An Energy Management System (EMS) is a suite of generation and transmission applications software tools used to monitor, control, and optimize the performance of generation and transmission systems. Energy management systems are designed to reduce energy consumption, improve the utilization of the system, increase reliability, and predict electrical system performance as well as optimize energy usage to reduce cost. Over the past 40 years and more, I have been able to visit EMS installations in many states and in several other countries. Each site visited was somewhat unique in style, size, operational set-up and wall displays.
From the late 1960’s until the early 1990’s, energy management systems were highly customized for many of the 200 large American utilities (then mainly IOUs involved with vertically integrated operations) that required the capabilities offered by such technology as was available in that era. Several of these early systems were developed with precursor versions of today’s “digital twin” technology in the form of an operator training simulator which mimicked the real-time operational energy management system.
Early Days
Control Data Corporation (Minnesota) had been a leading supplier of EMS mainframe hardware platforms and systems to U.S. utilities through most of the 1970’s, with computers from Harris Corporation (Florida), IBM (New York) and GE (Arizona) also supplying mainframe and early minicomputers to serve as the platforms for early EMS applications. Early international EMS suppliers, like Westinghouse UK, ABB, Areva and Siemens were instrumental in supplying systems used in Western Europe, Asia and South America and in a few African countries (South Africa primarily). Some of these suppliers used international computer manufacturers including the French company, Groupe Bull (Honeywell Bull)
The era of “forklift” system replacements occurred for 30 years or more after the introduction of large EMS installations, at least through the first two generations of systems.
Vendor switches occurred among many of the first- and second- generation systems users, meaning hardware and software were both to be replaced with third and fourth generation systems available during the 1990s through 2010 era. These third-generation systems became available from start-up firms led by ESCA (Washington) and OSII (Minnesota) as well as from the principal global EMS suppliers like ABB, GE and Siemens – all active EMS market participants in North America. Moore Systems (Texas) also developed EMS capabilities. ESCA became a key business unit of Areva T&D, while OSII remained independent until its recent acquisition by AspenTech (and AspenTech’s parent, Emerson), finalized in 2022.
There were also a few custom systems developed during the late 1960’s to early 1970’s by defense and aerospace firms. Consolidated Edison procured a system developed by Boeing Corporation, using IBM 360’s as platforms. The Canadian aerospace firm CAE developed an early EMS for PSEG in New Jersey and another for Grant County PUD in Washington state.
In 1997, GE and Harris Corporation (another aerospace/telecom equipment firm) had formed the GE-Harris Control Systems business based in Melbourne, Florida. A few years later, CAE sold its interests in utility control systems to another large Canadian firm, SNC Lavalin. In 2010, SNC Lavalin’s Energy Control Systems business was sold to GE. During the 1990’s, the French firm Areva T&D became a global market participant with its wide range of e-terra control systems and infrastructure offerings. The company’s electric power business units were first divided up and sold to Alstom and Schneider in 2009. By 2015, GE had acquired Alstom’s electric power business units, including the popular e-terra system offerings.
Minicomputers take over
During the late 1970’s and early 1980’s mainframe computers were being replaced as EMS platforms by minicomputers, led by offerings from Digital Equipment Corporation (DEC) and Hewlett-Packard (HP). Modcomp, Gould, Data General, Prime Computer and a few others were also providing SCADA systems platforms to early SCADA systems developers like ACS, QEI, Tejas Controls, Telegyr (L&G) and several others from 1975 onward.
Restructuring the Power Industry
During the late 1990’s and onward, many states had required major investor-owned utilities to separate (unbundle and restructure) generation operations from T&D operations. ISOs and RTOs were put in place nationwide just before the turn of this century and oversaw interstate transmission operations in conjunction with the 200 or so utilities owning transmission assets. By 2019 EMS vendors were taking note from the ADMS community and began using the term “advanced energy management system” (AEMS) to indicate significant new EMS capabilities including the integration of renewables and energy storage and their impact on grid operations and voltage stability. Coupled with the rapidly increased speed of processing and analyzing contingencies, and improving the ability to dispatch and curtail distributed energy resources, these developments have helped enhance operator capabilities and visibility into the real-time electric network.
As the power generation mix and transmission requirements have become more complex, AEMS developments and capabilities are keeping pace with such needs. The impact of artificial intelligence will continue to provide human operators with more and better information and will likely become a discriminator among the key AEMS market participants. Recently, generation management systems (GMS) have been developed that now include many of the generation-side applications that were (and continue to be) components of an EMS as described in our market overview report on GMS.
EMS/AEMS Components
Three major components of a modern EMS include:
- Native Services: data acquisition and control; graphical user interface; linkage/connectivity options to other systems; large database capabilities. There are many objectives of an energy management software including an application to maintain the frequency of a Power Distribution System and to keep tie-line power close to the scheduled values.
- SCADA Services: load shedding, load restoration, network status; sequential control, switch order management, playback of historical events.
- Advanced Power Systems Applications (or Network Application Services): to include generation dispatching and control [AGC], transmission security management; voltage transient stability; unit commitment; state estimation contingency analysis, demand forecast, and dispatcher training simulator).
Factors affecting current period activities in the EMS/AEMS market include improvements in linkages to external systems (ISO/RTO MMS, AI-enhanced analytics, ADMS, energy storage systems, DERMS, WAMS) as well as new capabilities to react to NERC/FERC changes in bulk power regulations, transmission monitoring (DLR), cyber security guidance, visualization software, intelligent alarm processing, renewables integration linkages) also provided by third party firms such as ETAP, Nexans, OATI, CYME, Milsoft and others.
Newton-Evans’ 2024-2026 Market Overview Series on OT/IT Systems
The values of EMS software provided by such suppliers to EMS installations are estimated in the OT/IT series of market overviews, as well as is the overall EMS domestic market size and market trends. Related to EMS in the Market Overview series on OT/IT systems, market management, GIS, CIS/CRMS, OMS, GMS, SCADA/DMS, ADMS, DERMS and cyber security software are also provided. These topics are each treated separately in the 2024-2026 series of OT/IT market overviews just released by Newton-Evans. More information on the OI/IT series can be found here: https://www.newton-evans.com/product/overview-of-the-2024-2026-u-s-electric-utility-market-for-ot-it-systems/.
Article Sources: OSII, PSC Consulting, Schneider Electric, GE Vernova, ETAP, Hitachi Energy, Siemens Energy, Schneider Electric, Newton-Evans archived files.
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