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How microgrids improve grid reliability and city resilience

<p>Microgrids -- where an electrical grid operates in &quot;island&quot; mode -- offer increased reliability for mission critical facilities and can help cities prepare for the next superstorm.</p>

Sandy -- yet another major storm to wreak havoc with the utility grid infrastructure on the U.S. East Coast – underscores a compelling reality: the status quo is no longer acceptable in today’s hyper-digitalized economy.

Consider this: The U.S. utility grid was graded a lowly D+ by the American Council of Civil Engineers in 2009. Lawrence Berkeley National Laboratory (LBNL) statistics show that 80 precent to 90 precent of all grid failures begin at the distribution level of electricity service. The U.S. average outage duration is 120 minutes annually and that number is getting worse while the rest of the industrialized world is less than 10 minutes and getting better.

What’s worse, recent evidence corroborates more severe weather is now business-as-usual. According to the Center for Research on the Epidemiology of Disasters, 100 million to 200 million people were affected by weather-related disasters between 1980 and 2009, with economic losses ranging from $50 billion to $100 billion annually.

What’s the answer, if one takes a big step back and takes stock of macro-trends driving business to link higher notions of sustainability with on-the-ground practicality? Enter the microgrid to the rescue.

Microgrids are really just miniature versions of the larger utility grid except for one defining feature: when necessary, they can disconnect from the macro-grid and can continue to operate in what is known as "island mode." Because of this distinguishing feature, microgrids can offer a higher degree of reliability for facilities such as military bases, hospitals and data centers, which all have "mission critical" functions that need to continue to operate no matter what.

A series of recent natural disasters -- including Sandy -- are helping to build the business case for microgrids. The magnitude 9.0 earthquake in Japan (and corresponding tsunami) was just one obvious example during 2011. (The Sendai 1 MW microgrid at Tohoku Fukushi University operated for 2 days in island mode while the surrounding region was without power.) Likewise, a number of collages, including Princeton and New York Universities, also relied upon their microgrids to keep power flowing to vital services during the more recent Sandy storm.

Connecticut is the first state in the United States to move forward with a policy program to promote microgrids. The state's push for microgrids is in response to Tropical Storm Irene in August 2011 and a rare blizzard in October 2011, both of which led to massive power outages. While the focus of this effort is to identify 150 viable microgrid sites, it is currently limited to a one-time $15 million grant and loan program covering the interconnection costs of microgrids for police and hospital facilities. In light of Sandy, don’t be surprised if other states such as New York and New Jersey follow in the footsteps of Connecticut.

Along with enhancing reliability, microgrids serve another useful function: they can help the larger grid stay in balance. As the world moves toward an energy system that looks more and more like the Internet, with two-way power flows thanks to growing reliance upon onsite sources of distributed generation (DG), this increasing dynamic complexity requires new technology.

But some forms of DG -- especially variable renewable resources such as solar or wind -- create a greater need for smart grid solutions, including microgrids. For example, recent trends in declining prices for solar photovoltaic (PV) systems certainly increase the need for aggregation and optimization technologies. Why? Distributed solar PV systems can create frequency, voltage and other power quality challenges to overall grid operations.

The fundamental architecture of today's electricity grid, which is based on the idea of a top‑down radial transmission system predicated on unidirectional energy flows from large centralized power plants, is clearly obsolete. We rely upon twice as many power plants as we actually need due to the massive inefficiency built into this system. If the electricity grid begins to resemble the Internet due to the proliferation of rooftop solar PV, then advanced aggregation systems such as the microgrid that will enable the sharing of resources will become vital.

Geographically, North America leads this microgrid market segment today, largely due to the relatively poor reliability of the incumbent utility power grid. Over the long-term, however, the hottest market will be in Asia and the developing world. Just as the developing world skipped land lines -- the equivalent of today’s radial, centralized transmission grid -- it may just jump to distributed microgrid networks instead (the analogy of cell phones.)

Consider the world's most massive power outage in history, which also occurred in 2012 in India and left over 370 million people in the dark this past July. Remote microgrids – those operating where there is no utility grid -- can serve as the anchors of new, appropriate scale infrastructure, a shift to smarter ways to deliver humanitarian services to the poor.

It is this fact that lies behind financial support rendered for remote microgrids by the United Nations, the U.S. Agency for International Development (USAID), and entities such as the Clinton Climate Initiative and the Bill Gates Foundation. Even Greenpeace has entered the fray, with a report extolling a bottoms-up distributed renewables strategy to export surplus solar power out of the Indian state of Bihar via microgrid networks.

From a global sustainability macro-perspective, the real work that needs to be done is in the developing world, the people that will determine the fate of our planet. If countries in Africa and Asia follow in our past footsteps when it comes to energy infrastructure, we are doomed. Clearly, instead of dumping our rejected products and technologies in emerging economies, ideas such as the microgrid would instead place these regions of the world at the forefront of appropriate scale technologies that solve, rather than create, problems.

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