What a real microgrid must be able to do
When I think back to my education in Microgrids, I go back to the Perfect Power Institute that coined the name and the requirements.
These requirements are not cheap add-ons to the grid, and Apple found out with building their headquarters in Cupertino to these standards, the US military also builds to these standards.
Let’s think about what we need:
1) Power that is clean and meets all the power quality standards of the industry, which can mean harmonic filters, reactors, solid state transformers, and other equipment to keep the voltage, frequency, harmonics, flicker and other issues within industry standards.
2) On site “fuel”, so that the microgrid can keep running without outside support. Fuel in this case could be storage, liquid fuels, hydrogen, and when available sunshine and wind.
3) 24/7 reliability, when a winter storm covers the solar PV, or a heat dome causes significant smog to form, and sunshine is not available (or it is the middle of the night) the microgrid has to have the ability to keep running and providing power. A 3 hour a day microgrid in Duluth in December is not really a microgrid, nor useful.
4) Load prioritization, demand response and load shedding to maintain power to the most critical loads needs to be in place. That means either people assigned to turn things off, or automation to turn things off, based on the amount of remaining fuel.
5) A plan for how long the microgrid will provide full output and various levels of output. Control systems that can help make the power last.
6) The ability to be fully independent of the rest of the world during operation, if the microgrid is needed, then likely things are disrupted in the nearby area, and depending on some external entity to do something when islanded means you don’t really have a microgrid.
This to me is a microgrid.
For most politicians and media professionals it seems that a microgrid is a couple of solar panels and a kilowatt or two of battery. This works if you only want part time and potentially dirty power, and are unable to island and operate.
There is a lot more to a real micro grid, but realize that these 7 requirements raise the cost of a microgrid. So do the other requirements not listed here.
