Smart grids and renewable energy
Smart grids represent a modernized electrical power infrastructure designed to enhance the efficiency, reliability, and security of electricity delivery. They achieve this by integrating advanced communication technologies, allowing for better interaction between consumers and utilities. This flexibility supports a diverse range of energy sources, particularly renewable ones such as solar and wind power. As more users adopt personal renewable energy systems, a smart grid can accommodate this influx, enabling individuals to sell excess power back to the grid.
The traditional power grid, rooted in designs from the late 19th and early 20th centuries, has become increasingly complex, comprising over 965,606 kilometers of transmission lines and thousands of power generators in the U.S. However, inefficiencies exist, such as energy losses during transmission. Smart grids address these issues by allowing for load shifting to off-peak times, optimizing energy use, and reducing reliance on less efficient power plants.
Additionally, the push for smart grid technology is driven by global challenges, including climate change and geopolitical events that affect energy supply. Modern initiatives are supported by government bodies, highlighting the critical need for a robust electrical infrastructure that can adapt to changing demands and promote the use of renewable energy sources. This evolution toward smart grids is essential in meeting future energy needs sustainably while fostering energy independence.
On this Page
Subject Terms
Smart grids and renewable energy
DEFINITION: Power grids that efficiently connect users with electrical power produced by a variety of sources
The Office of Electricity's initiatives for grid modernization guide the rebuilding of the current power grid with smart-grid technology and will provide the opportunity to make the delivery of electricity to consumers more efficient, reliable, and secure. Smart grids are also versatile enough to use different types of power sources, so their proliferation would encourage growth in the development of renewable energy sources such as solar and wind power.
The basic design of the current power grid in the United States and the design of many of its components go back to decisions made during the 1890s and the early twentieth century. The grid was originally constructed with power lines radiating outward from power plants to consumers and with interconnections so that if a generator went offline, another could pick up the load. The US grid has become a complex of some 965,606 kilometers (600,000 miles) of transmission lines connecting more than 9,200 power generators producing 1 million megawatts of power for American factories and homes. It is estimated that 9 percent of the energy fed into the grid is lost in transmission. A smart grid is more efficient and communicates with customers; it has the ability to shift load to off-peak hours and is versatile enough to accept power from a range of sources.
Generators may produce direct current (DC), which flows in one direction only, or alternating current (AC), which alternates its direction sixty times each second (in the United States). Almost from the first, it was decided to use AC because it can easily be transformed to high voltage and low current, and this reduces transmission losses. If power from another AC generator is to be added to the grid, it must have exactly the same frequency (60 hertz or cycles per second) and the same phase. It must rise and fall in exact lockstep with the power already on the grid; otherwise, power from the generator will cancel some of the power already on the grid, and it will be wasted. A smart grid has interfaces that exactly match the power from generators to the power already on the grid. As increasing numbers of electricity users install their own small windmill generators and solar cells, some have begun to produce sufficient power that they can sell what they do not use to the grid. Solar cells require an interface that converts DC to AC of the proper frequency and phase so that it can be added to the grid.
The amount of power used over the course of a day is not constant; rather, there are times of peak load, when more users—such as factories or homeowners and businesses running air conditioners—are drawing power from the grid. Newer generators are usually more efficient and less polluting than older generators, so these generators are always in use. Power companies run their least efficient generators only during peak load periods, and this electricity costs more to produce. Smart power meters inform consumers of changing power costs so that they may shift their usage to off-peak hours if they wish. This not only saves the consumers money but also allows the power companies to use only their more efficient generators if enough load is shifted.
High-voltage DC (HVDC) lines can transmit power with less loss than AC lines, so for transmission lines over 400 miles (650 kilometers) long, DC may be used. Alternating current is first transformed up to as much as 800 kilovolts and then converted to DC. At the destination power station, the DC is converted back to AC, and the voltage is reduced to typical substation voltage (2.4 to 33 kilovolts). Superconducting wire would be even more efficient, and trial smart grid projects involving such wire have been undertaken, such as Long Island’s Project Hydra.
Modernizing the current national electric infrastructure with smart grid technology to make it more reliable and efficient is the mission of the Office of Electricity. Individual customers and utility companies stand to benefit from smart grid technologies. The Office of Electricity leads the way in coordinating research and development in the public and private sectors to find the newest generation of technology and tools to optimize the electrical grid. The Office of Electricity, a division of the Department of Energy, is provided legislative support for the creation of smart grid technology through the Energy Independence and Security Act and its Smart Grid Advisory Committee and Smart Grid Task Force.
Experts point out that conflicts and climate change are accerlating the need for a smart grid. As Russia invaded Ukraine in 2022 and western countries banned the import of Russian oil, the global electricity demand increased by 3 percent. Climate change has exacerbated the energy situation. Globally, January to September 2022 had the sixth warmest temperatures in 143 years.
Bibliography
Blume, Stephen W. Electric Power System Basics for the Nonelectrical Professional. Hoboken, N.J.: Wiley-IEEE, 2007.
Bowman, Ron. The Green Guide to Power: Thinking Outside the Grid. Charleston, S.C.: BookSurge, 2008.
Fox-Penner, Peter. Smart Power: Climate Change, the Smart Grid, and the Future of Electric Utilities. Washington, D.C.: Island Press, 2010.
Khalid, Muhammad. "Smart Grids and Renewable Energy Systems: Perspectives and Grid Integration Challenges." Energy Strategy Reviews, Jan. 2024, doi.org/10.1016/j.esr.2024.101299. Accessed 23 July 2024.
"Grid Modernization and the Smart Grid." Department of Energy, www.energy.gov/oe/grid-modernization-and-smart-grid. Accessed 23 July 2024.
Schell, Christoph. "The Future of Energy Is Systemic, Open and Collaborative--and Runs on a Smart Grid." The World Economic Forum, 5 Dec. 2022, www.weforum.org/agenda/2022/12/the-future-of-smart-energy-is-systemic-open-and-collaborative/. Accessed 23 July 2024.