David Heim and Terry Mohn 2017-04-25 11:49:39
For commercial, industrial, and institutional power consumers with a heightened need for affordable, reliable, and resilient power supply, advanced microgrids can provide not only control over power sources and energy costs, but also “green” energy and peace of mind. Microgrids employ a wide range of onsite generation resources, along with energy storage and advanced central controls, to meet the critical power needs of end-users and provide monetized grid services that yield real revenue. While the potential benefits are vast, deciding to build a microgrid can be a very complicated proposition. To be successful, facility owners need to have the right people on board who understand how a microgrid is designed, how it operates at the base level, and how it interacts with the grid and the utility. Achieving Real-world Microgrid Objectives Founded in 1995, Minnesota-based Open Access Technology International, Inc. (OATI) is a provider of Software-as-a-Service (SaaS) solutions for Transmission Scheduling, Energy Trading, Risk Management, Smart Grid, and integration. To support all of these systems, OATI operates two NERC Critical Infrastructure Protection (CIP)-compliant Data Centers, built to the highest industry standards. They help ensure nearly 100% system availability for the company’s 1,800-plus customers. When deciding to build a new data center in Bloomington, MN, OATI considered a few options, including the traditional mission-critical facility model where the building receives its power from the grid and backup generation is available in case of an outage. OATI followed this model for its corporate headquarters in Minneapolis, and it works well. But for this new facility, however, the company decided to consider other alternatives. With a critical facility that must remain operational, whether the grid is or not, OATI knew they would need onsite generation, regardless of any other decisions. With the design and costs of that generation, they thought, why not do it in a way that utilizes that generation more intelligently and more efficiently? It didn’t take long to decide that developing the campus as a microgrid made sense from both an economic and reliability standpoint. OATI set out to achieve multiple objectives for the project. First, as a critical facility, there must be onsite generation to allow the building to ride through occasional grid interruptions, and even operate independently of the grid for extended periods of time. Second, the facility must be able to use all of its generation for regular operations (as opposed to occasional backup situations) to efficiently and effectively reduce its cost of operation. Finally, the facility must be able to interact with the local distribution grid in a positive way, and demonstrate how microgrids can support the local grid. Executing a Feasibility Study Before finalizing their decision to build the new OATI Microgrid Technology Center, the company conducted a thorough feasibility analysis to determine the practicality of the effort and what it would take to achieve their operational objectives. This analysis identified the scope of the project, the microgrid objectives (technical, economic, and environmental), and the budget estimate. OATI began the process with a site survey including the load inventory, an inventory of the technology they would need onsite, metering, distribution system, and utility interconnection. They also investigated the opportunity for energy efficiency programs, with the goal of reducing energy consumption before investing in more intensive engineering efforts. The next step was to model the system based on the information and data gathered during the site survey to find the most optimal microgrid design that would satisfy the company’s objectives, at the least cost. OATI modeled both the critical and interruptible AC and DC loads—which loads needed to stay on all the time (such as the servers running their customers’ SaaS applications) and which could be cut off if necessary. They also looked at potential onsite distributed energy resources (DERs), including solar PV systems, wind turbines, and energy storage options—including batteries, fuel cells, super capacitors, flywheels, hydrogen, as well as geothermal technologies. As part of the microgrid design phase, OATI modeled the fossil-based onsite generation they would need—diesel generators, CHP plant, and gas turbines—based on the equipment characteristics, the fuel flow, and the fuel efficiency curve. In this step, OATI engineers also determined that a combined cooling, heat, and power (CCHP) system was a technically feasible solution for the proposed site. The company modeled the utility rate structure, with energy consumption rates, demand charges, and fuel cost. The feasibility analysis also identified the key stakeholders in the microgrid project and determined what net metering, state and federal incentives, grants, and payments for reduction in emissions were available for the proposed system and microgrid ownership structure. It also addressed the costs of the project, including capital costs, replacement costs, fixed and variable operation and maintenance costs, and fuel costs, as well as various miscellaneous costs such as permitting, land-use approvals, administration and government approvals, required licenses, engineering services, civil construction costs, logistics, labor wages, and the cost of system upgrades. Finally, the analysis team performed sensitivity analyses of the final microgrid design to verify the robustness of the optimized system and to determine the variability of the output results, if any of the input data and assumptions were modified. The effect of uncertainties of input variables such as the future fuel prices, load growth, wind speed average data, and solar irradiation average data were also evaluated at this time. As evidenced by this extensive list, when it comes to microgrid development and implementation, there are a lot of moving parts—both literally and figuratively. To ensure each of their goals was being met, OATI also decided to develop its own microgrid optimization tool, which they dubbed OATI GridMind. Microgrid Optimization In addition to assembling the functional components of a microgrid, the company knew that it needed to optimize the various generation sources, energy storage, and prioritize loads to maximize economic value, improve reliability and resiliency, and minimize the facility’s carbon footprint. As a provider of SaaS solutions for the energy industry, OATI has unique capabilities that most other microgrid developers lack. They leveraged this expertise to develop OATI GridMind. This “microgrid optimization controller” sits over the top of the building and provides OATI with the ability to manage their load, generation, and storage assets economically, in both grid-connected and islanded modes of operation. GridMind knows all of the characteristics of the available generation sources and the status of the building itself, as well as how much electricity is being consumed by whom, and what OATI expects will be consumed. It also has the capability to integrate with utility’s operations and supply grid services and local resiliency from the microgrid’s generation. So, if the OATI microgrid loses its grid connection for whatever reason, GridMind will allow the lower-level controls to take over to make sure that the building is stabilized and that its operation is reliable. Through the experience OATI gained developing GridMind and the Microgrid Technology Center, they have shown that the technology works and can be used for other microgrid installations across the globe. The company’s goal is to pass on this knowledge on to others who are thinking about pursuing microgrid development, whether in greenfield projects like their own, or microgrid brownfield retrofits. Paving the Way for Others After the initial stages of developing the Microgrid Technology Center, OATI knew it could leverage its experience and provide a unique opportunity to showcase how the technology they used could work for other microgrid installations. To that end, USA Microgrids, the new microgrid development arm of OATI, was founded to deliver improved economics and reliable power, while making the planning, designing, building, operating, and maintenance of a microgrid hassle-free. DE David Heim is Chief Strategy Officer for OATI and Terry Mohn is Executive Consultant of Microgrid Business Development for OATI.
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