By Edward A. Sanchez — Jan. 16, 2023

The proponents of gasoline (and similar liquid hydrocarbon fuels, such as diesel) claim the fuels are much more practical and portable than battery packs, and are what you want to have in a “bug-out” scenario such as a widespread power outage or an off-grid situation such as a remote expedition or an isolated homestead or camp site. The power density of liquid hydrocarbon fuels is hard to argue with compared to current battery technology.

One gallon of gasoline has potential energy of 33.7 kWh, and diesel has potential energy of 40.7 kWh. The weight of a gallon of gasoline is approximately 6 pounds, and a gallon of diesel weighs approximately 7 pounds. Using current state-of-the art battery technology, you’re looking at a weight of at least several hundred pounds to get that level of power in a battery pack.

So there’s little arguing that liquid fuels are more practical from a volumetric and weight standpoint. But they key difference between liquid fuels and battery packs is that once liquid (or gaseous, for that matter) fuels are expended, you can’t put the genie back in the bottle, so to speak.

One reason for a battery pack’s weight is that it’s a permanent storage medium that can be replenished with fresh electrons, whether from the grid, solar, or a generator. As battery technology continues to evolve, expect the volumetric and weight penalty relative to gasoline or diesel to diminish. However, it may never reach volumetric/weight parity with good ol’ dino juice.

Anyway, having gotten the top-level topics out of the way, let’s unpack some of the relative advantages and disadvantages of both fuel types in different scenarios.

Portability: Advantage – Gasoline, But Not As Much As You Might Think
With current battery technology, gasoline has a decisive edge in portability and “bang for the buck” in volumetric efficiency. Basically, a gallon (or cubic foot, or whatever other measurement you want to use) of gasoline packs a lot more potential energy than an equivalent size battery pack. However, as is also the case in internal combustion vehicles, there is a substantial thermal loss in the combustion process. Gasoline generators are between 20% to 40% efficient. Taking the 33.7 kWh potential energy in a gallon of gas, you’re getting between 6.74 kWh to 13.48 kWh of output from of it.

Gasoline is a powerful fuel that’s easy to transport, but choosing between gasoline and a battery pack is not so simple. (Image courtesy bpcraddock)

With battery power stations, there are some transmission losses, both from charging and discharging, but the efficiency range is generally in the neighborhood of 80% to 90% – you’re getting out a majority of what you’re putting in. So yes, battery packs are undeniably heavier than gasoline alone, but remember, you also have to bring the generator too, which weighs between 40 to well over 100 pounds, based on output, so yeah, there is that.

With battery power stations, you don’t have to worry about lugging around liquid or gaseous fuels to refuel them. Simply plug them into an outlet (either in a building, or on your vehicle, if equipped) or plug in solar panels to recharge them. This advantage largely mitigates power stations’ disadvantage over gasoline generators.

Safety: Advantage – Battery
Yes, we’re all familiar with the battery fires of the Chevy Bolt and some of the early Tesla models. But statistically, these occurrences are very rare. Also, the emergence of LFP batteries, which have a much more stable chemistry, have largely eliminated this issue. Except in the extreme case of a fire, batteries are safer. And if gasoline catches fire, well, I think we all know what happens.

Gas powered or electric, all vehicles can catch on fire, but modern battery technology is making this an increasingly less likely scenario for EV owners. (Image by Riley Edwards)

Sustainability: Advantage – Battery
When I say “sustainability,” I’m not just talking about the feel-good green virtue-signaling aspect. Although that also applies. I’m talking about in a prolonged outage scenario where lines at gas stations stretch dozens or hundreds of cars deep, or the power outage is affecting gas stations as well.

If you have solar panels, or power output on your EV (think Ford F-150 Lightning, Hyundai Ioniq 5, etc.) you could top off your power station. With solar, effectively indefinitely. Yes, the recharge time can range between 4-8 hours, as opposed to mere minutes with gasoline. But again, in the scenario where there’s a widespread blackout that’s also affecting gas stations, you have an advantage with power station plus solar.

Refueling Time: Advantage – Gasoline
There’s no getting around the time advantage of refueling with liquid (or gaseous) hydrocarbon fuels. Even the fastest-charging DCFC stations can’t match the speed of topping off your tank. Will fast charging reach time parity with gasoline at some point? There’s a good chance it will, but I would guess we’re about a decade away from that on a widespread basis.

Gasoline and diesel are the undisputed refueling time kings — at least for now. (Image by Rudy and Peter Skitterians)

In the context of battery power stations, I’m not aware of any on the market currently that have a Level 3 DC input. The EcoFlow Delta Pro has a J1772 input that requires an adapter, but even with this option, it’s approximately an hour to recharge.

Availability During Blackouts: Advantage – Battery, Slightly
Unless you’re already prepared with a substantial supply of gasoline (or propane, which we will discuss shortly) on standby, and plenty in reserve, a topped-off battery pack (with solar) is more sustainable over the long term. We’re talking a matter of weeks or months. If we’re talking a few days up to a week, if you have enough gasoline or propane, you’ll probably fare fine.

Whole-house solutions like the Tesla Powerwall have distinct advantages over generators. (Image courtesy Tesla)

But in a quasi-apocalyptic scenario in which the power plants, grid, and infrastructure are totally decimated, gasoline is a finite resource and will likely be subject to hoarding, and a “Hunger Games”-like competition to obtain it. The same applies to propane, although unlike gasoline, propane can be stored almost indefinitely without degradation.

Storage: Advantage – Battery
Although it’s easy to think that gasoline generators are as simple as just “pull the cord” and go, the reality is a little more involved. When purchased new, all gas or propane generators have a specific “break-in” procedure before they can be used on a sustained basis, which typically involves running them under load for a specified time period, then changing the oil, sometimes for more than one cycle.

Once that’s out of the way, there’s the matter of the shelf life of gasoline. While “stale” gas is still combustible, varnish and deposits will eventually gum up the carburetor and fuel system. Fuel stabilizer can mitigate this issue to a point, but there is still ongoing maintenance with a gasoline generator. Propane is a much “cleaner” fuel from this standpoint, and largely eliminates the issue of fuel and fuel system degradation over time. Power output on dual-fuel generators is generally a little lower with propane than gasoline, so that’s a factor to consider.

Battery packs have a recommended storage state-of-charge (SoC), generally around 50% to 60% for prolonged periods. So there is the matter of periodically checking the SoC and making sure it’s within the recommended range. But this is much less complicated and tedious than with gasoline generators, which require periodic oil changes, spark plug changes, running fresh gas through them, or adding fuel stabilizer when in storage.

Final Thoughts: Strength in Diversity
As I’ve also said in the context of EV vs. ICE, there is no “magic bullet” solution that’s perfect for every person for every scenario all the time. From an objective standpoint, I think the best solution is having a reasonable stockpile of propane on-hand to run a dual-fuel generator. This can be used to power a whole house, or more power-hungry appliances (such as an electric stove or microwave), as well as to charge up a portable battery power station. Again, the big game changer is solar charging. Hypothetically, this will give you almost indefinite off-grid power, assuming you’re judicious with your use of power in an emergency situation.

Also, full disclosure, I’m not an experienced “prepper” or expert in emergency tactical scenarios. If you are, I invite you to contact us at hello@thewattcar.com and let us know what scenarios we might have overlooked in this analysis, and make your case for why one is better than the other, or a “hybrid” approach leveraging both. We look forward to hearing from you.

(Main image by Gam-IO, Peter Skitterians, and Ernest Ojeh)

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