A Future Engineer’s Take: U.S. Energy Association Coal Generation for Grid Stability

Jul 31, 2019

by ASME.org

A new weekly summer series from ASME Global Public Affairs Executive Intern Paul Cipparone, who is currently pursuing a Bachelor of Science in Mechanical Engineering at George Mason University.
 
I recently attended a briefing at the U.S. Energy Association by the Electric Power Research Institute (EPRI) called “Challenges of a Flexible Future: Coal Generation as a Tool for Grid Flexibility and Stability.” The program provided a comprehensive look at all of the different factors associated with energy generation and the transition to clean energy, with the central thesis that managing the transitionary period between fossil fuels and renewable energy will necessitate a balancing act between the strengths and weaknesses of every major power source. A hard, immediate switch to renewables is technically and economically impossible.

The event highlighted Mike Caravaggio, a Senior Program Manager at the Electric Power Research Institute and a Professional Engineer in the Province of Ontario. According to Caravaggio, a big problem with what are often considered the best renewable sources— wind and solar PV (photovoltaic)—is that they are non-dispatchable. This means that they cannot respond quickly to instant changes in energy demand due to their lack of storage capability. Energy regulation is supply and demand. It responds when people use power and when they don’t. Consequently, non-dispatchable power is not as economically viable because these sources cannot contribute to the supply: they can only eat away at the demand. Thus, they are still producing even when the price of energy is at its lowest every day (around 12:00 PM). The issue here is that the power they make is economically worthless at this time, but they cannot store it for when it is worth more (in the evening). In this case, they sometimes actually have to sell the power at a loss.

One solution to this problem is to sell the power to a market where it is a different time of day. This, however, creates the problem of dependence on that market and the hassle of importing and exporting power. It may lead to a situation where one is buying power at a high price and selling it at a low price. Another potentially obvious solution to this problem is external storage. Unfortunately, according to Caravaggio, the technology isn’t there yet. Despite falling battery costs, it will be another 5-15 years before we see rollout of an economical energy storage system at scale.

In response to these drawbacks, flexible operation of traditional energy sources has seen an uptick. This means only running these systems enough to generate power not generated by newly implemented renewables. Unfortunately, this can lead to further drawbacks. Many of these systems were not designed to stop and start like this, so it can lead to thermal and corrosion damage, and investors do not want to sink more money into maintaining these units that are increasingly being phased out. Research and development is underway to assess the best methods of running these systems flexibly, but that too takes money. Flexible operation can also ironically lead to the neutering of environmental controls that have been placed on some of these systems, actually leading to a bigger carbon footprint.

While Caravaggio’s presentation was fact-based, rigorous, and insightful, I believe the U.S. needs a more forward-looking vision. There is an imperative for leaders in energy research to focus on the energy transition and, as was stated in the program, there is a broader imperative for the U.S. to establish national goals to that end.  More info on the event is available here: https://www.usea.org/event/briefing-coal-generation-tool-grid-flexibility-and-stability

On a personal note, I am looking forward to going to more of these briefings! I am learning so much about the exciting things going on in the world of technology and I can’t wait to share my perspective on next week’s topic.

Paul Cipparone [cipparonep@asme.org]