Carol Brzozowski 2016-06-06 17:31:43
As described by the US Department of Energy (DOE), microgrids are localized grids that can disconnect from the traditional grid to operate autonomously, help mitigate grid disturbances for faster system response and recovery, and strengthen grid resilience. Microgrids also support a flexible and efficient electric grid through integrating an increasing deployment of renewable energy sources such as solar and wind as well as distributed energy resources such as combined heat and power (CHP), energy storage, and demand response. Microgrids are defined by their function, not their size, according to the Microgrid Institute. Thus, they can combine various distributed energy resources to form a whole system that’s greater than its parts. The Microgrid Institute categorizes microgrids in five applications: • Off-grid: located on remote sites and other areas not connected to a local utility network. • Campus: fully interconnected with a local utility grid, but can maintain some level of service in isolation from the grid, such as during a utility outage, located on university and corporate campuses, prisons, and military bases. • Community: integrated into utility networks, serving multiple customers or services within a community to provide resilient power for vital community assets. • District energy: provides electricity and thermal energy for heating and cooling of multiple facilities. • Nanogrids: small, discrete network units operating independently within a single building or single energy domain. The Green Energy Corp. also points out that microgrids can be connected to the utility grid to purchase power or sell power back to the grid as conditions dictate. They also can be designed to operate “islanded” when the utility grid is not available—that is, a defined group of electric circuits are physically disconnected from a utility system and operated independently. Other microgrid benefits include: • improved efficiency and long-term predictable energy cost; • a reduction in harmful emissions offset by optimal use of renewable resources and energy efficiency programs; • improved efficiency for the larger power grid; • power resilience against natural disasters such as earthquakes, tsunamis, and storms; and • security against cyber and physical attacks. In December 2013, a power outage left the residents of Idaho Falls, ID, without power for hours in sub-zero temperatures. That incident is one of many driving factors that have led to the Idaho National Laboratory (INL) to study the integration of run-of-the-river hydropower into a microgrid in an effort to create greater power reliability for Idaho Fall’s municipal power system. While the extended power outage in cold weather was one of the driving factors for INL to research microgrid options for Idaho Falls, “it’s looking overall at the role microgrids can play in providing flexibility and the stability to the distribution network and the community, such as Idaho Falls,” says Rob Hovsapian, INL’s power and energy systems group leader. In studying microgrids, INL’s research will focus on dispatching run-of-the-river hydropower first, and then stored energy, followed by a controlled brownout, which entails turning sections of the power distribution network on and off as needed during an emergency. In a real-time, lab-based digital simulation environment, INL simulates the Idaho Falls’ distribution network, examining the various forms of protection possible. That’s done as to not utilize new hardware, methodologies, and control systems in the actual distribution network “and create new problems as you’re trying to solve them,” notes Hovsapian. “The simulation environment allows you to emulate different kinds of conditions we want to see and different kinds of scenarios,” he says. “We validate it and create the schema and the protection scenarios prior to employing them.” As such, it enables researchers to simulate various real-world situations to increase their understanding of the interactions between grids and microgrids, including connections and disconnections. “The nature of run-of-the-river is that it’s a must-run hydro. Different energy storage options would allow you a short energy storage time to provide stability or flexibility to the system,” says Hovsapian. “Once we create that environment for Idaho Falls to do the protection system, it also allows us to do ‘what-if’ scenarios,” says Hovsapian. “If we add battery storage, what would that mean? What if they would like to add more solar panels?” One “what if” scenario requested by the DOE of the INL is to consider adding a hydrogen refueling station to the network because Idaho Falls has the largest federal bus system that the lab operates to take workers between the Idaho Falls to its site 25 miles away, Hovsapian adds. The project is expected to cost $1 million with funding coming from the DOE and is a collaborative effort of INL, the city of Idaho Falls, Schweitzer Engineering Labs, Washington State University, and Utah Associated Municipal Power Systems. A successful outcome will lead to Idaho Falls’ adoption of a microgrid to store and dispatch hydropower and other resources in a controlled brownout to avoid blackouts and amp up the reliability factor, says Hovsapian. The city would be able to disconnect from the grid if it becomes unstable and use its existing power generation—including run-of-the-river hydropower—to provide power for critical loads, such as hospitals. “Part of our work with Idaho Falls Power is to look at their distribution network, how their grid is set up, and who is on what network as far as a critical load,” he says. “Based on that, we establish where we’re going to put the automatic switching that will allow us space on their power generation and build switching to create brownout in some sections, but keep the critical loads up-and-running.” Hovsapian notes there are multiple run-of-the-river plants, inviting the question as to how they can use their internal generation in order to provide power for the critical load, such as hospitals, police stations, and the fire department. The DOE is interested in looking beyond the Idaho Falls project to ascertain if it is a technology transfer from which other utilities can benefit, since most northwestern US utilities have some sort of run-of-the river hydroelectric generation plant, notes Hovsapian. The DOE’s Water Power Program assessed the National Inventory of Dams to evaluate the potential of additional hydropower from non-powered dams (NPDs) that could contribute to the amount of renewable energy available across the nation. In executing a technical analysis that identified 54,000 NPDs in a hydropower resource assessment, Oak Ridge National Laboratory, with INL input, sought to estimate the maximum generation potentials of all NPDs in a nationally consistent manner. The findings: there is potential to add up to 12.1 GW in US NPDs. “We dam those rivers without power, so all of those have potential for a renewable generation that we can tap into,” says Hovsapian. “We’re not saying the entire 12.1 gigawatts can be converted to power, but a good percentage of that is a possibility to be converted to run-of-the-river plant that can be utilized.” The Idaho Falls project is expected to take 18 months to complete from its anticipated starting date of early April 2016. INL also is working on a microgrid project in Humboldt County, California for Pacific Gas & Electric (PG&E) on a Red Cross evacuation route site located at the Blue Lake Rancheria Hotel, a nearby casino and hotel. “In the event of an earthquake, they want to make sure their systems are all up and running and operational,” says Hovsapian, adding that INL is doing the risking, design, and testing for the project as hardware in a loop of all of the devices and technologies that will be used before the microgrid is deployed at the site. According to Humboldt, a magazine published by Humboldt State University (HSU), the California Energy Commission awarded a $5 million grant to the Schatz Laboratory and Rancheria to construct a renewable energy microgrid there as part of a collaborative effort including HSU students, Schatz researchers, PG&E, Siemens, INL, REC Solar, Tesla, and other partners. The system is expected to encompass a 0.5-MW photovoltaic array, a 1-MWh battery storage system, a 175-kW biomass/fuel cell power system, and several diesel generators. Upon completion of the microgrid, about 50% of the casino and hotel’s energy will be derived from renewable resources, exceeding the California Renewables Portfolio Standard requiring 33% of the state’s energy come from renewable resources by 2020. David Yuen Tam, executive vice president of business development and president of Asian regions for Green Energy, notes more widespread adoption of microgrids. Green Energy points out on its website that energy markets are undergoing disruptive change with the US grid being more than 100 years old and based on a centralized design. The aging infrastructure poses major reliability and security issues, with consumer confidence declining based on power pricing and availability. Meanwhile, utilities are moving from conventional power plants that rely on coal, nuclear, and gas to renewable and distributed generation. And utilities and regulators are beginning to accept microgrids as vital to the next-generation energy system. Green Energy provides turnkey services as a microgrid software provider, utilizing the Open Field Message Bus (OpenFMB) microgrid standard, which was recently ratified by the membership of the North American Energy Standards Board. Green Energy also provides a cloud-based subscription service enabling third-party developers to utilize GreenBus and Green Energy’s expertise in financing, building, and deploying microgrids. “We are in Eugene, Oregon, where we have one of the cheapest costs of power in the entire nation,” says Tam. “Yet in Oregon, we’re seeing a prolific explosion of microgrid interest and demand in the commercial and industrial market. There are different drivers for the demand on the West and East coasts, but nonetheless, there is interest in microgrids throughout the nation.” On the East Coast, cost and resiliency are the two drivers, notes Tam. “The East Coast has storms that knock out power for long periods of time,” he says, adding the company maintains an office in Raleigh, NC. “People can lose power for a week, two weeks or more. That should not be a normal thing, but unfortunately it is on the East Coast. The cost of power is higher than on the West Coast because they rely more on nuclear and coal. “Here on the West Coast, we rely more on hydro and coal and don’t have as many storms that knock out power for long periods of time. Being renewable and green is more socially acceptable. Everyone wants to have some grid independence and grid security.” While he’s seeing some movement toward microgrids in the Midwest, Tam says there is more of an interest in large-scale wind farms and large-scale community solar. “It’s really about the economics, the need, and the mentality towards it,” says Tam. “A lot of people aren’t worried about climate change or resiliency issues. They care about power. We’re seeing more microgrids being deployed in the agricultural sector in those areas. Farmers whose crops aren’t doing as well and have all of this land, realize they can use it for microgrids or large-scale community solar and wind farms and generate revenue off of the land.” One microgrid project Green Energy is working on is with the Eugene Water and Electric Board (EWEB), the state’s largest consumer-owned utility. The pilot project is expected to demonstrate the role of energy storage and microgrid technology in improving community resiliency and response in emergency situations when transmission lines and power facilities are down. Funding for the project comes from the DOE’s Office of Electricity Delivery and Energy Reliability, which awarded $250,000, and the Oregon Built Environment & Sustainable Technologies Center, which awarded $45,000 to EWEB and its development partners, Powin Energy and Green Energy. EWEB’s Grid Edge Demonstration project was developed to show how in disasters such as earthquakes or floods, diverse renewable power supplies can help provide critical services during response and recovery. The two-year demonstration project tests microgrid technology as well as renewable energy-based storage options for support for three types of community infrastructure: energy storage for a water and electricity emergency operations hub, a water pump station, and a multi-agency communications site. Sandia National Laboratories is providing technical assistance with support from the Clean Energy States Alliance. Green Energy leverages its open-source software platform “that allows us to be product-agnostic and not to vendor lock,” says Tam. “The utilities right now are in a position where they are trying to integrate renewables but don’t want to be vendor-locked into one technology, one brand, one company.” Green Energy’s GreenBus 3.0 is a next-generation automation platform designed for interoperability and application development in near real-time telemetry environments. It is based on a set of stateless microservices providing the distributed nature of a service-oriented architecture and the abstraction layer to field components and internal system services to support rapid application development. GreenBus 3.0 is supported on numerous Linux environments, including certification on RHEL 6. The OpenFMB project defines a framework providing a specification for intelligent power systems field devices to leverage a non-proprietary and standards-based reference architecture, which consists of Internet protocol (IP) networking and Internet of Things (IoT) messaging protocols, and standardized semantic models, to enable communications and peer-to-peer information exchange. Its focus is to create a standard framework specification to guide the industry on how OpenFMB devices can be implemented to drive field device interoperability. This NAESB standards development effort was supported by the Smart Grid Interoperability Panel, among other groups. Green Energy helped set the standard for microgrid controllers, says Tam. “In order for microgrids to deploy and flourish, there has to be a plug-and-play option,” he says. “Right now, everybody does it with their proprietary solutions and custom software. But there’s no standard being set to encourage and deploy a plug-and-play platform.” EWEB heavily relies on hydroelectricity, says Tam. The utility’s website shows that it owns four hydroelectric projects with a combined rated capacity of 189 MW, augmented by wind and cogeneration. “EWEB has identified 50 critical sites within this area, including their headquarters, their critical communication tower, and a critical pump station,” he explains. “Those will be three separate microgrids in different areas of the city that are critical but can be controlled at one operation center. We’re able to manage a fleet of microgrids—not a one-off solution for one project. “Those are critical sites because they know if a Cascadia comes into play that the infrastructure of the dams is too weak to survive. It’s very likely all of those dams will go down.” Tam is referring to the Cascadia Subduction Zone 9.0, a long-sloping fault that runs from Vancouver Island to northern California in which an earthquake could potentially exceed a 9.0 in magnitude. “EWEB has been saying hydro is great, but they want to find more ways to be more resilient, more green, and less dependent on hydro, even though hydro is an important part of what they do,” he says. With the state increase in the renewable portfolio standard, utilities are looking for projects that can take advantage of renewable energy credits (REC), says Tam. “The changes in legislation made it so that utilities are no longer able to bank RECs indefinitely and now are on a limited time period with an increase of potential REC and increase of load and continuing load growth, which is why utilities are encouraging more renewable energy projects,” he adds. “Utilities are now looking for ways to help finance microgrid projects that are renewable energy projects so they can get those renewable energy credits.” Oregon also has many climate refugees—people moving from California due to the drought and fires that have affected the state—says Tam, adding that the movement is expected to significantly impact Oregon’s population and thus its water resources, which serve as a large factor for hydropower. As is the case anywhere where hydropower exists, drought that goes unmitigated by rainfall and snowpack presents potential problems for EWEB, as does the age of its dams, says Tam, adding that the cost of repairing or replacing them must be passed on to ratepayers. Aside from power reliability issues, there are also security concerns. The value in open-source software, in contrast to proprietary software, is that it’s “very difficult to hack into and is ever evolving,” notes Tam. “We design it to be more scalable and have the knowledge of the open-source community, allowing us to constantly evolve and enhance our application, which provides a greater level of security on our platform.” The chance of someone taking down a microgrid for a particular building or city block is “very low” unless those doing so have targeted nefarious intents, he adds. “A hit on power stations or substations can knock out power for large areas. A similar effect happens when a car hits a power or telephone pole.” Green Energy designs its microgrids so that 85% of the power generated will be onsite generation using a high concentration of renewables, Tam says. “It’s still connected to the grid, but we are behind the meter on the consumer side of it,” he says. “We don’t put power back on to the grid. We help the end user have grid independence if they need it.” BE Carol Brzozowski specializes in topics related to energy and technology.
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