By Michael Hyland, Senior Vice President, Engineering Services, American Public Power Association
In the days leading up to mega Winter Storm Jonas in late January 2016, people on the East Coast worried about widespread power outages. Fortunately, there were just a few short-lived outages and the power grid more than held its own.
But what happens the next time a storm like Jonas hits? Would you not have to worry about outages if your community was part of a microgrid? After all, reliability is a key selling point for microgrids — they can provide power regardless of what is going on with the broader grid.
But things may be more complicated than the public has been led to believe. I worry that there is not enough of a “buyer beware” approach being taken to microgrids, especially those that run on distributed energy resources.
While microgrids have been around in some form for more than a century, many now include energy storage, solar energy, fuel cells, and electric vehicles. And while DERs do offer many benefits, a microgrid’s dependence on such resources could have very negative real-world consequences when an unexpected event occurs.
Life in a community microgrid
Let’s imagine we live in a New England community with our own microgrid. The microgrid includes dozens of houses with rooftop solar panels, a large number of electric vehicles, and a smattering of residential energy storage devices. Life is good.
Until another massive snowstorm sweeps across New England, producing heavy ice and sleet, weighing down branches, and triggering massive power outages. Life goes from being good to very complicated, very quickly.
At the first sign of trouble, our community decides to “island” or disconnect from the broader grid. Why worry — we live on our own little microgrid with a limitless supply of electricity, right?
Well, no. The problem is that when we disconnect from the main grid, the collective amount of generation in our microgrid is suddenly unable to supply 100 percent of load.
Those rooftop solar panels? With winter’s shorter days and less powerful rays from the sun, the panels haven’t been cranking out as much energy as during the summer. In the meantime, the storm has dropped more than 20 inches of snow and ice on the solar panels, temporarily eliminating them from the community’s resource mix.
Meanwhile, residential energy storage devices and electric vehicles start back feeding into the grid to cover the basics, such as heating and lighting. But they won’t be able to produce electricity for long.
Theoretically, the shopping mall a couple of miles away could offer a lifeline because it has a bank of electric vehicle charging stations. But who knows whether our own electric cars have enough power to get us to the mall? And there is no sign of snow plows, so we have no idea whether it will be a day, a week, or longer before we can drive out of the neighborhood.
Within days of the initial islanding, power goes out for the community.
Another factor in play is the dramatic level of demand destruction. Meals aren’t cooked. Clothes are not washed and dried. TV isn’t watched. Cars meant for travel are suddenly unavailable. All in an effort to conserve energy in our storage devices. If the outage lasts long enough, it could lead to life and death issues.
As we sit in the cold and dark, reality hits us — microgrids are not the be all and end all.
Why a microgrid?
We must do serious due diligence before taking the microgrid plunge. There should be a clearly articulated rationale for why we need a microgrid before we take on the cost, time, and effort.
Microgrids do offer benefits and make sense in certain situations. The military and hospitals, neither of which can afford to be without power for long periods of time, are logical candidates for microgrids.
Several public power utilities are also taking a closer look at microgrids. As American Public Power Association President and CEO Sue Kelly has noted, public power has “been there, done that — and we have the t-shirt” on microgrids. Many public power utilities started out as separate grids with their own generation, serving their own communities. However, communities need to make sure that any new microgrids aren’t a solution in search of a problem.
Let’s not forget that we are fortunate to have a first-rate power grid in America. It took a lot of hard work and resources to create this grid — and public power utilities have played a key role. We have a resilient grid to withstand storms like Jonas.
So regardless of how popular microgrids become in the years ahead, the country’s transmission and distribution system isn’t going away, nor should it.