U.S. Army

EXECUTIVE SUMMARY [Continue to full document]

The purpose of the preliminary site assessment is to determine whether Watervliet Arsenal has the desired characteristics to be selected as a demonstration site under the project "Demonstration of Natural Gas Engine Driven Air Compressors at Department of Defense Industrial Facilities" (NGEDAC).

The NGEDAC initiative is managed by the U.S. Army Construction Engineering Research Laboratory (CERL) and is being implemented by Technology and Management Services, Inc. (TMS) and Xenergy, Inc. under Contract/Delivery Order Number DACA 88-98-D0007-0002.

The preliminary assessment provides an overview of the facility’s compressed air system, outlines potential areas for reducing system demand, evaluates the general economics of a gas driven system at the site, and identifies potential benefits or problems associated with implementing a gas driven system. The site assessment was conducted by TMS and XENERGY personnel during the week of October 30, 2000.

The preliminary assessment concludes that the Watervliet Arsenal is a good candidate for additional consideration as a demonstration site. Initial consideration for locating the unit is in Building 110 along the South Wall.

The current air flow of the main system is approximately 2,000-2,500 acfm at a supply pressure of 83-85 psig. When the site visit was conducted, the main centrifugal compressor was not in operation. The estimated annual energy costs to operate the existing compressed air system is $306,000 when the centrifugal unit is operating (the normal situation) and $277,000 when the centrifugal unit is off line (the situation on the day of the site visit).

Based on an interruptible gas supply cost of $5.00 per million Btu, using NGEDAC technology to supply about two-thirds of the compressed air demand at Watervliet will reduce energy costs to $200,000 annually. This reduction translates into an energy savings of $106,000 relative to the costs associated with the normal operating configuration using the centrifugal unit and $77,000 relative to the costs associated with the centrifugal unit off-line.

A change in the price of natural gas of $1 per million Btu, will change the level of savings by $25,000.

If the Arsenal moves forward with a Level II Assessment, two specific demand reduction strategies should be explored. Potential reductions in air leaks on the order of 300 cfm could save $22,000 in annual operating costs. The use of low-pressure air or blowers for agitator applications could save even more. Figure 1 summarizes the existing and proposed NGEDAC system energy costs under various gas price scenarios.

Maintenance costs for the NGEDAC technology are $15,000 higher annually than the existing system based on the cost of a two-year comprehensive maintenance contract. The resulting net operating savings for NGEDAC technology is $91,000 with the centrifugal unit operating and $62,000 with the centrifugal unit off-line.

The preliminary estimate of the installed system cost for the gas technology is $350,000 to $400,000. This cost could vary up or down depending on specific installation conditions and desired equipment features. The preliminary capital cost estimates are based on system environmental emission limits of 2.60 gm/bhp/hr for NOx and 1.75 gm/bhp/hr for CO. The total estimated project cost does not include any potential electrical demand reduction rebates for which this project may qualify.

Other potential cost issues to be investigated in the design phase include assessing the price of natural gas, addressing potential environmental issues that currently appear to be minimal, and finalizing the overall equipment requirements so price estimates can be formalized.

The Watervliet site has a number of other positive aspects that help make it a good demonstration site. Gas supply is readily accessible, though it may be under-pressured. The Watervliet site provides for a fairly straightforward technology application. It affords the Department of Defense an excellent opportunity to test operating a "gas/electric hybrid system." In addition, the Arsenal would be provided an opportunity to gain experience in using one of the larger-sized units available with NGEDAC technology.