Transportable Microgrid with Energy Storage
Dr. Robert Schainker | Electric Power Research Institute, Inc.
This project’s overall objective is to demonstrate an innovative transportable microgrid with energy storage (TMES) technology to improve energy security at DoD military installations. The project will demonstrate a real-world, military based assessment of the TMES’s installed capital costs, operational costs, savings to investment ratio (SIR), safety features, technical and reliability performance metrics, use of existing and available host site generation, and be acceptable to the DoD facility management community, who will be responsible to operate and maintain the TMES. The TMES aims to effectively smooth power fluctuations from on-site photovoltaic units and reduce emissions from on-site diesel and other generation units.
The project objectives will be accomplished by including a Tesla 500 kW-4 hour energy storage subsystem and a 200 KVA synchronous condenser subsystem. These Tesla subsystems will provide rotational inertia that will enable the TMES to be deployed in a wide variety of DoD bases that have a wide range of real/reactive power characteristics. Thus, the TMES project will obtain necessary, credible capital cost, operating cost, real-world test data, safety features, reliability data, economic benefit data, and a tractable technology transfer plan. These project features will show the TMES can be commercialized in a timely and cost-effective manner, likely via a collaboration between the DoD and US electric utility industry.
The TMES will enable military installations to have improved reliable electric power supply by any one of the two operating modes:
- Islanding Electricity Supply Mode: Provide DoD site power using the TMES’s Tesla battery, synchronous condenser and available on-site military emergency diesel generator units and/or use PV, wind or other renewable generation units. In this mode, the TMES will provide power for at least 120 consecutive hours with a 1 MW minimum average power continuously being generated, and, be able to produce island power for a minimum of a 2 MW peak output power level for 4 consecutive hours.
- Local Electric Utility Supply Mode: Provide site power using the local electric utility connection where the TMES will use its ‘smart’ microgrid controller to minimize on-site generation costs, on-site emissions, or a combination of both.
The TMES will use Schweitzer protection relays that can easily be set for application to a wide variety of DoD sites, during both the above TMES operating modes, which will protect military site equipment and local public utility equipment from ground faults originating from “inside” the TMES and/or “outside” the TMES (i.e., ground faults originating inside the TMES that could impact/damage local utility equipment, and ground faults from the local utility that could impact/damage the TMES).
This project’s overall objective is to demonstrate an innovative transportable microgrid with
The benefits from this project include transportable, faster, and improved emergency power supply during electric grid blackouts and/or islanding events; lower carbon footprint when using emergency diesel generators, smoothing out the power fluctuations for solar PV units, providing seamless power output during microgrid islanding and grid resynchronizing events, improved microgrid output power factor during islanding and non-island conditions, and the capability to provide a minimum of four hours of 500kW power when operated in an islanding mode. The TMES is also capable of increased/decreased kW and hour ratings, due to its inherent ability to increase/decrease its capacity due to its modular design and its external connection ports to communicate and send control signals to other generation or energy storage units. The number of DoD and other sites where the TMES can be deployed is large, which over the next 20 years, could approach hundreds of sites throughout the U.S. As such, in about 5 to 10 years, commercial TMES units should have an installed capital cost of less than $1,200/kW, which would successfully compete with distributed generation units like fuel cells and micro turbines whose installed capital cost at this MW scale is in the $2,000/kW to $4,000/kW range. Based on a wide set of economic assumptions, the TMES’s Savings to Investment Ratio is currently estimated to be in the range of 1.5 to 3.5, and the TMES’s Payback Time Period is estimated to be in the range of 3.5 to 7.5 years.