Upgrading exergy - from electricity to potable water by REN-powered desalination

Abstract

As investment analyst mainly in the area of securities and in the face of actual market situation (zero interest rates in developed world, bubble-like prices in nearly every asset class due to central bank intervention etc.), finding or developing investments in real assets like infrastructure seems to make more sense. Combined with two topics of intrinsic interest - renewable energy and growing water scarcity - educational steps have been taken to get into these topics. This lead to the core question: is a combination of renewable energy and seawater desalination, enhanced by electrical energy storage, feasible and if not what may help to improve the financial situation? Therefore desalination technologies have been researched concentrating on the mature and commercially developed 'reverse osmosis'. On the one side the investment should be acceptable for investors only looking for commercialized technologies; on the other side renewable energy forms producing electricity (not heat) are in focus, especially photovoltaics (PV) as water scarcity and irradiation highly correlate. Enlargement is done by adding electrical energy storage (EES) as support for photovoltaics to reach at least a majority of sustainable energy production. Then the status-quo of desalination on Mediterranean Island gets depicted; during the research a desalination project with inconvenient outcome has been found. The findings of technological and plant research has been combined and re-calculated to find out if that plant would be an acceptable investment based on this thesis-assumptions. Three main and two sub-scenarios have been built and expressed as project and business finance calculations: the desalination plant; the plant with PV to supply 1/3 of energy demand; the plant with PV and EES to supply 2/3 of energy demand. Whereas the first two scenarios showed positive results along a spectrum of criteria, the last one ended negative due to immense investments in PV and EES. Here the two sub-scenarios come into play: support by 20% investment subsidy; support by lower EES investment costs and 20% investment subsidy. The former improved but is still not investable, the latter entered a kind of 'orange' zone as some parts reached slightly positive areas.