Combined Heat and Power, or CHP, is a system that produces electricity and useful thermal energy from a single fuel source. CHP improves efficiency by capturing heat that would normally be wasted in traditional power generation and using it for heating, hot water, or process loads. If you take one key point from this article, it is that CHP routinely achieves 60 to 80 percent total system efficiency because it uses both the electrical and thermal output. A standard generator or utility supply typically delivers only 30 to 50 percent efficiency because the heat produced during generation is lost to the environment.

Facilities that adopt CHP often see reduced fuel consumption, improved reliability, and lower emissions because they replace multiple separate systems with a single integrated system. E-Finity deploys natural gas microturbine and recip engine based CHP systems that operate continuously with ultra low emissions and very high availability. These characteristics make CHP an anchor technology for resilience-focused microgrids.

What CHP Actually Does and Why It Is Different From Traditional Generation

Conventional power generation wastes the majority of its fuel input as heat. A power only turbine or generator produces electricity, but the exhaust heat is vented and unused. CHP captures that heat and repurposes it as a valuable energy product. To do this, a CHP system routes hot turbine exhaust through a heat exchanger or heat recovery unit, producing hot water, steam, or thermal energy for absorption cooling.

The key difference is simple: CHP creates multiple useful energy streams from a single input. A traditional system creates only one. This structural difference explains why CHP consistently outperforms standalone boilers and standalone generators in total efficiency.

For example, consider a facility that uses separate systems for electricity and hot water. The generator may run at 35 percent electrical efficiency, and the boiler may run at 80 percent thermal efficiency. Combined, the total system efficiency ends up much lower because each unit uses fuel independently. CHP merges these two processes, raising overall efficiency and reducing total fuel usage.

How CHP Uses a Single Fuel Source to Deliver Two Outputs

A CHP system begins with a prime mover. This may be a natural gas microturbine, reciprocating engine, fuel cell, or turbine. Microturbines are particularly effective because they produce clean exhaust and maintain stable output even under varying load conditions. To do this, the turbine compresses air, injects natural gas, combusts the mixture, and spins a shaft to generate electricity.

The exhaust leaving the turbine remains extremely hot. CHP systems harness this heat through a heat recovery module. Depending on the facility’s needs, the recovered thermal energy can produce:
• Domestic or process hot water
• Low pressure steam
• High pressure steam for industrial processes
• Chilled water with the use of absorption chillers

This captured heat offsets what would normally be produced by separate boilers or heaters. It replaces fuel consumption that would have occurred elsewhere in the facility, which is why CHP reduces total energy expenses.

Why CHP Achieves Higher Efficiency: The Technical Basis

CHP improves efficiency because it increases the useful energy output of each fuel unit. To understand this, consider the three types of efficiency that matter:
• Electrical efficiency
• Thermal efficiency
• Total system efficiency

Electrical efficiency measures how much electricity is produced per unit of fuel. Thermal efficiency measures how much useful heat is recovered. Total system efficiency combines both.

A typical grid power source might have 33 percent electrical efficiency by the time electricity reaches the facility, especially when accounting for transmission losses. A microturbine CHP system might have 30-45 percent electrical efficiency on-site but can recover an additional 40 to 50 percent as thermal energy. Total system efficiency therefore reaches 70 to 80 percent.

To achieve this, engineers must size the heat recovery unit correctly. Oversizing leads to underutilized heat. Undersizing wastes potential recovery. The feasibility phase should include thermal load profiles to match the CHP output with real consumption patterns.

How CHP Lowers Emissions and Reduces Fuel Use

Emissions fall because CHP allows a facility to do the same amount of work with less total fuel. When electrical and thermal loads are met simultaneously, the facility avoids running inefficient boilers or pulling power from a distant grid with its own losses. To do this, the CHP system operates continuously, allowing the prime mover to maintain stable combustion, which further reduces emissions.

In many urban environments, natural gas microturbines operate with single-digit parts-per-million NOx output, often meeting strict air standards without aftertreatment. This is one reason CHP receives incentive support at both federal and state levels.

A manufacturing facility using 80 percent of its recovered heat can often reduce total fuel consumption by 20 to 40 percent compared to separate heat and power. This is a direct result of replacing two separate systems with one efficient unit.

CHP in Microgrids and Why It Improves Resilience

Microgrids require firm, stable power. Solar and storage alone may not support multi-hour outages or high thermal loads. CHP anchors a microgrid by providing continuous generation and heat recovery while batteries handle instantaneous transitions.

To do this, the microgrid control system dispatches the microturbine at baseload and engages storage for fast support. This combination enables seamless islanding. During outages, the CHP system carries the majority of load while recovered heat supports processes such as hot water, sterilization, space heating, or cooling.

One E-Finity project supporting a regional healthcare facility demonstrated this advantage. During outage simulations, the microturbine CHP system maintained critical electrical and thermal loads for the entire modeled event, while the battery supplied momentary ride-through. Had the facility relied on a boiler and separate generator, both systems would have required separate fuel, maintenance, and parallel operation under stress.

How to Evaluate Whether CHP Fits Your Facility

CHP delivers maximum value when electrical and thermal loads overlap. To determine whether CHP is a fit, analyze the following:
• Average and minimum baseload demand
• Thermal demand throughout the year
• Potential for hot water, steam, or cooling loads
• Hours of operation
• Fuel type and availability
• Emissions requirements

To do this, collect one year of interval load data for electrical consumption and build a matching thermal load profile. The engineering team should then match turbine sizing to baseload and heat recovery to thermal needs. A mismatch between heat output and thermal demand reduces efficiency gains.

CHP is a strong fit for facilities such as food processing plants, data centers with absorption chillers, hotels, hospitals, universities, manufacturing sites, and water treatment facilities.

How Heat Recovery Works in Practice

The heat recovery module is the engine of CHP efficiency. It extracts heat from the turbine exhaust and transfers it to a working fluid. This can take several forms:
• Water is heated directly for use in hydronic systems
• Heat is transferred to create steam
• Thermal energy powers absorption chillers for cooling
• Heat is stored in buffer tanks for load shifting

To do this correctly, engineers must map the exhaust temperature of the microturbine, the required thermal output, and the system’s return water temperature. The delta between these determines recovery potential.

A facility with stable hot water needs often achieves the highest thermal utilization rates. A facility with intermittent thermal loads may incorporate thermal storage so recovered heat is not wasted.