Reciprocating Engine Generators and Microgrids: Unsung Heroes of the Electric Grid

Aug. 11, 2016
The new Microgrid Knowledge guide, Reciprocating Engine Generators and Microgrids: The Last Defense Against a Power Outage, looks at a technology that gets little attention but serves a crucial role on the electric grid.

The new Microgrid Knowledge guide, Reciprocating Engine Generators and Microgrids: The Last Defense Against a Power Outage, looks at a technology that gets little attention but serves a crucial role on the electric grid. Reciprocating engine generators are often the last line of defense when all other resources fail in a power outage. That’s just one of the reasons they are so often found in microgrids. Below is an excerpt from the report.

Superstorm Sandy knocked out power to more than 2.6 million households and businesses in New Jersey, making it the hardest hit of 20 states swept by the 2012 storm. So it was somewhat astonishing that a small barrier island in New Jersey kept its power flowing.

It’s life line? Three diesel-fueled generators with reciprocating engines.

Seaside Heights Borough had originally purchased the generators for economic reasons—to save the community money. They were meant for use at times when grid electricity became costly.

But when Sandy devastated the town’s electrical infrastructure, the community quickly saw another benefit from its $4 million investment. Emergency workers were able to rely on electricity from the three, 2 MW generators as they located and rescued endangered residents. The generators powered the water supply, kept accommodations running for rescue workers and provided electricity to community residents.

The Seaside Heights story is replicated throughout communities large and small worldwide. When all else fails during storms, with power outages everywhere, reciprocating engine generators are the last line of defense.

Their importance has heightened with today’s increasingly severe weather, threats from cyber-terrorism, and equipment failures on aging electrical grids.

Yet, the story of reciprocating engines, this mainstay, is seldom told. Newer, flashier technologies capture the public imagination, such as smart grid, advanced analytics and energy storage.

“You may not hear a lot about them in the popular press, but reciprocating engine generators can be found almost everywhere—as backup to sophisticated electrical grids in places like North America and Europe and as primary sources of electricity in remote areas of India, Africa and South America,” said Jeffrey Powell, Product Manager at Fairbanks Morse Engine.

Times you wish you had a reciprocating engine generator…

Reciprocating engine generators provide needed services in a range of settings, many of them emergency-oriented. Consider the following:

▶▶During the 2014 weather emergency known as the Polar Vortex, temperatures plunged to record-breaking lows in large swaths of the U.S. Demand for natural gas heightened as homes and power plants vied for the resource. Energy prices skyrocketed. But one forward-thinking Michigan utility was able to avoid the market volatility through a combination of intelligently timed fuel purchases and use of reciprocating engine generators that could switch from natural gas to diesel fuel.

▶▶Sometimes power outages are all about location. Communities situated at the end of a utility distribution system tend to be more prone to the last-in-the-dinner-line syndrome: With larger populations served ahead of them, they are vulnerable to energy shortfalls that can lead to reliability problems. Consider the Florida community of Homestead, which faces the double-whammy of being both in a hurricane zone and south of Miami at the end of Florida Power & Light’s service area. Homestead maintains reliability with the help of one of the nation’s largest diesel generators, an important asset when natural gas supplies become limited, and Homestead must wait in line behind Miami.

▶▶About 17 percent of the world’s population lacks access to electric power, according to the International Energy Agency. Most of the energy poor live in sub-Saharan Africa or Asia, and many have no access to an electric grid. Often reciprocating engines serve as their only dependable source of power.

What’s ahead for reciprocating engine generators

Perhaps most interesting are the fuel pairings that involve reciprocating engine generators. These include dual-fuel generators, typically natural gas and diesel, and the emerging hybrid plants that match renewable energy with fossil fuel generators. Natural gas or renewable bring lower emissions to the partnership. Diesel bring an ability to start up generators quickly, which is important when a sudden outage occurs on the grid. Diesel also brings consistency and longevity of supply not always available with wind, solar and energy storage.

Given today’s need for reliable power, it’s little surprise that use of reciprocating engine generators is expected to increase. In fact, diesel reciprocating engine generators represent the fastest-selling, least expensive form of distributed generation technology in the world, says Navigant Research in its report, ‘Diesel Generator Sets’.

[clickToTweet tweet=”The fastest-selling, cheapest form of distributed generation.” quote=”The fastest-selling, cheapest form of #distributedgeneration.”]

Globally, the diesel reciprocating engine generator market is expected to increase from 62.5 GW in 2015 to 103.7 GW in 2024. This represents a $538 billion market over the time period.

The research firm sees natural gas reciprocating engine generators capturing increasing market share due to emissions regulations and lower fuel costs. But Navigant adds that the low capital cost and fast-start capabilities of diesel units make them well-suited for back-up power, oil and gas, facilities, and critical infrastructure applications.

At the same time, the market is evolving for natural gas and hybrid reciprocating engine generators, according to Dexter Gauntlett, senior research analyst with Navigant Research. For example, leading manufacturers have formed strategic partnerships with renewable energy companies to provide integrated hybrid and microgrid solutions targeting large customers concerned with diesel costs.

Another research firm, GlobalData forecasts that the global market for diesel generators will grow from $14.7 billion in 2016 to $17.6 billion in 2020.

“The price of a gas generator can be three to four times that of a diesel generator with the same specification,” said Prabhanjan Kumar Singh, GlobalData’s analyst covering power. “Although in the long term gas generators are more economical, they lose out to diesel generators due to their high start-up cost.”

Singh added that many developing countries around the world still lack adequate grid infrastructure for electricity transportation and some lack natural gas reserves.

“The absence of trans-national or domestic gas pipelines means the price of gas increases, making it a less preferred fuel option. In this way, power back-up units such as diesel generators play an important part in meeting electricity needs,” Singh said.

So the market is strong for diesel reciprocating engine generators, and it is growing for natural gas and renewable pairings. Contemporary society requires reliable electricity; reciprocating engine generators ensure it.

But what exactly is a reciprocating engine generator? We describe how the technology works in Reciprocating Engine Generators and Microgrids: The Last Defense Against a Power Outage, available for free download courtesy of Fairbanks Morse Engine.

About the Author

Elisa Wood | Editor-in-Chief

Elisa Wood is the editor and founder of She is co-founder and former editor of Microgrid Knowledge.

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