Learning Curve for Seawater Reverse Osmosis Desalination Plants: Capital Cost Trend of the Past, Present, and Future

Abstract

Seawater reverse osmosis (SWRO) desalination is expected to play a pivotal role in helping to secure future global water supply. While the global reliance on SWRO plants for water security increases, there is no consensus on how the capital costs of SWRO plants will vary in the future. The aim of this paper is to analyze the past trends of the SWRO capital expenditures (capex) as the historic global cumulative online SWRO capacity increases, based on the learning curve concept. The SWRO capex learning curve is found based on 4,237 plants that came online from 1977 to 2015. A learning rate of 15% is determined, implying that the SWRO capex reduced by 15% when the cumulative capacity was doubled. Based on SWRO capacity annual growth rates of 10% and 20%, by 2030, the global average capex of SWRO plants is found to fall to 1,580 USD/(m3/d) and 1,340 USD/(m3/d), respectively. A learning curve for SWRO capital costs has not been presented previously. This research highlights the potential for decrease in SWRO capex with the increase in installation of SWRO plants and the value of the learning curve approach to estimate future SWRO capex.

Unraveling the Historical Economies of Scale and Learning Effects for Desalination Technologies

“…Regarding the second aspect, the estimation of the traditional learning rate as a test for comparison provided the same result as the one obtained by Caldera and Breyer () for RO, thus validating the results. As mentioned above, RO shows the lowest economies of scale, and thus, the variation between the traditional and de‐scaled learning rates is small, resulting in a de‐scaled learning rate of 12%.…”

“…MAYOR noteworthy that some cases of diseconomies of scale have been detected in extremely large projects as analyzed and reported by Caldera and Breyer (2017), suggesting the possible existence of an upper limit above which the effect of economies of scale turns into a rebound effect. The de-scaled learning rate obtained for RO is also significant (12%), albeit considerably smaller than that of thermal technologies.…”

“…Desalination literature has repeatedly mentioned and emphasized the importance of scale economies and learning to explain the historical capital cost reductions observed in desalination technologies (Borsani & Rebagliati, 2005;Gao et al, 2017;Ghaffour et al, 2013;Karagiannis & Soldatos, 2008;Loutatidou et al, 2014;Mezher et al, 2011;Zhou & Tol, 2005). However, few studies have measured the extent of those effects individually and independently for the different technologies (Caldera & Breyer, 2017;Sood & Smakhtin, 2014;Wittholz et al, 2008). Furthermore, none of them has been able to completely unravel the role of the historical upscaling and learning processes marking the extent and pace of capital cost reductions.…”

Modeling of environmental aspects related to reverse osmosis desalination supply chain

“…Among the existing desalination technologies, reverse osmosis membrane technology accounts for 66% of the capacity utilized, followed by multi-stage flash and multi-effect distillation with 20% and 7% of the capacity utilized, respectively (3). Seawater accounts for 58% of the world's desalination water feed (4). Environmental impacts of seawater reverse osmosis (SWRO) desalination can be broadly classified into three categories, including energy consumption which releases carbon dioxide (CO 2 ) into the atmosphere, intake and brine discharge (5,6).…”

The Role of Desalination in an Increasingly Water-Scarce World

“…For more information about "The Current State of Desalination" from the IDA, see the website https://www.environmental-expert.com /news/the-current-state-of-desalination-152425.11. For example,Caldera and Breyer (2017) found that the cumulative global SWRO desalination capacity has doubled between 1977 and 2015 and its capital cost fallen by about 15 percent because of advances…”