unit's size and how heavily you load it.
Planning Backup Power for Your Home?
Stay powered through the next outage. We install portable generator hookups — manual transfer switches, interlock kits, and exterior inlet boxes for safe, backfeed-free connection — and we supply and install battery backup power stations (EcoFlow, Bluetti, Anker SOLIX) for silent, fuel-free runtime. Call (703) 997-0026 for a free in-home assessment.
Typical Gasoline Use by Output
| Generator Output | ~50% Load (gal/hr) | ~Full Load (gal/hr) |
|---|---|---|
| 2,000-3,500 W | 0.2-0.4 | 0.4-0.6 |
| 4,000-6,000 W | 0.4-0.6 | 0.6-0.9 |
| 7,500-9,000 W | 0.6-0.9 | 0.9-1.3 |
Example: a 6,000-watt portable inverter generator at half load burning ~0.5 gal/hr, with gasoline around $3.25/gallon, costs about $1.60/hour - roughly $20-$40 per day depending on runtime and load.
What Affects Generator Fuel Use
- Load: the biggest factor - a generator at 50% load uses far less than at full load
- Inverter vs. conventional: inverter generators throttle to the load and sip less fuel at light load
- Eco/idle mode: many inverter units have a mode that reduces engine speed when demand is low
Battery Power Station: Recharge Cost
A battery power station has no fuel. Its only running cost is the electricity to recharge it, which is inexpensive.
Recharge Cost Example
- Northern Virginia residential electricity averages roughly $0.13-$0.16 per kWh
- A 3.6 kWh EcoFlow Delta Pro full recharge: about $0.50-$0.60 of grid power
- A 6 kWh Delta Pro Ultra battery: about $0.80-$1.00 per full recharge
- Recharging from solar during an outage: effectively free
How Far a Charge Goes
Runtime is your stored kWh divided by your load. Examples on a single 3.6 kWh battery:
- Refrigerator + lights + devices (~300 W): roughly 10-12 hours
- Add a furnace blower cycling (~650 W average): roughly 5-6 hours
- Stack batteries or recharge from a generator/solar to extend further
Real-World Outage Cost Comparison
For a typical Northern Virginia home backing up essential circuits:
Portable Generator
- Summer outage (heavier load): roughly $25-$45/day in gasoline
- Mild-weather outage (light load): roughly $10-$25/day
- Plus the cost of keeping fresh fuel on hand
Battery Power Station
- Each full recharge: about $0.50-$1.00 of grid power per battery
- Solar recharge: free
- No standing cost, no fuel to buy or store
Reducing Running Costs
During Outages
- Turn off non-essential loads
- Raise the AC thermostat a few degrees
- Delay running the dryer or oven if possible
- Use LED lighting
System Design
- Right-size a portable generator (an oversized unit at light load is less efficient)
- Use load management to stretch a battery's kWh and run a smaller generator more efficiently
- Add solar input so a battery recharges for free during daylight
Total Operating Cost Summary
Over years of ownership, a battery power station almost always costs less to operate because recharging is cheap and there's no fuel to buy or replace. A portable generator costs nothing when idle but adds up during long or frequent outages - and you have to keep fresh fuel on hand. Many homeowners use a battery for the bulk of outages and reserve the generator for multi-day events.
Plan Your Backup Power Budget
At AJ Long Electric, we help you understand the full cost of backup power - including running costs - based on your specific equipment and your home's power needs.
Contact us for a complete cost analysis as part of your backup power evaluation. We provide honest, detailed estimates so there are no surprises.
