The first alternating current power system was installed in 1886. At that time, the grid was a centralized, unidirectional electrical power transmission and demand control system.

In the 20th century, local networks grew over time, and eventually became interconnected for economic and reliability reasons. By the 1960s, the power grids of developed countries had become very large, mature and highly interconnected, with thousands of "central" generating stations delivering power to major load centers via high-capacity power lines that then branched and split to provide power to smaller industrial and domestic users throughout the supply zone. The grid topology of the 1960s was the result of strong economies of scale: coal, gas and oil plants of 1 GW (1,000 MW) to 3 GW scale are still found to be profitable, due to efficiency-boosting characteristics that can be profitable only when stations become very large.

Power plants were strategically located to be close to fossil fuel reserves (either their own mines or wells, or near railways, highways, or port power lines). The location of hydroelectric dams in mountain areas also strongly influenced the structure of the emerging network. Nuclear power plants were located due to the availability of cooling water. Finally, fossil fuel power plants were initially highly polluting and were located as economically as possible in population centers once electricity distribution networks allowed them. By the late 1960s, grid electricity reached the overwhelming majority of the population of developed countries, with only peripheral regional areas remaining 'off the grid'.

Measuring electricity consumption is necessary on a per-user basis in order to allow appropriate billing according to the (highly variable) level of consumption of different users. Due to limited data collection and processing capacity during the period of grid growth, fixed tariff agreements were commonly put in place, as well as double tariff agreements where nighttime power was charged at a lower rate than daytime power. The motivation for the double tariff agreements was the lower demand at night. Dual tariffs made possible the use of low-cost night-time electrical energy in applications such as the maintenance of heat banks that served to 'smooth out' daily demand, and reduce the number of turbines that needed to be turned off during the night, in order to optimize the utilization and profitability of generation and transmission facilities. The measurement capabilities of the 1960s grid meant technological limitations on the degree to which price signals could be propagated through the system.

Through the 1970s to the 1990s, increasing demand led to an increasing number of power stations. In some areas, the electrical power supply, especially at peak times, could not keep up with this demand, resulting in poor power quality including blackouts, power outages, and brownouts. Electricity was increasingly relied upon for industry, heating, communication, lighting and entertainment, and consumers demanded ever higher levels of reliability.

Towards the end of the 20th century, electricity demand patterns were established: domestic heating and air conditioning led to daily peaks in demand that were met by a series of 'peak hour power generators' that could only be activated for short periods each day. The relatively low level of peak hour utilization of these generators (commonly, gas turbines are used due to their relatively lower capital cost and faster start-up times), together with the necessary redundancy in the electrical grid, resulted in high costs for electricity companies, which is transmitted in the form of tariff increases. In the 21st century, some developing countries such as China, India and Brazil were seen as pioneers in the implementation of smart grids.

Since the early 21st century, opportunities to leverage improvements in electronic communication technology to address power grid limitations and costs have become apparent. Technological limitations in metering no longer force peak energy prices to be averaged out and transmitted to all consumers equally. At the same time, growing concern about the environmental damage from fossil fuel-burning power plants has led to a desire to use large amounts of renewable energy. Dominant forms such as wind energy and solar energy are highly variable, therefore the need for more sophisticated control systems became evident, to facilitate the connection of sources to a highly controllable grid of energy from photovoltaic cells (and to a lesser extent wind turbines) has also, significantly, called into question the imperative for large, centralized power plants. Rapidly falling costs point to a major shift from centralized network topology to one that is highly distributed, with energy being both generated and consumed at the edges of the network. Finally, growing concern about terrorist attacks in some countries has led to calls for a more robust energy grid, which is less dependent on power plants that were perceived as possible targets of an attack.

An element common to most definitions is the application of digital processing and communications to the electrical grid, making data flow and information management central to the smart grid. Several capabilities are the result of the deeply integrated use of digital technology with energy grids, and the integration of new grid information flows into utility processes and systems is one of the key issues in the design of smart grids. The power plants are now making three kinds of transformations: the improvement of the infrastructure, called the strong network in TOLUCA; In addition to the digital layer, which is the essence of the smart grid; and the transformation of business processes, necessary to capitalize on investments in smart technology. Much of the modernization work that has been happening in power grid modernization, especially substations and distribution automation, is now included in the overall smart grid concept, but is more comprehensive still evolving as well.

Smart grid technologies emerged from earlier attempts at using electronics for control, measurement and monitoring. In the 1980s, automatic meter reading was used to track loads for large customers, and became the advanced metering infrastructure of the 1990s, whose meters could store information on how electricity was used at different times of the day. Smart meters add continuous communications so monitoring can be done in real time, and can be used as a gateway to demand response, aware devices and “smart plugs” in the home. The first forms of this type of demand management technologies were dynamic demand aware devices that passively sensed the load on the network by monitoring changes in power frequency. Devices such as industrial and domestic air conditioners, refrigerators and heaters adjusted their duty cycle to avoid activation during times the grid was suffering from a peak condition. Starting in 2000, Telegestore an Italy Project was the first to network a large number (27 million) of homes using smart meters connected via low-bandwidth power line communication. Some experiments used the term broadband over power lines (BPL), while others used wireless technologies such as promoting mesh networking for more reliable connections to disparate devices in the home, as well as supporting metering of other utilities, such as gas and water.

Monitoring and synchronization of wide area grids was revolutionized in the early 1990s when the Bonneville Power Administration expanded its smart grid research with prototype sensors that are capable of very rapid analysis of power quality anomalies over large geographic areas. The culmination of this work was the first operational Wide Area Measurement System (WAMS) in 2000. Other countries are rapidly integrating this technology – China has a comprehensive national WAMS system when its current 5-year economic plan is completed in 2012.

Early smart grid deployments include the Italian Telegestore system (2005), the Austin, Texas mesh network (since 2003), the Prime and Star projects for the Spanish smart grid (2007), and the smart grid in Boulder, Colorado (2008).[3]​.

The first alternating current power system was installed in 1886. At that time, the grid was a centralized, unidirectional electrical power transmission and demand control system.

In the 20th century, local networks grew over time, and eventually became interconnected for economic and reliability reasons. By the 1960s, the power grids of developed countries had become very large, mature and highly interconnected, with thousands of "central" generating stations delivering power to major load centers via high-capacity power lines that then branched and split to provide power to smaller industrial and domestic users throughout the supply zone. The grid topology of the 1960s was the result of strong economies of scale: coal, gas and oil plants of 1 GW (1,000 MW) to 3 GW scale are still found to be profitable, due to efficiency-boosting characteristics that can be profitable only when stations become very large.

Power plants were strategically located to be close to fossil fuel reserves (either their own mines or wells, or near railways, highways, or port power lines). The location of hydroelectric dams in mountain areas also strongly influenced the structure of the emerging network. Nuclear power plants were located due to the availability of cooling water. Finally, fossil fuel power plants were initially highly polluting and were located as economically as possible in population centers once electricity distribution networks allowed them. By the late 1960s, grid electricity reached the overwhelming majority of the population of developed countries, with only peripheral regional areas remaining 'off the grid'.

Measuring electricity consumption is necessary on a per-user basis in order to allow appropriate billing according to the (highly variable) level of consumption of different users. Due to limited data collection and processing capacity during the period of grid growth, fixed tariff agreements were commonly put in place, as well as double tariff agreements where nighttime power was charged at a lower rate than daytime power. The motivation for the double tariff agreements was the lower demand at night. Dual tariffs made possible the use of low-cost night-time electrical energy in applications such as the maintenance of heat banks that served to 'smooth out' daily demand, and reduce the number of turbines that needed to be turned off during the night, in order to optimize the utilization and profitability of generation and transmission facilities. The measurement capabilities of the 1960s grid meant technological limitations on the degree to which price signals could be propagated through the system.

Through the 1970s to the 1990s, increasing demand led to an increasing number of power stations. In some areas, the electrical power supply, especially at peak times, could not keep up with this demand, resulting in poor power quality including blackouts, power outages, and brownouts. Electricity was increasingly relied upon for industry, heating, communication, lighting and entertainment, and consumers demanded ever higher levels of reliability.

Towards the end of the 20th century, electricity demand patterns were established: domestic heating and air conditioning led to daily peaks in demand that were met by a series of 'peak hour power generators' that could only be activated for short periods each day. The relatively low level of peak hour utilization of these generators (commonly, gas turbines are used due to their relatively lower capital cost and faster start-up times), together with the necessary redundancy in the electrical grid, resulted in high costs for electricity companies, which is transmitted in the form of tariff increases. In the 21st century, some developing countries such as China, India and Brazil were seen as pioneers in the implementation of smart grids.

Since the early 21st century, opportunities to leverage improvements in electronic communication technology to address power grid limitations and costs have become apparent. Technological limitations in metering no longer force peak energy prices to be averaged out and transmitted to all consumers equally. At the same time, growing concern about the environmental damage from fossil fuel-burning power plants has led to a desire to use large amounts of renewable energy. Dominant forms such as wind energy and solar energy are highly variable, therefore the need for more sophisticated control systems became evident, to facilitate the connection of sources to a highly controllable grid of energy from photovoltaic cells (and to a lesser extent wind turbines) has also, significantly, called into question the imperative for large, centralized power plants. Rapidly falling costs point to a major shift from centralized network topology to one that is highly distributed, with energy being both generated and consumed at the edges of the network. Finally, growing concern about terrorist attacks in some countries has led to calls for a more robust energy grid, which is less dependent on power plants that were perceived as possible targets of an attack.

An element common to most definitions is the application of digital processing and communications to the electrical grid, making data flow and information management central to the smart grid. Several capabilities are the result of the deeply integrated use of digital technology with energy grids, and the integration of new grid information flows into utility processes and systems is one of the key issues in the design of smart grids. The power plants are now making three kinds of transformations: the improvement of the infrastructure, called the strong network in TOLUCA; In addition to the digital layer, which is the essence of the smart grid; and the transformation of business processes, necessary to capitalize on investments in smart technology. Much of the modernization work that has been happening in power grid modernization, especially substations and distribution automation, is now included in the overall smart grid concept, but is more comprehensive still evolving as well.

Smart grid technologies emerged from earlier attempts at using electronics for control, measurement and monitoring. In the 1980s, automatic meter reading was used to track loads for large customers, and became the advanced metering infrastructure of the 1990s, whose meters could store information on how electricity was used at different times of the day. Smart meters add continuous communications so monitoring can be done in real time, and can be used as a gateway to demand response, aware devices and “smart plugs” in the home. The first forms of this type of demand management technologies were dynamic demand aware devices that passively sensed the load on the network by monitoring changes in power frequency. Devices such as industrial and domestic air conditioners, refrigerators and heaters adjusted their duty cycle to avoid activation during times the grid was suffering from a peak condition. Starting in 2000, Telegestore an Italy Project was the first to network a large number (27 million) of homes using smart meters connected via low-bandwidth power line communication. Some experiments used the term broadband over power lines (BPL), while others used wireless technologies such as promoting mesh networking for more reliable connections to disparate devices in the home, as well as supporting metering of other utilities, such as gas and water.

Monitoring and synchronization of wide area grids was revolutionized in the early 1990s when the Bonneville Power Administration expanded its smart grid research with prototype sensors that are capable of very rapid analysis of power quality anomalies over large geographic areas. The culmination of this work was the first operational Wide Area Measurement System (WAMS) in 2000. Other countries are rapidly integrating this technology – China has a comprehensive national WAMS system when its current 5-year economic plan is completed in 2012.

Early smart grid deployments include the Italian Telegestore system (2005), the Austin, Texas mesh network (since 2003), the Prime and Star projects for the Spanish smart grid (2007), and the smart grid in Boulder, Colorado (2008).[3]​.