Blue Energy

Electricity production from fresh and salt water

The Blue Energy project involves the development and testing of reversed electrodialysis. This process uses polymeric-ion-exchange membranes and is capable of producing electricity by harnessing the difference in salinity between fresh and salt water. The principle of reversed electrodialysis has been proven at the lab level using expensive electrolysis membranes. Electricity can be generated by stacking membranes, so that membranes that select positive ions alternate with membranes that select negative ions. Since the cost of developing such membranes is currently prohibitive, the viability of the technology depends on developing less expensive membranes.

Project
In preparation for the development of ion-selective membranes, we have patented a process in which inexpensive polyethylene is electrically modified. Since work on the process began, its performance has improved a hundredfold, but further optimization is required. In another line of investigation, KEMA is preparing innovative membranes from inexpensive monomers and activating agents. This process has yielded membranes whose performance matched that of commercially available membranes. A large European project (REApower, FP7) has recently started. This project will investigate all aspects of the use of reverse electrodialysis, from the development of novel membranes to non-standard applications of the technology, such as saline waste flows and salt fields.

Benefits
Every year, more than 100 billion cubic meters of fresh water flows into the sea from the Netherlands alone. Mixing fresh (river) and salt (sea) water generates 0.5 kWh per cubic meter of fresh water, thus giving Blue Energy huge potential.

Objective
With the development of new, less expensive membranes, a novel form of renewable energy can be made available for worldwide application. Future Blue Energy plants can be situated where fresh water flows into the sea, or even at industrial sites with saline waste-water flows. In recognition of his membrane development work, KEMA’s Dr. Rob Ross won the ID-NL prize for best energy development. Once the low-cost membranes currently under development become available, a commercially viable full-scale unit can be promoted.

Project coordinator 
> KEMA, the Netherlands

Project details 
> SenterNovem, Multilateral Development 
> Duration: 2009-2010
> European Union coordinated project duration: 2010-2014