Gas turbine microgrids are getting smarter, offering new services, and gaining new customers, as we explain in this excerpt from Gas Turbine Microgrids: Reliability and Sustainability through Intelligence.
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Gas turbine microgrids are growing in sophistication as microgrid controllers become more advanced.
Control technology tends to accomplish such functions as islanding and frequency control. More advanced controls — including those being developed by Solar Turbines — offer the ability to automatically leverage energy prices. They can calculate best pricing among on-site resources at any given moment or between the grid and the microgrid.
New advanced controllers also may leverage resources for lowest emissions, greatest use of renewables, reduction of grid congestion or system demand, or other variables.
The bottom line is that an advanced microgrid is ultimately a technology tailored to solve a customer problem. As a result, microgrids are rarely developed in a plug-and-play fashion. Instead, they often require a great deal of pre-installation study by an experienced and knowledgeable energy company.
“Microgrid control is a question of operating philosophy,” said Herman Snodgrass, Solar Turbines design engineer for microgrid control systems. “The more complex the system, the more we need a clear definition of the customer’s control philosophy. Everybody does things a little bit differently.”
Customer base changing and growing
Gas turbine microgrids are not only growing more sophisticated, but they also are finding a wider customer base. Early microgrid customers tended to be universities and hospitals. Today microgrids are increasingly being installed by cities and towns, data centers, manufacturers, business parks, stores and in a few instances, residential housing developments.
Electric utilities also are increasingly pursuing microgrids, either on behalf of their customers or to bolster their grid. AEP, Duke Energy, Exelon, National Grid and Pacific Gas & Electric are among the utility giants with microgrid development plans.
While utilities offer a large potential market of gas turbine microgrids, hurdles remain to their full market participation.
“A key problem is lack of regulatory clarity when it comes to utilities. Microgrids are not clearly defined in regulation,” said Chris Lyons, power generation program manager at Solar Turbines. “Some policymakers describe them as generation, others as distribution or reliability assets.”
As a result, it is unclear whether or not utilities can recover microgrid investments in their rates, especially in restructured states. “Until public utility commissions define microgrids and resolve this problem, many utilities may move slowly on microgrid investments,” he added.
Unconventional microgrid customers
Other less conventional markets also offer promise for microgrid technology—these include ships, planes, offshore rigs and mines.
For example, an offshore oil rig that experiences a generation shortfall or disruption, might use microgrid controls to shed loads, so that its critical needs are met. The controller will turn off power to some lights or unnecessary living quarter services, so that it can keep load pumps functioning.
If the platform goes totally black, it faces a time-consuming restart process.
“You have to go start your diesel generators. You have to slowly bring everything back up. So, if they have an outage, it is huge. The first time our system spares them an outage, it pays for itself,” Snodgrass said.
Gas turbine as a microgrid backbone
The microgrid industry’s growth depends on education, Lyons said. Many energy customers still do not understand the full capabilities of an advanced gas turbine microgrid, especially one that uses combined heat and power (CHP).
For example, many are unaware of a CHP plant’s spinning reserve capability when the unit is operating at partial load.
“They are still very efficient but also have the ability to provide quick dispatching power to offset the arrival of cloud cover over a PV plant, or other interruptions in renewable power supplies. At the same time, they provide valuable VARs (Volt Amperes Reactive), supporting the distribution system,” he said.
Such quick response makes gas turbines a central part —a backbone—of today’s advanced microgrid, added Daniel Fingleton, program manager for strategic growth and special projects at Solar Turbines. “They offer a bridge to more renewable energy and lower carbon emissions.”
Microgrids are gaining traction worldwide. And as they do, expect to see growing use of gas turbines to serve them.
