Skip to content ↓

Covid-19 shutdown led to increased solar power output

As the air cleared after lockdowns, solar installations in Delhi produced 8 percent more power, study shows.
Listen
Press Inquiries

Press Contact:

Karl-Lydie Jean-Baptiste
Phone: (617) 253-1682
MIT News

Media Download

Shutdowns in response to the Covid-19 pandemic have resulted in lowered air pollution levels around the world. Researchers at MIT, and in Germany and Singapore have found that this resulted in a significant increase in the output from solar photovoltaic installations in Delhi, normally one of the world’s smoggiest cities.
Download Image
Caption: Shutdowns in response to the Covid-19 pandemic have resulted in lowered air pollution levels around the world. Researchers at MIT, and in Germany and Singapore have found that this resulted in a significant increase in the output from solar photovoltaic installations in Delhi, normally one of the world’s smoggiest cities.
Credits: Image: Jose-Luis Olivares, MIT

*Terms of Use:

Images for download on the MIT News office website are made available to non-commercial entities, press and the general public under a Creative Commons Attribution Non-Commercial No Derivatives license. You may not alter the images provided, other than to crop them to size. A credit line must be used when reproducing images; if one is not provided below, credit the images to "MIT."

Close
Shutdowns in response to the Covid-19 pandemic have resulted in lowered air pollution levels around the world. Researchers at MIT, and in Germany and Singapore have found that this resulted in a significant increase in the output from solar photovoltaic installations in Delhi, normally one of the world’s smoggiest cities.
Caption:
Shutdowns in response to the Covid-19 pandemic have resulted in lowered air pollution levels around the world. Researchers at MIT, and in Germany and Singapore have found that this resulted in a significant increase in the output from solar photovoltaic installations in Delhi, normally one of the world’s smoggiest cities.
Credits:
Image: Jose-Luis Olivares, MIT

As the Covid-19 shutdowns and stay-at-home orders brought much of the world’s travel and commerce to a standstill, people around the world started noticing clearer skies as a result of lower levels of air pollution. Now, researchers have been able to demonstrate that those clearer skies had a measurable impact on the output from solar photovoltaic panels, leading to a more than 8 percent increase in the power output from installations in Delhi.

While such an improved output was not unexpected, the researchers say this is the first study to demonstrate and quantify the impact of the reduced air pollution on solar output. The effect should apply to solar installations worldwide, but would normally be very difficult to measure against a background of natural variations in solar panel output caused by everything from clouds to dust on the panels. The extraordinary conditions triggered by the pandemic, with its sudden cessation of normal activities, combined with high-quality air-pollution data from one of the world’s smoggiest cities, afforded the opportunity to harness data from an unprecedented, unplanned natural experiment.

The findings are reported today in the journal Joule, in a paper by MIT professor of mechanical engineering Tonio Buonassisi, research scientist Ian Marius Peters, and three others in Singapore and Germany.

The study was an extension of previous research the team has been conducting in Delhi for several years. The impetus for the work came after an unusual weather pattern in 2013 swept a concentrated plume of smoke from forest fires in Indonesia across a vast swath of Indonesia, Malaysia, and Singapore, where Peters, who had just arrived in the region, found “it was so bad that you couldn’t see the buildings on the other side of the street.”

Since he was already doing research on solar photovoltaics, Peters decided to investigate what effects the air pollution was having on solar panel output. The team had good long-term data on both solar panel output and solar insolation, gathered at the same time by monitoring stations set up adjacent to the solar installations. They saw that during the 18-day-long haze event, the performance of some types of solar panels decreased, while others stayed the same or increased slightly. That distinction proved useful in teasing apart the effects of pollution from other variables that could be at play, such as weather conditions.

Peters later learned that a high-quality, years-long record of actual measurements of fine particulate air pollution (particles less than 2.5 micrometers in size) had been collected every hour, year after year, at the U.S. Embassy in Delhi. That provided the necessary baseline for determining the actual effects of pollution on solar panel output; the researchers compared the air pollution data from the embassy with meteorological data on cloudiness and the solar irradiation data from the sensors.

They identified a roughly 10 percent overall reduction in output from the solar installations in Delhi because of pollution – enough to make a significant dent in the facilities’ financial projections.

To see how the Covid-19 shutdowns had affected the situation, they were able to use the mathematical tools they had developed, along with the embassy’s ongoing data collection, to see the impact of reductions in travel and factory operations. They compared the data from before and after India went into mandatory lockdown on March 24, and also compared this with data from the previous three years.

Pollution levels were down by about 50 percent after the shutdown, they found. As a result, the total output from the solar panels was increased by 8.3 percent in late March, and by 5.9 percent in April, they calculated.

“These deviations are much larger than the typical variations we have” within a year or from year to year, Peters says — three to four times greater. “So we can’t explain this with just fluctuations.” The amount of difference, he says, is roughly the difference between the expected performance of a solar panel in Houston versus one in Toronto.

An 8 percent increase in output might not sound like much, Buonassisi says, but “the margins of profit are very small for these businesses.” If a solar company was expecting to get a 2 percent profit margin out of their expected 100 percent panel output, and suddenly they are getting 108 percent output, that means their margin has increased fivefold, from 2 percent to 10 percent, he points out.

The findings provide real data on what can happen in the future as emissions are reduced globally, he says. “This is the first real quantitative evaluation where you almost have a switch that you can turn on and off for air pollution, and you can see the effect,” he says. “You have an opportunity to baseline these models with and without air pollution.”

By doing so, he says, “it gives a glimpse into a world with significantly less air pollution.” It also demonstrates that the very act of increasing the usage of solar electricity, and thus displacing fossil-fuel generation that produces air pollution, makes those panels more efficient all the time.

Putting solar panels on one’s house, he says, “is helping not only yourself, not only putting money in your pocket, but it’s also helping everybody else out there who already has solar panels installed, as well as everyone else who will install them over the next 20 years.” In a way, a rising tide of solar panels raises all solar panels.

Though the focus was on Delhi, because the effects there are so strong and easy to detect, this effect “is true anywhere where you have some kind of air pollution. If you reduce it, it will have beneficial consequences for solar panels,” Peters says.

Even so, not every claim of such effects is necessarily real, he says, and the details do matter. For example, clearer skies were also noted across much of Europe as a result of the shutdowns, and some news reports described exceptional output levels from solar farms in Germany and in the U.K. But the researchers say that just turned out to be a coincidence.

“The air pollution levels in Germany and Great Britain are generally so low that most PV installations are not significantly affected by them,” Peters says. After checking the data, what contributed most to those high levels of solar output this spring, he says, turned out to be just “extremely nice weather,” which produced record numbers of sunlight hours.

The research team included C. Brabec and J. Hauch at the Helmholtz-Institute Erlangen-Nuremberg for Renewable Energies, in Germany, where Peters also now works, and A. Nobre at Cleantech Solar in Singapore. The work was supported by the Bavarian State Government.

Press Mentions

Fast Company

Fast Company reporter Kristin Toussaint writes that a study by MIT researchers finds shutdowns and lockdowns caused by the coronavirus pandemic led to clearer skies and increased solar output in Delhi. “I think we’ve been able to get a glimpse of how the world can look like if we actually have clean air,” says research scientist Ian Marius Peters.

Related Links

Related Topics

Related Articles

More MIT News

Music video screenshot showing about 20 rectangular boxes on a black background featuring MIT Syncopasian members singing

A cappella for a cause

MIT Syncopasian’s musical performance features the poem “Things We Carry On The Sea” by Wang Ping and invites Asian members of the MIT community to help celebrate AAPI Heritage Month.

Read full story