How a Microgrid Works


Installing your own nuclear power plant in your backyard isn't an option, but imagine if even a portion of your electrical needs could be met locally.
Installing your own nuclear power plant in your backyard isn't an option, but imagine if even a portion of your electrical needs could be met locally.
Joe Sohm/Digital Vision/Getty Images

Once upon a time, there was a kingdom ruled by an all-powerful king. Each day, the King would visit the villages in his domain, bringing every household the wonders of daily life: cold meats and cheeses, artificial lighting, air conditioning and the complete filmography of Vin Diesel on a high definition plasma screen.

So the people watched "Chronicles of Riddick," snacked on fruit pops and reveled long into the night. However, with each passing month, the King demanded a timely -- and costly -- tribute from his people, often raising the prices of this monetary token for seemingly no reason. Then one day when the King came by, he brought none of the glorious gifts they'd grown to depend on -- not even a bag of frozen peas or a screening of "The Pacifier."

When the people asked the king what had happened, he told them that a tree had fallen over on a power line in a village on the far side of the kingdom. While the people didn't think this was exactly fair, what could they do? Who would bring them such fine electric gifts if not the King? It wasn't as if they could make these things themselves.

This scenario resembles what has long been the relationship between the average U.S. resident and the power grid that supplies his or her electricity. For decades, we've depended on an outdated, centralized system that wastes power and occasionally fails to meet everyone's needs. In 1996, for example, a damaged power line in Oregon left 12 million customers in eight states without power. Yet, as is typical under tyrannical rule, there hasn't been a lot of choice in the matter. Electricity has remained the exclusive domain of wholesale power companies with virtually no retail competition for the customers' money.

The idea of the microgrid is changing all this, however. The villagers in our example have concocted a scheme to produce their own power and build their own local seat of electrical clout. Maybe the King will be a little more reasonable about how he divvies the fruit pops now.

The Independence of Localized Power Grids

This environmentally friendly housing community in the Dutch town Amersfoort demonstrates some of the solar technology that could power a microgrid.
This environmentally friendly housing community in the Dutch town Amersfoort demonstrates some of the solar technology that could power a microgrid.
AP Photo/Serge Ligtenberg

Fortunately for the American public, the move toward a more dependable and efficient power grid isn't a mere grassroots movement. The U.S. Department of Energy is currently pursuing a strategy to create a smart grid, an automated, cleaner and less-centralized means of meeting the nation's energy demands. For more information on this undertaking, read "How the Smart Grid Will Work."

The idea of a localized power grid or microgrid fits into this overall strategy in several key ways. First, the more power produced on a local level, the less a community will need to import from outside power plants or leech off the network. Many of the nation's energy woes are due to the electrical equivalency of a run on the bank. Temperatures suddenly skyrocket, so more people crank up the air conditioning -- which puts a huge drain on the grid. If there's not enough to go around, then not everyone gets power -- at least until sufficient energy becomes available elsewhere on the grid.

Think of a home garden: The more produce you grow in your backyard, the less you're going to need to buy from the grocery store. And if you have enough tomatoes on hand or produce prices at the store become ridiculous, you could simply quit going to the grocery store. You might even be able to sell your excess crop to a local farmer's market. Now imagine doing all of this with homespun electrical energy.

Naturally, the key enabler to all of this is technology. Fuel cell, micro tube, reciprocating engine, solar cell and wind farm development have reached the point where a small network of assorted generators can provide power to neighborhoods, retail areas and even industrial facilities. In a microgrid-enabled future, you might not have to drive to the hydroelectric dam one state away to see where your electricity comes from. Instead, you might find the source in the refrigerator-sized micro turbine behind your house and in the wind farm on the outskirts of town.

One particularly interesting concept involves driving home in the evening and plugging your electric car into an outlet. Oh, but you wouldn't be using the microgrid to charge your car; you'd be using your car to charge the microgrid. This approach is called vehicle to grid technology.

Micromanaging the Microgrid

While barely the size of a tractor-trailer, Los Angeles' John Ferraro Building Fuel Cell Power Plant provides enough energy for 250 homes. This technology plays a key role in many microgrid plans.
While barely the size of a tractor-trailer, Los Angeles' John Ferraro Building Fuel Cell Power Plant provides enough energy for 250 homes. This technology plays a key role in many microgrid plans.
David McNew/Getty Images News/Getty Images

One of the key advantages to the microgrid approach is that it allows local users to make smarter choices regarding their use of power, turning them from cowering subjects under an all-powerful king to empowered consumers in a flexible energy economy. It's the difference, again, between growing a small plot of tomatoes for local use and running an industrialized farm. Which farmer can really claim to have a hand in the rearing of his or her crops?

As previously mentioned, microgrids don't necessarily exist apart from the larger, nationwide power grid. When it makes economic sense, a local community could purchase electricity from outside sources. If prices were to rise, it could all but completely cut itself off from the grid, only using the grid's overpriced juice in the event of local shortages.

Microgrids will not only allow for the optimization of power sources, but also power uses. For instance, a properly equipped microgrid could deal with an energy shortage not by cutting off all power, but selectively killing feeds to certain ends. For instance, the system might prioritize vital communications and healthcare-related energy expenditures, while cutting power to superfluous uses or to appliances such as refrigerators which can usually get by with occasional, short-term power outages.

Another huge advantage to local power production is the optimization of heat energy. Large power plants also tend to create a great deal of unused heat. In fact, between 60 and 80 percent of a typical power plant's energy consumption never becomes electricity. On a local level, however, that energy could be used to heat water for regional use.

Already, cities, industries and military bases around the country are in various stages of implementing microgrid technology -- just one component of a more efficient and dependable energy future.

Explore the links on the next page to learn even more about the future of power production and consumption.

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More Great Links

Sources

  • Ecobee.com. 2009. (Aug. 3, 2009)http://www.ecobee.com/
  • Krotz, Dan. "Microgrids: reliable power in a small package." Berkeley Lab. Feb 28, 2003. (Aug. 10, 2009)http://www.lbl.gov/Science-Articles/Archive/EETD-microgrids.html
  • Merchant, Brian. "Good News: 8.3 Million US Homes Now Have Smart Meters." TreeHugger.com. July 21, 09. (Aug. 3, 2009)http://www.treehugger.com/files/2009/07/smart-meters-us-millions.php
  • "The Smart Grid: An Introduction." U.S. Department of Energy. 2009. (July 29, 2009)http://www.oe.energy.gov/1165.htm
  • "Vehicle to Grid Technology." University of Delaware. 2009. (Aug. 10, 2009)http://www.udel.edu/V2G/index.html