The North American Electric Reliability Corporation (NERC), Balancing and Interchange Operator Certification (BI) is an intermediate-level credential for professionals who operate bulk electric systems. System Operators monitor power flows, voltages and status of equipment on the transmission system, and ensure the safe and reliable operation of the bulk electric system. Candidates for the BI are expected to have knowledge of resource and demand balancing, transmission, emergency preparedness, contingency analysis and reliability, and managing communications and data.