Open Access

The transport sector is facing challenging transformations in order to reach the climate goals according to the European Green Deal. This review aims to compile a comprehensive set of available energy and greenhouse gas (GHG) emission data to estimate a) road transportation and site-related GHG emissions from logistics companies and b) impacts of mitigation measures discussed in literature. Out of an initial set of 1,050 hits, about 77 publications were identified that provide quantitative values for energy consumption or GHG emissions. The largest part of literature on energy demand and emissions in logistics deals with transport, with 62 out of 77 publications, which accounts for the majority of the energy demand in the logistics sector. The majority of published data is based on individual case analyses and modeling studies, reflecting the heterogeneity of the industry. As there is no standardized method for collecting GHG emissions for the logistics sector, the system boundaries and quantitative values of the published data vary considerably, making comparisons and evaluations difficult. The most common system boundary is “freight transport within a given area”, followed by “logistics site”, “vehicle routing”, “supply chain” and “corporate footprint”. Reported energy and GHG reduction potentials focus on the optimization of building services efficiency, intralogistics processes and transport-related processes (route planning, driving behavior, vehicle efficiency and load factor). The greatest potential for reducing GHG emissions in the logistics sector lies in replacing fossil fuels for trucks with green fuels or electrification, combined with restructuring urban delivery networks. Publications of Logistics Research (2023) 16:9 DOI_10.23773/2023_9 actual consumption or transport-specific metrics are rare in the literature. The quantitative values reported can only be interpreted correctly if the context in which they occur is specified in terms of a logistics reference value; this is why the effects of the mitigation measures applied also vary in the literature. The further development of standardization in the field of emissions recording by transport companies and the consensus on a uniform reference value are therefore key drivers for the quantification and reduction of GHG emissions in the logistics sector.

With ongoing real-term reductions in the cost of renewable energy technologies, opportunities to reduce carbon emissions within industry have improved. While the South African industrial sector has been investing in photovoltaics to meet electricity requirements, little has been done to replace fossil fuels used for the generation of process heat, representing two-thirds of the energy consumed. While previous studies have demonstrated the benefits and limitations of solar thermal (ST) energy solutions for industrial applications, recent developments in high-temperature heat pumps (HTHP) offer opportunities for novel configurations, including the use of renewable energy like photovoltaics (PV). This study compares the techno-economic benefits of solar thermal energy systems with PV-supported HTHP systems within the South African beverage sector. After a general consideration, simulation calculations are presented for selected applications. The cost of heat is determined for PV-heat pump systems operating on a stand-alone basis and with heat storage. The study finds that the levelised cost of heat of US$0.050-0.073/kWhth is at least twice that of coal-fired steam boilers. The study, therefore, calls for further work on optimising systems minimising steam requirements, and thereby improving the economics of heat pumps and for a coordinated effort to support the development and financing of high-temperature heat pumps for industrial applications.

Ethylene–propylene–diene rubber (EPDM) scrap was devulcanized in an internal mixer with varying amounts of dibenzamido diphenyl disulfide (DBD) at temperatures below 200°C. The devulcanization effect and sol–gel analyses of the devulcanizates, and the mechanical properties of the sulfur‐cured revulcanizates were studied. Residual DBD was still present in the sol at 160°C and degraded DBD at 200°C. DBD affects the curing leading to poor properties. So, the temperature must be adjusted according to the DBD concentration to obtain a superior recyclate for sealing systems. At 0.4 wt% DBD, the degradation reaction was already complete at 120°C, but only 52% and 61% of the tensile strengthσand strain at breakεof the virgin material were achieved. At 160°C and 2 wt%, the degradation reaction was complete, and the DBD effect on properties was small; 65% and 86% ofσandεwere recovered, respectively. To prevent property degradation, 200°C was required at 3.9 wt% DBD, resulting in 97% and 95% ofσandε, but only 70% of hardness.

The present work is a comparative study of the effects of mechanical shear, temperature, and concentration of a chemical agent on the devulcanization process of post-industrial ethylene propylene diene (EPDM) rubber waste. Devulcanization was carried out in a heating press (no shear), an internal mixer (low shear), and a co-rotating twin screw extruder (high shear) at temperatures ranging from 100 to 200 °C. The efficiency of pure dibenzamido diphenyl disulfide (DBD) and a commercial devulcanizing agent, Struktol A89®, containing DBD were studied. Based on the results, the devulcanization process was upscaled from 40 g per batch to a continuous process with a capacity of 270 g/h. The parameters were fine-tuned regarding flow rate, screw speed, and temperature. Blends of virgin rubber (VR) and 25, 50, and 75 wt% recyclates were compared with blends of VR and 25, 50, and 75 wt% of untreated RWP. The quality of the recyclate was determined by rheometer tests, SEM images, TGA, and mechanical properties. The best results were obtained with 2 wt% DBD in the extruder with a temperature profile of 120 to 80 °C, 50 rpm, and 4.5 g per minute (gpm). The tensile strength and strain at break of the recyclate already met the requirements of DIN EN 681-1:2006 for the production of sealing systems. The compression set and Shore A hardness were restored by mixing recyclate with 25 wt% VR.