The “vulnerable” U.S. electric grid needs more microgrids for resilience, but outdated rules may get in the way, according to a new report by the National Academies of Sciences, Engineering and Medicine.
The congressionally-mandated report listed microgrids and other distributed energy resources (DERs) as among 12 fixes to bolster a grid that remains susceptible to “large-area, prolonged outages that could cost billions of dollars and cause loss of life.”
The National Academies of Sciences, which advises the nation on science and technology, released “Enhancing the Resilience of the Nation’s Electricity System” late last week. Congress initiated the study in 2014 following the massive outages caused by Superstorm Sandy.
The report comes as new threats emerge in the form of physical attacks or cyber strikes on the grid.
“While the U.S. has not been subject to a large physical assault or cyberattack, both pose serious and growing risks,” said M. Granger Morgan, professor of engineering at Carnegie Mellon University, who chaired the committee that prepared the report.
The report cited microgrids as a “particularly promising” means to improve grid resiliency, which the report emphasized is about more than just reducing power outages. A resilient grid also copes with outages efficiently, lessens their impact and regroups quickly – all capabilities offered by microgrids.
“There is enormous technical potential to using microgrids to make electric service more resilient in the face of loss of bulk grid power,” said the report.
Microgrids achieve resiliency by islanding from the central grid during an outage. Their on-site generators then supply local customers. Buildings served by microgrids can act as electrified oases, places of refuge where community members can seek shelter, charge phones, get medical help, buy food and fuel cars. Utilities also are designing microgrids to power headquarters that workers can use as base camp while restoring the grid.
But roadblocks exist to microgrid development, namely rules established as long as 80 years ago — before grid cybersecurity was an issue or microgrids a rising technology.
Stay on your side of the road
Among these are restrictions placed on non-utility players who distribute power to customers. These limitations come into play when a utility right-of-way separates a microgrid from a building that wants to contract for the microgrid’s service. In many states, the microgrid is not allowed to string a distribution line across the right-of-way, which is often a public road.
Confusion also exists about where, when and how a microgrid can sell power into wholesale markets. Since most North American microgrids serve customers during normal grid operations – not just when there is an outage – they have the technological capability to sell energy and other services to the electric grid.
But in a poll conducted by the report researchers, New Jersey said it is the only state that allows non-utility microgrids to sell electricity directly to “one customer across one right of way,” as well as sell power into the wholesale market.
Several states told the researchers that as a matter of law a non-utility player cannot build a microgrid, sell power to customers and be interconnected to the utility. Others said the matter was more complex, required special licensing, or that net metering opened a path to sales of power by the microgrid.
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Hindrances to microgrids, in the form economic obstacles, also exist on the transmission side of the electric grid, where high voltage wires transfer electricity from power plants to the grid. Today’s federal rules create financial incentives for utilities to invest in long-distance transmission lines, but not local ‘non-wires alternatives,’ such as microgrids and other DERs, said the report. Specifically, the 80-year-old Federal Power Act allows utilities to recover the costs of new transmission but not microgrids. This makes utilities naturally pre-disposed to favoring transmission investments over microgrids.
“The emerging relationships between DERs and the transmission and distribution systems have greatly outpaced the laws and regulations that govern their interactions,” said the report.
Still, there has been a steady rise in microgrid installations, the report noted, often by self-contained campuses where there are no utility rights-of-way to inhibit several buildings from sharing a microgrid. These include military bases, business parks and colleges, which are installing microgrids for resilience, as well as to gain higher quality and more efficient power.
Military bases, business parks and colleges install microgrids for resilience, as well as to gain higher quality and more efficient power.
Microgrids for resilience and more
Indeed, beyond resilience, economic reasons exist for such campuses to install private DERs and microgrids. Microgrids also offer benefits to the broader electric grid, the report said.
“Microgrids have several advantages for the electricity grid; for example, they can provide electricity during peak-usage hours and therefore forestall the need for expensive upgrades in central generation, transmission, and distribution systems. They can also be used to improve power quality and reliability for local consumers,” said the report.
Given these benefits, the academies called for:
- The National Association of Regulatory Utility Commissioners and state regulators to study regulatory changes to allow construction of privately owned microgrids that cross public rights-of-way.
- State legislatures and public utility commissions to explore economic, ratemaking, and other regulatory options for facilitating the development of private microgrids that provide resilience benefits.
At the same time, microgrid technology is rapidly evolving. Advanced microgrid controllers and sensors could make the grid more resilient during a power outage, but a “wide gulf” exists between these technical capabilities and their use in the real world, the report said.
To solve this problem, the report recommended that the Department of Energy support training facilities where utility engineers and private microgrid operators can gain experience operating microgrids. From this, the academies hope best practices will emerge that could be used widely by microgrids and regulators.
Microgrid-like distribution feeders
Finally, the report called for more study of a microgrid-like structure emerging on the grid, what the researchers called utility-operated islanded feeders.
As utilities modernize the distribution grid — adding automation, intelligent bi-directional switches and other advanced technologies — they open up the possibility of these microgrid-like structures. The new technologies allow the grid to reconfigure its topology and feed distribution circuits from more than one location. With this advanced ability, a distribution feeder could island, as a microgrid does, and supply local customers.
Among the other 12 grid fixes in the report — besides installation of microgrids for resilience — were several broad actions. These ranged from work on grid cybersecurity to emergency preparation for blackouts and federal study of the growing risk of interdependent infrastructure.
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