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Technical

Highlights

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-99-048

December 1999

Office of Transportation and Air Quality

Blue Sky Series Engines

What are Blue Sky Series engines?

They’re engines having lower emission levels than our mandatory standards—usually at least 40 percent cleaner. Meeting this voluntary standard earns manufacturers a Blue Sky Series designation for these engines. Manufacturers who choose to get this certification agree to keep

these engines at Blue Sky levels throughout their useful life.

Why is EPA setting up this voluntary program?

We want to encourage manufacturers to introduce innovative technologies that can reduce emissions below the mandatory levels. Current

programs have a single qualifying threshold and don’t try to differentiate

engines that operate cleaner to meet voluntary standards. In many cases,

technologies are promising, but companies haven’t developed them

enough so we can require a higher degree of control for all engines.

Creating a program of voluntary standards for low-emitting engines,

including provisions to make sure emissions remain low in the field, will

strongly advance the next generation of emission-control technologies. At

At the U.S. Environmental Protection Agency (EPA), we have finalized

emission standards for nonroad and marine diesel engines. Each

program has voluntary emission standards for certifying engines—

which we call Blue Sky Series engines—that operate much cleaner

than the regulations require.
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the same time, our certification will protect the public against false

claims of environmentally beneficial products.

What technologies can produce engines than meet

Blue Sky standards?

The most likely technologies include adding various devices that treat

exhaust gases or converting the engine to operate on an alternative fuel,

such as natural gas. Engines with these technologies have been operating

in pilot programs and other limited applications for several years.

Are Blue Sky engines available for sale?

Not yet. Although some manufacturers are close to being able to produce

them, as of this printing none has certified one. Mostly, that’s because

isolated requests for especially clean-burning engines don’t justify the

expense of developing them. As an operator, manufacturer, or government representative, you can advance this program by cooperating as

much as possible to identify common needs and interests. Collectively

identifying product needs across the country may at some point help a

manufacturer to justify offering the low-emission engines (and associated vehicles, equipment, or vessels).

What does the Blue Sky name mean for the

marketplace?

Once engines become available, states and potential buyers can judge the

costs and benefits of buying low-emission engines. State and local

governments are developing ways to add incentives for producing and

buying these engines. For example, State governments have started to

specify that companies should use equipment with Blue Sky Series

engines to gain an advantage in bidding on construction contracts . State

and local governments have also started asking companies that need

permits and environmental impact statements for new construction to use

Blue Sky Series engines, if possible.

The emission standards for marine diesel engines don’t start for a few

years, so manufacturers may take longer to make these engines available.

Once they do, port authorities may create incentives or requirements for

operators to buy them. For example, a port authority could require a

company wanting more presence in a port to use vessels with lowemitting engines.
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The Blue Sky Series programs are still very new. Several industry and

government representatives are exploring ideas to increase the effectiveness of the voluntary emission standards. To find out more about what is

happening and who is active in this field, see “Where can I get more

information” below.

How will EPA help make Blue Sky Series engines

marketable?

We’re eager to offer information and help people in industry and government communicate so Blue Sky Series engines can reach the marketplace. Of course, we’re limited in our ability or authority to add requirements or incentives that will encourage companies to buy and sell them.

Where can I get more information?

You can get electronic documents on nonroad and marine diesel engines

from the Office of Transportation and Air Quality’s web site at:

www.epa.gov/otaq/

For other information, please contact Alan Stout at:

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

2000 Traverwood Drive

Ann Arbor, MI 48105

(734) 214-4805

e-mail: stout.alan@epa.gov