The Grid, Part 1

A power market primer

This is the first in a short series of issues about the electrical grid in the United States. How we move electricity from one place to another is a very important part of the energy transition (from fossil fuels to renewables). It’s a huge topic, and one I keep learning new things about. In this first issue of the series, I describe in very general and basic terms how our current grid works. Later issues will talk about problems with the current grid and solutions, as well as how we can make the grid more resilient when there are hurricanes, tornadoes, wildfires, or other climate-related events. 

The electrical grid in the United States is regional, with three major regions: the eastern interconnection, the western interconnection, and Texas. Within those regions, two types of organizations operate the wholesale electricity market: regional transmission organizations (RTOs) and independent system operators (ISOs). There are seven RTOs and ISOs in the US. One of these, the Electric Reliability Council of Texas (ERCOT) has been in the news quite a lot lately. These seven grid operators coordinate and monitor the electric grid across large regions.

Image from https://www.epa.gov/green-power-markets/us-grid-regions

All of this is the sort of dry, hard-to-follow information that makes my eyes glaze over. It helps if I figure out how the electricity gets to MY house. That makes it more real, and also gives me some idea of how the whole system works. 

Where I live is part of the eastern interconnection, and our operator is the Southeastern Electric Reliability Council, or SERC. Each RTO/ISO oversees multiple power generators. The organization that generates the power that comes to my house is the Tennessee Valley Authority (TVA). 

TVA uses fossil fuel plants, nuclear plants, hydroelectric plans, and (not very many) solar sites to generate the power that they then sell to their customers, which are local utilities. 

(Brief Aside: 

TVA is facing criticism (I know people don’t click links, but that one leads to Bill McKibben’s newsletter and is excellent) currently for its plans to expand use of fossil fuels in the form of additional gas plants.

Building more gas plants right now is a terrible idea for a whole bunch of reasons: it’s expensive, the planet is heating up and gas contributes to that problem, and there are other, far better options. But all of that is a different article for a different day.)

Back to how the power market works where I live. 

So, all of the power grids from central Canada to the Atlantic coast and south to Florida are part of the Eastern interconnection and are tied together. Within that large region, there’s SERC, which operates the wholesale power market in the southeastern United States. One of the entities producing power to be sold under SERC is TVA, and TVA sells power to my local utility, which is the Electric Power Board (EPB). 

Image from https://www.serc1.org/about-serc

EPB serves all of Hamilton County, Tennessee, as well as parts of eight surrounding counties. The utility has almost 200,000 customers, and maintains 3,650 miles of transmission lines.  EPB is a little different from most local utilities in that it also offers internet service. It was, in fact, the first public utility in the country to install fiber and offer internet service. 

All of this market operates right in front of most of us, but without our noticing it too much. We expect a light to come on when we flip the switch. Power lines are such a common sight, we don’t even really see them most of the time. But when you think about the whole system, it’s pretty amazing.

I’ve always been fascinated with power lines. This is one of several photos I’ve taken randomly.

That’s why, when I learned that “the grid” is a serious problem when it comes to climate change I was very curious about why, and what needs to happen to make it not a problem. The answer to why is, like everything related to climate change, multi-faceted and layered—which is one reason I need a whole series of newsletters to talk about it.

Some of the problems for making the power grid more efficient and resilient are policy-related, like how permits for new transmission lines are issued, and some are physical, like how much load a power line can carry. Some have to do with who generates power and where. The next couple of issues will dive into all of those different issues and describe some of the smart work happening to address them.