Harnessing the power of rain

Physics students taking the Physics Special Topics module have investigated how viable rainfall is as a source of energy - particularly in comparison to solar energy.

Using a method similar to that used in hydroelectric dams, the students determined that a large container placed high above the ground collecting rain could then use the falling of the water to power turbines.

Because clouds gather water from large areas (25 times the size of the cloud), the students predicted that sufficient water could fall into the container so that a large amount of energy could be produced.

They worked out the amount of water falling over a given area and used this to calculate how much energy would be generated by this rainfall. It was discovered that the amount of energy created using the container depends on its altitude. The students then compared the amount of energy produced using this method to the energy that could be harvested by solar panels of the same area.

The team found that solar panels are a thousand times more efficient than an identical container placed on the ground. However, they also found that if the container was elevated by 1km then the same amount of energy could be obtained.

Lead author, Jeremy Hue stated: “After extensive research it has been determined that constructing a container that high off the ground is currently not economically viable, especially when compared to the cost of covering the same area in photovoltaic cells.

"As solar cells become more efficient and cheaper as technology improves these may become the status-quo for renewable energy in the future; however, we should not close ourselves off to innovation.”