It’s no secret that natural gas is being promoted by the industry as a “clean” alternative to other fossil fuels, or that it is catching on as a replacement for them. A more pressing question for our customers is, “What does that mean for power-generation equipment?” We also field questions on how much cleaner natural gas can be that other fossil fuels such as diesel, and whether or not these statistics make a natural gas generator a clear choice over a diesel one. Following are some of our thoughts.
Natural gas is one of the cleanest, if not the cleanest, fossil fuel energy source used in power generation. It completely eliminates mercury, and reduces CO2 (carbon dioxide) by up to 50%, NOx (nitrogen oxides - nitric oxide and nitrogen dioxide) by up to 67% and SO2 (sulfur dioxide) by up to 99% depending on the fuel it is replacing. Furthermore, when natural gas is delivered via a pipeline, it eliminates environmental considerations for on-site storage tanks, which the EPA now regulates (tanks constructed after Aug. 23, 2011).
However, that doesn’t mean that natural gas is the right fuel for every application. In addition to emissions, broad considerations such as equipment cost and fuel delivery/availability enter into the picture. There are also issues that users must evaluate closely based upon the application for the generator.
On the positive side, natural gas is not subject to wet stacking, a condition caused by carbonization of the fuel injectors when diesel generators run for long periods of time at less than 40% rated output. Wet stacking causes the engine to become clogged with a thick, fuel-soot mixture that makes it smoke and run rough, reducing fuel efficiency and engine life.
Natural gas delivered via pipeline or stored properly in a well-protected, enclosed tank isn’t subject to the buildup of sediment and fungal growth that plagues many diesel storage tanks.
On the negative side, a natural gas generator begins to derate (lose ability to operate at its power rating) at -20 degrees below zero. It also derates faster than diesel at high altitudes (approximately twice as fast – around 5% as opposed to 2-3% per 1,000 feet of altitude).
Natural gas produces approximately 40% fewer BTUs per unit than diesel.
Finally, natural gas engines burn hotter than diesel ones and for this and other reasons often have shorter lifespans.
These aren’t all the aspects of the natural gas versus diesel equation. There are also many mitigating factors purchasers should consider. For example, natural gas engines have traditionally been quieter than diesel ones, making them a prime choice for backup generators. However, newer, enclosed diesel generators are much quieter than their older, open-sided cousins.
Bi-fuel is also a big factor in the equation, because bi-fuel technologies enable a diesel engine to run with up to 70% natural gas, enabling operators that need or prefer diesel to enjoy the benefits of natural gas, as well.
HIPOWER SYSTEMS’ crack sales team has all the information purchasers need to help make the right choice of fuel source, as well as power rating and other important variables. We invite you to call us about your needs and criteria at 913-495-5557 or browse the equipment on our site. While you are there, sign up for myHIPOWER to gain access to extended site benefits.
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