{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T10:05:29Z","timestamp":1789553129716,"version":"build-2803163510"},"reference-count":55,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T00:00:00Z","timestamp":1789171200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004837","name":"Ministerio de Ciencia e Innovaci\u00f3n","doi-asserted-by":"publisher","award":["PID2022-138389OB-C32"],"award-info":[{"award-number":["PID2022-138389OB-C32"]}],"id":[{"id":"10.13039\/501100004837","id-type":"DOI","asserted-by":"publisher"}]},{"award":["PID2022-138389OB-C32"],"award-info":[{"award-number":["PID2022-138389OB-C32"]}],"id":[{"id":"https:\/\/ror.org\/05r0vyz12","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Membranes"],"abstract":"<jats:p>Salinity gradient energy, also known as blue energy, is a clean and renewable option for electricity generation with no direct CO2 emissions. Among the available technologies, pressure-retarded osmosis (PRO) stands out, although its large-scale implementation is not yet economically viable, so predictive models are essential to assess its real potential. In the present work, a multistage PRO system of up to three stages, with one\u2013three hollow-fiber membrane modules (HFMMs) arranged in series per stage, was simulated and the operating conditions were optimized. The model accounts for axial pressure drops, feed concentration and draw dilution along each module, considering two salinity gradients of 29.5 and 59.5 g L\u22121. The maximum net specific energy generation reached 421.48 Wh m\u22123 with three stages under the 59.5 g L\u22121 gradient. Adding HFMMs in series benefited the two-stage system but slightly penalized the three-stage one, and the net specific energy decreased monotonically as the ratio of pressure vessels between the first and the second stage increased. At least three stages are therefore required for a full-scale PRO system to become a net energy producer at moderate salinity gradients, and further energy should be sought through additional staging rather than through longer series.<\/jats:p>","DOI":"10.3390\/membranes16090299","type":"journal-article","created":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T09:34:01Z","timestamp":1789378441000},"page":"299","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Full-Scale Multistage Pressure-Retarded Osmosis for Osmotic Energy Generation: Optimization of Specific and Net Energy Production"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-5935-8714","authenticated-orcid":false,"given":"Daniel","family":"Su\u00e1rez-Alfonso","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering and Automation, University of Las Palmas de Gran Canaria, Campus de Tafira, E-35017 Las Palmas de Gran Canaria, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5209-653X","authenticated-orcid":false,"given":"Alejandro","family":"Ruiz-Garc\u00eda","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering and Automation, University of Las Palmas de Gran Canaria, Campus de Tafira, E-35017 Las Palmas de Gran Canaria, Spain"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"software","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Criscuoli, A. 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