The National Electrical Code (NEC) is expanding to include safety requirements for large-scale photovoltaic (PV), energy storage, and DC microgrid systems. In this speaker session, Mark W. Earley, P.E., chief electrical engineer at NFPA, secretary of the NEC Committee, and chief editor of the NEC Handbook, outlined the recent developments in these new technologies and systems.

Earley kicked things off by noting how energy storage is quickly becoming the means to address peak load management through demand response. He also provided a quick overview of the progression of battery technology over the years and noted how advanced lead acid and flow batteries have promise for significant improvement and application in the next 3 to 5 years.

After running through a list of some import definitions in the NEC such as battery, battery charge controller, cell, electrolyte, energy storage system, and energy storage system devices, Earley shared his insights on the Smart Grid Initiative underway in the United States. The dynamic optimization of grid operations will drive the deployment and integration of distributed resources, including renewable power sources. Examples of these systems include plug-in electric and hybrid electric vehicles and thermal storage air conditioning systems.

The 2017 Edition of the NEC features four new Articles to address the recent developments in the area of renewable energy systems:

• Large Scale PV Systems (Art. 691) — these systems supply power directly to the grid and often referred to as solar farms

• Energy Storage Systems (Art. 706) — permanently installed energy storage systems operating at over 50VAC or 60VDC in stand-alone or interactive with other electric power production sources

• Stand Alone Systems (Art. 710) — covers electric power production sources operating in stand alone mode

• DC Microgrids (Art. 712) — a direct current power distribution system consisting of one or more interconnected DC power sources, DC-DC converters, DC loads, and AC loads powered by DC-AC inverters

If you currently do work on any of these types of systems or hope to do so in the near future then you should definitely spend some time reviewing these new safety requirements.

On a closing note, Earley also informed session attendees of a new document that's in development right now for those that will maintain Energy Storage Systems. NECA 416, Recommended Practice for Installing and Maintaining Energy Storage Systems. It will cover battery systems, flywheels, capacitors and ultracapacitors, and smart chargers.