A NERC Tag, also commonly referred to as an E-Tag, represents a transaction on the North American bulk electricity market scheduled to flow within, between or across electric utility company territories. The NERC Tag is named for the North American Electric Reliability Corporation (NERC), which is the entity that was responsible for the implementation of the first energy tagging processes. NERC Tags were first introduced in 1997, in response to the need to track the increasingly complicated energy transactions which were produced as a result of the beginning of electric deregulation in North America.
Electric deregulation in North America The Federal Energy Regulatory Commission (FERC)'s Energy Policy Act of 1992 was the first major step towards electric deregulation in North America, and was followed by a much more definitive action when FERC issued Orders 888 and 889 in 1996, which laid the groundwork for formalized deregulation of the industry and led to the creation of the network of Open Access Same-Time Information System (OASIS) nodes. FERC is an independent agency of the U.S. Government and thus its authority extends only over electric utilities operating in the United States. However, NERC members include all of the FERC footprint as well as all of the electric utilities in lower Canada and a Mexican utility company. In the interest of reciprocity and commonality, all NERC members generally cooperate with FERC rules. The creation of OASIS nodes allowed for energy to be scheduled across multiple power systems, creating complex strings of single "point-to-point" transactions which could be connected end-to-end to literally travel across the continent. This frequently created situations where it was difficult or impossible for transmission system operators to ascertain all of the transactions impacting their local system or take any corrective actions to alleviate situations which could put the power grid at risk of damage or collapse. The NERC Tag was implemented as a result of this new problem introduced by deregulation.
NERC Tag versions
NERC Tag 1.x The earliest NERC Tag application was based on a Microsoft Excel spreadsheet, and was introduced in 1997. The form was usually completed by the power marketers or schedulers, by defining the date and time of the transaction, the physical path of the energy schedule from its point of generation to point of consumption, the financial path (buying/selling chain) of the energy schedule, the hourly energy amounts scheduled to flow, and also the OASIS transmission requests for each power system crossed which thereby documented that permission to cross each power system had been properly obtained. Elements of a NERC Tag included Control Areas (CA), Transmission Providers (TP), Purchasing/Selling Entities (PSE), transmission Points of Receipt (POR) and Points of Delivery (POD), as well as product codes for several transmission and generation priorities. The physical path was the most important aspect of the NERC Tag in terms of understanding the impact of a collection of individual transactions after they had been compiled into a single complete transaction. To complete the physical path it was necessary to identify the power system and power plant where the energy was to be generated, any and all power systems that would be utilized to move the energy to its eventual destination, and lastly the power system and location of the delivery point where the energy would be consumed (the "load"). When a NERC Tag was created in the spreadsheet, the information was then distilled into a small CSV formatted data packet which was disseminated via e-mail to all of the participants listed on the NERC tag. In this way, all participants of a transaction were able to determine which other electric utilities and power marketers were involved in the transaction, and what the roles of the other participants were. More importantly, in the event of a contingency such as a transmission line outage or generation failure, all participants could more easily be notified of the schedule change, and could then all act in cooperation to curtail the scheduled transaction. The NERC Tag 1.0 implementation was not capable of collecting schedule flow data in any useful way, but it did serve to familiarize schedulers with the demands of tagging their transactions, a process that would eventually be mandatory. A database of transmission scheduling points maintained by NERC through the Transmission System Information Networks (TSIN) that was originally developed for the OASIS nodes was greatly expanded to include additional information required in the process of creating NERC Tags. The spreadsheet-based NERC Tag application saw minor improvements in functionality and scope with small incremental changes which advanced it to NERC Tag 1.3, although there was not much discernible difference to the participants, and until version 1.4 was implemented, any previous version could still be used.
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