Spokane Microgrid Distributed Generation and Storage

Our team's mission is to design placement and integration of distributed generators and energy storage with the developing Spokane Microgrid.

Background
On November 17, 2015, a strong windstorm hit the City of Spokane. It severed the electric transmission from the Columbia River generating stations. It was over four weeks before Avista Utilities, the local electric power utility, fully restored electrical service.

Proposed Solution
Avista Utilities is working with Federal Programs such as Smart Cities to develop a Smart grid for Spokane. As a part of this Smart grid, a Microgrid will also be implemented. These improvements will improve reliability thus ensuring a greater level of service, and hopefully lowering cost accrued during blackouts such as the one caused by the windstorm.

Avista has contacted the University of Idaho (UoI) and has funded research groups to assist. Currently, there are three teams: the Master Control team, the Automated Generator Control (AGC) team, and the Smart Spokane team, described on this page.

Smart Grids
According to smartgrid.gov, a Smart Grid is an electrical grid that has been integrated with modern digital technology to allow it to sense and respond to changes in electric demand. Thus it creates a "two-way communication between the utility and its customers." This communication and response is increasingly more important as the customers can contribute to generation with renewable energy generators such as solar panels.

MicroGrids
The U.S. Department of Energy (DOE) defines a microgrid as a group of interconnected loads and distributed energy resources within a clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid. A microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or islanded-mode (1).

Hospital Generators
Determine complex power provided by the generators Identify the steps needed to convert the generators fuel supply from diesel to natural gas Assess changed in power output caused by the fuel change Collect full generator nameplate data of all the hospital generators Locate any other possible generators that can be slaved to the Smart Grid Controller

Relays
Determine how to use the relays to properly bring up DG’s and hospital backup generators Determine out how many connections can be made on a single relay Work with the Master Controller group on load shedding scheme and the sequencing of relay switching Determine measurements that need to be taken and sent to master controller</li> Figure out the most reliable and secure method of communication between the relay and master controller</li> Find the best market price for relays</li> Determine locations and amount of relays needed according to DG and backup generator specs</li>

Solar
 </li> Find the most reliable and highest quality solar generator on the market</li> Find the best locations to install the solar generators on the basis of space, and sun exposer</li> Learn how to best set up the transfer of energy to the grid</li>
 * Determine the maximum amount of solar generators that can be installed according to:</li>
 * -Location
 * -Cost
 * -Law/Property ownership

Energy Storage

 * Ascertain the best type of storage for each application
 * -Daily Discharge
 * -High Density Emergency Storage


 * Find the most reliable and highest quality energy storage device(s) on the market


 * Determine amount of energy storage devices needed in order to satisfy load profiles


 * Determine maximum amount of energy storage resources that can be installed (rooftop space, empty lots etc.)


 * Find best locations to install energy storage devices

Deliverables

 * A schematic detailing the interconnection of the distributed generators, the charge controllers, the battery banks, the converters, and the grid.
 * Low-scale simulation of the design
 * Map of recommend locations for distributed generators, battery banks, etc.

Integrating and Improving Existing Assets
Within the Microgrid area are three main hospitals, Deaconess, Sacred Heart, and Shriners. The fuel for the generators is currently diesel. To reduce the environmental impact from running these generators, the team petitioned the client, Avista to offer an incentive on the electrical rates if they would use a conversion kit to change the fuel consumed by the generators to natural gas.

Natural gas burns cleaner than diesel and is readily available in Spokane. It should also be cheaper than diesel. The team is currently investigating the change in energy output.

The team plans to investigate other equipement that would allow the generators to sync with the grid and follow the master controller commands.

Inter-team Cooperation: Control Communication
Smart Spokane has discussed the relays to be used will be Viper relays and the ATS appropriate to each generator. Discussion on data protocols and measurements will be held in the future.

Solar Generation
The team is currently investigating the best available locations for the solar panels using Google Earth. the client contact, Randy has mentioned that the Event Center is looking to place solar panels on its roof.

Further investigation into best market sources and energy storage will wait until each location data determined.

Energy Storage
The two current battery bank types under consideration are Lithium-ion and Vanadium Redox. These two battery banks are stored within a container similar to Intermodal containers seen on freight ships. The Lithium-ion has the higher energy density. Therefore the equivalent battery bank is smaller compared to the Vanadium Redox. The disadvantage of the Lithium-ion, is that it experiences a significant capacity loss from a charge/discharge cycle. The Vanadium Redox battery bank does have experience much capacity loss from frequent use (charge/discharge cycles.) Randy, the Avista representative reports, that they expect the Vanadium Redox battery to have a service life of about 20 years.

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