Solar Energy

Study reveals plunge in lithium-ion battery costs

Published

3 years ago

March 24, 2021

sarosh

Study reveals plunge in lithium-ion battery costs

The cost of the rechargeable lithium-ion batteries used for phones, laptops, and cars has fallen dramatically over the last three decades, and has been a major driver of the rapid growth of those technologies. But attempting to quantify that cost decline has produced ambiguous and conflicting results that have hampered attempts to project the technology’s future or devise useful policies and research priorities.

Now, MIT researchers have carried out an exhaustive analysis of the studies that have looked at the decline in the prices these batteries, which are the dominant rechargeable technology in today’s world. The new study looks back over three decades, including analyzing the original underlying datasets and documents whenever possible, to arrive at a clear picture of the technology’s trajectory.

The researchers found that the cost of these batteries has dropped by 97 percent since they were first commercially introduced in 1991. This rate of improvement is much faster than many analysts had claimed and is comparable to that of solar photovoltaic panels, which some had considered to be an exceptional case. The new findings are reported today in the journal Energy and Environmental Science, in a paper by MIT postdoc Micah Ziegler and Associate Professor Jessika Trancik.

While it’s clear that there have been dramatic cost declines in some clean-energy technologies such as solar and wind, Trancik says, when they started to look into the decline in prices for lithium-ion batteries, “we saw that there was substantial disagreement as to how quickly the costs of these technologies had come down.” Similar disagreements showed up in tracing other important aspects of battery development, such as the ever-improving energy density (energy stored within a given volume) and specific energy (energy stored within a given mass).

“These trends are so consequential for getting us to where we are right now, and also for thinking about what could happen in the future,” says Trancik, who is an associate professor in MIT’s Institute for Data, Systems and Society. While it was common knowledge that the decline in battery costs was an enabler of the recent growth in sales of electric vehicles, for example, it was unclear just how great that decline had been.

Through this detailed analysis, she says, “we were able to confirm that yes, lithium-ion battery technologies have improved in terms of their costs, at rates that are comparable to solar energy technology, and specifically photovoltaic modules, which are often held up as kind of the gold standard in clean energy innovation.””

It may seem odd that there was such great uncertainty and disagreement about how much lithium-ion battery costs had declined, and what factors accounted for it, but in fact much of the information is in the form of closely held corporate data that is difficult for researchers to access.

Most lithium-ion batteries are not sold directly to consumers – you can’t run down to your typical corner drugstore to pick up a replacement battery for your iPhone, your PC, or your electric car. Instead, manufacturers buy lithium-ion batteries and build them into electronics and cars. Large companies like Apple or Tesla buy batteries by the millions, or manufacture them themselves, for prices that are negotiated or internally accounted for but never publicly disclosed.

In addition to helping to boost the ongoing electrification of transportation, further declines in lithium-ion battery costs could potentially also increase the batteries’ usage in stationary applications as a way of compensating for the intermittent supply of clean energy sources such as solar and wind. Both applications could play a significant role in helping to curb the world’s emissions of climate-altering greenhouse gases.

“”I can’t overstate the importance of these trends in clean energy innovation for getting us to where we are right now, where it starts to look like we could see rapid electrification of vehicles and we are seeing the rapid growth of renewable energy technologies,” Trancik says. “”Of course, there’s so much more to do to address climate change, but this has really been a game changer.””

The new findings are not just a matter of retracing the history of battery development, but of helping to guide the future, Ziegler points out. Combing all of the published literature on the subject of the cost reductions in lithium-ion cells, he found “very different measures of the historical improvement. And across a variety of different papers, researchers were using these trends to make suggestions about how to further reduce costs of lithium-ion technologies or when they might meet cost targets.”

But because the underlying data varied so much, “the recommendations that the researchers were making could be quite different.” Some studies suggested that lithium-ion batteries would not fall in cost quickly enough for certain applications, while others were much more optimistic. Such differences in data can ultimately have a real impact on the setting of research priorities and government incentives.

The researchers dug into the original sources of the published data, in some cases finding that certain primary data had been used in multiple studies that were later cited as separate sources, or that the original data sources had been lost along the way. And while most studies have focused only on the cost, Ziegler says it became clear that such a one-dimensional analysis might underestimate how quickly lithium-ion technologies improved; in addition to cost, weight and volume are also key factors for both vehicles and portable electronics. So, the team added a second track to the study, analyzing the improvements in these parameters as well.

“Lithium-ion batteries were not adopted because they were the least expensive technology at the time,” Ziegler says. “There were less expensive battery technologies available. Lithium-ion technology was adopted because it allows you to put portable electronics into your hand, because it allows you to make power tools that last longer and have more power, and it allows us to build cars” that can provide adequate driving range. “It felt like just looking at dollars per kilowatt-hour was only telling part of the story,” he says.

That broader analysis helps to define what may be possible in the future, he adds: “We’re saying that lithium-ion technologies might improve more quickly for certain applications than would be projected by just looking at one measure of performance. By looking at multiple measures, you get essentially a clearer picture of the improvement rate, and this suggests that they could maybe improve more rapidly for applications where the restrictions on mass and volume are relaxed.”

Trancik adds the new study can play an important role in energy-related policymaking. “Published data trends on the few clean technologies that have seen major cost reductions over time, wind, solar, and now lithium-ion batteries, tend to be referenced over and over again, and not only in academic papers but in policy documents and industry reports,” she says.

“Many important climate policy conclusions are based on these few trends. For this reason, it is important to get them right. There’s a real need to treat the data with care, and to raise our game overall in dealing with technology data and tracking these trends.”

“”Battery costs determine price parity of electric vehicles with internal combustion engine vehicles,” says Venkat Viswanathan, an associate professor of mechanical engineering at Carnegie Mellon University, who was not associated with this work. “Thus, projecting battery cost declines is probably one of the most critical challenges in ensuring an accurate understanding of adoption of electric vehicles.”

Viswanathan adds that “the finding that cost declines may occur faster than previously thought will enable broader adoption, increasing volumes, and leading to further cost declines. … The datasets curated, analyzed and released with this paper will have a lasting impact on the community.”

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Solar Energy

3D-printed microstructure forest enhances solar steam desalination

Published

3 days ago

July 24, 2024

sarosh

3D-printed microstructure forest enhances solar steam desalination

by Clarence Oxford

Los Angeles CA (SPX) Jul 24, 2024

To address the global freshwater scarcity issue, researchers in Singapore have developed advanced solar steam generators (SSGs) for seawater desalination. This method, powered by renewable energy, mimics the natural water cycle by using solar energy to evaporate and purify water, offering a potentially cost-effective solution compared to traditional, energy-intensive desalination techniques. However, current SSG technologies face limitations due to the complexity of fabricating designs that maximize surface area for optimal water evaporation.

Drawing inspiration from nature, the team utilized 3D printing to create innovative SSGs. Their findings, published in Applied Physics Reviews, highlight a novel technique for manufacturing efficient SSGs and introduce a groundbreaking method for printing functional nanocomposites using multi-jet fusion (MJF).

“We created SSGs with exceptional photothermal performance and self-cleaning properties,” said Kun Zhou, a professor of mechanical engineering at Nanyang Technological University. “Using a treelike porous structure significantly enhances water evaporation rates and ensures continuous operation by preventing salt accumulation – its performance remains relatively stable even after prolonged testing.”

The technology works by converting light to thermal energy, where SSGs absorb solar energy and convert it to heat to evaporate water. The porous structure of the SSGs aids in self-cleaning by removing accumulated salt, ensuring sustained desalination performance.

“By using an effective photothermal fusing agent, MJF printing technology can rapidly create parts with intricate designs,” Zhou added. “To improve the photothermal conversion efficiency of fusing agents and printed parts, we developed a novel type of fusing agent derived from metal-organic frameworks.”

The SSGs feature miniature tree-shaped microstructures that mimic plant transpiration, forming an efficient, heat-distributing forest.

“Our bioinspired design increases the surface area of the SSG,” Zhou explained. “Using a treelike design increases the surface area of the SSG, which enhances the water transport and boosts evaporation efficiency.”

In both simulated environments and field trials, the SSGs exhibited a high rate of water evaporation. The desalinated water consistently met drinking water standards, even after extended testing.

“This demonstrates the practicality and efficiency of our approach,” Zhou said. “And it can be quickly and easily mass-produced via MJF commercial printers.”

The team’s work shows significant potential for tackling freshwater scarcity.

“Our SSGs can be used in regions with limited access to freshwater to provide a sustainable and efficient desalination solution,” said Zhou. “Beyond desalination, it can be adapted for other applications that require efficient solar energy conversion and water purification.”

Research Report:3D printing of bio-inspired porous polymeric solar steam generators for efficient and sustainable desalination

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Solar Energy

Renewables overproduction turns electricity prices negative

Published

3 days ago

July 24, 2024

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Renewables overproduction turns electricity prices negative

By Nathalie Alonso and Catherine Hours

Paris (AFP) July 24, 2024

With the proliferation of solar panels and wind turbines an unusual phenomenon is becoming more and more frequent: wholesale electricity prices turn negative.

While that may brighten the mood of consumers whose power bills have surged in recent years, it could undermine the further development of renewables, a key element in the fight against global warming.

The increasingly frequent phenomenon is “extremely problematic” for the wind and solar sector, said Mattias Vandenbulcke, strategy director of the renewables industry group France Renouvelables.

“It allows some to have harmful, even dangerous rhetoric which says ‘renewables are useless’,” Vandenbulcke said.

In southern Australia, wholesale electricity prices have been negative some 20 percent of the time since last year, according to the International Energy Agency.

The share of negatively priced hours in southern California was above 20 percent in the first half of the year, more than triple from the same period in 2023, the IEA said.

In the first six months of the year in France, there were negative prices around five percent of the time, beating the record set last year, according to the electricity grid operator RTE.

In Switzerland the price tumbled as far as -400 euros (-$436) per megawatt hour on July 14. The lowest prices are usually recorded around midday during the summer when solar production is at its peak.

– ‘A warning signal’ –

The trend has been accelerating for the past three years as demand in Europe has unexpectedly dropped since the Covid pandemic and the war in Ukraine.

Prices turn negative on the spot wholesale electricity market when production is strong while demand is weak.

Around a fifth of the total is traded on this market, where electricity is bought for the following day.

Negative prices help reduce the bills of consumers, said Rebecca Aron, head of electricity markets at French renewables firm Valorem, but the impact is delayed and difficult to discern among the other factors that send prices higher and lower.

Large, industrial consumers that can shift production to times when prices are negative and buy on wholesale markets can reap the biggest rewards.

Negative prices are “a warning signal that there is way too much production on the electrical grid”, said energy analyst Nicolas Goldberg at Colombus Consulting.

Electricity grids need to be kept constantly in balance. Too much can lead to the electricity to increase in frequency beyond norms for some equipment. Too little can lead to some or all customers losing power.

There are currently few options to stock surplus electricity production so producers have to reduce output.

Many renewable producers stop their output when prices are set to turn negative. It takes one minute to stop output at a solar park, two to three minutes for a wind turbine.

But not all stop their production.

– Tripling renewables –

“Renewable energy can be controlled, but depending on production contracts, there might not necessarily be an incentive to stop,” said Mathieu Pierzo at French grid operator RTE, which has the responsibility for balancing the electricity load.

Some producers are paid a fixed price under their contract or are compensated by the state if prices fall below a certain level.

Fossil fuel and nuclear power plants can adjust their production to some extent, but halting and restarting output is costly.

In the future, solar and wind will also have to “participate more in balancing the electricity system”, Pierzo said.

Solar and wind production is set to rise further as nations agreed at the COP28 climate conference last year to triple renewable energy capacity by 2030 as part of efforts to limit warming to 1.5 degrees Celsius compared with pre-industrial levels.

“Rising frequency of negative prices sends an urgent signal that greater flexibility of supply and demand is needed,” the Paris-based IEA warned last week.

“The appropriate regulatory frameworks and market designs will be important to allow for an uptake in flexibility solutions such as demand response and storage,” it said.

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Solar Energy

NREL explores long-term strategies for sustainable perovskite solar panels

Published

3 days ago

July 24, 2024

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NREL explores long-term strategies for sustainable perovskite solar panels

by Clarence Oxford

Los Angeles CA (SPX) Jul 24, 2024

Researchers at the National Renewable Energy Laboratory (NREL) are examining the future of perovskite solar panels, focusing on scaling, deploying, and designing panels to be recyclable.

Perovskite solar panels could play a key role in global efforts to reduce greenhouse gas emissions. With the technology still in its developmental stages, researchers are emphasizing the importance of designing these panels to minimize environmental impact.

“When you have a technology in its very early stages, you have the ability to design it better. It’s a cleaner slate,” said Joey Luther, a senior research fellow at the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) and coauthor of the newly published article in the journal Nature Materials. “Pushing perovskite PV toward enhanced sustainability makes more sense at this stage. We’re thinking about how we can make sure we have a sustainable product now rather than dealing with sustainability issues toward the end of its practical life.”

The article highlights the PV research community’s influential position to prioritize remanufacturing, recycling, and reliability efforts, aiming to make perovskite PV one of the most sustainable energy sources available.

“Perovskites could unlock the next evolution of high-efficiency PV, and it is our responsibility to assure they are manufactured, used, and recycled sustainably,” said the lead author of the study, Kevin Prince, a former graduate researcher at NREL who now researches perovskites at Helmholtz Zentrum Berlin in Germany.

While silicon solar panels dominate the industry and cadmium telluride (CdTe) panels have established recycling programs, perovskites are at a critical point where sustainability issues can be addressed from the start.

The most effective circular economy begins at the design stage, considering materials sourcing, product lifetime, and end-of-life management. Researchers suggest assessing environmental impacts by looking at carbon emissions during production, embodied energy, sustainable material sourcing, and module circularity.

The journal article identifies critical sustainability concerns for each component of a perovskite solar panel. For instance, lead can be diluted with metals like tin to reduce lead content, though this may affect PV efficiency and durability. Expensive precious metals such as silver and gold could be replaced with cheaper alternatives like aluminum, copper, or nickel. Fluorine-tin oxide is recommended over the scarcer indium-tin oxide for front electrodes.

“We want to have the lowest amount of embodied energy in the fabrication,” Luther said. “We want to have the lowest amount of emissions in the fabrication. At this stage, now is the chance to look at those components. I don’t think we have to change anything. It’s more a matter of what decisions should be made, and these arguments should certainly be discussed.”

The authors discuss various ways to improve the circularity of perovskite panels. Remanufacturing involves reusing parts from old modules to make new ones, while recycling converts waste materials into raw materials for reuse. Attention is needed for the specialized glass used in perovskite modules, which is crucial for structural support and protection while allowing maximum sunlight penetration. Establishing a recycling pathway for this glass will be essential as PV deployment increases.

Silvana Ovaitt, a PV researcher and coauthor of the paper, noted that cleaner electricity grids will lead to cleaner manufacturing processes, further reducing emissions.

“Another concern is the transportation of the final modules and the raw glass because those are the heaviest items,” Ovaitt said. “Local manufacturing will be a great way to reduce those carbon impacts.”

The researchers explain that increasing the durability of PV modules, thereby extending their useful life, is a more effective approach to reducing net energy, energy payback, and carbon emissions than designing for circularity alone. A longer lifespan means panels won’t need to be recycled as often.

“Ultimately, we want to make them as durable as possible,” Luther said. “But we also want to consider the aspects of whenever that time does come. We want to be deliberate about how to take them apart and to reuse the critical components.”

Research Report:Sustainability pathways for perovskite photovoltaics