Generator fuel: natural gas, propane, or diesel?
Natural gas, propane, and diesel each have specific trade-offs. For most Marin homes, natural gas wins — but not always.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Natural gas: connected to utility, unlimited runtime, cleanest emissions, requires existing gas service (most Marin homes have it). Propane: tank-stored, finite runtime per tank fill, slightly higher BTU per gallon than natural gas, works where natural gas isn't available. Diesel: highest power output per unit, longest storage life, but louder, higher emissions, more maintenance, requires fuel storage. For typical Marin residential: natural gas if available (90% of homes); propane if not (most West Marin); diesel rare for residential.
01Why fuel choice matters more than generator brand.
Most homeowners focus on generator brand (Generac vs Kohler vs Cummins) and overlook fuel choice. Fuel selection has bigger long-term impact: it determines runtime during extended outages (multi-day PSPS events common in Marin), ongoing operating cost, install scope (gas plumbing vs fuel tank vs delivery infrastructure), maintenance requirements, and noise/emissions profile. Brand differences within a fuel type matter less than the fuel type decision itself.
Marin-specific factors favor natural gas where available: PG&E natural gas service reaches most populated Marin (county-wide except some West Marin and unincorporated areas), eliminating the runtime concern that plagues other fuels during multi-day outages. Natural gas runs continuously as long as gas service is intact (PSPS events shut off electricity but typically not gas). For West Marin homes without natural gas service, propane is the practical choice — manageable storage tank, regular delivery, adequate runtime per fill.
02The three fuel types compared.
Natural gas — best for connected Marin homes
Pros: unlimited runtime, no fuel storage, cleanest emissions, lowest operating cost per kWh. Cons: requires PG&E gas service (90% of populated Marin has it), depends on gas service remaining operational. Best for: vast majority of Marin homes with existing gas service.
Propane — best for West Marin and off-gas-grid
Pros: works where natural gas isn't available, longer storage life than diesel, cleaner than diesel. Cons: tank requires space (typically 250-1,000 gallon residential), finite runtime per tank (~3-7 days of typical use), delivery scheduling. Best for: West Marin, unincorporated areas, homes without natural gas service.
Diesel — rare for residential
Pros: highest power density, long fuel storage life, robust mechanics. Cons: loudest of three options, highest emissions, requires fuel tank storage (typically 100-500 gallons), more involved maintenance schedule. Best for: larger commercial buildings, agricultural properties, sometimes ranch/estate applications. Rare for typical Marin residential.
03What we install in Marin.
Marin residential standby generators are roughly 75% natural gas, 23% propane, 2% diesel. Natural gas dominance reflects PG&E gas service coverage and the practical advantage of unlimited runtime during multi-day PSPS events. Propane installations cluster in West Marin (Inverness, Olema, Stinson Beach, Bolinas) and unincorporated areas without natural gas service — typically 500-1,000 gallon underground or above-ground tanks paired with 14-22 kW generators.
Generator sizing typically: 14-22 kW for essential loads coverage, 22-30 kW for whole-house coverage. Generac and Kohler are the dominant residential brands; Cummins covers some larger or commercial-grade installations. Total Marin installation cost: $12,000-$18,000 for typical essential-loads natural gas, $14,000-$20,000 for propane (includes tank infrastructure), $25,000-$48,000 for whole-house natural gas or larger configurations.
Common questions.
Will my natural gas service stay on during PSPS events?
Generally yes. PSPS (Public Safety Power Shutoffs) target electricity service in fire-risk weather conditions. Natural gas service typically continues operating during PSPS events because gas infrastructure is buried and doesn't pose the same wildfire ignition risk as overhead electrical lines. There can be exceptions during major emergencies, but for typical PSPS events, natural gas remains available — which is the core value proposition for natural gas standby generators in Marin.
How big a propane tank do I need?
Depends on generator size and desired runtime. A 22 kW generator running at moderate load consumes roughly 2.5-3.5 gallons of propane per hour. For 3-day continuous runtime: 180-250 gallons. Most Marin propane installations use 500-1,000 gallon tanks for comfortable margin and infrequent refills. Larger tanks ($2,000-$5,000 above smaller tanks) reduce delivery frequency and provide buffer during extended outage scenarios.
What about propane during weather events?
Propane delivery can be disrupted during major weather events (atmospheric rivers, fire evacuation scenarios). Larger residential tanks mitigate this — a 1,000 gallon tank at 50% fill provides ~7-10 days of generator runtime regardless of delivery availability. Strategy: keep tank above 50% during PSPS season (October-November typically in Marin), schedule fills proactively. Most Marin propane suppliers (Suburban Propane, Ferrellgas, AmeriGas) handle Marin reliably.
Can I switch fuel types later?
Most generators are fuel-specific (factory configured for natural gas, propane, or diesel). Some 'dual-fuel' generators can switch between natural gas and propane with field conversion, but performance and warranty often differ from native-fuel operation. Practical answer: choose fuel carefully at install time; switching later usually means replacing the generator. For homes adding natural gas service after installing a propane generator, the propane setup continues working — no need to switch unless propane delivery becomes problematic.
How do you handle pricing — flat fee or hourly?
Both, depending on scope. Routine service calls and predictable scope (panel replacement, EV charger install, transfer switch install, fixture replacement) are flat-fee quoted up front. Diagnostic visits and emergency scope are hourly because we don't know what we'll find. Either way, you get a written quote before work starts on anything significant, and we don't proceed beyond the quote without your sign-off.
How quickly can you schedule?
Depends on scope and season. Emergency dispatch: same-day across Marin County (1-3 hours business hours, 1-4 hours after-hours). Same-day standard service: 3-6 hours from call when capacity allows; otherwise next business day. Scheduled service work: 1-3 weeks typical. Larger projects requiring permits and PG&E coordination: 4-12 weeks depending on scope. We're upfront about timeline at the quote stage.
What warranty do you offer on work?
Our standard residential warranty: 2 years on labor, manufacturer warranty on parts (varies by product — typically 1-10 years). Major installs (panels, generators, EV chargers) often have longer manufacturer warranties (5-10 years). If there's an issue with our work in the warranty period, we come back and fix it at no cost. We also stand behind work past warranty — repeat customers and referrals matter more than a transactional fix.
Are you licensed and insured?
Yes. California State License Board C-10 Electrical Contractor #989290, in good standing. Carry general liability insurance and workers' compensation insurance as required by California law. Bondable on projects requiring it. Happy to provide proof of insurance to clients or property managers on request. License lookup: cslb.ca.gov.
Talk to a licensed electrician in Marin.
Family-run, C-10 #989290, 20+ years in the trade. Honest scoping, fair pricing, work that lasts.