Being able to capture solar energy in space and then transfer it to Earth would allow for almost unlimited energy harvesting and help allay fears that fossil fuels are ruining solar energy efforts. On top of that, it would help negate the effects of shadows and clouds on collecting solar energy with solar panels. But how exactly can we bring the energy we collect in space back to Earth? Well, there are currently two methods that scientists are working to use: laser-based and microwave-based.
Efforts to harness solar energy in space, however, are far from limited. use solar power to generate nearly infinite power in space, and it’s likely that space agencies will turn to solar power to help power lunar bases as more countries strive to explore the lunar south pole in search of water. However, here on Earth, it is also crucial to find a way to bring this energy back to the surface. Especially as we continue to see growing concerns about climate change and the effects of fossil fuel-fired electricity generation. Capturing power in space is simple. With no clouds or other obstacles to block solar energy from reaching the solar panels, we simply set up the hardware and wait for the energy to accumulate. However, its transfer through the atmosphere and clouds is another story. But it’s a problem that scientists have been tackling for years, and this is how they plan to do it.
Microwaves provide constant energy
According to a Caltech video explaining how wireless power transfer works, a microwave-based system works off a phenomenon known as interference. Dr. Ali Hajimiri, co-director of the Space Solar Energy Project at Caltech, explains it by describing putting both hands in a river and observing the ripples it creates. There are areas where the energy from both hands combines, becoming stronger, and then areas where it is weaker and cancels each other out.
The idea of wireless power transfer, however, is to focus on how the energy interferes with each other and direct it in the same direction, thereby reducing the actual interference caused by the sources. This allows you to keep the signal strong without losing as much energy. The downside of delivering power via microwave, however, is that creating and positioning the satellites can be expensive. Additionally, they are often located so far in orbit that they cannot be easily maintained, according to the U.S. Department of Energy. However, laser delivery could help.
How would laser energy delivery work?
The second method researchers plan to use to provide solar energy is through infrared laser beams. One company, Overview Energy, has already experimented with this idea, even going so far as to capture solar energy and then transmit it from an airplane to a receiver on the ground in 2025. The advantage here is that the laser is considered safer than constantly transmitting microwaves from a microwave-based system.
There are some limitations, however, particularly in Overview Energy’s system, which uses near-infrared lasers, namely the fact that near-infrared lasers cannot penetrate clouds. As such, a system using lasers would need to rely not only on satellites orbiting Earth, but also a series of receivers positioned in the sky to help capture the energy as it is transmitted to the final receiver on the ground. This means more moving parts, which ultimately means more chance of something going wrong.
Still, the U.S. Department of Energy says a laser system could be cheaper and easier to maintain. And, according to Overview Energy, the laser would be scalable, allowing it to be expanded or contracted as needed. However, as with all such electrical systems, the actual electricity we use will only be produced when the energy reaches the ground.
