Sunny Outlook

Space-Based Power

By Joel Nelson on Aug 27, 2019 in Energy

Solar power is a burgeoning alternative energy source that accounts for 1.6% of total U.S. electricity generation and encompasses enough installed capacity to power 12.3 million homes. It’s the second-fastest source of new generation on the U.S. power grid, but it’s not flawless. Arrays that capture solar energy don’t work at night or when obscured by cloud cover, atmosphere or seasonality.

The United Nations estimates the global population will be 9.6 billion by 2050, so the rush is on to find new ways to generate large quantities of clean energy. For decades, scientists have explored putting solar arrays where night never falls and clouds don’t form and power transmission need not be interrupted by fickle weather or unfavorable orbital tilt. Specifically, in geostationary or low-Earth orbit, where satellites could capture solar energy, convert it into a microwave or a laser and beam it to Earth. Ground-based receivers would then convert the energy into useable electricity and add it to the electric grid.

“If solar power is going to be the principal so-called ‘dispatchable’ baseload source of power that replaces today’s fossil-fuel-powered electric-generating stations, inherently you have to have the generating source be available all the time,” environmental scientist Dr. Deanna Conners wrote in 2018.

Efforts to put space-based solar power generation into production have been hindered by cost and technology impediments. But recent developments are bringing the concept closer to reality. In 2018, scientists at the California Institute of Technology announced that they created a prototype lightweight tile, the building block of solar arrays capable of harnessing and transmitting solar energy from space. Earlier this year, China announced plans to place the first solar power station in geostationary orbit by 2050. Other countries in Asia and Europe are working on their own projects.

A microwave transmitting satellite would be massive, weighing more than 88,000 tons and sporting solar reflectors almost two miles wide. Such a system would likely require as many as 40 launches to get all the necessary materials into orbit. Laser-transmitting satellites would be smaller and cheaper but impose other problems, including concerns over the potential militarization of space and smaller transmitting capacity per spacecraft. Other barriers to space-based power generation center around potential interference with radio, television, cell phone, military and industrial transmissions, along with finding enough land for the receivers.

One of the key attractions of space-based power generation is its potential to deliver clean, reliable energy to remote communities without relying on the traditional grid to a large local power plant. “About a quarter of humanity has no electric power whatsoever. And so this is an enabling technology that could leapfrog the electric-power transmission grid on Earth, and have the same effect that the cellular phone system had on communications,” Conners said.

Space-based solar power remains a multibillion-dollar proposition fraught with technical, political and safety roadblocks. Its deployment might not be just around the corner. But, the U.S. Department of Energy says, “many technologies already exist to make this feasible, and many [others] aren’t far behind.”

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