Microgrid & Microturbine Power Trends

Providing resiliency across diverse applications

Credit: iStock/ktsimage

There are interesting developments happening with microgrids these days. Utilities are adding them to stabilize their grids, and communities are developing a peer-to-peer consumer energy trading system to buy and sell electricity generated by their solar systems.

Microgrids have also become the hottest concept as alternatives to the aging utility grid—passing up distributed generation and smart grids—as a topic among local government planners, universities and schools, and utility planners, particularly because of their ability to provide backup power when the weather turns ugly. Technology companies such as Siemens, S&C Electric, and Schneider Electric have created new divisions to design and build them.

Policy makers are finding it politically wise to promote microgrids as well. New York, Connecticut, and Massachusetts are sponsoring and funding microgrid projects that they hope will provide reliability and resilience in the face of major storms like Superstorm Sandy.

In 2015, the New York State Energy Research and Development Authority awarded 16 cities across the state $100,000 each to evaluate how microgrids can expand customer choice, ensure power reliability, improve resiliency, and preserve the environment. It supports Governor Andrew M. Cuomo’s Reforming the Energy Vision (REV) initiative. The cities will be aided by Siemens, Power Analytics, and Booz Allen, which will study the technical and economic feasibility of the projects.

The New York REV is an energy modernization initiative begun by Governor Cuomo in April 2014 to “fundamentally transform the way electricity is distributed and used in New York State.” The intent is to move to a more market-based, decentralized approach to delivering energy. Millions of dollars are going to communities throughout the state to build microgrids as part of this initiative.

Connecticut has granted $23 million to nine microgrid projects in Bridgeport, Fairfield, Groton, Hartford, Middletown, Storrs, Windham, and Woodbridge. In 2015, it awarded $5.1 million in grants in its second solicitation to two cities and will offer another $10 million in a third solicitation. Schneider Electric, Green Energy Corp., and ZHP Systems will be partnering with the first city, Milford. Bridgeport is the second city and will be provided power by FuelCell Energy for buildings at the University of Bridgeport.

Massachusetts awarded $7 million for community microgrid and resiliency projects in September 2014, part of a larger $40 million program to prevent power outages in critical infrastructure in the state’s towns and cities. The awards went to Berkley/Taunton, Boston, Greater Lawrence Sanitary District, Northampton, South Essex Sewerage District, and Springfield. Three cities will develop microgrids, the rest will install cogeneration or combined heat and power (CHP) systems.

Here we need to differentiate between microgrids and distributed generation. Microgrids are distribution networks that connect a set of generation assets located within a specific geographic area and provide power to a group of buildings, such as a school or university campus. A microturbine, or solar system serving one building, is considered distributed generation, and not a microgrid.

However, microturbines, for the most part, are only part of this revolution. Capstone, which dominated the microturbine field in the mid 2000s, has left its competitors in the dust and has over 8,600 units providing distributed generation in all kinds of applications around the world, up from over 4,000units in 2007. These include installations for oil, gas, and other natural resources, critical power supply, renewable energy, transportation, and marine installations. It now offers 30-, 65-, 200-, 600-, 800-, and 1,000-kW models, which can be grouped to operate in series.

Ingersoll Rand, its largest competitor in 2007, sold its microturbine business to FlexEnergy in 2010. FlexEnergy now markets its 250- and 333-kW units in the oil and gas industries, and for landfill, digester, and wastewater treatment as well as in combined heat and power applications.

Bruce Beihoff, the director of technology and innovation for the Mid-West Energy Research Consortium in Milwaukee, WI, argues that microturbines are good for smaller building-level applications. A bank of microturbines could provide reliable power in a combined heat and power configuration, and each can be brought online as the building needs power. On the other hand, larger combined-cycle gas turbines are 60% efficient, compared to a microturbine’s 40%, and are attractive at the substation level and are better at load-following.

Credit: Mid-West Energy Research Consortium The first completed building in Century City Business Park

Credit: Mid-West Energy Research Consortium
The first completed building in Century City Business Park

Three Capstones in Microgrids
Capstone microturbines are operating in three microgrids today. Jim Crouse, executive vice president for sales and marketing at Capstone, explains the microgrid as evolving. “We’re often running with the utility grid as the only power source” in a building.

The most intriguing and spectacular application is at a ski resort in Russia where 38 microturbines, operating on liquefied methane, are providing the only power available to the lodge, other buildings, and the ski lift. The lodge is located 54 kilometers from St. Petersburg and the nearest power line.

Another one of the three Capstone microturbine installations in a microgrid is at the Sierra Nevada Brewery, which commissioned its microgrid in the first quarter of 2016. It includes the microturbine, a solar system, and battery storage. The brewery had already installed a solar system in 2007, and a fuel cell in 2005.

To improve grid power applications on Santa Catalina Island off the coast of California, in 2012 Southern California Edison (SCE) installed 23 Capstone microturbines—60 kW each, to produce 1.5 MW—alongside six diesel generators, which had been providing power to the island for many years. A sodium sulfur battery energy storage system was added along with the microturbines. The microgrid was added to reduce the emissions from the diesel generators, which now have catalytic converter controls installed. SCE says that 21 microturbines are currently operating to balance island demand and provide peak shaving capacity, and two are out of service.

Credit: Capstone Capstone’s model 65-kW microturbine was installed at Oncor’s Lancaster, TX, microgrid.

Credit: Capstone
Capstone’s model 65-kW microturbine
was installed at Oncor’s Lancaster, TX, microgrid.

Capstone has its own programmable logic control system and sensors, which interface with other building automated systems. “Controls are one of the key aspects of monitoring a microgrid,” says Crouse. These controls can also be programmed if the customer chooses to do so.

Microturbines do have an advantage over diesel engines or solar turbines most often used in microgrids, Crouse says. They operate with built-in inverters, just as solar and wind systems do, “so we can control our power output.” Engines and turbines require synchronous switchgears, but they are all built into the Capstone microturbine.

The third Capstone microgrid installation is at Oncor, an electrical distribution utility in Texas. In 2014, the company decided that it wanted supplemental experience with microgrids. It acquired several power generating technologies, including a microturbine, and installed them at a 100-acre site with five multi-use facilities in Lancaster, TX, explains Michael Quinn, vice president and chief technology officer at Oncor.

The staff worked with several different vendors along with S&C Electric and Schneider Electric on adapting the technologies to work in unison with the grid. The microgrid became operational in March 2015. “We specifically partnered with Capstone because of the size of their microturbine, and we see great potential,” says Quinn.

The system is able to take power from the grid, and is able to use the power generated at the site to offset the grid power. They also designed the system to isolate the microgrid from the utility grid and have the facility rely on the microgrid technologies.

Capstone’s 65-kW microturbine is joined by two solar arrays to total 106 kW. Two lithium-ion energy storage units, 25 kW and 200 kW, can be charged either onsite or from the grid. There are also four legacy diesel generators. Combined, the microgrid has a peak capacity of 900 kW and is scalable to meet any load requirement. The facilities are connected to a 13.2-kV distribution feeder and can be isolated to work independently of the grid.

“If we can use the least expensive grid power at night, we will use that source to charge the storage,” says Quinn.

There are no current plans to add another Capstone unit, but Quinn says they will add a wind turbine onsite at some point.

“We see a microgrid as an extension of the larger grid. It’s a unique reliability tool,” says Quinn. “We don’t see microgrids as a threat. We try and provide our customers with high reliability, and microgrids increase that reliability.”

The microgrid is not being run on a regular schedule. Instead it is being put through test scenarios including energy arbitrage, energy demand management, and Voltage/VAR management. Quinn says the staff is right in the middle of testing.

Landscape view of Milwaukee, Wisconsin’s Century City Business Park, which will include microgrids in its infrastructure.

Credit: Mid-West Energy Research Consortium
Landscape view of Milwaukee, Wisconsin’s Century City Business Park, which will include microgrids in its infrastructure.

Microgrids For Industry
The City of Milwaukee, Wisconsin, Redevelopment Authority and the Century City Redevelopment Corporation, along with financial help from other city and federal agencies, have developed an 86-acre regional business park to attract advanced manufacturing companies and to create jobs in the greater Milwaukee area. Microgrids will form a core part of the park’s infrastructure.

The Century City Business Park, with $40 million in investments so far, is being developed in a reclaimed industrial area of Milwaukee in several phases. The first two phases are being developed by General Capital Group, a part owner of the business park, along with the City of Milwaukee.

Alan Perlstein, executive director and CEO of Mid-West Energy Research Consortium, says that the non-profit consortium was hired to partner with the Electric Power Research Institute (EPRI) and We Energies, the local utility, to work out the design for multiple microgrids to promote the concept of an “ecotechnology ecozone” in the business park.

The consortium and its partners are now working to deter­mine load requirements, define the technology to be installed, and design system integration, says Perlstein.

The first of five buildings in Phase 1, at 52,000 square feet, is now built and the second building is in the design phase. The completed building held its open house on April 15. Companies are expected to be able to move in by the end of 2016, according to Bruce Beihoff, the director of technology and innovation for the consortium.

Beihoff says all types of generation are being considered, including gas turbines for combined heat and power, reciprocating engines, energy storage, solar, wind, and geothermal. He says locations are available for both solar and wind. A water reclamation facility will also be included to filter and recycle wastewater.

EPRI is bringing in the National Renewable Energy Laboratory wind survey group to determine what wind resources are available, Beihoff adds.

Perlstein says three different microgrid designs will be created to accommodate light, medium, and heavy manufacturers. The idea is to integrate the microgrids with the utility grid and with each other, allowing them to harmonize and maintain power supply within the buildings, and to island themselves in case the utility grid shuts down in an emergency. Test beds for distributed energy systems will be built into the microgrid so that companies can build and test equipment for smart grids.

Beihoff explains that microturbines are 10% more efficient than reciprocating engines at 40%, and about 50% quieter. However, they do not start fast, taking about 10 minutes to reach full power, and are not particularly adept at load following. That said, Beihoff notes that microturbines can meet the US Environmental Protection Agency’s emissions requirements for turbines.

Perlstein says, “We will complete the conceptual design for the microgrids with EPRI in May,” and present it to We Energies. Then, the team will present the design to the Milwaukee Common Council for further input. Once funding is obtained, the microgrids will be designed, built, and tested.

EWEB Seeks Grid Resiliency
The Eugene Water and Electricity Board (EWEB) is developing small interconnected microgrids at three sites on its system to better understand the impact and value of integrating customer– or utility–owned distributed generation into its system. The goal is to provide community resiliency in the face of disasters such as earthquakes, floods, and fire. The microgrids are also being designed to provide ancillary grid services.

EWEB was awarded $250,000 from the US Department of Energy’s Office of Electricity Delivery and Energy Reliability. The Oregon Department of Energy is contributing an additional $45,000. Power Engineers, Hailey, ID, is providing consulting services. EWEB is also finalizing an agreement with Sandia National Laboratories, which will provide other technical assistance.

EWEB chose three sites in its service territory based on their contribution to critical community needs for water, electricity, and emergency communications. The sites include the Roosevelt Operations Center, The Blanton Heights Radio Communications site, and a potable water pump station.

The Roosevelt Operations Center already has one 75-kW solar photovoltaic (PV) system installed on parking structures, and two Cummins diesel generators: 125 kW for life safety and 1 MW for standby distribution. Additional 25-kW solar PV systems will be installed at each of the sites. A 250-kW scalable containerized lithium-ion energy storage supplied by Powin Energy Corporation will be installed at the Roosevelt Operations Center, and 125-kW lithium-ion energy storage units will be installed at the other two sites.

Credit: EWEB The solar system at Eugene Water and Electric Board’s Roosevelt Operations Center will anchor the microgrid to be built there.

Credit: EWEB
The solar system at Eugene Water and Electric Board’s Roosevelt Operations Center will anchor the microgrid to be built there.

Oregon Growing Microgrids
Green Energy Corp. is a microgrid project developer and developer of open source software focused on controllers for microgrids. It is based in Eugene, OR. It partners with such companies as Duke Energy, Schneider Electric, Microgrid Institute, Powin; and utilities such as EWEB, San Diego Gas and Electric, and PEPCO on most of its projects.

According to David Tam, senior vice president of business development at Green Energy, the company’s business is structured to work with developers and third party partners to design and finance projects, construct, and then operate and maintain the microgrid as an energy provider. It also licenses its open-source Green Bus software platform to support the project.

Of the several projects Tam discusses, the most intriguing are the cannabis projects. He says the company is working with an owner and developers who have purchased 100,000-square-foot warehouses in the industrial areas of Eugene, Hillsboro, and Portland.

Credit: Trane Santa Rosa, California is developing a microgrid at its Laguna Waste Water Treatment Plant to support the local grid.

Credit: Trane
Santa Rosa, California is developing a microgrid at its Laguna Waste Water Treatment Plant to support the local grid.

Each warehouse will be divided into 10,000- to 20,000-square-foot spaces for rental to growers. A microgrid will be built to provide constant, reliable power and temperature controls for the growing environment in each rental area.

The power sources will depend on location, says Tam. Most will have solar or other type of renewable energy source, energy storage batteries, and cogeneration at each site. “We may also use ground-sourced geothermal wells,” he says. The design is to serve 85% of the customer’s load, with a high concentration of renewables.

These projects are in the development stage and additional developer partners are being sought, Tam says.

Green Energy has created Green Bus, an open-source software platform for microgrid controllers, called an Open Field Messaging Bus or FMB. It features real-time telemetry and is cloud-based. Utilizing an open-source, non-proprietary platform provides Green Energy a competitive advantage, argues Tam.

He describes the market landscape for microgrid controllers as highly competitive, with over 100 companies providing their own control software. Green Energy has to compete with large equipment suppliers, such as Siemens and GE that promote and integrate their own proprietary software controls, as well as small specialty software companies such as Optimal Power and Princeton Power Systems, he says.

Tam says hydro system stability is driving interest in microgrids in Oregon. He quotes experts who say the risk of earthquakes is rising in the state–Eugene had a 4.1 level earthquake recently. The collapse of any dams following an earthquake would also strain local water systems.

Green Energy is working with another Oregon client to design a microgrid for an assisted living and retirement campus. While the cost of microgrid power will be close to utility pricing, the client says the driver for them is the ability to market green power. They are willing to pay for the value added and resiliency of a microgrid, Tam says.

Waste Plant Serves Grid
Trane and the City of Santa Rosa look at the microgrid being developed at the city’s Waste Treatment Plant not only as a revenue source, but also as a distributed energy resource serving the local utility distribution system in peak demand times and in emergencies, a new role for the plant.

This new role expands the plant’s value. It now provides critical balancing and other power quality support services that are needed to allow more renewables onto the local grid.

The Laguna Wastewater Treatment Plant, operated by the City of Santa Rosa in northern California, treats wastewater from approximately 230,000 customers and recycles approximately 17.5 million gallons of water per day. It generates power on a daily basis from one of four, three-year-old, rotating Cummins reciprocating engine generating sets. They operate on a combination of digester gas produced at the plant and up to 10% natural gas.

The waste treatment plant has a daily peak electrical load of between 3 and 4 MW, and draws the remaining power it needs from Pacific Gas and Electric’s distribution system. The plant generates about 30% of the power it needs, and the remaining 70% it imports from the distribution grid costs up to $3.5 million a year.

Credit: EWEB Santa Rosa’s Laguna Waste Water Treatment Plant operates four reciprocating engines which will anchor a microgrid with a solar system and energy storage.

Credit: EWEB
Santa Rosa’s Laguna Waste Water Treatment Plant operates four reciprocating engines which will anchor a microgrid with a solar system and energy storage.

Trane, a brand of Ingersoll Rand, was awarded a $5 million competitive grant from the California Energy Commission to help upgrade the plant with solar, energy storage, and an advanced automation solution, thus creating a microgrid that is anticipated to stabilize energy costs and provide additional revenue sources for the city.

The microgrid will serve the plant headquarters and several other buildings plus all process loads. The plant is served by a single meter and receives power at the substation at the 69 kV level.

To meet local emissions requirements, the plant is currently limited to operating only one generating set at any given time. The new microgrid design will improve on that restriction. Two of the generating sets will be equipped with catalytic converters and will be able to operate daily to produce more power.

A 125-kW solar PV system and lithium-ion energy storage, capable of delivering 3 MW of power, will be installed and operational by the fourth quarter of 2016.

An advanced analytics platform will be operational by the end of this year, based on the cloud-based Trane Intelligent Services, giving the plant behind-the-meter capabilities. Plant operators will have the ability to visualize what’s going on with the equipment, make decisions on load shedding, for example, and when to sell power into the wholesale market.

As Michael Day, utility and smart grid sales lead for Trane, describes it, the plant engineers will be able to “keep their hands on the throttle” while also selling surplus capacity back to the grid.

The company describes Trane Intelligent Services as a “comprehensive portfolio of building energy management services.” It processes information for review, facilitates analysis to show how much and when a building consumes energy, and helps develop and implement strategies to control energy and operational costs.

The microgrid will have the capability to island the wastewater treatment plant in the case of an emergency, such as a major storm or flooding, at the command of a system operator such as PG&E or the California Independent System Operator, says Day.

Loss of grid power at the plant has been infrequent, Day says. But looking forward, with increased variable renewable generation coming onto the grid decreasing power quality, these power interruptions may increase, he says. The microgrid will allow for a smooth transition from the grid to island mode during power interruptions and reduce the potential for dropped service.

Day says the local grid needs to meet variable loads, which in the past was handled by a central utility power plant controlled by the utility. A microgrid can provide new resources to the grid, in the form of new generation load, provide flexible ramping capacity, and provide a revenue stream to the wastewater treatment plant, he adds.

A People’s Microgrid
A company called Transactive Grid is developing a community microgrid in the Gowanus and Park Slope neighborhoods of Brooklyn, where residents can buy and sell solar energy. Transactive Grid, described as “an innovative new peer-to-peer energy transaction platform,” will allow energy trading among homeowners with solar systems to create, buy, and sell energy to each other.

Computer-controlled energy measurement systems are installed in homes and linked into a community to allow residents to make independent transactions, according to an April 11 press release.

The first solar power transaction between a buyer and seller was announced in April. It was made possible using secure “Ethereum Blockchain” software with payments via PayPal. Lawrence Orsini, cofounder of Transactive Grid, calls

it the first proof of concept for the new microgrid. Special software called “Smart Contracts” will make units of energy able to be bought and sold within the local community. BE_bug_web


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