Nanofluidics for a breakthrough in blue energy harvesting – BlueEnergy

Access to cheap and abundant sources of energy now becomes a key challenge for our modern society [Chu2012]. Several opportunities for renewable energy production are nowadays available, ranging from solar and wind to water-based power generation [Logan2012]. It is furthermore accepted that a mix of various energy harvesting technologies should be proposed to partially replace the fossil fuels.
Accordingly, our interest in this project is to propose alternative, sustainable sources of energy, the potential of which has been overlooked up to now. We target sustainable sources of energy which are based on membrane process involving liquids as a vector. This is in particular the case of osmotic power, which refers to the production of electric energy on the basis of salinity gradients – typically between river and sea water (or brines)–. This technology has a considerable potential, as 1 TeraWatts may be harvested worldwide [Logan2012], representing 1000 nuclear reactors. However power yields from existing techniques are not high enough to make such process a game-changing technology, and this represents a key bottleneck in their development.
Our strategy to tackle this challenging question is to embrace the whole range of scales, from the nanoscale properties of fluid transport to the large scale demonstration with membranes made of targeted nanomaterials.
It relies on two key assets:
First, the new opportunities offered by the recent progress in fundamental science of fluid transport at the nanoscales, which is the domain of nanofluidics [Bocquet2010]. New models of fluid transport are now emerging from the confinement of liquids at the nanoscale. These new nanoscale properties can be fruitfully harvested to provide new perspectives and potential breakthrough in the domains of energy conversion and desalination process. Our bottom line is therefore that the efficiency of energy conversion process can be strongly increased as compared to the state of the art by making use of specific processes and new functionalities occuring at nanoscale, such as those described in this project.
Second, and most important, is our recent discovery, published in the review Nature in 2013, of a new means to harvest osmotic energy: a new nanomaterial, Boron-Nitride (BN) nanotubes, generates electric currents from salinity gradients with an unprecedented efficiency, more than two orders of magnitude larger than state-of-the-art technologies [Siria2013].
Our objective in this project is therefore to provide a link between fundamental research on nanofluidic transport and the energy harvesting domain, with the aim of step progress in efficiency of conversion process. To achieve this challenging task, we propose:
(i) on the one hand to develop a unique nanofluidic platform, including new tools for flow and field characterizations, static properties of ion repartition near interfaces and their correlation with transport properties. This unique platform will be achieved by gathering the expertise of the three labs in the consortium. After a strong effort in the development and benchmarking of reference systems, we propose to screen different promising materials to test their potential for osmotic energetic conversion. This effort will be accompanied by the modeling of the liquid behavior in confinement and near interfaces, from ab initio simulation to statistical physics theory, in order to fully predict and understand the materials properties required for efficient energy conversion.
(ii) on the other hand, we will explore the global transport through macroscopic membranes made of new nanoscale materials. The design of such new membranes, made of Boron Nitride nanotubes, as well of Boron-Nitride sheets and alternative promising nanomaterials, is a technological challenge that we will address.
Our ultimate objective is to make the proof-of-concept for the industrial viability of the proposed avenue for osmotic energy harvesting.