Standby generation as a profit center

Natural gas-powered reliability.


This Waukesha mobile standby generator set could also be used in a demand-response role to reduce utility demand and energy charges at times of peak use. Courtesy: General ElectricFor healthcare centers, universities, and government facilities, it has been typical to install diesel engine-generator sets as standby generation. They are able to pick up critical elements of the facility electrical load if the utility power goes down. Diesel engines start quickly and, if properly maintained and periodically tested, provide reliable backup power. But what if another approach could supply reliable power not just to cover short-term outages, but could carry a major part of the site load in demand-response service, supplementing central-station power at peak times? Such a solution exists.

Natural Gas Engine-Generators

In a recent presentation at a Technology and Market Assessment Forum conducted by the Energy Solution Center, Aaron Trexler, Waukesha Senior Product Line Manager from GE Power discussed this alternative route. He noted the traditional approach for facilities that require standby power was diesel-fuel powered engine-generator sets. These are often sized between 500 kW and 3 MW. If properly maintained, they operate reliably for the relatively short hours needed in standby service.

However, Trexler noted, diesel units have their limitations. "They require on-site fuel storage for two or more days of operation, and that fuel has to be kept in good condition. Because of emission restrictions, unless they have significant upgrades for pollution control, they cannot be operated other than in emergency service.

Emission Restrictions on Non-Emergency Diesel

He explained that recent court decisions have confirmed emission restrictions for standby engines used on demand-response applications. "According to the U.S. Court of Appeals for the District of Columbia Circuit, beginning May 2, 2016, engines used for any demand response activity must meet emissions requirements for non-emergency engines. They must be fully compliant. Older engines are not grandfathered — they must be updated. Demand response with diesel just got more expensive, and fast-start natural gas units are a viable alternative."

Trexler suggests as an alternative that institutional and industrial owners should consider these natural gas-fired engine-generator sets such as the Jenbacher and Waukesha models offered by General Electric. "These units not only provide reliable standby power, but can also be used in a demand-response mode, reducing utility demand charges and providing economical site energy for 1,000 hours a year, or more. They are no longer a 'stranded asset,' but in effect become a profit center.

Rapid Start Now a Feature

Trexler indicates that at one time natural gas engines couldn't meet the requirement to carry full load within 15 seconds. This has been overcome. This criterion for rapid startup in emergency situations can now be achieved by many Waukesha and Jenbacher natural gas engines, matching the performance of diesel engines. Qualifying Waukesha sets are available in sizes from 200 kW to 3.6 MW, and Jenbacher sets range from 200 kW to 10.0 MW. "These units are well proven, with over 36,000 units operating in over 170 countries."

Trexler noted the high efficiencies available with today's natural gas-fired engines, with proven performance levels ranging from 35% to 50%, depending on size and type. "Application of gas-fired engine-generators in combined standby and demand-response service can show a payback as short as two and a half years. If yours is also a potential cogeneration application, it could be even sweeter."

Large gas-fired engine-generator sets such as this Jenbacher unit are in widespread use around the world for demand-response or full-time power supply as well as serving as a reliable backup unit with a 15 second start time. Courtesy: General ElectricAlternative Gaseous Fuel Options

Several of the GE lines of engine-generator sets are designed to use alternate gaseous fuels such as propane, CNG and LNG. This makes them practical alternatives even when there are no pipeline gas sources. This also fulfills the need when it is a critical standby classification that requires on-site fuel storage.

He noted that conversion of existing diesel engines to dual fuel (diesel+gas) service has some significant limitations. "You're still using diesel fuel, so there are emission restrictions. Unlike engines designed for natural gas, these conversions do not have pistons, cylinder liners, crevice volumes or bowl configurations designed for gas. Their efficiency and reliability suffers. Our gas engines are designed to combust air/fuel in such a way to extract the maximum amount of power. The same cannot be said of today's dual fuel engines."

Striking Fuel Cost Comparison

Additionally, Trexler pointed out the fuel economies with natural gas as compared with diesel. He indicated that with diesel at $1.88/gallon, the fuel cost would be $14.56/MMBtu, compared with natural gas at $2/MMBtu. "This would result in a diesel-only fuel cost for electricity of $131/MWHr versus $24/MWHr with pipeline natural gas."

He states that the cost of a natural gas-fired unit would typically be about 50% more expensive that a standby-only diesel. However, if the gas unit operates for 2,500 hours per year in demand-response mode, the project payoff is 2.5 years. This assumes no cogeneration application. There is no payoff for the diesel unit, because it can only operate in standby situations.

Quieter and Cleaner

Other advantages of gas engines include the fact that they are significantly quieter than diesel units. According to Trexler, the difference can be as high as 20 dB. Gas units on pipeline have no limitation on operating hours, and require relatively inexpensive emission controls as compared with diesel. He indicates the diesel unit will require five to ten times more expensive emission controls.

Now that the rapid-start issue has been overcome, for most institutional owners the choice of natural gas engines for combined standby and demand-response service is obvious. It's the way for your standby system to pay its way. When you are installing standby power, keep this option in front of you.


Energy Solutions Center Info on Engine Generation

DOE Information on Distributed Energy

General Electric Power Generation

This article originally appeared in the Gas Technology Summer 2016 issue.

Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
October 2018
Tools vs. sensors, functional safety, compressor rental, an operational network of maintenance and safety
September 2018
2018 Engineering Leaders under 40, Women in Engineering, Six ways to reduce waste in manufacturing, and Four robot implementation challenges.
GAMS preview, 2018 Mid-Year Report, EAM and Safety
October 2018
2018 Product of the Year; Subsurface data methodologies; Digital twins; Well lifecycle data
August 2018
SCADA standardization, capital expenditures, data-driven drilling and execution
June 2018
Machine learning, produced water benefits, programming cavity pumps
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
October 2018
Complex upgrades for system integrators; Process control safety and compliance
September 2018
Effective process analytics; Four reasons why LTE networks are not IIoT ready

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Material Handling
This digital report explains how everything from conveyors and robots to automatic picking systems and digital orders have evolved to keep pace with the speed of change in the supply chain.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
Design of Safe and Reliable Hydraulic Systems for Subsea Applications
This eGuide explains how the operation of hydraulic systems for subsea applications requires the user to consider additional aspects because of the unique conditions that apply to the setting
click me