Harnessing Rainfall Energy: Spanish Researchers Exploring Electricity Generation from Raindrops and Dew
A single drop of water can do more than just splash – it can release electricity. That’s the idea behind several international and European projects studying how to harness “blue energy”. In Spain, a group of scientists is looking to combine this source with solar energy to design hybrid panels capable of producing electricity even on cloudy days, with direct applications in low-consumption technologies and smart cities.
### How Rain Electricity Works
Rain electricity and triboelectrification: when a drop hits certain materials, it deforms their surface and transfers electric charges, generating a potential difference. Triboelectric nanogenerators (TENG), developed since 2012, were the technological leap that allowed capturing this energy, although in very small quantities.
### International Advances
In 2020, researchers at the City University of Hong Kong managed to light 100 LED bulbs with a single drop using a special triboelectric generator. That same year, they introduced a system to maintain stable electric charges for months, using electrohumectation. These advances showed that, although it won’t replace the sun, rain can have specific energy uses.
Possible Applications
Rain energy represents less than 0.1% of solar energy, making it unfeasible for charging mobile phones or powering homes. However, it can be used to operate environmental sensors, systems in pipelines, or portable devices without relying on batteries. This low-consumption use is ideal for wearables and smart city sensor technology.
Projects in Spain
In Seville, the DropEner project is working with mini generators called Trecxels, smaller than a drop and transparent thanks to indium-tin oxide, allowing them to be integrated into windows, roofs, or solar panels. The challenge lies in the interaction with water: ensuring that drops do not slip too quickly or become stuck, preventing the passage of others.
The Bet on Hybrid Panels
The most ambitious idea is to combine solar and rain energy in the same system. Hybrid panels aim to capture both raindrops and dew condensation, a more stable and frequent phenomenon. If current limitations are overcome, these panels could represent a breakthrough in energy efficiency and sustainability.
A Complementary Future
Experts agree: rain won’t replace the sun, but it can be a valuable ally. Its energy contribution, though modest, offers independence from batteries and fossil fuels in specific applications. In a world demanding decentralized and sustainable solutions, every drop of water could become useful electricity for daily life.
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