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