Featured Project – Lumbee River Electric Membership Corporation – North Center


Lumbee River EMC is a member owned electric coop with approximately 50,000 members in parts of Hoke, Scotland, Cumberland, and Robeson Counties in North Carolina. This was the design team’s first Net Zero Energy Office Building that actually got fully built with renewable energy so that it truly operates as a Net Zero Energy Building. A lot of education was provided during the design and construction phase to Lumbee River about solar PV, the Net Zero Energy concept, and the opportunities to change rate structures and operational methods with such a building. Lumbee River became such a believer in the concept that they decided to use it for their next new, 15,000 SF facility which opened in February 2016.

Design Highlights:
• EUI = 18 (National average 50)
• Solar thermal system
• Natural gas generator
• Battery storage system that provides 35KWh output of 208VAC/60Hz
• 414 panel solar PV system capable of 110Kw DC and 70Kw AC
• Full geo-exchange system
• VRV HVAC system

Energy conservation is achieved through highly-efficient thermal envelope using enhanced insulation in the walls and roof, an air-tight building wrap, horizontal louvers placed over south-facing windows, high-efficiency LED lighting that uses only 0.4 watts per sq. foot, and energy-star appliances.
The building uses a highly sophisticated Building Automation System to limit the peak power and control the energy consumption, utilizing the battery storage system to keep the peak power low, even on high energy consumption days. Optima designed the plumbing, fire protection, and electrical systems for this building, partnering with another firm who provided the HVAC design and a controls firm for the BAS design. All building systems will be commissioned as well.