Behind the scenes: Inside a renewable energy control center in downtown Chicago

Hidden among downtown Chicago’s glass and steel skyscrapers is the brain of a 21st-century power plant that is split into pieces and spread out across the U.S.

The Invenergy Control Center operates and monitors the Chicago-based clean-energy company’s fleet of wind turbines, natural gas generators and energy-storage systems, representing more than 4,000 megawatts (MW) of capacity across dozens of projects in North America.

With a slight resemblance to NASA mission control, technicians hunker over multiple monitors at workspaces arranged in rows before an oversized bank of displays that offer status updates in real-time. But instead of keeping a spaceship afloat in space, these controllers are working to keep low- and zero-emission energy sources up and running in Illinois, Texas, Washington and elsewhere.

Invernergy’s control center sits squarely at the crossroads of energy and information technology, a fundamental principle undergirding the smart grid. Weather conditions, asset power generation, fuel prices and a host of other metrics are aggregated in a single mindhive for operators, power schedulers and engineers to watch for anomalies and perform remote troubleshooting as needed.

“Turbines have quite a bit of complex circuitry,” says Brad Purtell, Invenergy’s director of wind operations support. “There are a lot of things that can cause a turbine to fault out. That’s where remote operations come in.”

Some fixes are surprisingly simple. If ice builds up on a turbine’s windvane or anemometer, for example, a controller can manually yaw the turbine to break up the ice. Others are more complicated and require controllers to remotely reset part or all of a turbine’s circuitry. For even more complex issues, on-site technicians can be called up for manual inspections and corrections.

Working behind the scenes

The Invenergy Control Center is an example of one node in an increasingly networked power system that leverages advanced communications and renewable, variable energy sources to make sure the lights stay on.

Last week, the U.S. Energy Information Administration (EIA) announced that, in March, wind and solar power combined to make up more than 10 percent of U.S. electricity generation for the first time. Texas — where Invenergy has 12 wind projects — produces more wind power than any other state, according to EIA.  

Invenergy recently broke its own wind production record when its fleet of turbines combined to generate 3,842 MW of renewable power — 84 percent of its total capacity. Across its lifetime, Invenergy’s portfolio has saved an amount of carbon dioxide emissions equivalent to taking more than 10.5 million cars off the road for a year, according to the company.

All of that emissions-free generation is great news for the environment, but as the penetration of wind and solar on the grid continues to increase, it can complicate the economics and engineering of keeping power supply and demand in constant balance. But that’s where the Chicago control center, and facilities like it, work quietly behind the scenes to help address the challenges of variable generation.

“If you were to look at our fleet, and the impact that we have, and all of the control coming from this center — it is a solution,” Purtell says. “It has solved problems in the Midwest. It has solved problems in [grid operator] PJM, with the batteries being able to regulate that frequency.”

1,000 points of data

Behind every Invenergy wind turbine is 1,000 points of data, Purtell says, with another 1,000 points of data in each substation. All of that information — including wind speeds, power generation, voltage and fault information — makes its way back to the control center where controllers and power schedulers are on hand 24 hours a day, seven days a week.

Each Invenergy project is represented in a column of operational information, displayed in text and simple line graphs on the control center’s main screens. The layout of the data was designed mostly in-house, with Invenergy’s controllers helping to shape what information is displayed and how. Everything is color-coded, with grays and whites signifying normal operations, while eye-catching colors suggest something requires attention.

Underneath it all is a custom-built, centralized Supervisory Control and Data Acquisition system that enables the control center to quickly and securely share asset data with transmission operators and balancing authorities, which maintain reliability across the regional power grid and ensure power supply meets demand.      

“It brings all of the projects into one platform and all of the communications to those different entities goes through that system,” Purtell says.

Because of the control center’s significant position in two different interconnections (Texas Interconnection and Eastern Interconnection), the facility is categorized as a “Medium Impact” system by the North American Electric Reliability Corporation (NERC). This means that Invenergy’s control center has to meet certain physical and cyber-security metrics established by NERC.

Invenergy’s facility is the culmination of a roughly decade-long evolution. What started out as an oversized closet lined with monitors evolved into a more substantial facility in Lombard, Illinois, a suburb west of Chicago. But Invenergy has expanded rapidly since then. In 2007, the company had 275 wind turbines in its portfolio — now it has roughly 10 times that number. The Lombard center soon proved inadequate, and Invenergy decided to bring its control operations downtown in July 2015, where it can coexist with market operations and the company’s other units.

It remains a unique setup to this day. Few wind farm owners also operate their assets, typically opting instead for a manufacturer or other third party to handle the day-to-day functions. EDF Renewables Service has an operations control center in San Diego, California, and Duke Energy operates one in Charlotte, North Carolina.

Invenergy’s work earned it the American Wind Energy Association’s 2017 award for excellence in operations, but, ultimately, the control center’s goal is a simple one.

“If [the turbines] are continuing to make power, then we are doing our job,” Purtell says.

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