Table 1.

Highlights of conventional LCA of municipal solid waste and waste-heat ORC plants.

ORC Heat Source	LCA FU	Boundary	Inventory Database	LCIA Method	Tool/Software	Remark	Reference(s)
MSW incinerator burning infectious medical waste	1 kWh of electricity	Cradle to grave, Thailand	SimaPro embedded Ecoinvent	ReCiPe 2016 (Mid-point/end-point)	SimaPro	For a plant life of 20 years, a very small single point environmental impact of 0.348 mPt was obtained for the plant, with the construction phase responsible for about 87 %.	(Chaiyat, 2021b; Kythavone and Chaiyat, 2020)
MSW-Hyacinth combustion	1 kWh of electricity	Cradle to grave, Thailand	SimaPro embedded Ecoinvent	ReCiPe 2016 (Mid-point/end-point)	SimaPro	The study revealed that 0.6078 kg of CO2-eq is emitted for the production of 1 kWh of electricity from the ORC plant, with about 0.18 kg of CO2-eq from the combustion of 1 kg of the newly introduced hyacinth fuel.	(Intaniwet and Chaiyat, 2017)
Waste heat from biogas engine	170 kW of electrical power	Cradle to grave, EU	GaBi 6.0 database and literature	GHG emission calculation	GaBi 6.0	For a plant life of 10 years, a scenario whereby ORC is used to produce additional electricity from exhaust gases of a biogas engine led to CO2 reduction by at least 280 tonnes per annum.	(Uusitalo et al., 2016)
Waste heat recovery in coke production industrial process	1 kg of coking coal	Cradle to grave	NS	GHG emission calculation	SimaPro	Generation of electricity from waste heat could save 11 kt of CO2 per annum.	(Walsh and Thornley, 2013)
Waste heat recovery from electric arc furnace steelmaking	200 kW of electrical power	Cradle to gate	Ecoinvent	ReCiPe	SimaPro	Based on the ReCiPe LCIA method, integration of an ORC plant for heat recovery and electricity generation would reduce environmental impact on human health by 2.3% relative to the business-as-usual scenario, and it would reduce the total endpoint scores by about 1.3% (0.27 points).	(Lin et al., 2016)
Recovery of waste heat from biogas combined heat and power systems	1 MWh of electricity	Cradle to grave	Real data from plant operators	ReCiPe	SimaPro	Adoption of ORC for waste heat recovery in biogas CHP plants can reduce environmental impacts by about 1.6–5.8%, compared to cases where the waste heat is not recovered.	(Bacenetti et al., 2019)
ORC from a generic low-grade heat source	1 kWh of electrical energy	Cradle to grave	Literature data and GaBi database	TRACI (US EPA)	GaBi	Based on 20 years lifetime of the plant, the authors reported that ORC as a benchmark technology outperformed a new osmotic heat engine technology in terms of environmental feasibility.	(Hickenbottom et al., 2018)
A generic low-temperature heat source	30 kW of electricity production	Cradle to grave	Literature data	Selected indicators (GWP–CO2–eq, Eutrophication, Acidification, etc)	Excel	The study investigated particularly the environmental effect of working fluid leakage on environmental impacts of ORC plants and found that the effects are very significant. Specifically, about 30% of ORC GWP was found to be due to leakage of R227ea working fluid, 28% for R245fa, and 24% for R236ea.	(Li, 2019)
Generic waste heat ORC	1 kWh of electricity production	Cradle to grave	Literature data and National (Chinese) database	Environmental Toxicology and Environmental Chemical Society; IPCC	NS	The contributions of the different phases of the project to the overall environmental impact were in focus in the study, and results revealed that the construction phase contributed the most to the GWP and eutrophication potential of the plant, based on different working fluids.	(C. Liu et al., 2013)
Waste heat recovery ORC	1 kWh of electricity	Cradle to grave	Literature data and Chinese database	Selected indicators (GWP–CO2–eq, Eutrophication, Acidification)	NS	The study showed that the aa production of electricity by ORC using waste heat of cement production process can lead to a reduction in CO2 emission by 7743–9628 tons for a 4000 t/d cement production process.	(Wang et al., 2015)

NS – not specified.