Solar panels in space could be clean-energy gold mines

Good News Notes:

Solar power has been a key part of humanity’s clean energy repertoire. We spread masses of sunlight-harvesting panels on solar fields, and many people power their homes by decorating their roofs with the rectangles. 

But there’s a caveat to this wonderful power source. Solar panels can’t collect energy at night. To work at peak efficiency, they need as much sunlight as possible. So to maximize these sun catchers’ performance, researchers are toying with a plan to send them to a place where the sun never sets: outer space.

Theoretically, if a bunch of solar panels were blasted into orbit, they’d soak up the sun even on the foggiest days and the darkest nights, storing an enormous amount of power. If that power were wirelessly beamed down to Earth, our planet could breathe in renewable clean energy, 24/7.

That would significantly reduce our carbon footprint.

Against the backdrop of a worsening climate crisis, the success of space-based solar power could be more important than ever. The state of the climate is in the spotlight right now as world leaders gather in Glasgow, Scotland, for the COP26 summit, which has been called the “world’s best last chance” to get the crisis under control

CNET Science is highlighting a few futuristic strategies intended to aid countries in cutting back on human-generated carbon emissions. Next-generation tech like space-based solar power can’t solve our climate problems — we still need to rapidly decarbonize our energy systems — but green innovation could help achieve the goals of the Paris Agreement: Limit global warming to well below 2 degrees Celsius (3.6 degrees Fahrenheit) by the end of the century. 

An unlimited supply of renewable energy from the sun might help us do that.

From science fiction to fact 

For decades, space solar power has lived in the minds of science fiction lovers and scientists alike.

In the early 1900s, Russian scientist-mathematician Konstantin Tsiolkovsky was steadily churning out a stream of futuristic designs envisioning human tech beyond Earth. He’s responsible for conjuring things like space elevators, steerable rockets and, you guessed it, space solar power.

Since Bell Labs invented the first concrete “solar panel” in the ’50s, international scientists have been working to make  Tsiolkovsky’s sci-fi fantasy a reality. They include Japanese researchers, the US military and a team from the California Institute of Technology spearheading the Space Solar Power Project

Space solar power “was investigated extensively in the late 1960s and the 1970s, sort of in the heyday of the Apollo program,” said Michael Kelzenberg, senior research scientist on the project. 

Unfortunately, due to the materials’ weight and bulk, the era’s technology wasn’t advanced enough to cost-effectively achieve the feat. It would’ve been exceptionally difficult to send classic solar panels to space via a rocket without breaking the bank.

“The distinctively unique and defining feature of the Caltech approach is a focus on reducing the component mass by 10 to 100 times,” said Harry Atwater, the project’s principal investigator. “This is essential to reducing both the manufacturing and the launch costs to make space solar power economical.”

A sky full of solar panels

Instead of rocketing traditional solar panels to space, the Caltech team advocates a new type of panel that’s lighter, more compact and foldable. They suggest dispatching into orbit a large number of these airy, mini solar panels resembling tiles. 

Each individual tile has everything it needs, like photovoltaics, to harvest solar energy. When connected in space, the little squares essentially make a giant renewable energy mine floating around Earth.

Though the team has been looking at a range of composites to create the ideal ultralight structure, some are actually less effective when compared with Earth-based solar panels. But Kelzenberg notes that in space, “effectiveness” earns a new meaning.

“The increase in effectiveness really comes from the fact that by putting them in space, they get plenty of intense sunlight because the sunlight doesn’t have to come through the atmosphere,” he said. “They also get sunlight, basically, 24 hours a day.”

When the sun shines on these panels, they’d absorb bundles of direct current, or DC, energy. In the team’s mechanism, that energy would get translated into radio frequencies. The next step would be to bring that power down to Earth. 

That would happen, according to the team, through microwave radiation. Radio frequency energy would be beamed toward our planet onto areas reminiscent of solar fields in the desert. But in place of what are typically solar panels, these regions would contain receivers with antennas that collect the harvested energy. 

It’s basically wireless energy transfer, something Nikola Tesla famously alluded to in the late 19th century.

Using such radiation, Kelzenberg says, allows the system to operate in rain and fog, at night and during gentle storms, only risking disruption by the most severe weather. However, one question often raised about wireless radiation patterns is whether they would adversely impact vegetation or features of the land….”

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