Life Cycle Greenhouse Gas Emissions Research Articles

Deduction of carbon footprint for membrane desalination processes towards carbon neutrality: A case study on electrodeionization for ultrapure water preparation

Decarbonization of the industrial sector, especially in power generation, is vital for achieving carbon neutrality. The life-cycle greenhouse gas (GHG) emissions, namely carbon footprint, of a technology under the decarbonizing macro-environment should be deduced to reveal further opportunities for GHG reduction. Herein, a case study on ultrapure water (UPW) preparation by electrodeionization (EDI) was investigated through life cycle assessment (LCA) and compared with a conventional mixed-bed ion exchange (MBIX) technology. The carbon footprint of the EDI process was quantified as 1.30 kg CO2-eq/metric ton UPW, which is 27.73 % lower than the MBIX. With a decarbonized power grid and recycling of wasted EDI modules, the carbon footprint will be reduced by 91 %. Meanwhile, the proportion of module production and waste management will increase to 18 %. Thus, we suggest reducing the process energy consumption and improving the current efficiency of the EDI process by process modeling and optimization. With the decarbonization of electricity, the degraded reuse of plastic and the recycling of ion-exchange membranes and resins could be considered. The application of LCA to quantify the carbon footprint and provide suggestions for low-carbon designs could be extended to membrane desalination or industrial processes, supporting the revolution towards carbon neutrality.

The development of life cycle greenhouse gas emission footprints of novel pathways for the solvent-assisted and solvent-electromagnetic heating oil sands extraction processes

Steam-based oil sands extraction methods are emissions-intensive. Solvent-assisted and solvent-electromagnetic heating are alternative methods with the potential to lower greenhouse gas emissions (GHG). However, identifying an energy-efficient process pathway for these technologies remains a major concern. This is a gap in the research. In this study, we developed simulation models to assess the performance of solvent-assisted, solvent-electromagnetic heating, and steam-assisted oil sands extraction central processing facilities. Three central processing facilities (pathways) were developed for solvent-assisted and solvent-electromagnetic heating processes to recover bitumen and solvent from emulsions. Pathways I and III use a low-temperature and a high-temperature distillation system, respectively, to purify the solvent. Pathway II uses a high-pressure separator to lower the amount of non-condensable gases in the solvent. Each pathway was applied to a deep and a shallow reservoir. Sensitivity and uncertainty analyses were conducted to present the GHG emission results. The results show that pathways I and III produce satisfactory solvent purity and minimize solvent losses in the central processing facility, and pathway II does not. Pathway II can be applied when a high degree of purity is not required. The life cycle GHG emissions from pathways I and II may not be favorable to the solvent-assisted process if the electricity emission factor and solvent-to-oil ratio are high. The lowest GHG emissions are from pathway III. The life cycle GHG emissions of the solvent-electromagnetic heating extraction in pathway III range from 34.4 to 61.7 and 23.3 to 43.9 kgCO2e/b-e for the deep and shallow reservoirs, respectively, while solvent-assisted emissions range from 26.6 to 48.2 and 20.2 to 40.0 kgCO2e/b-e for the deep and shallow reservoirs, respectively. Steam-assisted gravity drainage emissions range from 72.7 to 111.6 kgCO2e/b. The results show that solvent-assisted and solvent-electromagnetic heating processes can provide better performance than steam-assisted gravity drainage when a high-temperature distillation is installed in the central processing facility to recycle the solvent.

Development of novel dimethyl ether – Glycerol blends with improved viscosity and miscibility for potential compression-ignition engine application

Dimethyl Ether is a promising diesel alternative fuel due to its significantly low well-to-wheels greenhouse gas emissions from certain renewable pathways and soot-free combustion characteristic. However, in a compression-ignition engine, the fuel injection system exhibits decreased durability due to the dimethyl ether’s extremely low viscosity (i.e., 0.15 cSt @ 40 °C). In this study, the viscosity of dimethyl ether is improved to the level of No.2 diesel fuel (i.e., 1.9 cSt @ 40 °C) via glycerol blending. To prevent the phase separation between glycerol and dimethyl ether, effective co-solvents are determined based on different selection criteria: Hansen Solubility Parameter-based “averaged solubility distance”, viscosity, oxygen mass content, health and environmental impacts, and renewable production capability. As a result, propylene glycol and di-propylene glycol are selected as the final co-solvents and are used to form the two final dimethyl ether blends: i) Michigan DME blend I (i.e., dimethyl ether/dipropylene glycol/glycerol); and ii) Michigan DME blend II (i.e., dimethyl ether/propylene glycol/glycerol). The minimum mass ratio of co-solvent to glycerol to prevent the phase separation is measured to be 1.5 and 1.65 for Michigan DME blend I and II, respectively, at 40 wt% dimethyl ether content. The kinematic viscosity of the two final blends was successfully improved to the level of No. 2 diesel fuel at around 40–43 wt% dimethyl ether content, a higher dimethyl ether content than any previous blends reported. A preliminary engine demonstration result with one of the final dimethyl ether blends (i.e., Michigan DME blend I) is also briefly presented here with suggestions for future improvement. While the current article covers the blend development part of the current research, its companion article covers the life-cycle greenhouse gas emissions assessment for one of the final dimethyl ether blends (i.e., Michigan DME blend II).

Project-based sustainable timing series decision-making for pavement maintenance using multi-objective optimization: An innovation in traditional solutions

Pavement maintenance timing series (PMTS) optimization at the project level should consider multiple interventional maintenance impacts within the planning horizon, while making trade-offs between investment and environmental burden, which is difficult to address with traditional methods, partly due to the lack of understanding of the interaction mechanism between the sustainable objectives. To bridge this gap, this paper presents a customized project-based PTMS decision-making method using multi-objective optimization, and applied it to explore the PMTS generation mechanisms by decomposing the sustainable objectives. Results show that among the three sustainable objectives, life-cycle agency cost and greenhouse gas (GHG) emissions drive the timing series formation of maintenance technologies, and GHG emissions can also limit the “greedy” growth of non-zero decision variables, while the integral function form of the benefit of pavement maintenance can improve the lowest performance condition. In addition, the proposed approach allows for the maximization of the trade-offs between the three sustainable objectives using the Euclidean norm strategy, while providing a prioritized set of potential PMTS solutions. Based on that, a benefit-to-cost & GHG emissions ratio model (BCGRM) was proposed to compare with the above tri-objective optimization model in generating PMTS. Since the non-dominating nature of the three objectives cannot be directly considered, BCGRM will get higher investment benefits by increasing the maintenance frequency.

Integrating Prospective Scenarios in Life Cycle Engineering: Case Study of Lightweight Structures

Lightweight design is a common approach to reduce energy demand in the use stage of vehicles. The production of lightweight materials is usually associated with an increase in energy demand, so the environmental impacts of lightweight structures need to be assessed holistically using a life cycle assessment. To estimate the life cycle environmental impacts of a product in its developmental stage, for example, by life cycle engineering, future changes in relevant influencing factors must be considered. Prospective life cycle assessment provides methods for integrating future scenarios into life cycle assessment studies. However, approaches for integrating prospective life cycle assessment into product development are limited. The objective of this work is to provide the methodological foundation for integrating future scenarios of relevant influencing factors in the development of lightweight structures. The applicability of the novel methodology is demonstrated by a case study of a structural component in a steel, aluminium, and hybrid design. The results show that appropriate decarbonisation measures can reduce the life cycle greenhouse gas emissions by up to 95 percent until 2050. We also found that shifts in the environmentally optimal design are possible in future scenarios. Therefore, the methodology and data provided contribute to improved decision-making in product development.

Revisiting electric vehicle life cycle greenhouse gas emissions in China: A marginal emission perspective

The accurate estimation of electric vehicle (EV) life cycle greenhouse gas (GHG) emissions is critical for policymakers to predict and manage the reduction of GHG emissions due to transportation electrification. Most previous studies in the Chinese context evaluated the EV life cycle GHG based on the annual average emission factor (AAEF). However, the hourly marginal emission factor (HMEF), which is conceptually more appropriate than AAEF for evaluating the GHG implications of EV growth, has not been applied in China. This study fills this gap by estimating the EV life cycle GHG in China based on the HMEF and comparing it with AAEF-based estimates. It is found that the estimates based on the AAEF substantially underestimate the EV life cycle GHG in China. Moreover, the influences of the electricity marketization reform and changes in the EV charging mode on the EV life cycle GHG in China are analyzed.

Cost and Life Cycle Emissions of Ethanol Produced with an Oxyfuel Boiler and Carbon Capture and Storage.

Decarbonization of transportation fuels represents one of the most vexing challenges for climate change mitigation. Biofuels derived from corn starch have offered modest life cycle greenhouse gas (GHG) emissions reductions over fossil fuels. Here we show that capture and storage of CO2 emissions from corn ethanol fermentation achieves ∼58% reduction in the GHG intensity (CI) of ethanol at a levelized cost of 52 $/tCO2e abated. The integration of an oxyfuel boiler enables further CO2 capture at modest cost. This system yields a 75% reduction in CI to 15 gCO2e/MJ at a minimum ethanol selling price (MESP) of $2.24/gallon ($0.59/L), a $0.31/gallon ($0.08/L) increase relative to the baseline no intervention case. The levelized cost of carbon abatement is 84 $/tCO2e. Sensitivity analysis reveals that carbon-neutral or even carbon-negative ethanol can be achieved when oxyfuel carbon capture is stacked with low-CI alternatives to grid power and fossil natural gas. Conservatively, fermentation and oxyfuel CCS can reduce the CI of conventional ethanol by a net 44-50 gCO2/MJ. Full implementation of interventions explored in the sensitivity analysis would reduce CI by net 79-85 gCO2/MJ. Integrated oxyfuel and fermentation CCS is shown to be cost-effective under existing U.S. policy, offering near-term abatement opportunities.

Proposal of Zero-Emission Tug in South Korea Using Fuel Cell/Energy Storage System: Economic and Environmental Long-Term Impacts

This study presents the results of economic and environmental analysis for two types of zero-emission ships (ZESs) that are receiving more attention to meet strengthened environmental regulations. One of the two types of ZES is the ZES using only the energy storage system (All-ESS), and the other is the ZES with fuel cell and ESS hybrid system (FC–ESS). The target ship is a tug operating in South Korea, and the main parameters are based on the specific circumstances of South Korea. The optimal capacity of the ESS for each proposed system is determined using an optimization tool. The total cost for a ship’s lifetime is calculated using economic analysis. The greenhouse gas (GHG) emission for the fuel’s lifecycle (well-to-wake) is calculated using environmental analysis. The results reveal that the proposed ZESs are 1.7–3.4 times more expensive than the conventional marine gas oil (MGO)-fueled ship; however, it could be reduced by 1.3–2.4 times if the carbon price is considered. The proposed ZESs have 58.7–74.3% lower lifecycle GHG emissions than the one from the conventional ship. The results also highlight that the electricity- or hydrogen-based ZESs should reduce GHG emissions from the upstream phase (well-to-tank) to realize genuine ZESs.

Life cycle assessment of a PEMFC-based distributed energy system for hotel application

Hydrogen fuel cell can not only generate electricity efficiently, but also provide a large amount of thermal energy by recovering the waste heat of the fuel cell stack. This study proposed a PEMFC-based distributed energy systems (PEMFC-DES) containing of input energy, PEMFC-based combined cooling, heating and power (PEMFC-CCHP) system and building loads. The performances of energy, environment, economics of the proposed system are investigated through life cycle assessment (LCA) under different hydrogen-electricity contribution rates (RH ), hydrogen production methods and hydrogen gas prices. The results show that the hydrogen production method has a greater impact on primary energy consumption and greenhouse gas emissions. At RH = 1.0, the greenhouse gas emission of coal-to-hydrogen is 2.1 times higher than that of the baseline system. The life cycle primary energy consumption and greenhouse gas emissions of the wind-to-hydrogen are the smallest at RH = 1, which are 85.14% and 87.64% lower than that of the baseline system respectively. Additionally, when the hydrogen price is lower than 20 CNY/kg, the total life cycle cost is lower than that of the baseline system.

Tracking the life-cycle greenhouse gas emissions of municipal solid waste incineration power plant: A case study in Shanghai

Municipal solid waste incineration (MSWI) has become the predominant waste-to-energy technology in China. The present work addresses an onsite greenhouse gas (GHG) emissions accounting approach for MSWI plants. A comprehensive life-cycle GHG emissions assessment model was developed and applied to a case study in Shanghai. Different methods (Method 1: CO2 concentration measurement-based method; Method 2: O2 concentration measurement-based method; and Method 3: Intergovernmental Panel on Climate Change (IPCC) 2006 guidelines-based method) were compared for calculating the fossil CO2 emissions (FCO2E) originating from waste incineration. The results indicate that the deviations of FCO2E among different methods could be effectively reduced by modifying the dry matter (DM) content since the waste in China is commonly featured by high moisture content. Moreover, the life-cycle GHG emissions of MSWI in each month ranged from 11.2 to 622.4 kg CO2-eq/t MSW, in which FCO2E yielded the most significant impact. The seasonal characteristics of GHG emissions were directly related to variations in the waste components. In particular, a high plastics fraction in the waste streams after source separation contributed to high levels of GHG emissions originating from Chinese MSWI plants. It was demonstrated that GHG emissions increased by approximately 12.1 kg CO2-eq/t MSW with a 1% increase in the plastics fraction. Therefore, properly increasing the recycling rate of plastics and improving the power generation efficiency could effectively reduce the GHG emissions associated with MSWI.

A comparative analysis of carbon reduction potential for directly driven permanent magnet and doubly fed asynchronous wind turbines

AbstractWind power generation does not emit greenhouse gases or pollutants, but there are some carbon emissions from the manufacturing, transportation, operation, and waste disposal of wind turbines. Directly driven permanent magnet and doubly fed asynchronous wind turbines currently have the largest market share in China, but few Chinese studies have compared their differences in carbon reduction potential. This paper uses life cycle assessment (LCA) to quantitatively analyze the full life cycle carbon emissions of the two wind turbines to determine which type of wind turbine has greater carbon reduction potential, obtaining the following results. (1) The full life cycle greenhouse gas emissions of 2.5 MW directly driven permanent magnet and doubly fed asynchronous wind turbines are 8.48 and 10.43 g CO2/kWh, respectively. The direct‐driven permanent magnet wind turbine is superior in terms of carbon reduction. (2) The stage with the greatest impact and the greatest difference between the two wind turbines in the full life cycle is the production stage, during which the carbon emissions of the directly driven permanent magnet and doubly fed asynchronous wind turbines are 1.045 × 106 and 1.210 × 106 kg, respectively. (3) According to sensitivity analysis, proper waste disposal and transportation can reduce carbon emissions from wind turbines. These research findings can be used to help achieve carbon peaking and neutrality goals, as well as the technological development of wind power enterprises.

Impact of climate change on the life cycle greenhouse gas emissions of cross-laminated timber and reinforced concrete buildings in China

With the urgency of addressing climate change, cross-laminated timber (CLT) has become a sustainable material to substitute reinforced concrete (RC) in building applications. There is a growing number of studies on the life cycle assessment of CLT buildings worldwide, mainly based on historical weather files. This study integrates climate change on life cycle greenhouse gas emissions (LCGHGE) in CLT and RC buildings in five climate zones, including the product and construction (P&C), operational and End-of-Life (EoL) stages. The CCWorldWeatherGen tool is used to generate future weather data (i.e., the 2020s, 2050s and 2080s) for the A2 emissions scenario. The simulation results show heating demands will decline significantly and cooling demands will rise in all cases. By the 2080s, global warming will result in an average LCGHGE of 33.09% and 38.90% higher than the baseline scenario for RC and CLT buildings, respectively. Strategies to reduce space cooling demand and decarbonize electricity will become increasingly important in the future. The average LCGHGE of CLT buildings is 27.53%, 26.22%, 24.67% and 22.19% lower than those of RC alternatives in the baseline, the 2020s, 2050s and 2080s, respectively. The study demonstrates that the lower greenhouse gas (GHG) emissions and the greater benefits from EoL from CLT buildings outweigh the operational GHG savings benefits from the thermal mass of RC buildings, even when climate impact is taken into account. Therefore, CLT buildings are a feasible way to reduce GHG emissions from buildings in China.

The global warming potential and the material utility of PET and bio-based PEF bottles over multiple recycling trips

Biomass use and recycling are among the few options to reduce the greenhouse gas (GHG) emissions of the growing plastics sector. The bio-based plastic polyethylene furanoate (PEF) is a promising alternative to polyethylene terephthalate (PET), in particular for small bottle applications. For the first time, we assessed the life cycle global warming potential (GWP) for 250 mL PET and PEF bottles over multiple mechanical (MR) and chemical (CR) recycling trips in the Netherlands. We found that bio-based PEF would offer 50–74% lower life cycle GHG emission after one recycling trip compared to PET, depending on the waste management case. Our results also show that deposit-based recycling systems significantly reduce the cumulative cradle-to-grave net GHG emissions for both bottle types, especially when multiple recycling trips are applied. We propose complementary material utility (MU) indicators to reveal synergies and trade-offs between circularity and GWP: While deposit-based CR shows the best performance in terms of MU, it falls behind deposit-based MR when it comes to net GHG emissions due to the energy intensity of CR. Hence, combining mechanical and chemical recycling could contribute to achieving the goals of the circular economy and climate change mitigation alike.

Integrated biochar solutions can achieve carbon-neutral staple crop production.

Agricultural food production is a main driver of global greenhouse gas emissions, with unclear pathways towards carbon neutrality. Here, through a comprehensive life-cycle assessment using data from China, we show that an integrated biomass pyrolysis and electricity generation system coupled with commonly applied methane and nitrogen mitigation measures can help reduce staple crops' life-cycle greenhouse gas emissions from the current 666.5 to -37.9 Tg CO2-equivalent yr-1. Emission reductions would be achieved primarily through carbon sequestration from biochar application to the soil, and fossil fuel displacement by bio-energy produced from pyrolysis. We estimate that this integrated system can increase crop yield by 8.3%, decrease reactive nitrogen losses by 25.5%, lower air pollutant emissions by 125-2,483 Gg yr-1 and enhance net environmental and economic benefits by 36.2%. These results indicate that integrated biochar solutions could contribute to China's 2060 carbon neutrality objective while enhancing food security and environmental sustainability.

Carbon footprint analysis and carbon neutrality potential of desalination by electrodialysis for different applications

Low-carbon water production technologies are indispensable for achieving sustainable development goals and mitigating global climate change. However, at present, many advanced water treatment processes lack a systematic assessment of related greenhouse gas (GHG) emissions. Thus, quantifying their life-cycle GHG emissions and proposing strategies toward carbon neutrality is urgently needed. This case study focuses on electrodialysis (ED), an electricity-driven desalination technology. To analyze the carbon footprint of ED desalination in various applications, a life cycle assessment model was developed based on industrial-scale ED processes. For seawater desalination, the carbon footprint is 59.74 kg CO2-eq/metric ton removed salt, which is one order of magnitude lower than that of high-salinity wastewater treatment and organic solvent desalination. Meanwhile, the power consumption during operation is the main hotspot of GHG emissions. Power grid decarbonization and improved waste recycling in China are projected to reduce the carbon footprint up to 92%. Meanwhile, the contribution of operation power consumption is expected to reduce from 95.83% to 77.84% for organic solvent desalination. Through sensitivity analysis, significant non-linear impacts of process variables on the carbon footprint were determined. Therefore, it is recommended to optimize the process design and operation to reduce power consumption based on the current fossil-based grid. GHG reduction for module production and disposal should also be emphasized. This method can be extended to general water treatment or other industrial technologies for carbon footprint assessment and reducing GHG emission.

Life-Cycle Assessment of Biochemicals with Clear Near-Term Market Potential

The urgent need for greenhouse gas (GHG) emission reductions to mitigate climate change calls for accelerated biorefinery development and biochemical deployment to the market as structural or functional replacements for chemicals produced from fossil-derived feedstocks. This study evaluated the energy and environmental impacts of 15 biochemicals with clear near-term market potential and their fossil-based counterparts, when applicable, on a cradle-to-gate basis. Three of these chemicals are produced exclusively from biomass; eight are predominantly produced from fossil-derived feedstocks; and four are predominantly produced from biomass. For the 12 cases that can be produced from either feedstock, eight exhibited fossil energy consumption and GHG emission reductions when produced from biomass instead of fossil-derived feedstocks between 41%–85% and 35%–350%, respectively. Water consumption results were mixed because several of the biobased pathways consumed more water. Annually, replacing the predominantly fossil-fuel-based chemicals with biobased alternatives could avoid 120 MMT CO2e emissions and save 1,500 PJ of fossil energy. The potential of these chemicals as coproducts in integrated biorefineries was analyzed in terms of market, economics, and environmental effects with an emphasis on GHG emissions. Adipic acid, succinic acid, acrylic acid, propylene glycol, 1,4-butanediol, 1,3-butadiene, furfural, and fatty alcohol are promising coproduct candidates based on their low life-cycle GHG emissions.

Life-cycle greenhouse gas emission assessment for bike-sharing systems based on a rebalancing emission estimation model

Bike sharing is regarded as a green transportation mode, while the existing studies on its greenhouse gas (GHG) emission assessment seldom consider bike-rebalancing process. In this research, a Bike Sharing System-Rebalancing Emission Estimation Model (BSS-REEM) was proposed to conservatively quantify historical GHG emitted by rebalancing vehicles. Taking the largest bike sharing system (BSS) in North America as a case, we comprehensively assessed its life cycle GHG footprint considering the system's infrastructures, rebalancing process and cycling activities and analyzed the GHG reduction benefits of using pedal and electric trikes to assist trucks in dispatching bikes. Results showed that the bike rebalancing activity level fluctuated throughout 2020 and 56.1% of bikes were dispatched by vehicles and the rest driven by customers' incentive mechanisms. The annual conservative GHG emission of bike rebalancing was 92.1 tCO2-eq when merely diesel trucks were used. Such emissions would be reduced with trikes to assist rebalancing. The emission reduction driven by riding in 2020 reached 14,333.6 tCO2-eq, representing 1.8 times of the entire system's GHG emissions over its service life. Quantifying GHG emissions of the bike-rebalancing process promotes a systematic and comprehensive environmental evaluation of BSSs, providing a basic for their sustainable management.

Quantitative assessments of GHG and VOCs emissions of asphalt pavement contained steel slag

Using steel slag aggregate in asphalt pavement is recognized as novel alternative to enhance the environmental benefits, however, lacking quantitative analysis on its air components emissions largely hinders the fulfilment of sustainable road development. The study conducted the comparative research for the steel slag and the natural aggregate asphalt pavement from asphalt volatile organic compounds (VOCs) and greenhouse gas (GHG) emissions. The self-assembled gas generator and gas chromatography-mass spectrometer (GC–MS) were used to study the characteristics of asphalt VOCs. Moreover, the GHG emissions of asphalt pavement life cycle have been quantified with a prospective life cycle assessment (LCA). Different from traditional cognition, the research results showed that using steel slag aggregate in asphalt mixture would cause more asphalt VOCs and GHG emissions than natural aggregate in the life cycle of asphalt pavement. Specifically, comparing to the natural aggregate, the asphalt pavement contained steel slag aggregate generated extra 2 % to 30 % concentrations for primary VOCs components, and 11.86 t equivalent CO2 in the 20-year life cycle of asphalt pavement. The study provides valued reference for air pollution controlling and low-carbon development of asphalt pavement.

Comparative life cycle greenhouse gas emissions assessment of battery energy storage technologies for grid applications

With an ever-increasing penetration of renewable energy sources into the power grid, the development and commercialization of large-scale energy storage systems (ESSs) have been enforced. It is imperative to evaluate the environmental sustainability of ESSs in grid applications to achieve sustainable development goals. In the present work, a cradle-to-grave life cycle analysis model, which incorporates the manufacturing, usage, and recycling processes, was developed for prominent electrochemical energy storage technologies, including lithium iron phosphate batteries (LIPBs), nickel cobalt manganese oxide batteries (NCMBs), and vanadium redox flow batteries (VRFBs). A case study was conducted based on per MWh of energy stored. The greenhouse gas (GHG) emissions of LIPBs, NCMBs, and VRFBs under the Chinese electrical grid peak-shaving scenario were determined to be 323, 263, and 425 kg CO2-eq/MWh, respectively. The key components contributing to the GHG emissions were identified. The GHG emissions of different batteries in renewable energy sources (photovoltaic and wind) were evaluated. Moreover, the GHG emissions under the future electricity mixes were predicted according to the carbon peaking and carbon neutrality goals. The GHG emissions of LIPBs, NCMBs, and VRFBs under the Announced Pledges Scenario could be reduced by approximately 23–27% in 2030 and 66–75% in 2050. Moreover, sensitivity analysis was performed, indicating that the GHG emissions were directly linked with the round-trip efficiency. The results could promote the environment, policy, and business model optimization efforts for large-scale energy storage in low-carbon power systems.

Life cycle greenhouse gas emissions of low-temperature process heat generation by external compound parabolic concentrator (XCPC) solar thermal array

New solar-based technologies are currently being developed as prospective low-carbon sources of heat for industry, which require life cycle assessment to determine their actual decarbonization potential relative to current heat sources. We performed the first life cycle assessment of the external compound parabolic concentrator (XCPC) solar array, a novel low-concentration and non-tracking solar thermal technology capable of providing low-to medium-temperature heat (up to 250 °C). Primary data on the materials and performance of the XCPC were used in this analysis. The embodied greenhouse gas (GHG) emissions associated with manufacturing the technology are 92.4 kg CO2eq/m2, cradle-to-gate. The life cycle GHG emissions cradle-to-grave over a 25-year lifetime under conditions in the Central Valley of California are 129.7 kg CO2eq/m2. On the basis of thermal energy delivered, the XCPC has a carbon footprint of 5.8 g CO2eq per kWhth. These results indicate that the XCPC can generate low temperature heat with a carbon footprint 97% lower than natural gas and 98% lower than propane combustion in regions of high solar insolation.