Scientists have long considered the potential of harvesting the Earth’s magnetic field for energy and extensive research has been conducted into its influence. One theory proposes that the process of induction could be utilized to draw energy from the planet’s magnetic field through the use of moving conductive materials. However, there’s one major barrier to its plausibility, which is explained in more detail below.
Is it possible to harvest energy from the Earth’s magnetic field?
For context, let’s consider the Earth’s magnetic field. It extends from the interior of the planet into space, where it protects the Earth from ultraviolet radiation by deflecting most of the charged particles in solar winds away from the Earth’s ozone layer.
The magnitude of Earth’s magnetic field at the surface is between 0.000025T and 0.000065T. Extensive research has been conducted into the field’s impact on human health, and it was also a focus of famous scientist Nikola Tesla in the early 1900s, who wanted to investigate whether electric signals could be transmitted via the magnetic field.
It appears that the likelihood of energy being harvested for any realistic use depends on one condition. Researchers say that it would take more energy to move whatever conductive materials are used than the energy generated in the induction process. However, the possibility of harvesting energy in a system where the movement already exists is far more plausible, and this is the direction that new research is taking.
How was the energy harvesting theory tested?
Basic testing of the concept of harvesting energy from the Earth’s magnetic field was conducted in a remote area of Australia where no other magnetic field exists except that of the Earth. This was to ensure that whatever energy was gathered would assuredly only come from this source so the findings remained pure.
Conductive wires were fitted to a moving vehicle, and the researchers detected an induced voltage proportional to the number of wires and the car’s speed. Findings indicated that the energy required to move the car was greater than the energy generated in the induction process.
However, in applications where, for example, a vehicle is already moving and it’s not for the purpose of generating power, the energy generated in the induction process could be used to offset energy losses. It’s being investigated whether this form of power generation could be applied to topping up the charge of batteries in electric or hybrid vehicles when they are already in motion. This would extend the vehicle’s driving range.
Possible applications of the new system for objects already in motion
One of the most practical applications of the magnetic field energy system is to address challenges with extending the range of electric vehicles. This has particular potential for areas that have limited charging facilities and infrastructure and the extra power would be used to reduce energy losses as well as supplement the battery power.
This could be done by embedding the conductive wires in the car’s roof. This would break useless eddy currents that create drag and instead harness the induction to recharge the vehicle’s battery.
The successful experiments conducted with the vehicles in the remote Australian region proved three significant hypotheses:
- An electromagnetic field is indeed induced in conductive wires when they are cutting the lines of Earth’s magnetic field
- The amplitude of the induced electromagnetic field is proportional to the speed of the car
- The electromagnetic field is proportional to the number of wires used
These conclusions show how important is to develop numeric models to predict changes in Earth’s magnetic field.