Wilmington, NC: Solar Still Saving City

ARTICLE | Dec 30, 2014

How would you like to be able to heat and cool a 6,100-square-foot building for $944 for an entire year? Last year, the City of Wilmington’s “green” street sweeper facility at 17th and Marsteller streets did just that.

In 2009, the city opened its first “green” building by renovating an old, abandoned city garage and turned it into a green facility that now houses street sweepers used for downtown cleaning.

The electric bill for the facility was just $944 last year, or less than $80 per month on average. Energy costs for a non‐green building of the same size are estimated to be $10,000‐$12,000 a year. In other words, the electric bill for this building for an entire year is less than what a non-green building would cost in just one month.

The building has several energy saving features, including solar power and solar heated water that is used to provide heat in the winter. To date, these features have generated more than 42,000 kWh of electricity – enough to light more than 8.5 million light bulbs for one hour or, light the Christmas tree in Rockefeller Center nightly for about 3-1/2 years.

During mild weather conditions, the solar panels produce more energy than the building uses. This extra electricity is financially credited back to the city and is used to cover months when very hot or cold weather results in higher usage.

Anyone interested in seeing how the building is doing can access the city's website to see this web page that shows live tracking of how much energy the solar panels are generating.

Green features of the city’s Streetsweeper facility:

  • Site and building re-use – The city is reusing a building it already owned; much of the existing structure was also reused in construction, including the roof, steel, lumber and concrete slab.
  • Solar power - Solar panels installed on the roof produce enough electricity to power the entire building, and there is also the potential to produce extra electricity for financial credit from the power company each month.
  • Radiant floor heating - Solar panels on the roof heat water that is pumped through tubing in the floor of the building to provide heat during the winter.
  • Stormwater runoff - To capture runoff flowing from the site, several stormwater improvements were installed, including a bioretention area that treats runoff from the parking lot and rooftop. Also, a significant amount of asphalt that causes stormwater runoff was removed and a cistern was installed to capture runoff from the roof. The rainwater captured from the roof will be used to irrigate the surrounding landscape.

For more details, click here to see the city’s award winning application for an environmental stewardship award.

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