The process of generating the electricity used in our lives puts a significant burden on the Earth’s environment. Burning fossil fuels results in various pollutants and greenhouse gases that cause global warming. Nuclear power creates hazardous radioactive waste. Different types of renewable energy can have a negative impact on the environment. We need to use less electricity or use it more efficiently to reduce such negative consequences.

One good practice is utilizing energy that is wasted meaninglessly in our daily lives. For example, converting solar energy, thermal energy, or kinetic energy around us into electricity can save electricity produced by power plants. Such technology is called “energy harvesting.” Harvesting means collecting or obtaining resources. The term “energy harvesting” means that we collect the energy around us.

We can harvest energy from a range of sources. One of them is our body. The human body also generates energy, such as thermal energy. Our body is like a heater that maintains a constant temperature of 36.5 degrees Celsius. In general, the heat does nothing but warm the air around the body.

However, this heat can be used to generate electricity through the thermoelectric effect. The thermoelectric effect is a phenomenon in which electricity is generated by making a circuit with two different materials and keeping the temperature of both sides different. If you make clothes from materials that create a thermoelectric effect, you can generate electricity by using the heat of your body. The electricity could be used for charging or operating portable electronic devices.

Let’s think about kinetic energy that is produced when we move. Some wristwatches run on their own without requiring a battery or manual winding. They are self-wound on the wrist while you move. The kinetic energy of our body is used for winding.

In the past, bicycle headlights worked in the same way. The wheels of a bicycle were connected to the headlights, and the power of the spinning wheels generated electricity to light the light. Therefore, the faster you bike, the brighter the light; when you stop, the light goes off. It takes a little more effort from the rider, but the light is turned on without batteries. What if bicycles could generate electricity while pedalling to charge mobile devices? It would be like killing two birds with one stone, saving energy while exercising.

We can also use the piezoelectric element to generate electricity using the movement of our bodies. When pressure is applied, electricity flows.

This is called the “piezoelectric effect.” If a floor with heavy foot traffic or a shoe sole is made with piezoelectric elements, the impact energy generated when people step on the ground can be converted into electrical energy. It can also be used on roads with heavy traffic.

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Additionally, you can obtain energy from the flow of blood in the body or from glucose in the blood. Glucose is one of the body's preferred sources of fuel. This electrical energy can be used in medical devices inside the human body, such as pacemakers and biosensors.

Even insignificant energy in nature can be harvested. Small-scale solar or wind power generation is another type of energy harvesting. Calculators powered by tiny solar cells can work without batteries as long as there is sunlight. Even small wind generators can provide energy to devices that require less power, such as sensors.

In addition to the solar and wind power with which we are familiar, scientists are looking into obtaining energy from unusual sources. Static electricity, which surprises us when we take off our clothes or touch something on a dry day, has tens of thousands of volts, but only lasts for a very short time. Research is underway to collect such contact electrification and use it as electrical energy. It can even produce electricity by collecting radio waves in the air with a special antenna.

Although the amount of electricity obtained by energy harvesting is not significant, it can be useful in places with lower power consumption. Collecting and using such a small amount of energy will be of great help in solving the energy issues threatening our planet.