Redundancy ensures continuous power
Serving customers worldwide necessitates the need for continuous business operations—even in the event of an outage.
When Red Ventures, the country's largest technology-enabled platform for growing sales using multiplatform customer experiences, embarked on an 180,000-sq-ft expansion to its Charlotte, N.C.-area global headquarters, operational capability was essential. The company serves the needs of customers across the globe and has seen tremendous growth—doubling its workforce in the past 5 yr—to the point where its impressive headquarters campus now serves as data center, call center, and critical office environment (see Figure 1). This need to serve customer partners around the clock also necessitated the need for continuous business operations—even in the event of an outage.
"This is a high-profile facility with a global operation that required standby power to provide operational capability in the event of a utility outage," said Andy Shadrick, president of Charlotte N.C.-based PowerWorks Electric, the electrical contractor on the project. "We were instructed to provide a generator capable of carrying the entire building load with no interruption to the normal business environment."
Dale Lancaster, chief technology officer of Red Ventures, elaborated on its importance, "Given that every minute of downtime costs us thousands of dollars per minute, we needed a backup power solution that was guaranteed to work without any single point of failure."
The PowerWorks team was brought into the project through Greg Wiley, PE, at Optima Engineering in Charlotte, N.C. Wiley recognized the importance of a reliable, cost-effective source of backup power that could also accommodate the design-build nature of the plan. "The initial design made provisions for a single 2,750-kW diesel-fueled generator," he said. "We understood the value of revising the initial plan to accommodate the client's need for reliability, but we also needed to stay on budget. Plus, the option had to fit within the footprint of the preliminary backup power solution."
Getting the most out of a backup solution
"A generator is like an insurance policy. If utility power dies, you need that policy to kick in—that's why reliability is paramount," said Shadrick. "A single-source solution is completely out-of-service during periods of routine maintenance, plus the potential of wet-stacking issues associated with not being able to adequately exercise the equipment with the necessary load prompted us to explore alternatives."
Given the mission critical nature of the project, a paralleled genset approach seemed to be more advantageous than a single generator. In addition to increased redundancy—which equates to enhanced reliability—operating the backup power systems in parallel also offered Red Ventures the benefit of scalability, which could be important if the company continues its current rate of growth.
"Based on research, we were convinced that paralleling genset technologies had come a long way since the days when traditional systems were prone to failures in their efforts to provide redundant backup power," said Lancaster. "Generac's Modular Power System (MPS) with onboard paralleling appeared to be a great solution that helped us get comfortable with the advanced approach to backup power."
Opting for N+4 redundancy
"From previous experience, the PowerWorks team had great success with Generac's MPS," said Shadrick. "It's a modular approach to standby power without the need for the traditional and costly paralleling equipment required by legacy systems. Essentially, it's the new plug-and-play of standby power that's finally bringing the advantages of multiple generators into a simple era of new technology."
Scott Collins of Generac distributor National Power Corp., Charlotte, N.C., was asked to design an alternative backup power system. "My recommended approach consisted of three 1-MW Gemini systems, offering a total of 3,000 kW of backup power that fit into a footprint that was similar to the preliminary single-engine unit. There were no changes in the way the transfer system functions," he said (see Figure 2).
Each Gemini system features two 500-kW engines contained in a single enclosure (see Figure 3). With the paralleled system designed for Red Ventures, when the need for power is triggered, the first 1,000 kW of power is available within 6 sec. The entire 3,000-kW system will be on and at full capacity in less than 10 sec.
"When Red Ventures realized the MPS system can provide N+4 for the critical load and N+1 for the entire load—all at the same price point and within the same footprint—the choice became apparent," said Collins (see Figure 4).
"Most important, the facility is never without access to power, even during system maintenance. And when you're following the standard quarterly maintenance system, especially at a mission critical facility, 4 days of exposure over the course of a year is critically unacceptable."