Duke Sees Growth in Green Microgrids. Plus News from Congress, Stem & Axiom

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Green microgrids part of Duke’s new sustainability plan

Duke Energy highlights green microgrids as a possible “new growth initiative” in its recent corporate sustainability report.

Microgrids aren’t new, but “Duke Energy’s efforts to power them with renewable energy have caught the attention of the industry,” says the report.

For example, Duke has built a reseach microgrid in Charlotte that provides backup power to a city fire station using a solar array and a large battery. “When storms rolled through Charlotte last summer, the system provided power to the fire station twice – without any action by the company. ” The system was so fast that the fire station didn’t notice the microgrid was providing power,” the report said.

Other green microgrids highlighted by Duke were:

  • Mount Sterling in the Great Smoky Mountains National Park in North Carolina, which will serve a communications tower and
    replace traditional poles and wires in the 13 acre-park.
  • Two microgrids for public safety facilities in Montgomery County that Duke Energy Renewables is building in Maryland with Schneider Electric.
  • The ‘coalition-of-the-willing’ project in Mount Holly, N.C., where Duke and industry stakeholders are researching future microgrid technology.

The green microgrids are part of a larger goal by Duke to cut carbon dioxide emissions 40 percent from 2005 levels by 2030. Duke is retiring older, centralized coal units and now produces 28 percent its power from natural gas and 38 percent from zero emission sources, including nuclear, hydropower, wind and solar.

Oregon senator pushes for US to join the 100% renewables club 

A U.S. senator from Oregon has even bigger sustainable goals. Sen. Jeff Merkley has introduced a bill to phase out fossil fuels and completely replace them with clean renewable energy by 2050.

Co-sponsored by Senator Bernie Sanders (VT), Senator Ed Markey (MA) and Senator Cory Booker (NJ), the “100 by ’50 Act” wouldamp up renewable energy and energy efficiency and the electrification of transportation and heating, while putting a halt to the development of fossil fuel plants.

The 100 percent renewables movement may be for dreamers, but it has gained some steam in recent years. The bill backers point to local government efforts to go all green, as well  450 officials, organizations, businesses and community leaders that called on Congress to adopt the 100% goal.

Stem brings its virtual power plant concept to New York

California energy storage company Stem has expanded its reach into New York and is working with more than 20 companies that want to to deploy 14 MWh of energy storage systems across 80 locations to reduce energy costs and strengthen the local grid.

Stem’s pipeline includes programs with Consolidated Edison and the New York State Energy and Research and Development Authority (NYSERDA). Some of the first systems are being installed at four theaters in the New York City in partnership with a leading cinema chain as part of a NYSERDA technology commercialization program (ETAC-CI).

Stem sees its network of customer-sited systems serving as virtual power plants that immediately delivers capacity when and where needed.

Whole Foods gets cooler

Axiom Exergy has completed the first installation of its thermal energy storage solution at a Whole Foods Market store in Los Altos, California. Called the Refrigeration Battery, the system offset use of electricty for refrigeration — up to 1040 kWh for up to 10 hours a day over the course of several months.

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Refrigeration represents up to 55 percent of an average supermarket’s electricity consumption. Research shows that by shifting electricity demand to off-peak hours, supermarket owners can take advantage of lower night-time rates to reduce a store’s expensive on-peak electricity demand by up to 40 percent, according to Axiom.

The technology works by leveraging the store’s existing refrigeration system. It  “cooling” at night by freezing tanks of salt water when energy costs are low. Then, when electricity prices peak during the afternoon, the Refrigeration Battery discharges like any other battery to provide uninterrupted cooling services.

“Given the unique shape of a supermarket’s demand profile, which is relatively flat compared with other commercial buildings,Whole Foods Market needed a cost-effective energy storage solution capable of providing long-duration load shifting, as opposed to peak shaving typically provided by electrochemical systems,” said Anthony Diamond co-founder and chief technical officer of Axiom Exergy.

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About Elisa Wood

Elisa Wood is the chief editor of MicrogridKnowledge.com. She has been writing about energy for more than three decades for top industry publications. Her work also has been picked up by CNN, the New York Times, Reuters, the Wall Street Journal Online and the Washington Post.


  1. […] Duke Sees Growth in Green Microgrids. Plus News from Congress, Stem & Axiom (microgridknowledge.com) […]

  2. […] the Energy Vision, has spurred various virtual power plant experiments, including a project at four theaters in the New York City in partnership with a leading cinema […]

  3. […] Vision, has spurred various virtual power plant experiments, including a project at four theaters in the New York City in partnership with a leading cinema […]