Selecting a Gas Turbine for Combined Heat and Power Projects

Selecting the right gas turbine is a critical decision for any combined heat and power (CHP) project. The best choice balances electricity generation with usable heat demand.

Beyond power output, project managers must assess heat demand, fuel flexibility, efficiency, operating conditions, and lifecycle costs to find a solution that supports both technical and commercial goals.

A structured selection process can reduce project risks, improve energy utilization, and provide a stronger foundation for reliable long-term operation.

Start With the Site’s Electricity and Heat Demand

Begin with hourly electricity and thermal demand data, ideally covering at least one full year. Monthly averages can conceal seasonal peaks, shutdowns, and periods of low heat consumption.

Identify the required heat medium, temperature, pressure, and quality. A plant needing high-pressure process steam has different requirements from a facility using hot water for space heating.

Compare the timing of both demands. A gas turbine may produce attractive amounts of electricity, but excess heat has limited value when the site cannot use or economically export it.

For each operating scenario, establish minimum, typical, and peak loads. Include expected production changes, maintenance periods, and future expansion so the selected equipment remains useful beyond commissioning.

Size the Gas Turbine Around Usable Heat and Operating Hours

In many industrial CHP projects, thermal demand provides the starting point for sizing because recovered heat is difficult to store or export without additional infrastructure.

Compare turbine exhaust flow and temperature with the heat recovery system’s requirements. The heat recovery steam generator, or HRSG, must deliver the required steam conditions across realistic operating loads.

Then check electrical output against site demand, grid import arrangements, and any export restrictions. A heat-led solution may still require purchased electricity during peak electrical demand.

An electricity-led design can be appropriate when power is especially valuable or export is permitted. However, quantify periods of unused heat and their effect on project economics.

Evaluate multiple equipment sizes and configurations using the same hourly demand profile. A smaller unit operating steadily can outperform a larger unit that frequently runs at part load.

Multiple units may improve operational flexibility and resilience, but they also add equipment, controls, maintenance interfaces, and capital cost. Compare those tradeoffs against the site’s actual reliability requirements.

Compare Efficiency at Real Operating Conditions

Do not select a turbine solely on its published electrical efficiency or combined efficiency. Confirm the fuel basis, reference conditions, load point, and definition of useful heat.

Combined efficiency generally relates net electricity and useful recovered heat to fuel input. Heat that is generated but cannot be used should not be counted as a project benefit.

Use consistent lower heating value or higher heating value assumptions across all bids. Mixing these bases can make competing efficiency figures appear different when they are not.

Request performance data at full and part load, including exhaust characteristics. Model expected starts, shutdowns, standby periods, and degradation over time rather than assuming continuous design-point operation.

Account for site conditions such as ambient temperature, elevation, humidity, inlet losses, and exhaust backpressure. Hot weather and high elevation can reduce available output and alter project returns.

Ask suppliers to distinguish gross turbine output from net plant output after auxiliary consumption. Compare guaranteed figures at specified site conditions, not just nominal catalog ratings.

Check Fuel Supply, Emissions, and Heat Recovery Together

Confirm fuel composition, pressure, temperature, availability, and contractual limits early. Gas quality variations can affect combustion, output, emissions, and the need for fuel treatment or compression.

Where supply interruption is a material risk, investigate dual-fuel capability or an alternative operating arrangement. Include switching requirements, storage, permitting, and the cost of maintaining backup fuel.

If hydrogen blending is being considered, obtain a specific supplier confirmation for the proposed fuel composition and operating range. Future capability should not be treated as a guaranteed feature.

Establish applicable emissions limits and permitting requirements before finalizing the configuration. Combustion technology, exhaust treatment, and monitoring equipment can affect cost, layout, and operating flexibility.

Supplementary firing can increase steam production when demand exceeds the heat available from turbine exhaust. Assess its fuel consumption and emissions separately when comparing overall project performance.

Also review HRSG bypass arrangements, startup requirements, water treatment, condensate return, and steam integration. These interfaces determine whether recovered heat can be delivered reliably and safely.

Build a Lifecycle Cost Comparison

Evaluate each shortlisted option using the same project horizon, operating profile, fuel price assumptions, electricity tariffs, and financial parameters. Document assumptions so decision-makers can challenge them.

Include turbine and generator costs alongside the HRSG, installation, civil works, grid connection, fuel systems, emissions controls, engineering, commissioning, and owner’s costs.

Operating costs should include fuel, water, consumables, routine maintenance, planned overhauls, spare parts, and labor. Model the timing of major maintenance rather than using only an annual average.

Calculate the value of electricity and useful heat using the site’s actual alternatives. Account for demand charges, standby tariffs, export limits, and the cost of backup boilers where applicable.

Test sensitivity to fuel prices, power prices, operating hours, and heat utilization. A project that works only under optimistic assumptions needs further review before equipment is ordered.

Use metrics such as net present value and payback alongside availability and operational risk. The lowest purchase price is not necessarily the lowest-cost solution over the project life.

Assess Reliability, Delivery Risk, and Supplier Support

Define the consequences of an unplanned outage for both production and heat supply. Determine whether grid power, standby boilers, spare equipment, or contractual service response can cover interruptions.

Review maintenance intervals, overhaul scope, spare parts lead times, and local service capability. Ask for evidence of relevant operating experience with comparable fuels, duty cycles, and applications.

Confirm the delivery schedule for major equipment and identify dependencies such as permits, utility connections, and long-lead components. Include realistic allowances for installation, testing, and commissioning.

For projects with multiple contractors, assign clear responsibility for performance at equipment interfaces. In particular, align turbine exhaust guarantees with HRSG design assumptions and plant acceptance tests.

SINO-QNP’s EPC services cover power plant projects up to 400 MW, with scope options spanning feasibility, design, construction, commissioning, and operator training.

For a specific CHP project, confirm the proposed contracting scope, exclusions, guarantees, and service arrangements. An integrated delivery approach can reduce coordination gaps when responsibilities are clearly documented.

Use a Consistent Selection Checklist

Before requesting final proposals, issue suppliers the same load profiles, site conditions, fuel specification, emissions requirements, grid constraints, and expected operating philosophy.

Require bids to state net output, useful heat delivery, fuel consumption, part-load performance, maintenance assumptions, delivery dates, and warranty conditions under defined site conditions.

Compare technical compliance first, then evaluate lifecycle economics and delivery risk. Record deviations and clarify whether proposed performance guarantees apply to individual equipment or the integrated plant.

The right gas turbine is the one that meets the site’s electricity and usable heat needs reliably at an acceptable lifecycle cost. Verify that fit across realistic operating scenarios before committing.