Due to limitations in technology, water on earth’s surface that is contained in tides, waves and rain is not efficiently converted into electrical energy. However, a droplet-based electricity generator (DEG) has recently been developed by a science and research team from the City University in Hong Kong. Allowing high energy-conversion efficiency, the DEG features a field-effect transistor (FET)-like structure that is more productive and efficient than counterparts without FET-like structures, creating instantaneous power density a thousand times higher. Spending two years on the DEG, the team also discovered that the efficiency of the power generation is not affected by humidity, and seawater and rainwater can be used to generate energy. This recent development helps advance research of water energy generation. A leader of the team, Professor Wang, hopes that the recent outcomes of the DEG can help set the path to harvesting water energy in order to solve global problems of renewable energy shortage.