The North American gas industry changed in fundamental ways in the 1990s. Deregulation created an energy marketplace filled with opportunities for innovations not possible under the old system.

Gas company organizations became leaner to meet competitive pressures and began to outsource such functions as engineering and construction. At the same time, energy companies faced demand for additional facilities, from city gates to measurement points, to meet customer needs.

The old way of doing business, which required extensive project development schedules to accommodate everything from facility permitting to equipment selection, would not do. The shift from rate-based monopolies to a market-driven competitive energy industry required new ideas and new ways of looking at pipeline facilities.

Deregulation, clean air policies and ever-increasing levels of gas consumption created an unprecedented demand for new interconnections to gas transmissions systems. On the utility side, higher demand charges and competitive commodity rates made new liquefied natural gas (LNG) peak shaving facilities a viable alternative to long-term gas contracts. In all cases, shorter project schedules required new types of preapproved, premanufactured facilities for suppliers and end users.

A group of gas industry engineering professionals saw the need for a new solution, so they formed Northstar Industries in 1996.

Complete system solution

Northstar recognized the need for a complete system solution to the interconnection process with interstate gas pipelines as well as other applications, including new LNG facilities, that used proven components in innovative ways.

The large number of new interconnects, ranging from the inner cities to remote rural locations, combined with constrained corporate budgets to demand a complete, preapproved solution to the complex process of building a portable, low-profile, quiet, code-compliant and environmentally friendly interconnect to a gas transmission line.

Northstar set out to create a prototype of a premanufactured, modular gate station. The resulting design was based on a 100 MMcf/d station that can be skid-mounted or contained in a precast concrete building. The self-contained 12- by 60-ft facility includes filtering, metering, regulating, preheat, odorant, SCADA and power equipment. Based on that original prototype, Northstar developed premanufactured LNG plants and other pipeline topside facilities for odorization, preheating, SCADA and pig launchers and receivers.

The facility, which offers capacities ranging to 500 MMcf/d, can be used as a stand-alone city gate or as the control center for LNG peak shaving installations. Because each modular station is designed for specific needs using standard components, it can be used as a stand-alone installation, or each individual module can operate independently.

Northstar fabricates the modular systems at an 85,000-sq ft workspace that also houses its full-service staff. The company has been technically and commercially approved to provide these services and systems by every major pipeline in the country and by many power developers and local distribution com­panies (LDCs).

Northstar also provides engineering for new pipe­lines, AM/FM services, operations and maintenance plans and network analysis, and ongoing field services for meter inspections and small capital projects.

City gates

Each city gate station tends to be slightly different, depending on the needs of the utility and gas transmission company. However, most stations have common equipment, including systems for metering, gas regulation, SCADA, odorant injection, heating and power.

In the past, these city gate stations typically were constructed individually and onsite, an expensive and time-consuming process.

Also, gate stations often consist of several separate buildings. The transmission company and the utility would own certain separate equipment that they also wanted housed separately. Not only did this hinder efficiency, but it also left a larger footprint.

Gate station construction can be complicated by location. Stations might be sited in remote rural areas or in urban neighborhoods sensitive to everything from noise and odor to environmental aesthetics. Gate stations in or near neighborhoods can face a lengthy and often contentious approval process. Those in rural areas are more prone to power outages and may be difficult to service.

The answer is a manufactured, portable, modular, single-building approach that combines key gate station functions, including filtering, metering, flow control, preheating, pressure regulation, gas analysis and odorization. It also can be configured to supply power and heat to a host site.

Developing the prototype

In 1997, Northstar constructed its first prototype to meet the demands of a fast-track project. Two interconnects – one for 50,000 dekatherms per day and a larger, 100,000-dekatherm-per-day facility – were required to connect Peco Energy Co., an LDC, to the Duke interstate pipeline. The project had a tight budget, and negotiations with neighborhood groups were complicated by environmentally based objections to the project.

The original design called for multiple field-constructed buildings, with large, in-line heaters for filtering, metering, flow control, preheating, regulating and SCADA functions. Because of opposition from nearby neighborhoods, the project faced a long, confrontational approval process that might ultimately be futile.

Northstar worked with the LDC and the pipeline to develop an innovative solution that would satisfy the technical needs and neighborhood concerns. A preliminary engineering process supported the use of the new technology. The prototype and a sister facility eventually were built to supply the new loads. The revised project had a lower profile, a smaller footprint and an eight-month completion schedule. Together, these efficiencies resulted in a sophisticated, highly capable facility that came in significantly under budget and on schedule.

Each module can be used separately or together to provide filtering, metering, regulating, preheating, SCADA and power for interconnection with the interstate pipelines.

The modular station makes new interconnects less complicated by providing a system for measuring, heating, odorizing and controlling the process for a remote feed. For example, the modules can be used separately to serve as an inline heater, DAC room or mainline odorizer.

The station also can be put onsite with LNG storage tanks or propane storage tanks to provide measuring, heating and odorizing control during the storage and vaporization process.

Users

Complete stations and interconnect services have been used for several pipeline connections to power plants and new franchise areas.

Installed facility sizes have ranged from 2,500 dekatherms per day to 500,000 dekatherms per day. Facilities have been installed for Duke Energy, El Paso Energy, Calpine, NRG, Williams Pipeline, ANR Pipeline, PNGTS, Maine Natural Gas, Energy East and Bay State Gas, along with several LDCs and independent power companies.

Individual modules have been used for topside facilities on new pipelines, for MLV site buildings, mainline odorizers, gas heaters, chromatographs and LNG facilities throughout North America. These facilities are supplying energy to new gas distribution franchises, industrial customers and power plant projects.

LNG facilities using Northstar Industries system have been installed in Greenville, N.C., for Greenville Utilities, and in Whately, Mass., for Berkshire Gas.