GRM 2010 GRM 2011

Abstract Details

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Title of Paper:
Economical assignment of seawater desalination systems supplied by renewable technologies
Paper Proposal Text :
Desalination, Photovoltaic, Renewable technology

1. Motivation
The rising number of the installed renewable technologies that produce electricity (like photovoltaic in Germany), results based on the technological learning, in continuous reduction of the system costs in the recent years. Especially, investment costs of photovoltaic systems (PV modules and associated inverters) show a reduction of about 64 % in the last six years [1].
The combination of the mentioned system cost reduction, by rising prices of conventional energy sources like oil, obtains a higher interest in using renewable technologies for electricity or heat/steam production in coming years.
According to the mentioned developments, the aim of this paper lies in economical assessment of existing sea water desalination plants based on the utilization of alternative energy sources and comparing outcomes with currently used energy generation units.
2. Approach
After explanation of [2] the sea water reverse osmosis plants (SWRO) are the most economic technologies for large-scale seawater desalination processes. The used steam in desalination process, more precisely, reverse osmosis process, is mostly generated by co-generation units (combined generation of electricity and heat), which are powered by oil. According to [3], costs of utilized oil in such units, which produces clear water as sub-product, are subsidised in the Gulf region and are in a range of about 0.75 cents per bbl (marginal oil production costs are about $3 per bbl). The opportunity costs of used oil for such plants are calculated by actual prices on world energy exchange markets. Thereby, transportation fees are considered, too.
Therefore, two supplying systems of SWRO plants are analysed and compared in this paper in terms of energy generation costs for desalination plants. First, one is the current situation which is based on co-generation units fuelled by subsidised oil as primary energy sources. Second, an analysed concept is derived based on installation and utilization of large-scale photovoltaic with additional storages ensuring a reliable clean water production.
The paper tries to find out whether the sum of energy subsidies and opportunity costs of current system are able to realise SWRP plants that are supplied by renewable energy sources or when the associated break-even point can be reached from economic point of view. Alternatively, the concept of concentrated solar power (CSP) has also been compared with the current system.

[1] German solar Industry Association, statistical analysis of German photovoltaic market, September 2012
[2] Young M. Kim (2009): Overview of system engineering approaches for a large-scale seawater desalination plant with a reserve osmosis network, published by Elsevier, ScienceDirect, Desalination, doi:10.1016/j.desal.2008.10.004
[3] Cost of primary energy used for desalination facilities in Gulf region, expert interview, 2013