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The Electric Grid

We use electricity every day—to turn on the lights, to charge our phones, and to keep our food cold. But most of us don’t make our own electricity. Instead, we get it from the electric grid, an interconnected network of power lines and other infrastructure that allows us to move electricity from power plants to our homes, businesses, and factories. Though it’s often generally referred to as “the electric grid,” countries can have more than one: for example, the U.S. has three quite separate electric grids that span the country.

The electric grid—and how electricity is generated—plays a crucial role in slowing and stopping climate change. Currently, almost two-thirds of our electricity around the world is generated by burning fossil fuels, a process that releases large amounts of carbon dioxide and other planet-warming greenhouse gases and is among the primary causes of climate change.¹ At the same time, the grid is vulnerable to extreme weather events, like hurricanes² and heat waves, that are becoming more common or more intense as our planet warms.

To slow down—and to protect ourselves—from climate change, energy experts say our grid must become cleaner and more adaptable.

How the grid works

In 1879, a power company in San Francisco connected a coal-fired steam engine to two generators, powering 20 lightbulbs—and creating the first electric grid.³ Innovation took off from there, from inventions as simple as switches that allow us to turn on and off appliances without shutting down the grid; as far-reaching as transcontinental “transmission lines” that move electricity over hundreds of thousands of miles⁴; and as complex as utilities, which are companies that make sure there’s enough electricity for all users on an electric grid.

Today, most electricity worldwide is generated in large power plants that run on fossil fuels like coal and natural gas, and, to a lesser extent, from low-carbon sources like nuclear, wind turbines, solar panels, and running water (“hydropower”).⁵ Electric utilities and other entities in charge of operating the grid decide when to turn on or ramp up certain kinds of power production based on expected demand. There’s a constant balance between generating enough electricity to meet demand—and prevent blackouts—while not producing too much electricity, which can lead utilities to take costly measures like disconnecting certain generators from the grid.

Cleaning up the grid

Electricity accounts for 40% of our global greenhouse gas emissions from energy.⁶ Curbing emissions from electricity hinges on switching to low-carbon electricity sources, such as solar, wind, hydropower, and nuclear. One key way to speed up this transition is for utilities to no longer build new power plants that run on fossil fuels. This is already happening in some parts of the world, with countries like South Korea, Indonesia, and Poland pledging to no longer allow new coal-fired power plant development.⁷ Another is to close fossil fuel power plants before they were scheduled to shut down; over the last ten years, U.S. power companies announced the retirement of more than 500 coal power plants.⁸ At the same time, utilities will need to build or buy power from new low-carbon electricity generators to keep up with growing demand.⁹

The grid also needs to be adapted to handle the influx of “variable” and “distributed” energy sources. Wind and solar power are “variable”— while a coal-fired power plant can burn as much coal as is stored at the plant, grid operators can’t just make the wind blow or the sun shine when they need more electricity. The variability of wind and solar makes it harder to control the flow of electricity from these sources onto the electric grid. And, as more homes and businesses install solar panels on their roofs and land and send their power back to the grid, utilities need to account for managing the flow of this “distributed” energy generation.

Researchers and utilities are looking at a number of ways to make our grid smarter—that is, better equipped to handle more low-carbon electricity while reducing costs and power outages. Upgrading the existing grid by building new transmission lines to better move power from wind farms and other renewable resources in rural areas to urban areas is one way to do this. Local distribution systems can be adapted to better handle electricity flowing onto the grid from local power generators, and to provide flexibility to the main grid. Other ways to upgrade our grid include accompanying variable power sources with large batteries to store electricity for later use and installing more sensors and smart appliances to better balance electricity production and use.

A grid for a changing climate

Climate experts say that a key way to lower greenhouse gas emissions is to power our cars and home appliances with low-carbon electricity instead of fossil fuels, what’s commonly called the “electrification of everything.” In addition, more than 750 million people in low-income countries lack access to electricity, and there is a global goal to connect them to the grid by 2030.¹⁰ These transitions would require a lot more electricity than we generate today —researchers have estimated that by 2050, total electricity generation would need to increase at least 2.5 times from today’s levels.¹¹

As electricity provides more of our energy needs, and as climate change worsens certain kinds of storms,¹² protecting the grid from power outages becomes even more important. One way to do this is to create “microgrids” by accompanying distributed generation with battery storage. This allows communities to separate from the main grid during storms and draw on stored electricity to keep the lights on even if the main grid goes down. Puerto Rico, for example, is looking at using these “microgrids” to help protect critical services like hospitals and water purification when hurricanes hit.¹³ Another way is to encourage “demand management,” which is to strategically shift demand for electricity over time or uses to prioritize the most critical needs. For example, people could be encouraged to use less electricity during times of high demand, like waiting to run a clothes dryer until after a summer heat wave, when air conditioning is most important; or charging electric cars at night when other electricity needs are low. Using more efficient appliances, like EnergyStar appliances, also will help people reduce the amount of electricity they consume. The combination of these micro-actions, which don’t significantly affect people’s comfort, can help avoid severe blackouts.¹⁴

Published May 24th, 2022.

Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license (CC BY-NC-SA 4.0).

Photo Credit

Yana Petkova via Unsplash

Footnotes

¹Ritchie, Hannah, and Max Roser. “Electricity Mix.” Our World in Data, 28 Nov. 2020, https://ourworldindata.org/electricity-mix#:~:text=In%202019%2C%20almost%20two%2Dthirds,been%20pretty%20stagnant%20for%20decades.

²Kossin, James P., et al. “Global Increase in Major Tropical Cyclone Exceedance Probability over the Past Four Decades.” Proceedings of the National Academy of Sciences, vol. 117, no. 22, 2020, pp. 11975–11980., https://doi.org/10.1073/pnas.1920849117.

³Bakke, Gretchen Anna. The Grid: The Fraying Wires between Americans and Our Energy Future. Bloomsbury, 2017.

⁴“Electricity Explained: How Electricity Is Delivered to Consumers.” U.S. Energy Information Administration, 3 Nov. 2021, https://www.eia.gov/energyexplained/electricity/delivery-to-consumers.php.

⁵“Key World Energy Statistics 2021 – Transformation.” International Energy Agency , International Energy Agency, 2021, https://www.iea.org/reports/key-world-energy-tatistics-2021/transformation#electricity-generation.

⁶“Greenhouse Gas Emissions from Energy: Overview .” International Energy Agency, International Energy Agency, 2021, https://www.iea.org/reports/greenhouse-gas-emissions-from-energy-overview/drivers-of-co2-emissions.

⁷Plumer, Brad, and Lisa Friedman. “Over 40 Countries Pledge at U.N. Climate Summit to End Use of Coal Power.” New York Times, 4 Nov. 2021, https://www.nytimes.com/2021/11/04/climate/cop26-coal-climate.html.

⁸“More U.S. Coal-Fired Power Plants Are Decommissioning as Retirements Continue.” Today in Energy, U.S. Energy Information Administration (EIA), 26 July 2019, https://www.eia.gov/todayinenergy/detail.php?id=40212.

⁹Reuters. “Emissions Set to Rise with Global Power Demand - IEA.” Reuters, 14 Jan. 2022, https://www.reuters.com/business/energy/emissions-set-rise-with-global-power-demand-iea-2022-01-14/#:~:text=Global%20electricity%20demand%20rose%20by,report%20on%20the%20electricity%20sector.

¹⁰United Nations Statistics Division. “Ensure Access to Affordable, Reliable, Sustainable and Modern Energy for All.” United Nations, United Nations, 2021, https://unstats.un.org/sdgs/report/2021/goal-07/.

¹¹International Energy Agency , 2021, Net Zero by 2050 - A Roadmap for the Global Energy Sector - Summary for Policymakers, https://iea.blob.core.windows.net/assets/7ebafc81-74ed-412b-9c60-5cc32c8396e4/NetZeroby2050-ARoadmapfortheGlobalEnergySector-SummaryforPolicyMakers_CORR.pdf. Accessed 18 Apr. 2022.

¹²Intergovernmental Panel on Climate Change, Working Group I, 2021, Climate Change 2021: The Physical Science Basis Summary for Policymakers, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf.

¹³Jeffers, Robert Frederic, et al. 2018, Analysis of Microgrid Locations Benefitting Community Resilience for Puerto Rico, https://www.osti.gov/biblio/1530167.

¹⁴Menati, Ali, and Le Xie. “A Preliminary Study on the Role of Energy Storage and Load Rationing in Mitigating the Impact of the 2021 Texas Power Outage.” 2021 North American Power Symposium (NAPS), 2021, https://doi.org/10.1109/naps52732.2021.9654452.

by Pablo Duenas Martinez, Research Scientist at MIT Energy Initiative

with Elizabeth Gribkoff, MIT Climate Portal Writing Team

Related MIT Groups

MIT Energy Initiative

More resources for learning

EPA: "U.S. Electricity Grid & Markets" (article)

U.S. Energy Information Administration: "Electricity explained: How electricity is delivered to consumers" (article)

MIT Energy Initiative: "The Future of the Electric Grid" (article)

Pacific Northwest National Laboratory (PNNL): "How a Smart Electric Grid Will Power Our Future" (article)

Energy.gov: "Reimagining and rebuilding America’s energy grid" (article)

Energy.gov: "Grid-Connected Renewable Energy Systems" (article)

TILclimate Educator Guide: Electric Grid and Climate Change

TILclimate Educator Guide: Electric Vehicles and Climate Change

Topics

Energy

Batteries, Storage & Transmission

Want to learn more?

Listen to this episode of MIT's "Today I Learned: Climate" podcast on the electric grid.

Laur Hesse Fisher: [00:00:00] Hello and welcome back to TIL Climate, the show where you learn about climate change from real experts. I’m your host Laur Hesse Fisher, from the MIT Environmental Solutions Initiative, in lovely Cambridge, MA.

Energy is the lifeblood of our society. It fuels the production of our food, and things we use every day, and powers our homes, cars, and workplaces. The cost of energy impacts the price of pretty much everything. A world without the cheap and abundant energy that we have today, well, we wouldn’t recognize it.

And yet, generating energy for electricity and heat is our society’s number one source of greenhouse gas emissions. And as those emissions cause global temperatures to rise, coastlines to recede, and natural disasters like wildfires, floods, and hurricanes to intensify… well, the world we’re creating is one we won’t recognize either.

So, in this second season, we’ll be looking closer at how energy is generated and used, and what options we have for keeping the lights on without continuing to emit dangerous levels of CO2. Sometimes this is called “decarbonizing” our energy. We’ll speak with experts who’ll answer questions like, how do fossil fuels like coal, oil, and natural gas compare to each other… and to other non-fossil fuel energy like wind, solar, and nuclear? Is it really possible to capture and store CO2 from power plants? What is fusion and will it really solve all of our energy problems? And why are solutions that sound straight-forward, like replacing fossil fuel plants with solar panels and wind farms, actually a lot more complicated in reality?

We’ll answer these questions and more. To produce this season, we’re partnering with the MIT Energy Initiative who is doing a set of companion episodes. Check out their podcast for longer-form interviews with our same guests. You can find the link in our show notes or search for “MIT Energy Podcast.”

OK, let’s get started. In this season’s first episode, we’re going begin at the beginning: with the electric grid, which are networks that bring most of us our electricity. We’ll explore how it was built, how it works, and the challenges we need to overcome to decarbonize our energy.

We sat down with Harvey Michaels, a senior lecturer in the MIT Sloan School of Management.

Harvey Michaels: [00:02:39] My focus area is energy management which deals with the wise use of energy, energy efficiency, smart grid and related opportunities to mitigate climate change.

Laur Hesse Fisher: [00:02:50] But let’s start at the beginning. At the dawn of the electric age.

Harvey Michaels: [00:02:54] most people rate the creation of the electric power grid as probably the number one thing that happens in the 20th century.

So electricity is a very intriguing and complex technology that became something really important when Thomas Edison made the lightbulb. And once he had that, he had to invent an electric utility so that people would have electricity to run these light bulbs.

Laur Hesse Fisher: [00:03:21] In 1884, he opened Pearl Street Station in Manhattan, NY. This was the first-ever commercial power plant. Over time, more and more people wanted in on the action and more power plants started appearing across the country.

Harvey Michaels: [00:03:35] This powered major cities the United States, but it wasn't really until the Great Depression in the 1930s under a part of the New Deal to create power plants for rural America. And by the time the Depression was over at the end of the 1930s pretty much everybody in the United States had power.

We would build larger and larger electric power plants, and these were powered either by burning fossil fuels-- oil, gas, coal -- and using those to create steam in a boiler and the boiler steam would turn a generator -- an electric turbine -- and in the process would create the flow of electrons.

Laur Hesse Fisher: [00:04:20] Right: fossil fuels are really good at producing steam and this steam is used to push a turbine. It’s the movement of the turbine that then generates the electricity, and helps send it to our homes.

Harvey Michaels: [00:04:32] So a generator is really a spinning magnet that is pumping electrons into the wires and it's creating this flow of electrons that goes first into very high voltage wires, which are called transmission lines. And then it goes to a more local distribution network where it steps down in transformers to lower voltage and flows through the city streets or in the local neighborhood wires to people's homes.

Laur Hesse Fisher: [00:05:11] That might all sound very obvious; you probably see these wires every day. But there is a fascinating feature of our electric grid that most people don’t think about -- and it’s incredibly important when we’re talking about energy and climate change.

Harvey Michaels: [00:05:26] The complexity of the grid is that there needs to be exactly the right amount of power put into the wires to serve all the instantaneous needs of all the people on the system. It doesn't really have the ability to store electricity in the wires themselves. So the electric company has to create a system so the amount of power that's being injected into the wires is just about exactly equal to the amount of electricity that's being taken out of the wires.

If it has too many electrons in the wires it can essentially pump them into the ground. But it's wasted at that point. So the idea is to have it just about right.

Laur Hesse Fisher: [00:06:12] But if there is too little energy in the wires to keep up with demand, people lose power. We have traditionally dealt with this problem by having two kinds of power plants: the kind that supplies most of our energy needs, and the kind that can be easily turned on -- or dispatched -- when energy demand suddenly gets high.

Harvey Michaels: [00:06:31] Some of the larger plants that run on fossil fuels like coal take several hours to start up or to turn off. So the tendency is to run them pretty smoothly over a long period of time. Those kind of power plants are called base load plants.

Laur Hesse Fisher: [00:06:49] Baseload plants are great for making sure that there’s some energy available at all times.

Harvey Michaels: [00:06:55] since the amount of electricity modulates so much depending on the time of day and the weather you need to have some power plants which are easy to turn on and turn off.

Laur Hesse Fisher: [00:07:08] We need dispatchable plants to pick up the slack for these high-intensity periods. And for the most part, in the US, these dispatchable power plants run on natural gas.

Harvey Michaels: [00:07:20] And a natural gas plant can be turned on quickly and produce a lot of electricity quickly. It's a pretty expensive power plant to run: it costs more to make a kilowatt hour with a gas turbine. But you need it because we need to balance the system.

Laur Hesse Fisher: [00:07:37] So using less energy during these high intensity periods -- like the early evening when a lot of people come home from work -- can be one way to help decrease these peaks and avoid needing to turn on these dispatchable plants.

The thing is, the fastest-growing sources of low-carbon energy -- wind and solar -- kind of disrupt this balance because they don’t always add electricity to the grid at the exact time we need it. We have less control over it.

Harvey Michaels: [00:08:05] And when you have a confluence of events where there isn't any wind blowing and the sun isn't out and there's a really strong draw for electricity then you need the system to still be able to work which means you need to have a lot of safety built into it.

Laur Hesse Fisher: [00:08:25] This is a big deal when talking about how to add more wind and solar energy to the grid and yet still making sure there’s enough energy for everyone. There are ways of dealing with this and we’re going to have an entire episode on this issue of what’s called intermittent power, and batteries and storage, so stay tuned. We’re also going to have an episode on nuclear power, which is a low-carbon source of baseload power.

For now, we haven’t talked about two other major uses of energy: heat and transportation. But they are super relevant to discussing the future of our electric grid. We’re really dependent on using natural gas to heat our buildings and oil to power our vehicles. And so a lot of the conversation among energy experts on how to lower emissions from heat and transportation -- is to electrify them.

Harvey Michaels: [00:09:18] To stop climate change we need to both make our electric grid mostly carbon free and make our buildings mostly electric. And to do that we need to switch off of using gas for heat and hot water. We need to stop using as much gasoline for automobiles and use more electricity for those things.

Laur Hesse Fisher: [00:09:49] So there are a lot of changes in store for our grid: It’s going to accept an increasing amount of variable wind and solar energy; and it’s going to get an even bigger draw as more electric cars come online and buildings start using more electricity for heat.

There is so much to dig into here, which is this entire season is dedicated to the future of low-carbon energy, which we’re doing in collaboration with the MIT Energy Initiative.

In the coming episodes, we’ll help you understand where our energy comes from now, the different options we have for reducing CO2 emissions, and the opportunities and challenges of these options. We hope that, when you vote or talk about these issues with your representatives, colleagues or friends, these episodes can help give you a foundation to make strong, informed decisions about our energy future.

If you’re hungry for more right now, search for MIT Energy podcast for the MIT Energy Initiative’s companion episode.

I’m Laur Hesse Fisher from MIT Environmental Solutons Initiative. Thank you to Harvey Michaels for speaking with us and, as always, thank you for listening.

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