In case you haven’t noticed, there’s quite a buzz of activity taking place on the renewable energy, on-site power generation, and energy storage fronts. Everyone — from state legislators/regulators to utility executives to building owners/operators — is trying to sort through the myriad of integration and operating challenges that accompany these new developments.
As design engineers, systems integrators, and installers forge ahead with new designs for these energy supply projects, the safety of the individuals who will operate and maintain these systems must not be ignored. That’s why the dedicated members of the NEC Code-Making Panels have been working hard to address this issue in the 2017 Edition of the NEC, which is scheduled to be published later this year.
At this point in time, it looks like four new Articles in this edition of the Code will focus on the generation, distribution, and interconnection of energy. They include:
Article 691, Large-Scale Photovoltaic (PV) Electric Supply Stations — As noted in the Scope, this proposed Article covers “the installation of large-scale PV electric supply stations operated for the sole purpose of providing electric supply to a system operated by a regulated utility for the transfer of electrical energy with a generating capacity of no less than 5,000kW. Electric supply stations are locations containing the generating stations and substations, including their associated generator, storage battery, transformer, and switchgear areas. Facilities covered by this article have specific design and safety features unique to large-scale PV facilities as indicated in 691.4.”
Article 706, Energy Storage Systems — As noted in the Scope, this proposed Article “applies to all permanently installed energy storage systems (ESSs) operating at over 50V AC or 60V DC that may be stand-alone or interactive with other electric power production sources.”
Article 710, Stand-Alone Systems — As noted in the Scope, this proposed Article “covers electric power production sources operating in stand-alone mode.”
Article 712, DC Microgrids — As defined in Sec. 712.2 of this proposed Article, “a direct current microgrid is a power distribution system consisting of one or more interconnected DC power sources, supplying DC-DC converters, DC loads, and/or AC loads powered by DC-AC inverters. A DC microgrid is typically not directly connected to an AC primary source of electricity, but some DC microgrids interconnect via one or more DC-AC bidirectional converters or DC-AC inverters.”
Although the specifics of these new rules and requirements won’t be completely finalized for a couple of months, I thought it was important to bring the work being done in this area to your attention now. The timing seemed right, especially since our cover story this month focuses on the developments taking place in the area of zero net energy (ZNE) buildings. As freelance writer Tom Zind points out in his article, “The Balancing Act,” achieving ZNE status can only be accomplished with an on-site alternative energy generation component. However, the complexities of net metering issues and building control performance present many challenges to those involved in these types of projects.