1. Micro-turbine/generators gas-fired, have recuperators to capture exhaust heat for improving engine efficiency and heating water

This microgrid is not located on an island, a sequestered military site, or in a state with incentives for distributed energy. And it’s not serving a tech or clean/green stock darling of Wall Street with an amped-up market value seeking to remake the electricity industry in its own image. Rather, it’s an advanced microgrid serving the world headquarters of Black & Veatch in Overland Park, Kan. B&V, one of the industry’s venerable engineering, procurement, and construction (EPC) companies is helping to pave the way for further microgrid deployment.

The term microgrid has been around for at least 15 years. Like so many buzzy phrases before it—clean coal, smart grid, distributed power, clean tech—its definition is tough to pin down. CCJ ONsite defines it as a set of generating assets with diverse energy resources operated in an integrated fashion to serve the electrical and thermal-energy needs of a building, a campus, a cluster of commercial buildings, a town, or a neighborhood as a supplement to, and typically in parallel with, a utility grid.

These systems can enhance resiliency and sustainability, or make energy costs more predictable; whether for those in the utility system or located in island or remote regions with limited or no connection to the grid. The diversity and integration of the assets in Black & Veatch’s microgrid are perhaps the most striking:

• Two 65-kW gas-fired micro-turbine/generators, equipped with recuperators to capture exhaust heat and raise turbine efficiency. Turbine exhaust heat is also used to heat water for the building HVAC system (Fig 1).

• 50-kW of rooftop solar PV panels split equally between two wings of the company’s innovation pavilion. A string of micro-inverters manages the DC-AC interface.

• 100-kW lithium-ion battery energy storage system (BESS) to shave peak load, manage voltage and frequency response of the variable output solar PV, provide backup power in the event of emergencies, and others ensure that building electrical demand is met under virtually all but the most extreme outage conditions (Fig 2).

• Forty-five electric vehicle charging stations, two installed in 2011, seven new ones as part of the microgrid, and 36 in partnership with a local utility.

• Liquid extraction from a geothermal resource beneath the campus to improve overall HVAC efficiency and keep walkways free of ice in winter.

2. Energy storage is provided by a 100-kV lithium battery system. It helps shave load peaks

Other important features include islanding capability from the utility grid in the event of a utility power outage and the application of B&V’s home-grown energy management system and software based on the company’s Asset 360 cloud-based analytics platform. The microgrid, which can produce around 1300 MWh annually, was commissioned at the end of April 2015.

“Each individual piece of the system, and the system as a whole, is monitored 24/7/365 so we can gain insights into operations and how to improve performance,” said Jason Abiecunas, project manager and microgrid business lead for Black & Veatch. “Real time and historical data are displayed at interactive touch screens in our Innovation Pavilion, along with usage profiles for the east and west wings, and floor by floor.”

“It’s important for us to be leaders in continued technology evolution,” continued Abiecunas, “microgrids aren’t going to replace the prevalent utility industry infrastructure, but building and operating our own microgrid better prepares us to provide new services to our traditional utility clients and other emerging owner/operators of localized electricity infrastructure.”

Microgrids are receiving added attention these days because of another buzz word issue—resiliency. Some industry observers theorize that a distributed architecture for power generation and delivery may someday be more reliable than the traditional “big iron” centralized approach, prone to high-profile outages from weather and other catastrophic events that appear to be on the rise (sidebar).

But the big-iron approach is, generally, so reliable that the average customer experiences only one to two hours with no electricity a year. Reliability is different from power quality, though, and power quality is the more important metric in today’s world of digital everything.

The combination of centralized and decentralized models may create the best resiliency scenario.

Microgrids predate the central-station model

Microgrid may be a new word in your vocabulary, but it’s certainly not a new idea. There were hundreds of thousands of microgrids operating in the US about the time of the Great Depression, before the benefits of integrating large central stations, high-voltage transmission lines, and distribution systems into an electric system were made available nationwide by the Rural Electrification Administration (REA).

For microgrids in the US, this latest “fling” with the technology is not driven by need, as it was in the early 1900s, but by the idea that the power quality will be better, the reliability of energy supply will be higher, the cost of energy will be lower, etc. The jury is still out. As with most everything else, microgrids will be a positive in some instances, a marginal solution in others. Industry grey heads may remember the “total energy” movement of the late 1960s and early 1970s; it fizzled when utilities reduced the price of energy to large customers and owners faced the realities of O&M staffing and the cost of upkeep.

Sure, microgrid technology is much more advanced today than it was in the 1920s, 1930s, and 1940s when Delco-Light and similar systems dominated the market. But the technologies used to generate bulk power today also are much more efficient, premium fuel is readily available at affordable cost (in the US, at least), and reliability of electric supply likely never has been better. Do your homework before making a big-dollar commitment.

The editors spoke with two industry seniors born into farm families about what life was like before the REA distribution lines got to their homesteads. Clyde Maughan, president, Maughan Generator Consultants, who just turned 89, recalled his experiences (including a gasoline fire) with the Delco-Light unit on the family’s Idaho farm. “Limited capability,” he said. Maughan will be presenting at the Generator Users Group meeting, Nov 4-5, 2015, if you want details.

Rodger Anderson of DRS Technologies, perhaps best known industry-wide for his vane pinning solution to lock in place airfoils in GE frames, hails from Minnesota. REA distribution lines got to his family’s farm in 1949. He remembers their Delco-Light system well. It differed from Maughan’s in that the engine started automatically when battery voltage dropped to a given level; the Maughan engine was manual start/stop.

Marshall, the closest city (population about 4000 in the early 1940s) to the Anderson farm had a municipal microgrid, with heat recovered during the production of electricity also delivered to customers via a downtown thermal loop. Seems everything old is new again.

In case you’re thinking renewables is one of the big differences between these ancient microgrids and today’s, guess again. Anderson said the farm next to theirs was powered by a Jacobs Wind Energy System. Attend the upcoming CTOTF™ fall meeting, where Anderson will be presenting on Frame 5 fixes, and you can tap into his microgrid experience.

Consider taking a few minutes to trace the history of microgrids. The summary linked here provides valuable perspective.