Imagine an electric bill of about $52 per month for a 6,100 square-foot house. That's the bill for the City of Wilmington's 6,100 square-foot green street sweeper facility at 17th and Marstellar streets. In 2016, the electric bill for the facility was just $623, or less than $52 per month on average. Although more than 9,500 kWh of electricity was generated by the building’s energy saving features in 2016, the facility used less than 8,000 kWh. The electricity not used was fed back into the power grid and the city realized a cost savings of more than $875.
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. Energy costs for a non-green building of the same size are estimated to be about $12,000 per 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 about 63,300 kWh of electricity – enough to light more than 12.6 million light bulbs for one hour, charge more than 11.7 million smartphones, or light the Christmas tree in Rockefeller Center nightly for more than 5 years.
Green features of the city’s street sweeper 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 information, visit http://www.wilmingtonnc.gov/home