APEX REGIONAL LANDFILL

Producing electricity is tough to do if your goal is a zero carbon footprint and a net reduction in air pollution. Yet that’s exactly what JBA Trusted Advisors Les Fernandez and JJ Wisdom helped accomplish at Apex Regional Landfill north of Las Vegas. They helped design a gas turbine generating plant that produces 11 megawatts of electricity for Nevada Energy – enough to power 6,000 homes using biofuel.

• The landfill is one of the nation’s largest, serving first as a quarry for the region’s roads and buildings and then as a repository for all of its solid waste.
• The operators have long been installing pipes to vent landfill gas, providing an opportunity to collect it and use it as a biofuel.
• It’s an important piece in the region’s renewable energy puzzle.

challenge

As beneficial as the technology can be, it cannot work everywhere, since only the largest landfills can produced enough gas to be economically feasible. Other challenges include:

• Landfill gas is only about 50% methane, necessitating a great deal of processing before it’s ready for a combustion turbine.
• Systems would have to perform flawlessly, given the number of utility customers who would depend on the plant for power.
• Documentation was crucial as well, given the utility’s requirements and the fact that operators would have to be able to troubleshoot quickly and efficiently should there ever be a problem.

the solutions

The electrical systems were designed by JBA Engineering Consultants and the mechanical systems by Concord Engineering of Voorhees Township, New Jersey. The mechanical systems remove moisture and pollutants from the landfill gas, compress it, pipe it about a mile to the turbines, then chill it before combustion.

• The JBA team designed all of the electric lines for the plan, documenting thousands of power and control wires individually. “I have spreadsheets that give each wire a name, note where it originates, where it’s going to, and how it’s routed,” Wisdom explains.
• An Allen Bradley SCADA system, integrated by the JBA team, provides process control and monitoring for all of the plant’s processes, including the turbines and gas handling.
• JBA handled the interface with the utility, including the design and integration of a metering system to help monitor the generators and to measure the electrical output going to the utility.
• JBA integrated a GSU (generator substation unit transformer) in the switch yard to provide protection for the site so it can instantly and automatically disconnect from the grid should there be any kind of power surge. “Let’s say a car hits a utility pole and the lines come down,” Fernandez explains. “The current is running at 200 amps, but all of a sudden it can jump to 10,000. At 10 MW, that’s probably 10,000 horsepower, not something you want surging back into your system.”
• Lighting protection was also an important concern, with proper grounding crucial to the design.

Frank Skinner, Senior Project Manager for DCO Energy, the developer and a partner in the plant’s operator, says DCO has a history with JBA and felt they could count on them for this out-of-the ordinary electrical design. “They were great,” he says. “Les is brilliant, an unbelievable guy. We were very happy with the work that he and JJ did.”.

The design process was exacting, but it has paid off in flawless operation since the generating plant was opened in 2011.