Optimal scenario balance of reduction in costs and greenhouse gas emissions for municipal solid waste management
To reduce carbon intensity, an improved management method balancing the reduction in costs and greenhouse gas (GHG) emissions is required for Tianjin’s waste management system. Firstly, six objective functions, namely, cost minimization, GHG minimization, eco-efficiency minimization, cost maximization, GHG maximization and eco-efficiency maximization, are built and subjected to the same constraints with each objective function corresponding to one scenario. Secondly, GHG emissions and costs are derived from the waste flow of each scenario. Thirdly, the range of GHG emissions and costs of other potential scenarios are obtained and plotted through adjusting waste flow with infinitely possible step sizes according to the correlation among the above six scenarios. And the optimal scenario is determined based on this range. The results suggest the following conclusions. 1) The scenarios located on the border between scenario cost minimization and GHG minimization create an optimum curve, and scenario GHG minimization has the smallest eco-efficiency on the curve; 2) Simple pursuit of eco-efficiency minimization using fractional programming may be unreasonable; 3) Balancing GHG emissions from incineration and landfills benefits Tianjin’s waste management system as it reduces GHG emissions and costs.
- Research Article
2
- 10.1016/j.oneear.2021.11.008
- Dec 1, 2021
- One Earth
Major US electric utility climate pledges have the potential to collectively reduce power sector emissions by one-third
- Conference Article
1
- 10.15396/eres2021_48
- Jan 1, 2021
National and international agreements aim to limit climate change and thus call for a reduction of greenhouse gas (GHG) emissions to nearly zero. A wide range of technologies promise to reduce the heat demand of buildings and also promote renewable energies. One of these technologies is the use of solid building structures as thermal storage, so called thermally activated building parts or TABS. Thermal simulations of such energy concept for a typical single-family house with 140 m² living space featuring a heat pump, a solar thermal collector and TABS show that the share of solar heat for heat supply can be increased, resulting in a decreased use of the heat pump and thus a lower demand of electric energy. This leads to reduced greenhouse gas emissions and lower operating costs. Furthermore, the simulations show that larger sizes of the TABS and the solar thermal collector lead to lower demand of electric energy. To secure a reduction of greenhouse gas emissions and costs over the whole lifecycle of a building also production and dismantling, disposal and recycling must be considered. A Life Cycle Cost (LCC) Analysis shows that TABS in combination with solar heat reduce LCC, expressed as present values, by app. 34%. The reductions are mainly due to the lower operating costs of the heating system. Increasing the size of south-facing solar collectors leads to asymptotically decreasing costs. For the less favourable orientations to the West and East, the optimum size of the collector is between 30 and 40 m², depending on the orientation and the size of the TABS. A minimum size of the TABS must be available, while additional TABS do not lead to further reductions. Also in an ecologic sense, the use of TABS in combination with solar heat is beneficial. The simulations in this research show that the greenhouse gas (GHG) emissions over the whole lifecycle can be reduced by 27%. Again, the reduction mainly results from the decreased demand of electric energy and only slightly higher GHG emissions from the production of the TABS. Larger collector sizes lead to asymptotically reduced GHG emissions, when south facing. In contrast, orientations to the East and West lead to increased GHG emissions as the size of the collector increases. Integrated systems of heat pumps, solar thermal collectors and TABS could also be considered for multi-family housing and other building types. Simulations of LCC and LCA offer a suited means for assessing economic and ecologic impacts of innovative buildings concepts and should be used on a wider scale, ideally in combination.
- Conference Article
1
- 10.5339/qfarc.2016.eepp1669
- Jan 1, 2016
Energy-related activities are a major contributor of greenhouse gas (GHG) emissions. A growing body of knowledge clearly depicts the links between human activities and climate change. Over the last century the burning of fossil fuels such as coal and oil and other human activities has released carbon dioxide (CO2) emissions and other heat-trapping GHG emissions into the atmosphere and thus increased the concentration of atmospheric CO2 emissions. The main human activities that emit CO2 emissions are (1) the combustion of fossil fuels to generate electricity, accounting for about 37% of total U.S. CO2 emissions and 31% of total U.S. GHG emissions in 2013, (2) the combustion of fossil fuels such as gasoline and diesel to transport people and goods, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. GHG emissions in 2013, and (3) industrial processes such as the production and consumption of minerals and chemicals, accounting for about 15% of total U.S. CO2 emissions and 12% of total ...
- Research Article
49
- 10.1186/s12711-019-0459-5
- Apr 29, 2019
- Genetics, Selection, Evolution : GSE
BackgroundSocietal pressures exist to reduce greenhouse gas (GHG) emissions from farm animals, especially in beef cattle. Both total GHG and GHG emissions per unit of product decrease as productivity increases. Limitations of previous studies on GHG emissions are that they generally describe feed intake inadequately, assess the consequences of selection on particular traits only, or examine consequences for only part of the production chain. Here, we examine GHG emissions for the whole production chain, with the estimated cost of carbon included as an extra cost on traits in the breeding objective of the production system.MethodsWe examined an example beef production system where economic merit was measured from weaning to slaughter. The estimated cost of the carbon dioxide equivalent (CO2-e) associated with feed intake change is included in the economic values calculated for the breeding objective traits and comes in addition to the cost of the feed associated with trait change. GHG emission effects on the production system are accumulated over the breeding objective traits, and the reduction in GHG emissions is evaluated, for different carbon prices, both for the individual animal and the production system.ResultsMultiple-trait selection in beef cattle can reduce total GHG and GHG emissions per unit of product while increasing economic performance if the cost of feed in the breeding objective is high. When carbon price was $10, $20, $30 and $40/ton CO2-e, selection decreased total GHG emissions by 1.1, 1.6, 2.1 and 2.6% per generation, respectively. When the cost of feed for the breeding objective was low, selection reduced total GHG emissions only if carbon price was high (~ $80/ton CO2-e). Ignoring the costs of GHG emissions when feed cost was low substantially increased emissions (e.g. 4.4% per generation or ~ 8.8% in 10 years).ConclusionsThe ability to reduce GHG emissions in beef cattle depends on the cost of feed in the breeding objective of the production system. Multiple-trait selection will reduce emissions, while improving economic performance, if the cost of feed in the breeding objective is high. If it is low, greater growth will be favoured, leading to an increase in GHG emissions that may be undesirable.
- News Article
1
- 10.1289/ehp.119-a384a
- Sep 1, 2011
- Environmental Health Perspectives
For all its cachet, you might think that hybrid drivetrain technology is inherently green. But only 13 of 34 hybrid vehicles assessed achieve better than a 25% reduction in greenhouse gas (GHG) emissions, and just 3 exceed a 40% reduction, according to an evaluation by the Union of Concerned Scientists (UCS).1 Moreover, reductions in GHG emissions do not necessarily correlate with reductions in other toxic emissions. Like any engine output–improving technology, hybrid technology can boost both fuel efficiency and power—but the more you boost one, the less you can boost the other. That dichotomy spurred the UCS to develop its “hybrid scorecard,” which rates each hybrid according to how well it lives up to its promise of reducing air pollution.2 All the vehicles were from model year 2011 except for one, the 2012 Infiniti M Hybrid. First the UCS scored each hybrid on how much it reduced its GHG emissions relative to its conventional counterpart, on a scale of zero (least reduction) to 10 (greatest reduction). These scores reflect the percentage in fuel efficiency gain. For example, the Toyota Prius gets 50 mpg3 compared with 28 mpg for the comparable Toyota Matrix. This represents a 44.0% reduction in GHG emissions, earning the Prius a GHG score of 9.4. At the bottom of the scale, the 21-mpg hybrid VW Touareg reduces GHG emissions only 10% over the 19-mpg conventional Toureg, for a score of 0.0. With a 46% improvement, the luxury Lincoln MKZ Hybrid had the greatest reduction over its conventional counterpart. The UCS also scored hybrids for absolute emissions (rather than relative to the conventional model) of air pollutants including particulate matter, carbon monoxide, hydrocarbons, and nitrogen oxides. These scores, on a scale of zero (dirtiest) to 10 (cleanest), are based on California certifications for tailpipe emissions. As the scorecard showed, a vehicle that emits less heat-trapping gases may not necessarily emit less of other air pollutants. For example, the Mercedes Benz S400 Hybrid scored 9 on air pollution reduction, alongside the Prius and the Lincoln MKZ, but only 1.3 on GHG emissions. HYBRID SCORECARD: Top 10 Nonluxury Hybrids by Total Environmental Improvement Score “Hybrid technology doesn’t add additional challenges [to reducing exhaust pollutants] that can’t be addressed through design of the vehicle’s emission controls,” says Don Anair, senior vehicles analyst at the UCS. “Numerous manufacturers of hybrids are meeting the lowest emissions levels. Hybrid manufacturers who aren’t delivering the lowest smog-forming emissions have chosen not to do so.” Each vehicle’s air pollution and GHG scores were averaged into a total “environmental improvement score,” again with the MKZ and the Prius leading the pack, and the Touareg scraping bottom. The UCS also scored “hybrid value” (the cost of reducing GHG emissions in dollars per percent reduction) and “forced features” (options you must buy with the hybrid whether you want them or not). HYBRID SCORECARD: Top 10 Luxury Hybrids by Total Environmental Improvement Score Luke Tonachel, vehicles analyst with the Natural Resources Defense Council, compliments the scorecard for illustrating that hybrid technology is not automatically green. He says, “We should improve the efficiency of all vehicles, and [hybrid technology] is just one technology that can get us there if applied with that goal in mind.” Nonetheless, Jamie Kitman, the New York bureau chief for Automobile Magazine, questions the wisdom of emphasizing percentage improvement in gas mileage rather than absolute miles per gallon. At 21 mpg, the hybrid Cadillac Escalade 4WD represents a 29% improvement over the 15-mpg conventional model, saving nearly 2 gallons per 100 miles. But the hybrid Escalade is still a gas guzzler, and Kitman says he wishes people would see through the marketing that encourages them to buy SUVs and “crossovers” rather than ordinary cars, which are more efficient than either. Says Anair, “The scorecard shows that automakers can pair hybrid technology with advanced emission controls to help tackle climate change while reducing the health impacts from breathing polluted air.” However, he adds, alluding to the stark variation in how much hybrid technology boosted fuel efficiency, “Not all automakers are delivering on the full promise of this technology.”
- Research Article
5
- 10.30638/eemj.2018.099
- Jan 1, 2018
- Environmental Engineering and Management Journal
Livestock production is under growing public and scientific scrutiny for its greenhouse gas (GHG) emissions. This article contains a preliminary assessment of the inclusion of upstream life-cycle GHG emissions in concentrated feeds design, using the most common nonlinear programming optimization algorithms to determine feed composition. First, GHG emissions are included as costs in a single criteria optimization problem. The unit price of GHG emissions was obtained using a genetic algorithm. Second, GHG emissions are included as a target function to minimize in a multi criteria optimization problem using goal attainment programming. Results obtained after both optimization methods were applied to two case studies, namely fattening pigs and rabbit feeds. Changing ingredients in concentrated feed blends has a marginal effect on GHG emissions due to mandatory nutritional constraints. If the optimization is unconstrained, the maximum possible decrease in GHG emissions is 27.5% for the pigs feed, accompanied by increasing costs and a decrease in feed nutritional quality. To maintain nutritional integrity, the maximum possible reduction in GHG emissions is 7.5%. Considering cost as an optimization variable in the problem, the maximum decreases are even lower. It is possible to decrease emissions by 71% for the rabbits feed, but the cost of the reduction is higher than the opportunity cost for farmers to reduce GHG emissions using other strategies. These results are qualitatively robust but critically depend on feed ingredients GHG emissions and cost data.
- Research Article
3
- 10.3390/su9020182
- Jan 26, 2017
- Sustainability
With the global challenge of climate change, it becomes crucial to understand the factors that can guide carbon intensive companies to comply with environmental regulations through significant reductions in greenhouse gas (GHG) emissions. Using the natural-resource-based view, the argument in this paper is that focusing on sustainability-driven resources by companies is a way to meet environmental compliance and reduce GHG emissions while gaining differential competitive benefits. A specific analysis on Alberta case has discussed large GHG emitters’ environmental compliance mechanisms in the context of their sustainability resources. The aim is examining if large GHG emitters in Alberta related to corporations having sustainability resources are complying with the Specified Gas Emitters Regulation (SGER) reduction requirement through cleaner-production driven internal mechanisms. The paper examines the existence of the sustainability resources in the reporting companies related to large GHG emitters responsible for 86% of total GHG reported by facilities with emissions above the threshold of 100 kilotonnes of GHG per year under SGER in Alberta. Corporations are found not using their sustainability resource potential to achieve internal reductions in GHG emissions throughout their facilities. Thus, some recommendations are presented for Alberta case as well as for environmental regulations in other jurisdictions that can potentially help policy makers improve their climate change regulations and achieve their global targets and enable companies to gain competitive advantage while meeting GHG reduction compliance.
- Research Article
21
- 10.3390/ani12172185
- Aug 25, 2022
- Animals : an Open Access Journal from MDPI
Simple SummaryLivestock accounts for an estimated 80% of total agricultural greenhouse gas emissions, making abatement of greenhouse gas emissions from livestock a high-priority challenge facing animal nutritionists. Mitigating greenhouse gases in ruminants without reducing animal production is desirable both as a strategy to reduce global greenhouse gas emissions and as a way of improving dietary feed efficiency. The inclusion of feed additives in the diets of ruminants can reduce energy losses as methane, which typically reduces animal performance and contributes to greenhouse gas emissions. The present study evaluated the abatement potential of nine essential oil blends to mitigate greenhouse gas emissions. The inclusion of the blends resulted in a reduction in greenhouse gas emissions and in vitro apparent dry matter digestibility with higher values noted for the control treatment. A similar trend was noted for in vitro truly dry matter digestibility with higher values noted in the control treatment. The efficiency of microbial production was greater for the blends. The inclusion of the blends affected the total and molar proportion of volatile fatty acid concentrations. Overall, inclusion of the blends modified the rumen function resulting in improved efficiency of microbial production.The current study evaluated nine essential oil blends (EOBs) for their effects on ruminal in vitro dry matter digestibility (IVDMD), efficiency of microbial production, total short-chain fatty acid concentration (SCFA), total gas, and greenhouse gas (GHG) emissions using two dietary substrates (high forage and high concentrate). The study was arranged as a 2 × 2 × 9 + 1 factorial design to evaluate the effects of the nine EOBs on the two dietary substrates at two time points (6 and 24 h). The inclusion levels of the EOBs were 0 µL (control) and 100 µL with three laboratory replicates. Substrate × EOBs × time interactions were not significant (p > 0.05) for total gas and greenhouse gas emissions. The inclusion of EOBs in the diets resulted in a reduction (p < 0.001) in GHG emissions, except for EOB1 and EOB8 in the high concentrate diet at 6 h and for EOB8 in the high forage diet at 24 h of incubation. Diet type had no effect on apparent IVDMD (IVADMD) whereas the inclusion of EOBs reduced (p < 0.05) IVADMD with higher values noted for the control treatment. The efficiency of microbial production was greater (p < 0.001) for EOB treatments except for EOB1 inclusion in the high forage diet. The inclusion of EOBs affected (p < 0.001) the total and molar proportion of volatile fatty acid concentrations. Overall, the inclusion of the EOBs modified the rumen function resulting in improved efficiency of microbial production. Both the apparent and truly degraded DM was reduced in the EOB treatments. The inclusion of EOBs also resulted in reduced GHG emissions in both diets, except for EOB8 in the high forage diet which was slightly higher than the control treatment.
- Supplementary Content
- 10.22004/ag.econ.260829
- Aug 29, 2017
- AgEcon Search (University of Minnesota, USA)
At the UN climate change conference in Paris in November 2015, Norway committed itself to a 40% reduction in greenhouse gas (GHG) emissions by 2030 compared to 1990 levels. Agriculture accounts for 8% of Norway’s total GHG emissions. If GHGs from drained and cultivated wetland (categorized under land use, land use change and forestry) are included, the share is 13%; this for a sector that accounts for roughly 0.3% of GDP. As is the case in most countries, agriculture is currently exempt from emission reduction measures, including the European Union’s Emissions Trading System (ETS), in which Norway participates. But the country has recently signaled its intention to include agriculture in future emission reduction efforts. Consideration is being given to how best to achieve GHG reductions in the sector. A recent report by the Norwegian Green Tax Commission, established by the government to evaluate policy options for achieving emission reductions, (Government of Norway, 2015) emphasizes the importance of including agriculture. The Commission suggests that agricultural emissions should be taxed at the same rate as for other sectors. It also recommends that reductions in the production and consumption of red meat should be specifically targeted, through cuts in production grants to farmers and the imposition of consumption taxes. Unsurprisingly, this proposed policy shift is extremely controversial and faces resistance, particularly from the farmers’ unions. Farmers argue that the maintenance of domestic agricultural production is crucial for achieving national food security objectives, in addition to pursuing other aims such as the maintenance of economic activity in rural areas and landscape preservation. Food security, which has been a key policy objective since the end of the Second World War, has been interpreted in Norway as requiring high levels of selfsufficiency in basic agricultural commodities. To achieve this, substantial subsidies are provided to farmers and domestic prices of many commodities are kept at high levels by restricting imports. The Organization for Economic Cooperation and Development (OECD) estimates that the total financial support provided to Norwegian agriculture in 2015 was equivalent to 62% of the value of gross farm receipts, which made Norway (along with Switzerland) a leader in the amount of support provided to agriculture by the 50 OECD member and non-member countries monitored by the Organization (OECD, 2016). In this paper we analyze policy options for achieving a 40% reduction in agricultural GHG emissions, consistent with the economy-wide target, while imposing the restriction that national food production measured in calories should be maintained (the food security target). This is consistent with the way that the Norwegian government identifies the country’s food security objective. In section 2 we outline the current situation with respect to GHG emissions in Norwegian agriculture. In section 3 we illustrate the policy issues involved by considering two product aggregates that are intensive in the use of land for crop production (grainland) and grassland, respectively. The aggregates are based on data for the main commodities in Norwegian agriculture relating to GHG emissions, land use, caloric content, subsidies, and costs per unit of production. We show that even though the opportunity set (i.e., the production combinations that are possible within technical constraints) is narrow, a 40% cut in emissions is achievable by substituting from ruminant products that are intensive in the use of grassland to products based on grainland. We also show that the emissions reduction both reduces government budgetary costs and land use, i.e., ruminant products are characterized by relatively high subsidies and land use. Two-dimensional analysis ignores the fact that per unit emissions from dairy production are low compared to other ruminant products (i.e., beef and sheep production). Both in terms of production value and agricultural employment, dairy farming is the most important component of Norwegian agriculture. Consequently, milk production deserves to be separated from ruminant meat production. Finally in section 4, we present a detailed analysis 3 of policy options derived from a disaggregated model that includes all the major products in Norwegian agriculture. In the model-based analysis, we examine first the imposition of a carbon tax, while maintaining existing agricultural support policies and import protection, and achieving the food security (production of calories) target. Since the imposition of a carbon tax in agriculture presents both technical and political challenges, we then examine an alternative approach of changing the existing structure of agricultural support to approximate the same result. We show that it is possible to change current subsidy rates to mimic the carbon tax and calorie target solution. The explanation for this is that ruminant products not only generate high emissions per produced calorie, but they are also the most highly subsidized products. Meat from ruminants is relatively unimportant in achieving Norway’s food security objective of calorie availability.
- Conference Article
- 10.36334/modsim.2013.b2.christie
- Dec 1, 2013
The dairy Carbon Offset Scenario Tool (COST) was developed to explore the influence of various abatement strategies on greenhouse gas (GHG) emissions for Australian dairy farms. COST is a static spreadsheet-based tool that uses Australian GHG inventory methodologies, algorithms and emission factors to estimate carbon dioxide, methane and nitrous oxide emissions of a dairy farm system. One of the key differences between COST and other inventory-based dairy GHG emissions calculators is the ability to explore the effect of reducing total farm emissions on farm income, assuming the strategy was compliant with Kyoto rules for carbon offsets. COST provides ten abatement strategies across the four broad theme areas of diet manipulation, herd and breeding management, feedbase management and waste management. Each abatement strategy contains four sections; two sections for data entry (baseline farm data specific to the strategy explored and strategy-specific variables) and two sections for results (milk production results and GHG/economic-related results). Key sensitive variables for each strategy, identified from prior research, and prices for milk production and carbon offsets are adjusted through up/down buttons, which allows users to quickly explore the impact of these variables on farm emissions and profitability. For example, if the cost to implement an abatement strategy is doubled, what carbon offset income would be required to negate this additional cost? Results are presented as changes in carbon offset income, strategy implementation cost, additional milk production income and net farm income on a per annum and on a per GHG emissions intensity of milk production basis. COST currently contains a comprehensive range of strategies for GHG abatement, although some strategies are still in development. As new technologies or farm management practices leading to a reduction in GHG emission become available, these too will be incorporated into COST. To date, two dairy-specific abatement methodologies have been legislated as part of Australia’s commitment to reducing on-farm GHG emissions through it’s the carbon offset scheme, the Carbon Farming Initiative (CFI) and are incorporated into COST. These are the ‘Destruction of methane generated from dairy manure in covered anaerobic ponds’ and the ‘Methodology for reducing greenhouse gas emissions in milking cows through feeding dietary additives’. As an example, we explored the mitigation option Replace supplements with a source of dietary fats (reflecting the second above-mentioned CFI legislated abatement strategy) as feeding a diet higher in dietary fats has been shown to reduce enteric methane emissions per unit of feed intake. A 400 milking herd was fed a baseline diet of 2.6% dietary fat. By replacing grain with hominy meal, at a rate of 5.0 kg dry matter/ cow per day for 90 days during the 3 summer months, the summer diet fat concentration was increased to 6.4%. Enteric methane emissions were reduced by 40 tonnes of carbon dioxide equivalents (t CO 2 e) per annum for the farm. Waste methane and nitrous oxide emissions were also reduced by 0.5 and 1.6 t CO 2 e/annum, respectively. However, as reductions from these two sources of GHG emissions do not qualify for payment with this CFI methodology, their reduction could not be included as an offset income. At a carbon price of $20/ t CO 2 e, the reduction in enteric methane emissions was valued at $800/farm. The implementation cost of replacing grain with hominy was valued at $18,000/farm due to the hominy meal costing an additional $100/t dry matter compared to the grain. However, the additional milk production achieved due to the higher energy concentration of the diet resulted in an additional 70,200 litres and based on a summer milk price of $0.38/ litre, this equated to an additional income from milk valued at $26,676/farm. The overall result was a net increase in farm profit of $9,476/farm when paid on a reduction in total GHG emissions. COST can quickly allow users to ascertain the level of GHG emission reduction possible with various mitigation options and explore the sensitivity of key variables on GHG emissions and farm profitability.
- Research Article
26
- 10.1016/j.sciaf.2023.e01843
- Aug 5, 2023
- Scientific African
Greenhouse gas (GHG) emissions reduction in the electricity sector: Implications of increasing renewable energy penetration in Ghana's electricity generation mix
- Research Article
35
- 10.1021/es4020585
- Oct 18, 2013
- Environmental Science & Technology
Alternative methodologies for the reduction of greenhouse gas (GHG) emissions from crude palm oil (CPO) production by a wet extraction mill in Thailand were developed. The production of 1 t of CPO from mills with biogas capture (four mills) and without biogas capture (two mills) in 2010 produced GHG emissions of 935 kg carbon dioxide equivalent (CO2eq), on average. Wastewater treatment plants with and without biogas capture produced GHG emissions of 64 and 47% of total GHG emission, respectively. The rest of the emissions mostly originated from the acquisition of fresh fruit bunches. The establishment of a biogas recovery system must be the first step in the reduction of GHG emissions. It could reduce GHG emissions by 373 kgCO2eq/t of CPO. The main source of GHG emission of 163 kgCO2eq/t of CPO from the mills with biogas capture was the open pond used for cooling of wastewater before it enters the biogas recovery system. The reduction of GHG emissions could be accomplished by (i) using a wastewater-dispersed unit for cooling, (ii) using a covered pond, (iii) enhancing the performance of the biogas recovery system, and (iv) changing the stabilization pond to an aerated lagoon. By using options i-iv, reductions of GHG emissions of 216, 208, 92.2, and 87.6 kgCO2eq/t of CPO, respectively, can be achieved.
- Research Article
13
- 10.3390/en10101515
- Oct 1, 2017
- Energies
In this paper, we used the life-cycle analysis (LCA) method to evaluate the energy consumption and greenhouse gas (GHG) emissions of natural gas (NG) distributed generation (DG) projects in China. We took the China Resources Snow Breweries (CRSB) NG DG project in Sichuan province of China as a base scenario and compared its life cycle energy consumption and GHG emissions performance against five further scenarios. We found the CRSB DG project (all energy input is NG) can reduce GHG emissions by 22%, but increase energy consumption by 12% relative to the scenario, using coal combined with grid electricity as an energy input. The LCA also indicated that the CRSB project can save 24% of energy and reduce GHG emissions by 48% relative to the all-coal scenario. The studied NG-based DG project presents major GHG emissions reduction advantages over the traditional centralized energy system. Moreover, this reduction of energy consumption and GHG emissions can be expanded if the extra electricity from the DG project can be supplied to the public grid. The action of combining renewable energy into the NG DG system can also strengthen the dual merit of energy conservation and GHG emissions reduction. The marginal CO2 abatement cost of the studied project is about 51 USD/ton CO2 equivalent, which is relatively low. Policymakers are recommended to support NG DG technology development and application in China and globally to boost NG utilization and control GHG emissions.
- Research Article
58
- 10.1021/es500052h
- Mar 20, 2014
- Environmental Science & Technology
Solid waste management (SWM) systems must proactively adapt to changing policy requirements, waste composition, and an evolving energy system to sustainably manage future solid waste. This study represents the first application of an optimizable dynamic life-cycle assessment framework capable of considering these future changes. The framework was used to draw insights by analyzing the SWM system of a hypothetical suburban U.S. city of 100 000 people over 30 years while considering changes to population, waste generation, and energy mix and costs. The SWM system included 3 waste generation sectors, 30 types of waste materials, and 9 processes for waste separation, treatment, and disposal. A business-as-usual scenario (BAU) was compared to three optimization scenarios that (1) minimized cost (Min Cost), (2) maximized diversion (Max Diversion), and (3) minimized greenhouse gas (GHG) emissions (Min GHG) from the system. The Min Cost scenario saved $7.2 million (12%) and reduced GHG emissions (3%) relative to the BAU scenario. Compared to the Max Diversion scenario, the Min GHG scenario cost approximately 27% less and more than doubled the net reduction in GHG emissions. The results illustrate how the timed-deployment of technologies in response to changes in waste composition and the energy system results in more efficient SWM system performance compared to what is possible from static analyses.
- Preprint Article
- 10.5194/egusphere-egu23-10136
- May 15, 2023
As part of the Net Zero Carbon Water Cycle Program (NZCWCP) for Victoria state in Australia, we have sought to understand the potential to reduce household energy consumption and related Greenhouse Gas (GHG) emissions by influencing water use. Digital metering data disaggregated into 57 million discrete water usage events across 105 households at a resolution of 10 millilitres at 10 second intervals from June 2017 to March 2020, from a previous Yarra Valley Water (Melbourne, Australia) study, was analysed, together with the dynamic relationship between the multiple energy sources (natural gas, grid electricity, solar) used to heat water for showers in each hour of the day. Water-related energy (WRE) use, including water desalination and treatment, pumping, heating, wastewater collection and treatment, comprised 12.6% of Australia&#8217;s primary energy use in 2019. Water heating (by natural gas and electricity) comprised the largest component of WRE use for across residential, commercial, and industrial sectors. Furthermore, 69% of Victoria&#8217;s total water usage was by residential customers in 2020-2021. WRE GHG emissions were around 3.8% of Victoria&#8217;s total GHG emissions in 2018. Showers (~50% of residential WRE), system losses (~27% of residential WRE), and clothes washers (~9% of residential WRE) are the three largest components of WRE consumption. The main objective of this work is the creation of industry-accessible tools to improve knowledge and management options from the understanding of reductions in cost and GHG emissions from household showering WRE use. Potential options considered, to reduce water and energy use, as well as associated GHG emissions and customer utility bills, include (a) behaviour management such as water and energy pricing to change time of use behaviours, and (b) the adoption of efficient shower head improvements. Shower WRE and GHG emissions were found able to be strongly impacted by small changes in daily routines. GHG emissions reduction from showering could be reduced up to 20 (in summer) - 22% (in winter) by shifting demand time of showering or replacing residential showerheads. Extrapolated to state and Australian scales, reductions in water usage could be up to 14 GL (Victoria) and 144 GL (Australia), and reductions in GHG emissions 1,600 ktCO2eq (Victoria) and 17,300 ktCO2eq (Australia). It provides fundamental new information which could inform a suite of new management options to impact water-related energy from showers, and related GHG emissions and customer water and energy cost.