A three-man research team of scientists at Stanford has devised a new way to generate electric energy, using only the regular heat properties of the Earth’s surface. This new method, as explained, works even at the dead of the night without too many physical restrictions.
Earth gets a significant portion of its energy from the Sun. This is how life cycles form on Earth — from plants absorbing sunlight to aid in photosynthesis, to animals feeding on those plants, which would then be prey to other animals. Humans too, have artificially harnessed this energy in the form of photovoltaic cells, and the solar energy industry continues to grow, as renewable energy technologies get better over time.
However, much as sunlight itself is a source of energy, the heat produced by the Sun on Earth also envelops the planet with untapped potential energy. Unlike, sunlight, which can only be directly harnessed during the day, this passive heat energy flows through the planet, and can be relatively easier to harvest since it can be used even during the night.
This is the entire premise that led to the development of a makeshift heat-based generator for the researchers. As explained by their report in the magazine Joule, the system is made up of a black-coated aluminum disk, that is directly connected to off-the-shelf thermoelectric generators.
To generate electricity, heat from the ambient temperature of the Earth’s atmosphere flows through the thermoelectric generators, and are then directed upwards using the lower-temperature coated disk. This then creates a net electric energy output, which can be used by any appropriate appliance or device.
Now, considering that the makeshift device was only able to light up a tiny LED bulb (see feature image), one may think that this is not an idea worth pursuing. But we must remember that first, this is a proof of concept. It is the first design of its kind and is not intended to be the final iteration of the technology. Second, from our perspective, the setup basically created energy out of nothing. Nothing, in the sense that no other complex setup was required, and no fuel or direct source of energy was used. Simply the ambient heat of the Earth was enough to light the bulb up.
In addition, because it is primarily introduced as an auxiliary, or a secondary energy source, its most efficient application is to maintain energy output, or to keep a renewable energy system lasting just long enough for it to become operational again. This is not just limited to night use, where a solar array might wait for several hours before it is able to generate power via the Sun again next morning. This can conceivably be also used for let’s say, wind turbines, during extended periods without strong winds.
In any case, the concept alone is already interesting enough for even smaller applications. Ultra-low-power monitoring sensors, for example, may even directly use this type of energy to essentially provide power for it indefinitely. If sufficiently developed further, its low cost may also allow it to be used in areas where electric lighting is usually unavailable.