A Feasibility Study - Aaltodoc - Aalto-yliopisto

1 Introduction
1.1 Framework
“Water is essential for all dimensions of life” (World Bank Institute 1999). But how
much water do we have and is that amount enough? Our planet has roughly 1400
million km 3 of water, out of which only less than 10 million km 3 is easily available as
fresh water (Gleick 1993). With an increasing population these numbers lead to the
undeniable conclusion that in the future there will be less water for each person (Mosey
2009). Moreover, the number of people already suffering from a lack of water is 700
million, and it has been estimated that in 2025 there will be over 1,8 billion people
suffering from lack of water (UN-Water 2011).
The need for fresh water will increase in the future. Our planet has a huge reservoir of
water in the oceans, but it is saline and thus unsuitable for direct use as drinking water.
However, there is a way to tap this resource: seawater desalination. In essence, through
the use of energy, salts are removed from seawater and the resulting product is fresh
water.
There are many different ways to desalinate seawater, but they are usually divided into
two major categories: thermal and membrane. Thermal methods are essentially
distilling. Seawater goes through a phase change, producing fresh water and salts while
requiring vast amounts of heat energy. In contrast, membrane methods utilize pressure
with semi-permeable membranes to separate salts from water. In essence, membrane
methods take advantage of the different chemical structures of salt and water molecules.
Natural resources have always been limited and with the current consumption of raw
materials, humankind would need over 1,5 planet Earth’s to sustain the current pace
(Global Footprint Network 2012). One type of resource that is diminishing at an
alarming rate is fossil fuels, which produced in 2008 roughly 85 % of all the used
energy (EIA 2011). They are non-renewable by character and thus will eventually run
out. Also, their use releases greenhouse gases to the atmosphere increasing global
warming. Due to these facts, there is an ever increasing tendency to move to renewable
ways of energy production.
In light of the current state of our world, there are two things that are urgently needed.
Firstly we need energy that does not pollute or run out. Secondly we need a way to
produce more water, especially in a way that does not require vast amounts of energy
and is overly expensive. The solution to this dilemma will be topic of this thesis: the
AaltoRO concept - production of fresh water using desalination powered by the
renewable energy of the seas.
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