Sourced from the Washington Blade
In Washington, D.C., buildings are responsible for 74 percent of the city’s greenhouse gas emissions. As threats from climate change become more severe, particularly impacts from more intense heat and rain events, it has become a city priority to rein in those emissions and plan for a more sustainable future.
Just a few months before Mayor Muriel Bowser signed the Clean Energy DC Omnibus Amendment Act into law, the D.C. Department of Energy and Environment finalized its Clean Energy DC plan. This plan highlights more efficient buildings, particularly those that are net zero energy, to curb greenhouse gas emissions.
A building has achieved net zero energy when its annual energy usage is equal to or less than the amount of energy created onsite by using innovative technologies and renewable power generation. Some building owners may not know the best strategies to use to reduce energy usage in their buildings, let alone target net zero energy. While the following tactics may not be applicable to every building, the broader engineering principles of reduction, reclamation, absorption, and generation—especially when implemented together—can help target net zero energy goals.
There are many ways to reduce energy consumption, such as installing LED lights and energy efficient appliances. In addition, reusing as much material as possible during a renovation project can reduce a building’s carbon footprint by keeping waste out of the landfill.
The District now requires new construction to capture the first 1.2 inches of rain on-site to stem the flow of water and protect local rivers. A cistern can reclaim rainwater by filtering and treating it for non-potable uses like flushing toilets and irrigating plants.
Installing and irrigating a hydroponic phytoremediation, or green, wall can improve indoor air quality. The green wall allows air to be circulated through the roots of live plants where it is cleaned and filtered before passing back into the building. When working with a building’s HVAC system, this process provides a large energy cost savings.
A municipal sewer heat exchange system is an innovative way to absorb thermal energy from wastewater. This system taps into the sewer line and diverts wastewater to a settling tank that is then circulated inside the building. An exchange system extracts energy from the water for heating and cooling before the water is returned to the sewer.