Microgrids - self-contained electrical generation and distribution grids that may or may not be connected to the national electric grid - offer increased reliability for those connected to them. When the main grid loses power, a microgrid can disconnect from it and continue to generate and distribute power to its local customers. Microgrids are popping up in applications where power failures would be catastrophic: military bases, medical facilities, and now ... college campuses.
While you might not think of a college campus as a “mission critical” place, Illinois Institute of Technology (IIT) experienced three to four power outages per year, resulting in numerous research experiments being delayed or ruined. University officials estimated that those power failures cost IIT about $1 million per year. Also, IIT wanted to incorporate renewable energy sources - partly for educational purposes and partly to save money. Combining those two factors, they decided to build a microgrid.
I spoke with engineers from S&C Electric Company, the company that designed and installed the IIT microgrid. They gave me some of the technical details and shared some insights on the design and implementation of this project. The main goal was to increase reliability. That’s a two-pronged problem: external power failures and internal circuit faults.
Campus-wide power outages can also be caused by faults within the campus wiring itself. The old system had a main point of entry for electricity, with each building fed radially from that point. Certain faults on campus - a short circuit, for example - could bring the entire system down. Fault isolation and correction was time consuming. One of the first design decisions was to change the distribution from a radial layout to a multiple loop configuration with each building being fed from two different locations. A fault in one loop wouldn’t necessarily bring the entire system down, as buildings that weren’t part of the fault could get their power from another loop. Intelligent substations are capable of isolating and bypassing a fault, allowing unaffected buildings to remain powered and providing fault-location data for technicians. Click here for a demo of how that works.
While the project isn’t complete yet, they’ve installed three out of ten loops. To date, the microgrid has cost about $3 million, plus another million for the batteries. If I extrapolate that out, the completed project could cost upwards of $13 million. Let’s call it $15 million to adjust for inflation. Remember when I mentioned the $1 million per year they were losing due to experiments being interrupted by power failures? Given that, I see a 15 year payback period. Not bad for a college campus that expects to be around for much longer than 15 years. I realize that’s a simple payback calculation. There are extraneous variables involved, many of which are unknown at the moment. Even if you double that estimate, it’s pretty reasonable for a college campus. Also, this project was partly funded by a microgrid research grant from the US Department of Energy, so IIT didn't actually spend that entire amount. You can call that a government subsidy if you want, but I call it an investment. The lessons they learned while building this microgrid will help make future microgrids less expensive and more reliable.
What does the future hold for the IIT microgrid? The addition of smart metering and communication equipment will help to make real-time decisions about when it’s better to buy energy from the grid and when it’s more economical to generate it locally. Next, they plan to add more renewable energy sources and enter into a net-metering agreement to sell energy back to the grid. That will help recoup the costs of adding renewables.
The Smart Grid and microgrids are two keys to converting our power generation to more renewable sources of energy. If the Department of Energy wants to expand its research and development in these areas, I can't think of a better place than a college campus.