You may have heard of water drought. Could the ‘energy’ drought be next?
Renewable energy prices have fallen by more than 70 percent over the past decade, prompting Americans to drop fossil fuels for greener, less polluting energy sources. But as wind and solar power continue to infiltrate, grid operators will have to plan large-scale oscillations.
Upmanu Lal, a professor at the Columbia School of Engineering and Columbia Climate, issued the warning.
“Designers of renewable energy systems need to focus on changing wind and solar patterns over the weeks, months and years, as water managers do,” he said. “You can not manage such variation with batteries. You will need more capacity.”
In a new modeling study in the journal Patterns, Lal and Columbia Ph.D. Student Yash Amonkar shows that the energy of the sun and wind varies widely over days and weeks, not to mention months and years. They focused on Texas, which is the nation’s largest producer of wind power and the fifth largest solar producer. Texas, like many other countries, has a self-construction phase that makes it an excellent laboratory for listing the promise and risk of renewable energy systems.
Researchers have drawn up 70-year-old historical wind and solar power data and developed an AI model to predict network-level “drought” probabilities when the daily production of renewables falls below the target. Under a limit set at 30 percent, one-third of all days are low-productivity days, and researchers found that Texas could face a daily energy drought of up to four months.
Lal said the drought of this length could not be offset by batteries, and if the system relied solely on solar power, the drought would last twice as long – up to eight months. “These innovations should help energy planners consider alternative ways to save or generate electricity, or dramatically increase the efficiency of their renewable systems,” he said.
Expect future ‘energy’ drought across the continent of Texas and the United States
Six years ago, Lall and former graduate student David Farnham began research into air and solar variation at eight U.S. airports, where weather records were long and detailed. They wanted to see how much variation could be expected under an imaginary 100% renewable-energy phase.
Results published by Furnham in his Ph.D. Thesis, not surprising. Farnham and Lal found that the potential for sun and wind, like rain, varies greatly depending on the time of year and the location of wind turbines and solar panels. In eight cities, renewable energy efficiency has risen and fallen from a long-term average of one-third in some seasons.
“The term ‘energy’ droughts is so different from the 10-year cycle that the long-term average would be considered a major drought,” Lal said. “That was the beginning of the energy drought work.”
In the current study, Lal chose to enlarge Texas, a state with both sun and wind. Lal and Amonkar found that even though solar and wind generators are spread across the state, the ongoing renewable energy drought can last up to a year. In conclusion, renewables face a storage problem that can only be realistically solved by adding additional capacity or power sources, Lal said.
“In a fully renewable world, we need to develop more of nuclear fuel or hydrogen fuel or carbon recycling, or add more capacity to produce renewables if we want to avoid burning fossil fuels,” he said.
During periods of low rainfall, water managers pour fresh water through spigot by tapping municipal reservoirs or groundwater. There is no equivalent backup for solar and wind power systems. Batteries used to store excess solar and wind power on high light and windy days will only charge for a few hours, maximum only a few days. Hydroelectric plants provide a viable buffer, but not enough to carry the system through the incessant dry periods of sun and wind for a long time, Lal said.
“We will not solve the problem by building a bigger network,” he said. “Electric grid operators aim for 99.99% reliability, while water managers strive for 90 percent reliability. You can see how challenging this season can be for the energy sector and how valuable seasonal and long forecasts can be.”
In the next phase of research, Lal, along with Columbia engineering professors Vijay Modi and Polon Sue, will develop system-renewable surplus to see if energy can predict both drought and “flood”. Armed with these forecasts, they hope to predict the rise and fall of energy prices.
<div class="article-main__explore my-4 d-print-none"> Green hydrogen production by reduced wind and solar power </div> <hr class="mb-4"/> <div class="article-main__more p-4"> <strong>More info:</strong> K-Near Space Time Simulator, with applications for large-scale wind and solar power modeling, by Yash Amonkar et al. <i>Patterns</i> (2022) <a data-doi="1" href="https://dx.doi.org/10.1016/j.patter.2022.100454" target="_blank" rel="noopener">DOI: 10.1016 / j.patter.2022.100454</a> </div> <div class="d-inline-block text-medium my-4"> Presented by Columbia University <a class="icon_open" href="http://www.columbia.edu/" target="_blank" rel="nofollow noopener"> <svg> <use href="https://techx.b-cdn.net/tmpl/v2/img/svg/sprite.svg#icon_open" x="0" y="0"/> </svg> </a> </div> <!-- print only --> <div class="d-none d-print-block"> <p> <strong>Quote</strong>: You may have heard of water drought. Could the ‘energy’ drought be next? (2022, April 12) Retrieved April 13, 2022 from https://techxplore.com/news/2022-04-youve-heard-droughts-energy.html This document is subject to copyright. No part may be reproduced without written permission, except for any reasonable manipulation for the purpose of personal study or research. Content is provided for informational purposes only. </div> </div>https://connect.facebook.net/en_US/sdk.js</p>