Reusing old oil and gas wells may offer green energy storage solution

by Matthew Carroll for Penn News

University Park PA (SPX) Mar 19, 2025

Moving from fossil fuels to renewable energy sources like wind and solar will require better ways to store energy for use when the sun is not shining or the wind is not blowing. A new study by researchers at Penn State found that taking advantage of natural geothermal heat in depleted oil and gas wells can improve the efficiency of one proposed energy storage solution: compressed-air energy storage (CAES).

CAES plants compress air and store it underground when energy demand is low and then extract the air to create electricity when demand is high. But startup costs currently limit commercial development of these projects, the scientists said.

The researchers proposed a new geothermal-assisted compressed-air energy storage system that makes use of depleted oil and gas wells – the Environmental Protection Agency estimates there are around 3.9 million in the United States – and found it can improve efficiency by 9.5% over the existing technology. This means a larger percentage of the energy stored in the system can be recovered and turned into electricity, potentially boosting profits for operators.

“This improvement in efficiency can be a game changer to justify the economics of compressed-air energy storage projects,” said Arash Dahi Taleghani, professor of petroleum and natural gas engineering at Penn State and corresponding author on the study. “And on top of that, we could significantly avoid the upfront cost by using existing oil and gas wells that are no longer in production. This could be a win, win situation.”

Reusing depleted oil and gas wells would allow operators to access geothermal heat in hot rock formations underground, eliminating upfront costs of drilling new wells and potentially making the technology more appealing to industry, the scientists said.

Gases like compressed air increase in pressure as temperatures increase, meaning the heated wells could potentially store more energy, according to Taleghani. When electricity is needed, the heated, compressed air is released, driving a turbine to produce power.

“Without taking advantage of the geothermal setup, you could not get enough encouraging numbers,” Taleghani said, explaining that the team used numerical modeling simulations to find that placing CAES systems in abandoned oil and gas wells significantly increased the air temperature in the systems. “And on top of that, drilling new wells may not justify the economics of this type of storage. But by combining these two factors, and by going back and forth through modeling and simulation, we found this could be a very good solution.”

Energy storage options like CAES are particularly important in the transition to clean energy, according to the researchers, because they help address the intermittent nature of renewable sources. By storing excess renewable energy and releasing it when needed, energy storage contributes to grid stability and reliability.

“The problem is that sometimes when we need energy, there is no sunshine or there is no wind,” Taleghani said. “That’s a big barrier against further expansion of most of the renewable energy that is available to us. That’s why it’s very important to have some storage capacity to support the grid.”

Repurposing depleted oil and gas wells may also help mitigate potential environmental impacts of abandoned wells and potentially provide new job opportunities in areas with rich energy industry traditions, the researchers said.

In Pennsylvania alone, regulators estimate there are hundreds of thousands of orphaned and abandoned wells. If these wells are improperly plugged, or damaged, they can leak methane into the atmosphere and groundwater.

“If we use existing wells, we are basically hitting two birds with one stone,” Taleghani said. “First, we are sealing these wells. That stops any potential leaks. And then if we are repurposing these wells for energy storage, we are still using the infrastructure that is in place in these communities. It can potentially maintain employment in the area and allow communities to be part of the energy future.”

This research was conducted as part of the Repurposing Center for Energy Transition (ReCET) at Penn State. The center seeks to repurpose fossil energy infrastructure for energy transition applications, especially in legacy energy communities.

Also contributing from Penn State were Derek Elsworth, G. Albert Shoemaker Chair in Mineral Engineering and professor of energy and geo-environmental engineering, and Qitao Zhang, a postdoctoral scholar, both in the John and Willie Leone Family Department of Energy and Mineral Engineering.

Research Report:Underground energy storage using abandoned oil and gas wells assisted by geothermal

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Chinese battery behemoth CATL posts jump in annual profit

by AFP Staff Writers

Beijing (AFP) Mar 14, 2025

Chinese battery giant CATL announced on Friday surging annual profits despite a decline in revenue, as slowing demand for electric vehicles drives down the price of lithium.

The firm produces more than a third of all electric vehicle (EV) batteries sold worldwide, cooperating with major brands including Tesla, Mercedes-Benz, BMW and Volkswagen.

CATL has been aided by robust financial support from Beijing, which has sought in recent years to shore up domestic strength in certain strategic high-tech sectors.

Net profits were up more than 15 percent in 2024 compared to 2023.

Last year, CATL achieved a profit of 50.74 billion yuan ($7.01 billion), a filing at the Shenzhen Stock Exchange showed Friday.

The figure came in below a Bloomberg forecast of 51.47 billion yuan.

Revenue, meanwhile, fell 9.7 percent year-on-year to 362 billion yuan in 2024, the filing showed.

CATL had warned in January that its slide in sales last year was likely due to a “decline in the prices of raw materials such as lithium carbonate”, which had forced the firm to adjust prices.

Last year saw lithium prices decline significantly, partly due to market oversupply and less fervent consumer demand for EVs.

– Overseas expansion –

Founded in 2011 in the eastern Chinese city of Ningde, Contemporary Amperex Technology Co., Limited (CATL) was initially propelled to success by rapid growth in the domestic market.

CATL’s shares are publicly traded in Shenzhen, though it is now planning to seek a secondary listing in Hong Kong.

Last month, the firm started a Hong Kong listing application process — a first step towards what analysts say could be a blockbuster initial public offering for the financial hub.

Funds raised from a secondary listing could be used to accelerate CATL’s overseas expansion, particularly in Europe.

The battery giant is building its second factory on the continent in Hungary after launching its first in Germany in January 2023.

In December, CATL announced that it would work with automotive giant Stellantis on a $4.3 billion factory to make EV batteries in Spain, with production slated to begin by the end of 2026.

The firm’s international push comes as challenges in the domestic market mount.

Following years of rapid growth, the world’s largest EV market has begun to show signs of flagging sales amid a broader slowdown in consumption.

The trends have fuelled a fierce price war in the country’s expansive EV sector, putting smaller firms under huge pressure to compete while remaining financially viable.

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Artificial photosynthesis breakthrough replicates early plant processes

by Robert Schreiber

Berlin, Germany (SPX) Mar 17, 2025

Harnessing sunlight to convert carbon dioxide and water into sugars and oxygen is a remarkable feat of nature, accomplished through the intricate process of photosynthesis. This natural mechanism allows plants to derive energy from sunlight, fueling a sequence of reactions that sustain life on Earth.

Replicating photosynthesis in a laboratory setting promises significant benefits. Artificially harnessing solar energy could enable the conversion of atmospheric carbon dioxide into carbohydrates and other valuable compounds. Furthermore, as water splitting is part of photosynthesis, this approach holds potential for producing hydrogen fuel by isolating hydrogen and oxygen.

However, recreating this natural process is no simple task. Photosynthesis involves a series of complex reactions occurring in plant cells, mediated by a network of pigments, proteins, and molecules. Despite these challenges, research continues to make strides in mimicking nature’s design.

A notable advance has been achieved by Professor Frank Wurthner, a chemist at Julius-Maximilians-Universitat (JMU) Wurzburg in Bavaria, Germany. His team successfully replicated one of the initial phases of photosynthesis using an engineered array of artificial dyes and conducted an in-depth analysis of the system’s behavior.

This research, conducted in partnership with Professor Dongho Kim’s laboratory at Yonsei University in Seoul, Korea, was recently published in the journal Nature Chemistry.

The team developed a dye assembly that closely resembles plant cell light-harvesting complexes. The synthetic structure captures light at one terminus, facilitates charge separation, and then transfers electrons progressively through a series of steps to the opposite end. This assembly features four perylene bisimide dye molecules arranged in a vertical stack.

“We can specifically trigger the charge transport in this structure with light and have analysed it in detail. It is efficient and fast. This is an important step towards the development of artificial photosynthesis,” said JMU PhD student Leander Ernst, who was responsible for synthesising the stacked system.

Looking ahead, the JMU researchers plan to increase the number of dye components in their nanoscale stack to form a supramolecular wire. Such a structure would absorb sunlight and channel energy effectively across greater distances. Achieving this would mark significant progress toward new photofunctional materials that support artificial photosynthesis.

Research Report:Photoinduced stepwise charge hopping in p-stacked perylene bisimide donor-bridge-acceptor arrays.

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