Solar Energy for Water Purification: A Sustainable Solution
Processes for water purification require energy, for instance, to operate water pumps. Water is essential for humans to support numerous functions that sustain life. For this reason, approximately 4 percent of the total energy needed globally is used for water extraction and treatment. Decentralized systems particularly benefit from a solar-powered energy solution.
Fundamentals of Water Purification with Solar Energy
To obtain drinking water, untreated water undergoes various processes. Water can be sourced from wells, reservoirs, the sea, or other sources such as rainwater-fed reservoirs. Several processes like filtration, transportation using water pumps, desalination, or other measures to remove contaminants require energy. This energy for water purification can be supplied through solar power. Using solar energy contributes to the creation and sustainable operation of water systems.
Advantages of Solar Water Purification Systems
Expanding our view to consider the purification of water and the associated energy consumption in the global context of climate change, it becomes clear that water extraction holds significant potential to contribute to reducing greenhouse gas emissions. In the current situation, it is necessary to examine all areas of life and seize every opportunity to reduce energy production from fossil fuels. However, the ecological reasons are not the only factors in favor of switching to solar-powered systems. Economic factors also point towards solar energy. The development of solar cells is advancing relentlessly, and due to the solar mass market, the products are becoming increasingly affordable and are available and deployable virtually everywhere. In combination with improving battery storage, remote standalone systems can also be installed for long-term cost-effective decentralized use.
Technologies and Methods of Solar Water Purification
There are various methods and approaches for using solar technologies to purify water. One method of water purification is semiconductor photocatalysis. Titanium dioxide (TiO2) is used as a semiconductor catalyst, which, with the help of light, primarily UV light, produces hydroxyl radicals capable of decomposing nearly any compound. This way, contaminants in the water are broken down. The necessary UV light for the process is generated using electricity.
Another method is membrane filtration. This method requires pressure and vacuum to pass water through the membrane and filter out impurities. Electrically operated water pumps are needed for operation. Here too, solar energy is a welcome and sustainable energy source.
Not only is energy needed for purification itself, but to initiate a purification process, water must be transported. Even after purification, water is moved forward with the help of pumps. These pumps require energy, which can also be provided by solar energy.
Successful Global Application Examples
A highly successful project was implemented in Germany. The SOWARLA (Solar Water Purification Plant) was developed by the German Aerospace Center in cooperation with Hirschmann Laborgeräte GmbH and KACO new energy GmbH. The heart of the facility is a solar receiver, which enables the photocatalytic degradation of water contaminants. The advantage of this plant is that it reduces energy consumption by an astonishing 90 percent compared to conventional systems that operate with UV oxidation.
This example shows that solar technology must be considered independently of the application technologies available today. This means that concepts which today cannot be implemented due to energy consumption or the performance of current solar technologies may be standard tomorrow.
Future Prospects and Development Potential
In times of climate change and increasingly severe heatwaves followed by droughts, the issues of water extraction and CO2 emission reduction are becoming more prominent. The future of solar water extraction is not just a utopian dream or a pious wish, but rather an urgent necessity that carries almost exclusively advantages. It is becoming increasingly cost-effective and efficient, as well as a very reliable technology.