Page 64 - European Energy Innovation - Spring 2017 publication
P. 64

64  Spring 2017 European Energy Innovation


The water-energy nexus:

Making best use of the nexus,

saving energy and… water

By Tomas Michel, President, WssTP

The global water supply,                     brines resulting from industrial activity  or savings, directly saves water, and
            treatment and distribution       or saltwater desalination), as well as,    or makes water available for other
            sector is a critical enabler of  low and medium temperature residual        uses. There is growing recognition that
            our society: it guarantees our   heat travelling with used water, which     “saving water saves energy”, reducing
food, sanitation, energy, health and         could be used for industrial processes,    water cycle related energy use, and
wellbeing. Without it everything else        and or to reduce urban and domestic        carbon emissions. Yet, it is not always
in the 70 Trillion Euro global economy       heating costs. Further, biofuel and/       fully recognized that energy efficiency
would fail. Global projections however,      or biogas production from sewage           initiatives will in most cases indirectly
predict that growing demands from            sludge, represents another potential       deliver significant water savings.
manufacturing, electricity generation,       energy source from water.
agriculture and domestic use will                                                       Regrettably, water and energy resource
push world-wide water use up by              The water-energy nexus needs to            management and policies are often
55% in 2050. All these will increase         be considered holistically, and at all     conducted in separate silos, which in
the pressure of human activities             steps were water intervenes, from          isolation only focus on one resource
on our limited fresh-water sources.          the overarching water management           at a time, often excluding the other
Furthermore, water quality is declining      (combining smart-water and smart-          resource. When resources become
due to urban, industrial and agricultural    energy), to new solutions in various       scarce, this narrow focus becomes
pollution, impacting water availability of   steps of the water chain (energy           problematic. The interrelations and
sufficient quality for users, and different  harvesting and production at source,       interdependencies between water and
uses. Diffuse pollution significantly        heat recovery from different waters,       energy have already been pointed
affects 90% of river basin districts, 50%    decreased cooling needs). Water is         out, and are well known, hence the
of surface water bodies and 33% of           used in all phases of energy production    interconnected challenges and key
groundwater bodies across the EU.            and electricity generation, and while      issues affecting both sectors should
                                             some sources of fossil energy will         therefore be jointly addressed,
Highly interlinked with the availability     eventually be depleted, and then be        considering three relations: energy for
and use of water of desired quality and      substituted by renewable energies,         water, energy from water and water for
quantity is the water-energy nexus.          availability of sufficient water could     energy.
On the one hand, several steps of            eventually become the limiting
the water use and management cycle           factor for future energy, even long        European water and energy policies
(pumping were needed, transportation,        before predicted stocks of energy are      are still not sufficiently integrated, with
distribution in pressurized water            exhausted.                                 the result that important interrelations,
networks, heating, treatment, etc.)                                                     synergies and mutually important
demand large quantities of energy.           On the supply side, the intersection       aspects, are often overlooked. Water
On the other hand, energy production         between water and energy is apparent       and wastewater processes could
by all known available technologies          in the massive amounts of water            strongly benefit from more, and better,
(conventional or renewable) with the         needed to produce electricity and the      low carbon, low energy technologies.
exception of wind energy, requires           large amounts of energy required to        Most of these processes are still
significant quantities of water.             treat, process, and transport water. On    designed and operated relying on a
                                             the end-use side, energy and water are     constant energy supply, precluding
Water is a natural carrier of heat and       connected in our homes, businesses,        more massive adoption of renewable
energy gradients, which hold a high          and industrial facilities. The water-      energy sources, whose energy supply
potential to be re-used, and could thus      energy nexus actually means that           is variable in time. Meanwhile, efficient
improve energy efficiency in several         end-use efficiency programs directed       and cost effective technologies which
ways. Examples of this are chemical          towards saving water will also save        do exist to recover energy in various
concentration gradients (e.g. as in          energy. Conversely, energetic efficiency   forms from wastewater, are not yet fully

   59   60   61   62   63   64   65   66   67   68