Recent statements from Washington suggest that grid reliability will be threatened if old power plants using coal continue to be replaced by modern power plants using natural gas, wind power, and solar power. This is simply not true.
In April, energy secretary Rick Perry ordered a study on the reliability of the US electric grid amid “significant changes” happening in the power system. He said those changes included the “erosion of critical baseload resources”—namely coal and nuclear—and the “market distorting effects of federal subsidies,” by which he means support for wind and solar.
A leaked draft of the study last week—compiled by career Energy Department experts—said renewable energy is not harming the grid. The final version is due any day now, but Perry’s office indicated it might be quite different from the draft, fueling speculation that the study is merely an attempt to prop up coal and curtail the use of renewables. But regardless of its intentions, this notion of baseload power is outdated.
Let’s start with the basics. The planners and operators of the grid, mostly highly trained electrical engineers working at the utilities and regional system operators, must maintain an overall balance between the generation and use of electricity at all times. We flip a switch or turn on our TV whenever we wish, without checking with the utility first, so this is an orchestrated balancing act.
When things on the grid are working normally, this balancing act requires coordination of generation (to match the level we are using) and voltage throughout the grid (to keep the power flowing where it is needed). The level of use has always been a moving target, and dealing with this variability is nothing new. Adding new wind and solar power plants may increase the variability to some degree, because the wind and sun that “fuel” these power plants also vary, but this has been well studied and grid operators have sound approaches for forecasting and incorporating this additional variability.
The grid must also stay reliable even when something unexpected happens. For example, a large power plant—often a coal or nuclear one—or major transmission line may fail and disconnect from the grid in a fraction of a second. This happens quite often, yet you don’t even notice it. Generators across the grid quickly detect such an event and automatically provide extra power to stabilize the grid until the grid operators can make other adjustments to restore the normal balance.
In light of how the grid works, it is puzzling to see statements from the US Department of Energy about “baseload power is necessary to a well-functioning electric grid,” when by baseload they mean old, conventional coal power plants. Such plants made sense when we built them fifty years ago, but they have never been particularly good at ramping their output to help balance the grid. With today’s much lower prices of natural gas and amazing advancements in cheap wind and solar power, these old plants are now expensive to operate and more prone to the unexpected failures that cause reliability challenges.
The power system is now undergoing a technology revolution, similar to the innovation that we have previously seen with the internet and smart phones. It has been slower than other industries to experience the full impact of modern computers and digital communications, but the revolution is here now. New wind, solar, and battery storage power plants use fast computer-based digital controls and can communicate quickly with the grid control rooms, including following instructions to change their output to help balance the system and maintain reliability. New natural gas power plants similarly respond faster and more accurately than decades-old plants, and all of these new types of generation produce electricity that is both cheaper and cleaner. Changing to use the newer plants lowers our cost of electricity and provides a higher level of reliability.
Upgrading to new, better technology is a good thing. Cheaper, cleaner, and more reliable electricity is a great thing. Many skilled power system engineers are on the job, ensuring that this modernization will happen in a reliable way.