Published on March 11th, 2019 | by Steve Hanley0
China Exploring Space-Based Solar Power
March 11th, 2019 by Steve Hanley
Chinese scientists are building a new research facility in the southwestern city of Chongqing to study whether solar power generated by satellites in space can be transmitted down to the ground using microwaves to help provide electrical energy to the Earthlings below. According to China Daily, the 33-acre installation will take about two years to build and will be funded initially by a $15 million investment provided by the Bishan district of the city.
In theory, satellites equipped with solar panels would be placed into orbit high above the Earth. They would then be assembled into an enormous solar collector array that would beam electricity down to the Earth 24 hours a day. Think of it as giant wireless EV charger in the sky. One problem is current technology limits the transmission of electricity via microwaves to about 100 meters. Another problem is focusing the microwave energy so it doesn’t turn the Earth into a giant microwave oven, cooking everyone and everything below.
Xie Gengxin, deputy head of the Chongqing Collaborative Innovation Research Institute for Civil-Military Integration, says, “We plan to launch four to six tethered balloons from the testing base and connect them with each other to set up a network at an altitude of around 1,000 meters. These balloons will collect sunlight and convert solar energy to microwave before beaming it back to Earth. Receiving stations on the ground will convert such microwaves to electricity and distribute it to a grid.” If the tests are successful, researchers will launch new tethered balloons into the stratosphere for further tests, he said
Getting the electricity back to Earth is only one of the challenges lying ahead. First, the weight of the solar panels being shot into space must be reduced dramatically while maintaining current efficiency levels. Second, the entire system will be enormously expensive, with each solar satellite costing several billion dollars. Xie says he thinks a space-based power station could be in place by 2040.
The idea of collecting energy from sun and beaming it down to Earth was first proposed by American aerospace engineer Peter Glaser in 1968. Since then, it has been studied by others from time to time, including NASA, but the technical challenges have been too daunting to get much beyond the imagination stage. Now with advances in space travel and solar panel technology slashing costs over the past decade or so (shout out to Elon Musk and SpaceX), the idea is back on the table.
With some predicting the number of people on Earth will soar to 9 billion or more by 2050, the demand for electricity is expected to grow exponentially by then. Of course, it can be argued that limiting the human population to a number the Earth can support sustainably would also be a good idea, but that is an entirely separate conversation, one fraught with complex social and political connotations.
John Mankins, a physicist who led research by NASA into the idea of space-based solar energy in the 1990s, tells NBC News, “If you look at the next 50 years, the demand for energy is stupendous. If you can harvest sunlight up where the sun is always shining and deliver it with essentially no interruptions to Earth — and you can do all that at an affordable price — you win.”
Giant electronic “nets” covering 4 square miles would need to be built on the ground to capture the microwaves beaming down from above. Mankins believes a solar facility in space could generate up to 2 terawatts of power. In 2013, the world consumed about 18 terawatt-hours of electricity, according to ZME Science. That number could easily double by 2050.
The concept of making electricity in space and beaming down to the Earth is certainly appealing. “You don’t have to deal with the day and night cycle, and you don’t have to deal with clouds or seasons, so you end up having eight to nine times more power available to you,” Ali Hajimiri, a professor of electrical engineering at the California Institute of Technology, tells NBC News. He is the director of the university’s Space Solar Power Project.
But wouldn’t it be easier and cheaper to simply add more terrestrial solar plants and connect them with high voltage direct current super grids? As written on Quora and published on Forbes in 2016, it would take about 43,000 square miles of solar panels to generate 17.4 terawatts of electricity. Sounds like a lot, right? Actually, it’s not. The Sahara desert is 3.6 million square miles.
Professor Mehran Moalem, a physicist at UC Berkeley, wrote the Quora article. He says, “That means 1.2% of the Sahara desert is sufficient to cover all of the energy needs of the world in solar energy. There is no way coal, oil, wind, geothermal or nuclear can compete with this.”
But won’t that be terribly expensive? Not really. Moalem explains, “The cost of the project will be about five trillion dollars, one time cost at today’s prices without any economy of scale savings. That is less than the bail out cost of banks by Obama in the last recession. Easier to imagine the cost is 1/4 of US national debt, and equal to 10% of world one year GDP. So this cost is rather small compared to other spending in the world. There is no future in other energy forms. In twenty to thirty years solar will replace everything.”
Space-based or land-based, solar is the ultimate solution to the world’s needs for electrical energy. The choice will come down to simple economics. Right now, one could argue that a land-based system would be much cheaper and far more practical than assembling a gaggle of satellites in space. And it’s something that can be done starting today, not 20 years from now, which is the best case scenario for space-based power.
$5 trillion may sound like a lot to some people, especially the Jackass In Chief and his coterie of fossil fuel loving sycophants in Washington. But isn’t keeping the Earth habitable for humans worth at least as much as bailing out banks and insurance companies? It’s all a matter of perspective and getting our priorities straight.
Have a tip for CleanTechnica, want to advertise, or want to suggest a guest for our CleanTech Talk podcast? Contact us here.