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Combustion Turbine Power Plants

Lee Layton, P.E.


Course Outline

The course begins with an in-depth look at the natural gas industry including what natural gas is, and where it is found.  The course reviews the many different ways that natural gas is categorized and an attempt is made to help understand the concept of “gas reserves”.

Following a review of the natural gas industry, the course covers the thermodynamics of a combustion turbine, the types of combustion turbines, and methods to increase the efficiency of a combustion turbine.  Then, the course ‘walks’ the reader through a typical plant from the delivery of the natural gas to the exhaust of waste heat.  Finally, the course reviews some of the environmental concerns with natural gas-fueled power plants.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

After taking this course you should,

Intended Audience

This course is intended for electrical engineers and others who want to understand the operation of combustion turbine power plants.

Benefit to Attendees

Combustion turbines are used as a building block for combined cycle power plants and are used as stand-alone peaking units.  These units will be a major component of utility generator fleets for many years.  Understanding the benefits – and the environmental issues – of combustion turbines will help the reader understand the generation choices that utilities must make to meet future power needs.

Course Introduction

Combustion turbines (CT) are one of the primary workhorses of the power industry.  Because of the abundance of natural gas, new central station power plants will likely be combined cycle plants that use combustion turbines as the first stage as well as used individually as “peakers”.  Smaller CTs have characteristics favorable for use in distributed energy resource (DER) applications.

Small combustion turbines are found in a broad array of applications including mechanical drives, base load grid-connected power generation, peaking power, and remote off-grid applications. CTs can also be used in cogeneration applications usually with the addition of a heat recovery steam generator. Combustion turbines are also available in transportable configurations allowing the plant to be moved from one location to another.

Gas turbines are relatively inexpensive with capital costs ranging from $300-$1000/kW and the costs tend to increase with decreasing power output. Compared with reciprocating engines, combustion turbines tend to cost more for smaller sizes and less at the larger sizes.

The construction process for gas turbines can take as little as several weeks to a few months, compared to years for base load power plants.  Their other main advantage is the ability to be turned on and off within minutes, supplying power during peak demand. Since single cycle (gas turbine only) power plants are less efficient than combined cycle plants, they are usually used as peaking power plants, which operate anywhere from several hours per day to a few dozen hours per year, depending on the electricity demand and the generating capacity of the region. In areas with a shortage of base load and load following power plant capacity or low fuel costs, a gas turbine power plant may regularly operate during most hours of the day. A large single cycle gas turbine power plant typically produces 100 to 400 megawatts of power and has 35–45% thermal efficiency. 

Combustion turbines have relatively low installation costs, low emissions, high heat recovery, infrequent maintenance requirements, but low energy efficiency. 

Course Content

This course content is in the following PDF document:

Combustion Turbine Power Plants

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Course Summary

Natural gas is a vital fuel for maintaining America's thriving, robust economy and new natural gas resources will continue to allow natural gas to be a choice fuel for electric power generation for many years.  To meet growing demand and to diversify our energy supply, the United States needs to continue to exploit the benefits of shale gas as well as bring in natural gas from overseas in the form of liquefied natural gas (LNG).

Combustion turbines offer low capital costs, quick installation, high-temperature exhaust for steam generation, and high reliability.  The units suffer from high operating costs and have relatively low efficiencies compared to other central station power plants.  However, when combined with a heat recovery steam generator and used in a combined cycle power plant, combustion turbines offer a major advantage for future central station electric power generation.

Proximity to natural gas mainlines and high voltage transmission is the key factor affecting the siting of new combustion turbine power plants.

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.