Choosing a backup power supply: how the main options compare

Not every facility has the same tolerance for downtime, the same fuel access, or the same runtime needs. Here is how the most common backup power approaches stack up when reliability is the priority.

Diesel generator sets Long-established for emergency backup and quick to start, but they depend on stored on-site fuel, require regular exercising, and produce higher emissions. Runtime is capped by tank capacity and refueling logistics during extended outages.
Natural gas gensets Fed by the utility gas line, so they avoid on-site fuel storage limits and can run for extended periods. Emissions are lower than diesel, though availability still depends on the gas supply staying intact during a wider grid event.
Microturbine microgrids Capstone microturbines can run continuously as part of a microgrid, supplying primary power day to day and seamlessly carrying critical loads through a grid outage. Fewer moving parts mean lower maintenance, and waste heat can be recovered for CHP.
UPS (uninterruptible power supply) Bridges the momentary gap between an outage and generation coming online, protecting sensitive equipment from any interruption. It is a complement to on-site generation, not a substitute, since battery runtime is measured in minutes rather than hours.

Sizing backup power for non-data-center facilities

Hospitals, universities, manufacturing plants, and commercial properties each have their own load profiles and resiliency requirements. Getting the design right starts with a few core questions.

A backup power supply is only as good as the plan behind it. Sizing to peak load alone often leaves facilities either over-invested in idle capacity or short of the runtime they need when an outage stretches from minutes into days. The goal is a system matched to how the facility actually uses power and how long it must stay online without the grid.

For facilities outside the data center world, resiliency also means fuel redundancy. A system that can draw on utility natural gas for continuous operation, rather than depending solely on a finite on-site tank, changes what “extended outage” means. Pairing generation with a microgrid architecture lets a facility island from the grid, keep critical loads running, and use recovered heat to offset ongoing energy costs the rest of the year.

  • Critical vs. non-critical loadsIdentify which systems must never go down and which can be shed to extend runtime.
  • Required runtimeDecide whether you need to bridge minutes, hours, or days without the grid.
  • Fuel redundancyWeigh on-site stored fuel against a continuous utility gas supply for long outages.
  • Resiliency architectureDetermine whether islanding from the grid via a microgrid is needed for full independence.
  • Everyday valueConsider running the system as primary power with CHP so it earns its keep beyond emergencies.

Where backup power meets everyday efficiency

The strongest backup power strategies do not sit idle waiting for an outage. When on-site generation runs as part of a combined heat and power (CHP) system, the same equipment that carries your facility through a grid failure also cuts energy costs and reduces GHG emissions every day by capturing and reusing waste heat.

Building that capability into a microgrid takes it a step further, letting your facility island from the grid, prioritize critical loads, and maintain a reliable power supply on your terms. Explore our CHP solutions and microgrid services to see how continuous, efficient generation and dependable backup power can come from a single, well-designed system.

What is the difference between backup power and a UPS?

A UPS bridges the brief gap between an outage and generation starting, protecting sensitive equipment from any interruption. A backup power supply such as a generator or microturbine provides the sustained power that keeps a facility running through a longer outage. Most resilient designs use both together.

How long can a backup power system run during an outage?

It depends on the fuel source. Diesel gensets are limited by on-site tank capacity and refueling, while natural gas microturbines drawing on a utility line can run continuously as long as the gas supply holds, making them well suited to extended outages.

Can a backup power system also lower my energy costs?

Yes. When configured for combined heat and power, on-site generation recovers waste heat for use in the facility, cutting energy costs and emissions during normal operation rather than only serving as emergency equipment.

What size backup power system does my facility need?

Sizing depends on your critical loads, the runtime you need to survive without the grid, and whether you want the system to serve as primary power. A load assessment is the right first step, and our team can help scope it against your resiliency goals.