Industrial Wireless Power Transfer Today
Every day, we are surrounded by power that moves without wires. The Sun baths the earth in 173,000 Terawatts of energy that is wirelessly transferred over 150,000,000 kilometers [1]. Similarly, sunlight is collected on the ground and wirelessly transferred to towers at many solar plants around the world. At Ivanpah, during the day, billions of watts are continuously moved from the desert floor to the collection towers. The image below shows a typical day [2] in southern California.
This sounds like a huge number. At Ivanpah there are 173,500 heliostats [3] which have two mirrors each. The mirrors are 2.1 meters by 3.1 meters. This is a little smaller than the footprint of a car. So the total area for collecting daylight is 2,258,970 square meters or about 2.25 square kilometers. At 1000 Watts per square meters, this works out to just over 2.25 GW of solar power collected. With some losses for reflection efficiency and dust on the mirrors this is just over 2 billion watts.
However, this 2 billion watts is not always available. The challenge with solar on the ground is that clouds, weather, and night reduce the times that power is produced. At Ivanpah, this results in a capacity factor of 24%. In other words, the average output power is 24% of the rated peak of 392 MW [4].
In orbit, above the clouds and out of the shadow of the earth, it possible to collect solar power continuously. By using a better technology than mirrors, power can be delivered to earth regardless of the time of day or weather conditions. This potential to generate power continuously means a capacity factor of 100% and makes space based solar power (SBSP) a fundamentally different kind of renewable energy.
Gigawatts of power are moved today without wires. It possible to massively improve on this.
