Blue Energy: sustainable energy from sea and river water
Sun, Sea and… Energy! Sustainable energy production is a huge challenge in our world. Obtaining energy from environmental resources can play an important role in this regard.
Blue Energy is developing a technology to produce ‘blue energy' by mixing fresh water and seawater. As part of its outreach and education activities, the project produced teaching materials presenting this new technology. Secondary school students (aged 16-18) can learn about the scientific principles behind the technology and about its practical applications.
Using the Blue Energy learning resources students look at the underlying principles of Blue Energy, various important factors that influence the energy production, the design of the plant, the effect of scaling, and the choice of the optimal geographic location.
The module has been developed with the clear objective that the students themselves find out what Blue Energy is and the technique of this process. The theory does not directly give all the facts and knowledge to the student.
After discussing the theory and answering the questions, students should be able to focus on one particular aspect of the project. In this phase students conduct an investigation and present their results to their peers.
Coordinator: Wetsus, Centre of excellence for sustainable water technology, Netherlands, www.wetsus.nl
Target groups: college students, secondary school students, teachers
Topic: Applied sciences, Chemistry, Electronics, Energy, Environmental sciences, Geography
Start year: 2012
Contact person: Jos van Dalfsen, Manager Talent Program, Wetsus, Centre of excellence for sustainable water technology, email@example.com
The basic concept of Blue Energy technology is to generate an electric current by Reverse Electro Dialysis.
It is based on membranes: watertight plastic films that let salt through. By placing these membranes between the river water and the seawater, the mixing occurs via the salt transport through these membranes. Since dissolved salt is made up of positively charged sodium ions and negatively charged chloride ions, there are two types of membranes necessary: one that only allows the positive ions through, and one that only allows the negative ions to pass through.
By placing these membranes alternately between river water and seawater, a battery is created. Because the positive sodium ions move to the left and the negative chloride ions move to the right, there is a flow of charge; an electric current.
It is estimated that mixing fresh water and seawater can release the same amount of energy as a 200-meter high dam.
The Blue Energy teaching material aim to familiarise student with the concept and technology this project is developing. Students will explore the effect of Blue Energy, examine the application and discuss technical design.
The material consists of a theoretical part and a practical part / tutorial. It covers the following concepts:
• Calculating a footprint and what this says about our use of the planet.
• Climate issues and the possible solutions for the use of CO2. The hydrological cycle, the base of Blue Energy
• Main Laws of Thermodynamics applied to Blue Energy
• Power generation by means of variations in salinity gradients, Reverse Electro Dialysis (RED), Redox reactions
• Electrical circuit, Electrical conductivity of metals, Resistance RED
The project also provides a school toolkit for setting up and conducting the scientific experiments related to the Blue energy technology.