The environmental impact of organic Rankine cycle for waste heat recovery through life-cycle assessment

• LCA was proposed to evaluate the environmental performance of ORC.
• The ORC life cycle environmental emissions inventory was established.
• GWP is the most serious environmental impact, followed by HTP.
• The ORC with R113 exhibits the lowest environment impact load, followed by Pentane.
• The total GWP of ORC could be paid back in 5 years.

The LCA (life-cycle assessment) was applied to evaluate EI (the environmental impact) of ORCPW (organic Rankine cycle power-plant for waste-heat-recovery) in this paper. The model of LCA on the ORCPW was established. The life-cycle of ORCPW was divided into construction, operation and decommissioning phases. The inventory of environmental emissions was listed for the ORCPW with 7 different working fluids. The GWP (global warming potential), AP (acidification potential), EP (eutrophication potential), HTP (human toxicity potential), SWP (solid waste potential) and SAP (soot and dust potential) were investigated. Some EIs of ORCPW were compared with the EIs of other power generation modes. The results show that the construction phase of ORCPW contributes mostly to the GWP and EP. GWP is the most serious EI followed by HTP among all the environmental impacts. The average pay back times of greenhouse gas discharged from ORCPW is calculated on the basis of five other power generation modes. For 7 different working fluids, it is 3–5 years for CO2, about one year for CH4 and 3–6 years for NOx. But CO cannot be paid back during the life-cycle of ORCPW according to the average pay back time.