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Study claims perovskite solar cells can recoup their energy cost within three months

Study claims perovskite solar ...
Perovskite solar cells are reportedly able to recoup their energy cost much faster than normal silicon cells, although their short lifetime remains an issue
Perovskite solar cells are reportedly able to recoup their energy cost much faster than normal silicon cells, although their short lifetime remains an issue
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Energy payback time, or EPBT, for some of the best-known types of solar cells
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Energy payback time, or EPBT, for some of the best-known types of solar cells
The CO2 emission factor is currently higher for perovskite cells because their lifetime is much shorter
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The CO2 emission factor is currently higher for perovskite cells because their lifetime is much shorter
Perovskite solar cells are reportedly able to recoup their energy cost much faster than normal silicon cells, although their short lifetime remains an issue
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Perovskite solar cells are reportedly able to recoup their energy cost much faster than normal silicon cells, although their short lifetime remains an issue

Scientists at Northwestern University and the U.S. Department of Energy have found that perovskite cells, one of the most promising solar technologies of recent years, can repay their energy cost over 10 times faster than traditional silicon-based solar cells. The finding confirms that, once issues related to cell longevity are ironed out, perovskite cells could soon bring us solar energy on the cheap, and do so with less impact on the environment over their lifetime.

Solar panel installations are doubtlessly having a positive impact on the environment, but quantifying their carbon footprint with some degree of precision – which is useful for comparing them to other means of energy production, including other renewables – is not a straightforward process. To get a more complete picture, it's important to consider not only the carbon emissions saved during the panel's operating life, but also the amount of energy that goes into materials processing, manufacture, repair, maintenance and, once it is no longer useful, disposal of the panel.

According to this metric, called the cradle-to-grave life cycle assessment, a typical solar panel takes a fairly long time, between two and three years, to offset the energy costs that went into producing it. This is because silicon-based solar panels must be manufactured inside a clean room using high-purity crystalline silicon wafers that can only form inside specialized high-temperature furnaces.

Scientists at Northwestern University have now calculated that, by contrast, perovskite-based solar cells have an energy payback time (EPBT) of only two to three months. According to the researchers, this is not only much faster than a silicon-based cell, but also significantly better than any other type of commonly available solar cell.

Energy payback time, or EPBT, for some of the best-known types of solar cells
Energy payback time, or EPBT, for some of the best-known types of solar cells

Perovskite cells are the fastest-growing technology in the solar arena. Although they aren't quite as efficient at converting sunlight into electricity as silicon-based cells, they are catching up very quickly. More importantly, they are much cheaper to produce than normal panels, meaning that their commercialization could lead to a drastic drop in the cost of clean electricity.

Unlike traditional silicon-based cells, perovskites can be manufactured at a very low energy cost, without the need for sophisticated equipment, and in very few steps. A solution containing the electrode materials is coated onto a substrate and, once it evaporates, this solution produces dense layers of crystallized perovskite at a fraction of the cost and energy expenditure of other common solar panels.

According to the study, which analyzed the detailed energy expenditure for two different types of perovskite cells, raw materials contribute about 80 percent of the primary energy consumption for making the panels, suggesting that a better choice of materials could reduce the energy costs even further.

There are indeed plenty of issues with the current choice of materials for perovskite cells, which often make use of potentially toxic lead to absorb sunlight and improve conversion efficiency. The researchers also found that the use of gold, another common raw material, was even more problematic, since the process of mining this precious metal is extremely damaging to the environment.

But perhaps the biggest issue that perovskite cells are currently facing is that they are unable to brave the environment, since they are partly made from organic molecules that degrade quickly when exposed to the elements. Most perovskite cell designs currently lack a protective layer that could lengthen their lifetime, as this would reduce conversion efficiency.

The CO2 emission factor is currently higher for perovskite cells because their lifetime is much shorter
The CO2 emission factor is currently higher for perovskite cells because their lifetime is much shorter

Because of their very short lifetime, the researchers found that the overall CO2 impact of perovskite cells is still significantly higher than that of traditional silicon-based cells, which are much more durable with a reported average lifetime of approximately 20 years.

But if these issues are solved (which the researchers say could happen in as little as two years), perovskite cells could indeed rise to take the lion's share of the solar landscape in the near future, providing clean energy while having an even lower impact on the environment than the solar cells of today.

A paper describing the study appears in the latest issue of the journal Energy & Environmental Science.

Source: Northwestern University

13 comments
piperTom
The bureaucrats studied "energy cost"? !! How about actual economic cost? Nothing said! That would imply there's no good news. The energy cost is useful only if a number of other conditions are met, starting with there being a reliable way to forecast future climate - which there is not.
grtbluyonder
And their energy efficiency is? And their cost per kw is?
JohnRAllen
They can claim what ever they want, they just cannot make it true. I can't see how this means anything unless these particular Solar cells are to cheap to be worthwhile
tkj
Good .. but: Why not tell us what this stuff is~~!!
BZD
Pretty great that solar is becoming so efficient. In doing so it opening up lots of new areas where it can be used. One thing that will always be even better than efficient energy production is using less energy in the first place. Now that is not easy, but an area often almost ignored is isolation. Fx. the energy used to make rockwool aka stone wool isolation is saved 100-130 times over with the isolation it brings - and isolation can be about both keep warm and keeping cool.
habakak
Even if these panels become viable, they won't be much cheaper than silicone based panels. The industry would find a way to support high prices. Hopefully it will cause a revolution that will just wash high-priced suppliers out of the way. I hope this is what happens to the auto insurance industry when autonomous cars roll in. They are already thinking of ways around this. If the death toll drops from 40k per year to under 1k per year, there is no need for so much insurance. And why should liability increase if accidents decrease? I shudder at the thought of how this will turn out.
El Bonko
@piperTom "The bureaucrats studied "energy cost"? !! How about actual economic cost? Nothing said! That would imply there's no good news." First, they're scientists, not bureaucrats. As a bureaucrat, I can assure you that my job is not at all similar to theirs. Second, nothing said about economic cost simply means that they didn't study it. It's a separate matter. "The energy cost is useful only if a number of other conditions are met, starting with there being a reliable way to forecast future climate - which there is not." I think we can be fairly sure the sun will keep shining. If it doesn't, we won't have to think about energy costs anyway.
mookins
@piperTom: "Bureaucrats": what a dimwitted, Reagan-era rhetorical ploy. Economic costs are less than silicon, which is ALREADY AT GRID PARITY. That this obvious is left unsaid implies nothing except in your own fever dreams of conspiracy. And of course, saying that we can't know if Global Warming is real, is just you telling us that you've lost touch with reality. Today's Conservative, ladies and gentlemen.
mookins
@JohnRAllen: Yeah scientists make a lot of claims, like that the earth rotates around the sun. I guess to you that means it doesn't. Insightful! And things getting both better and cheaper means they're 'not worthwhile', now that's some grade A thinking right there! Conservative Logic.
Robert Bernal
piperTom: Economic costs are actually dependent upon energy costs. if a product requires say, 100kWh to make and it only generates say 600kWh, there will be less of a value than if it generates 2MWh. Also, and more importantly, the device has to get an energy payback of at least 7, according to other studies which point out the fact that civilization needs abundant energy above that which is needed to collect and store energy. This is why it is very important for scientists, you know, the people who try VERY hard at school and college to understand physics and chemistry, too do research so that when we deplete or fossil fuels, we'll have a backup plan. Also, it's not wise to alter the co2 content of the entire atmosphere, thus, another reason to use fossil fuels more WISELY.