Regional transmission organization (North America)

A regional transmission organization (RTO) in the United States is an electric power transmission system operator (TSO) that coordinates, controls, and monitors a multi-state electric grid. The transfer of electricity between states is considered interstate commerce, and electric grids spanning multiple states are therefore regulated by the Federal Energy Regulatory Commission (FERC). An independent system operator (ISO) is similarly an organization formed at the recommendation of FERC. In the areas where an ISO is established, it coordinates, controls, and monitors the operation of the electrical power system, usually within a single US state, but sometimes encompassing multiple states. RTOs typically perform the same functions as ISOs, but cover a larger geographic area. The two are similar, with an RTO being more clearly defined and born out of the concept of electrical grid reliability. The delineation between an ISO and an RTO is subtle to some and quite specific to others, as the similarities in the table below illustrate: In short, an ISO operates a region's electricity grid, administers the region's wholesale electricity markets, and provides reliability planning for the region's bulk electricity system. Today's RTOs do the same thing with an added component of greater responsibility for the transmission network, as established by the FERC. ==Background==

FERC Orders 888 & 889 In April 1996, the Federal Energy Regulatory Commission (FERC) issued two orders that changed the landscape of how electricity is generated, transmitted, and distributed throughout North America. Prior to these rulings, generated power and the subsequent energy provided to customers by local service providers was owned and controlled by single entities who often owned the entire generation, transmission, and distribution assets. Because these companies controlled the retail delivery of the energy from generation through their own power lines, consumers had little to no choice regarding whose electricity they were buying. In economic terms, this structure constituted an impediment for new providers who would want to generate power, move energy, or provide retail electricity to individual consumers. Order No. 888 addressed "Promoting Wholesale Competition Through Open Access Non-discriminatory Transmission Services by Public Utilities; Recovery of Stranded Costs by Public Utilities and Transmitting Utilities." and Order No. 889 added and amended existing rules "...establishing and governing an Open Access Same-time Information System (OASIS) (formerly real-time information networks) and prescribing standards of conduct." Order No. 888 Order No. 888 is often cited as the "Deregulation" of the electric industry. Deregulation, however, is not an accurate term. In actuality, the electricity industry is still regulated, depending on the region, by a series of federal, state, and local agencies and various public commissions. Order No. 888 is substantial in scope. Relative to this article, however, it defined two key elements: • An acknowledgment that barriers to competitive wholesale markets may exist and that those barriers must be removed • Permit utilities to recover stranded costs associated with providing open access to transmission In addressing #1 above, Order No. 888 defined the fundamental purpose of an ISO to "…operate the transmission systems of public utilities in a manner that is independent of any business interest in sales or purchases of electric power by those utilities." The order did not mandate or require the establishment of ISOs. Rather, in an attempt to comply with the FERC's order, groups of participants (or "Power Pools" composed of generators, transmission providers and utilities) partnered, and proposed to the FERC, for the right to establish designs of independent system operations. Through negotiation, collaboration and legal challenges, the first ISOs to emerge included California ISO, PJM Interconnection, New York ISO and New England ISO. Each proposed a slightly different market design according to their collaborative results. In order to facilitate competitive wholesale markets, Order No. 888 specified the unbundling of a utility's operations separating generation and transmission and distribution. In addressing #2 above, the original order (and subsequent clarification by the FERC) allows utilities, under certain defined circumstances, to seek extra-contractual recovery of stranded costs. The FERC continues to receive rehearing petitions regarding stranded cost recovery as it has clearly placed the importance on remedying what it terms as "undue discrimination" at the forefront. It is important to note that Order No. 888 was not met without objection among the public, academics and industry participants. Requests for rehearing and/or clarification were filed by 137 entities after the order's issuance. The majority agreed with the FERC's assertion for the need to harness the benefits of competitive electricity markets. Order No. 889 Order No. 889 amended rules establishing and governing the Open Access Same-time Information System (OASIS) (formerly real-time information networks) and prescribed standards of conduct for its use and access. Subsequent orders provided clarifications, standards and protocols. FERC Order 2000 Where as Order No. 888 provided for an entity (an ISO) to facilitate open access, it was not written with the intent to establish one. FERC Order No. 2000 was: Issued by the FERC on December 29, 1999, Order No. 2000 codified what it means to be an RTO including its minimum characteristics, functions and ratemaking policy. The order also stated its commitment toward open architecture with a stated goal that an RTO "...be designed so that they can evolve over time." The order still, however, does not mandate that a new entity called an RTO be created, nor does it mandate that an entity call itself an RTO to comply with the FERC's order. ==Independent system operators (ISOs)==

An independent system operator (ISO) is an organization formed at the direction or recommendation of the Federal Energy Regulatory Commission (FERC). In the areas where an ISO is established, it coordinates, controls and monitors the operation of the electrical power system, usually within a single US State, but sometimes encompassing multiple states. Similar to an RTO, the primary difference is that ISOs either do not meet the minimum requirements specified by FERC to hold the designation of RTO or that the ISO has not petitioned FERC for the status. Electric utilities that are located within the United States and engage in interstate commerce fall under FERC authority. Not all utilities are members of ISOs. All utilities and ISOs are responsible to meet the compliance of a larger organization called the North American Electric Reliability Corporation (NERC), which overlays the entire FERC footprint and includes a Mexican utility and several Canadian utilities. As such, international reciprocity is commonplace, and rules or recommendations introduced by FERC often are voluntarily accepted by NERC members outside of FERC's jurisdiction. Therefore, one Canadian Province is a member of a US-based RTO, while two others function as an Electric System Operator (ESO), an organization essentially equal to a US-based ISO. Within the United States one ISO, and its participating utilities, does not fall under FERC authority: The Electric Reliability Council of Texas (ERCOT). ERCOT falls under the authority of NERC and operates a reliability function, separate from its market function, in order to comply with NERC requirements. ISOs act as a marketplace operator in wholesale power, resulting from FERC order No. 888. Most are set up as nonprofit corporations using governance models approved by FERC and/or regional or local commissions. As of 2025, there were seven ISOs/RTOs within continental USA and two in Canada: • CAISO – California ISO • NYISO – New York ISO • Electric Reliability Council of Texas (ERCOT); also a Regional Reliability Council • Midcontinent Independent System Operator – Midcontinent ISO • ISO-NE – ISO New England • SPP – Southwest Power Pool • PJM – Pennsylvania-New Jersey-Maryland Interconnection • AESO – Alberta Electric System Operator • Independent Electricity System Operator (IESO); operates the Hydro One transmission grid for Ontario, Canada The New Brunswick System Operator (NBSO) was dissolved when New Brunswick's new Electricity Act went into effect in October 2013. There are regions of the United States where ISOs do not exist. Consequently, the utilities do not engage in wholesale power markets. The Pacific Northwest, and states east of California and west of the Dakotas, Nebraska, Kansas and Texas largely do not participate. The majority of Southeastern states do not participate in wholesale markets. While these regions must conform to open access as mandated by FERC, the power exchanges between utilities is mostly facilitated through bilateral contracts and power purchase agreements. FERC distinguishes three such traditional electricity markets: • Northwest includes Western Power Pool, the Rocky Mountain Power Area, and Nevada within the Western Electricity Coordinating Council (WECC); • Southeast bilateral market includes all or parts of Florida, Georgia, Alabama, Mississippi, North Carolina, South Carolina, Missouri and Tennessee within the SERC Reliability Corporation; • Southwest market includes Arizona, New Mexico, Southern Nevada Power Area within WECC. ==Regional transmission organizations (RTOs)==

An RTO is an organization formed at the approval of the Federal Energy Regulatory Commission (FERC). In the areas where an RTO is established, it coordinates, controls and monitors the operation of the electrical power system, usually within a single US State, but sometimes encompassing multiple states. The official definition for an RTO: "An entity that is independent from all generation and power marketing interests and has exclusive responsibility for grid operations, short-term reliability, and transmission service within a region." The designation of an RTO is largely one of scope. An organization wanting to achieve RTO status must petition the FERC for approval, and meet 4 minimum characteristics and 8 minimum functions: The RTO concept provides for separation of generation and transmission and elimination of pancaked rates, and it encourages a diverse membership including public power. Wider membership contributes to the establishment of an entity with the size necessary to function as an RTO. Seven grid operators, either independent system operators (ISOs) or RTOs, coordinate the power grid to ensure the reliable delivery of two-thirds of the electricity used in the United States to two-thirds of its population. Most are overseen by FERC. ISOs and RTOs coordinate generation and transmission across wide geographic regions, matching generation to the load instantaneously to keep supply and demand for electricity in balance. The grid operators forecast load and schedule generation to assure that sufficient generation and back-up power is available in case demand rises or a power plant or power line is lost. They also operate wholesale electricity markets that enable participants to buy and sell electricity on a day-ahead or a real-time spot market basis. These markets provide electricity suppliers with more options for meeting consumer needs for power at the lowest possible cost. ISO/RTOs provide non-discriminatory transmission access, facilitating competition among wholesale suppliers to improve transmission service and provide fair electricity prices. Across large regions, they schedule the use of transmission lines; manage the interconnection of new generation and monitor the markets to ensure fairness and neutrality for all participants. Providing these services regionally is more efficient than providing them on a smaller-scale, utility by utility. Today's power industry is far more than a collection of power plants and transmission lines. Maintaining an effective grid requires management of three different but related sets of flows – the flow of energy across the grid; the exchange of information about power flows and the equipment it moves across; and the flow of money between producers, marketers, transmission owners, buyers and others. ISO/RTOs play an essential role in managing and enhancing all three of these flows. In North America As of 2023, there were nine ISO/RTOs operating in North America: • Alberta Electric System Operator (AESO) – ISO • California Independent System Operator (CAISO) – ISO • Electric Reliability Council of Texas (ERCOT) – ISO • Midcontinent Independent System Operator, Inc. (MISO) – RTO • ISO New England (ISO-NE) – RTO • New York Independent System Operator (NYISO) – RTO • Ontario Independent Electricity System Operator (IESO) – ISO • PJM Interconnection (PJM) – RTO • Southwest Power Pool (SPP) – RTO Non-RTO transmission organizations Non-RTO transmission organizations include Columbia Grid and Northern Tier Transmission Group. ColumbiaGrid, a nonprofit corporation, is not a regional transmission organization (RTO) and has no plans to become one, but instead seeks to achieve many of the benefits of an RTO through incremental additions to its functions. ColumbiaGrid was formed after some of its members chose not to continue in efforts to form Grid West, a Northwest evolutionary structure with the ability to add functions and to move toward independent grid management. The ColumbiaGrid members, including the Bonneville Power Administration, several Washington State public utilities and two investor-owned utilities, wanted an organization with more limited functions and no independent ability to change. ColumbiaGrid performs single-utility transmission planning and expansion via an open and transparent process and is also establishing a multi-system OASIS portal. The former Grid West participants who had argued for an eventual RTO, mainly investor-owned utilities and state representatives from Oregon, Idaho, Montana, Wyoming and Utah, formed the Northern Tier Transmission Group (NTTG), a nascent effort open to evolution but initially focused on inexpensive and relatively easy improvements to grid management, including area control error (ACE) diversity interchange, currently underway; transparent methodologies for calculating available transmission capacity; and planning, as required by FERC Order 890. ==See also==