Islands in the Grid: How Microgrids Change the Story

Microgrids are not new. Hospitals, universities, government buildings and military bases have relied on backup generators and central heat and power (CHP) systems for years. But the emergence of renewable energy, especially solar PV, and a heightened need for more reliable and resilient electricity supply has in the last few years catapulted microgrids into the limelight.

Justin Rathke, president of Vergent Power Solutions and moderator of the Wednesday afternoon session titled “Distributed Energy in Microgrids – How Onsite Power Systems can be Integrated for Enhanced Resiliency,” said he counted at least five POWER-GEN International sessions that were related to microgrids—a topic that has seen little coverage at the event up until now.

Anne Hampson of ICF, one of four speakers in the session, has done extensive research on microgrids and distributed energy resources. She explained the traits of a microgrid, which include:

·       Distributed energy resources with the ability to island (disconnect completely) from the grid

·       Operations maintained through an active management system

·       Self-sustaining electricity source during grid/utility outage

Traditional microgrids were built to benefit the owner, but others can benefit from microgrids too, Hampson said.

Microgrids provide end users with resilient operations and reduced energy costs. They can allow utilities to defer their transmission and distribution investments and offer ancillary services. Additionally, they also can be valuable to society, by offering increased grid reliability and emissions reduction, she said.

“Natural gas CHP is an ideal anchor for microgrids,” Hampson said. “It compliments intermittent renewable energy.”

CHP leads all technologies in microgrid deployments by capacity. Currently, more than 4,400 installations, with locations in every state, make up 82 GW of CHP capacity in the U.S. In addition, 1,100 MW of microgrid capacity is installed in the U.S. and 50 percent of that capacity includes CHP, she said.

Microgrids and the 3Rs

Many things began to change after the September 11, 2001 terrorist attacks, including the idea that the U.S. electric power grid needed to be more secure. It was after Hurricane Katrina and superstorm Sandy that grid resiliency began to become a top priority. The need for a secure and resilient electricity supply has been a big driver of microgrid development, John Carroll, vice president of business development at Intelligent Power & Energy Research Corp., told the audience during his presentation.

“Economic optimization is a primary consideration,” he said, “but, the 3Rs—reliability, resiliency and redundancy–are critical.”

As DER integration into the grid causes uncertainty and increases grid operation complexity, microgrids can help grids adapt and become more flexible, Carroll said.

He also said as more generation sources and loads are added to microgrids, microgrid controllers become more and more important.

Like Carroll, Drew Gravitt, national account manager with Schneider Electric, also spoke about the importance of microgrid controllers.

In addition, he talked about the major trends in the “new energy world.” Decarbonization, digitization and decentralization are and will continue to be key drivers, he said.

Microgrids will be a big part of the energy future because they provide reliable energy, increase grid efficiency and optimization and are a source of “green” energy, Gravitt said.

Microgrid Case Study

Terry Mohn, executive consultant with OATI, a provider of utility software solutions used for trading, moving and delivering energy, was the only presenter in the session to talk about a specific installation.

OATI owns and operates two data centers in the Minneapolis area that contain data from nearly all electricity wholesale to retail transactions completed in the U.S. The reliability requirement for electricity running these data centers must be “six 9s,” Mohn said.

The company has always had backup power at both sites, but decided that it wanted to improve its reliability and resiliency. Management decided to build a microgrid.

“We wanted to optimize the use of our generation assets”.and build a bridge between the private facility owners and the utilities,” Mohn said.

Along with the microgrid, OATI is building a new building and campus. The microgrid will have several sources of generation, including roof-mounted solar panels and wind turbines, solar panels installed over a pond, a Capstone C600 CHP microturbine, battery storage and diesel generators that will be used for cold starts.

The microgrid will have 1 MW of capacity. The initial load is expected to be 600 to 700 kW and the extra capacity will be used as the facility is expanded, Mohn said.

All the speakers believe microgrids have an important role in the future of electricity generation and delivery and that they will continue to be built.

When asked what’s next for microgrids, Gravitt said he believes battery storage, which will allow more flexibility, will be the next big phase of microgrid development.

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