Avoided Carbon Dioxide Emissions Research Articles

An Environment Perceptive on Solar Installation for University Campus: A Case of Universiti Utara Malaysia

Sustainable energy has become the main agenda globally. Among the renewable energy (RE) sources, solar provides huge potential in electricity production due to the abundance of sun radiation. As tropical country Malaysia enriched with solar radiation the whole year. This paper aimed to study the environmental perspective towards solar installation in the UUM campus building. Climate change sharply decreased by implementing the solar photovoltaic (PV) system up to 91.2 % compared to the conventional source of electricity supply. The global warming impact of solar panel installation was in the range of 44.74 to 178.99 g CO2EQ / kWh. The most contributing process towards this impact was transportation. Installation PV in UUM campus, could avoided carbon dioxide emissions equivalent to 996 ton of waste recycled instead of landfilled or 47583 tree seedlings grown for ten years. Hopefully, the result encourages stakeholders to consume solar power as the primary source of renewable energy components on the way to achieving the Malaysia government’s target of 50% RE in electricity generation.

Escalating carbon emissions from North American boreal forest wildfires and the climate mitigation potential of fire management.

Wildfires in boreal forests release large quantities of greenhouse gases to the atmosphere, exacerbating climate change. Here, we characterize the magnitude of recent and projected gross and net boreal North American wildfire carbon dioxide emissions, evaluate fire management as an emissions reduction strategy, and quantify the associated costs. Our results show that wildfires in boreal North America could, by mid-century, contribute to a cumulative net source of nearly 12 gigatonnes of carbon dioxide, about 3% of remaining global carbon dioxide emissions associated with keeping temperatures within the Paris Agreement’s 1.5°C limit. With observations from Alaska, we show that current fire management practices limit the burned area. Further, the costs of avoiding carbon dioxide emissions by means of increasing investment in fire management are comparable to or lower than those of other mitigation strategies. Together, our findings highlight the climate risk that boreal wildfires pose and point to fire management as a cost-effective way to limit emissions.

Compost versus biogas treatment of sewage sludge dilemma assessment using life cycle analysis

The establishment of the Urban Wastewater Treatment Directive resulted in an immense increasing quantity of sewage sludge produced from wastewater treatment plants. With most up to date the “Ex-post evaluation of certain waste stream directives”, various legislation and strategies were derived from fulfilling the requirements resulting from this directive appropriately, in an economical and environmentally acceptable way. This paper intends to assess and compare the environmental impact of exploiting the sewage sludge in open windrow facilities for compost production versus using an anaerobic digester for the production of biogas. The two alternative post-processing pathways' environmental assessment is conducted with the use of the Life Cycle Assessment methodology. The investigation presented that the energy savings for managing sewage sludge for biogas production than producing compost are estimated at 27060 MJ per 1 t of input (SS), and the avoided carbon dioxide emissions are 697 kg/t of digested sludge. The scientific value of this study is that it provides a justified answer to the compost versus biogas dilemma, based on a quantified assessment of both methods' environmental aspects. Life Cycle Assessment's employment brings forth in-depth information regarding the energy embodied in compost and biogas production. The selection among the most ecological method relevant to sewage sludge exploitation is provided by thoroughly sophisticated decision-making. The life cycle stages of the analyzed mechanisms that have the most damaging consequences on the ecosystem include the composting and anaerobic digestion stage, whereas the least energy-consuming stages are the thickening, and drying process, in both scenarios. The Life Cycle Assessment outcomes indicated that the environmental impact of the anaerobic digestion process is lower than the composting process, in the range between 6.5% and 7.5%, across all environment effect levels.The exploitation of waste materials to produce useful products such as compost and biogas gives the final product added environmental value.

Assessment of the Current Potential of Hydropower for Water Damming in Poland in the Context of Energy Transformation

The present paper indicates that hydropower, including small hydropower plants (SHPs), may play a very important role in Poland’s energy transformation in the near future. The development of SHPs may also increase water resources in the steppe Poland. Additionally, the aim of the present research is to conduct the PEST analysis of SHPs in Poland, taking into account the SHP potential. For the first time, maps showing the power and location of potential SHPs on the existing dams in Poland are presented. SHPs should be an important element of energy transition in Poland, especially on a local scale—it is stable energy production. Our analysis shows that there are 16,185 such dams in Poland, while the total capacity of potential hydropower plants in Poland would be 523.6 MW, and the total number of new jobs is estimated at 524. It was calculated that the annual avoided carbon dioxide emissions will amount to 4.4 million tons, which will reduce Poland’s emissions by 1.4%. The construction of SHPs can bring significant environmental and economic benefits. As far as the PEST analysis is concerned, the political environment of SHPs in Poland can be described as unfavorable (2.86 points). The economical nature of PEST analysis (3.86 points) should be considered as friendly for the development of SHPs. The social nature of PEST analysis can be considered as neutral (3.36 points). The technological nature of the PEST analysis can be considered as neutral (3.21 points).

Transitioning from 100 percent natural gas power to include renewable energy in a hydrocarbon economy

Transitioning from heavy carbon fuels such as coal and oil to lighter carbon fuels and renewable energy is necessary to reduce greenhouse gas emissions to keep global temperatures less than 2 °C above pre-industrial levels. This study considers the transition from full natural gas power generation to include renewables via utility-scale photovoltaic (PV) facilities in the Caribbean small island state of Trinidad and Tobago. By using the EnergyPLAN software and hourly solar radiation and electricity data, the electric power generation and quantities of natural gas avoided for several hundred-megawatt PV facilities were estimated. The direct and opportunity savings that could be derived from the avoided natural gas is substantial for a small island state. Additionally, payback periods, avoided carbon dioxide emissions from the power generation sector and levelized costs of electricity make a strong economic case for utility-scale PV. As solar PV is intermittent, a smart energy system is suggested to provide affordable and efficient electricity generation and to include other renewable energy sources such as wind power and electric vehicles.

Environmental impact tradeoff considerations for wheat bran-based biocomposite

Bio-based materials are increasingly proposed as sustainable alternatives to fossil-based products. Before commercialization, however, the environmental performance of bio-based materials must be evaluated to ensure the sustainability goals are met. Biocomposites derived from natural fibers hold promises for achieving the desired sustainability while offering competitive performance. Here, we assess the sustainability tradeoffs of using wheat bran, a by-product of milling wheat grain, for biocomposite production. We design two systems to evaluate such decision from the perspectives of flour and biocomposite producers. Each system is compared to a business-as-usual scenario: 1) flour system uses bran at the end of grain milling for either fiber production or disposes of it as waste, and 2) biocomposite system compares producing a biocomposite with 30% bran fiber/70% polypropylene with a 100% polypropylene. Our comparative life cycle assessment shows that in flour system, using wheat bran for biocomposite production rather than wasting it, lowers the overall environmental impacts including global warming and fossil fuel depletion mainly due to bran fiber replacing polypropylene, and avoiding carbon dioxide emissions from bran degradation. In system 2, mixing bran fiber in biocomposite lowers greenhouse gas emissions (1470kgCO2eq/t) and fossil fuel depletion (2130 MJ surplus/t) compared to the fully petroleum-based material. We discuss several upstream (e.g. reducing the chemicals during wheat cultivation) and downstream (e.g. sodium hydroxide consumption during fiber extraction) options that can help improve the overall environmental performance of the studied systems. Our study provides decision-making information for a variety of stakeholders including wheat producers, millers as well as composite industries.

Liquid Air Energy Storage for Decentralized Micro Energy Networks with Combined Cooling, Heating, Hot Water and Power Supply

Liquid air energy storage (LAES) has been regarded as a large-scale electrical storage technology. In this paper, we first investigate the performance of the current LAES (termed as a baseline LAES) over a far wider range of charging pressure (1 to 21 MPa). Our analyses show that the baseline LAES could achieve an electrical round trip efficiency (eRTE) above 60% at a high charging pressure of 19 MPa. The baseline LAES, however, produces a large amount of excess heat particularly at low charging pressures with the maximum occurred at ∼1 MPa. Hence, the performance of the baseline LAES, especially at low charging pressures, is underestimated by only considering electrical energy in all the previous research. The performance of the baseline LAES with excess heat is then evaluated which gives a high eRTE even at lower charging pressures; the local maximum of 62% is achieved at ∼4 MPa. As a result of the above, a hybrid LAES system is proposed to provide cooling, heating, hot water and power. To evaluate the performance of the hybrid LAES system, three performance indicators are considered: nominal-electrical round trip efficiency (neRTE), primary energy savings and avoided carbon dioxide emissions. Our results show that the hybrid LAES can achieve a high neRTE between 52% and 76%, with the maximum at ∼5 MPa. For a given size of hybrid LAES (1 MW×8 h), the primary energy savings and avoided carbon dioxide emissions are up to 12.1 MWh and 2.3 ton, respectively. These new findings suggest, for the first time, that small-scale LAES systems could be best operated at lower charging pressures and the technologies have a great potential for applications in local decentralized micro energy networks.

A novel dynamic simulation model for the thermo-economic analysis and optimisation of district heating systems

This paper presents a novel dynamic simulation tool able to assess and optimize the energy, environmental and economic performance of standard and innovative district heating/cooling systems. To this aim, several design and operating parameters (e.g.: weather conditions, heat selling price for users, national unitary price of electricity, etc.) are dynamically taken into account. The heating and cooling demands and loads of the buildings to be fed by the network working fluid are dynamically calculated. The system pipeline network is modelled through a suitable plug-flow approach. Fluid temperatures are calculated in each network node. The optimization of several system design and operating parameters is achieved for different objective functions. A suitable analysis is considered for selecting the most convenient urban zones for system application. The whole simulation model is implemented in a suitable computer code written in MatLab. By such tool useful design criteria and feasibility analyses can be obtained. To show the capabilities of the presented simulation tool, a novel case study, referred to a district heating system supplied by an existing thermoelectric power plant, was developed. The conducted analysis is based on system optimizations focused on the number of users, the selling heat/electricity prices and system geometric features. As for example, for minimizing the system payback to about 14.0 year, the optimal number of users and network length are 5 × 103 and 2.7 km, respectively. In this case the primary energy savings and the avoided carbon dioxide emissions are about 11.0 GWh/y and 16.1 ktCO2/y, respectively.

Energy, Environmental and Economic Performance of an Urban Community Hybrid Distributed Energy System

Energy systems face great challenges from both the supply and demand sides. Strong efforts have been devoted to investigate technological solutions aiming at overcoming the problems of fossil fuel depletion and the environmental issues due to the carbon emissions. Hybrid (activated by both renewables and fossil fuels) distributed energy systems can be considered a very effective and promising technology to replace traditional centralized energy systems. As a most peculiar characteristic, they reduce the use of fossil sources and transmission and distribution losses along the main power grid and contribute to electric peak shaving and partial-loads losses reduction. As a direct consequence, the transition from centralized towards hybrid decentralized energy systems leads to a new role for citizens, shifting from a passive energy consumer to active prosumers able to produce energy and distribute energy. Such a complex system needs to be carefully modelled to account for the energy interactions with prosumers, local microgrids and main grids. Thus, the aim of this paper is to investigate the performance of a hybrid distributed energy system serving an urban community and modelled within the framework of agent-based theory. The model is of general validity and estimates (i) the layout of the links along which electricity is distributed among agents in the local microgrid, (ii) electricity exchanged among agents and (iii) electricity exported to the main power grid or imported from it. A scenario analysis has been conducted at varying the distance of connection among prosumers, the installed capacity in the area and the usage of links. The distributed energy system has been compared to a centralized energy system in which the electricity requests of the urban community are satisfied by taking electricity from the main grid. The comparison analysis is carried out from an energy, environmental and economic point of view by evaluating the primary energy saving, avoided carbon dioxide emissions and the simple payback period indices.

Evaluating the economic return to public wind energy research and development in the United States

The U.S. government has invested in wind energy research since 1976. Building on a literature that has sought to develop and apply methods for retrospective benefit-to-cost evaluation for federal research programs, this study provides a quantitative analysis of the economic social return on these historical wind energy research investments. Importantly, the study applies multiple innovative methods and varies important input parameters to test the sensitivity of the results. The analysis considers public wind research expenditures and U.S. wind power deployment over the period 1976–2017, while also accounting for the full useful lifetime of wind projects built over this period. Assessed benefits include energy cost savings and health benefits due to reductions in air pollution. Overall, this analysis demonstrates sizable, positive economic returns on past wind energy research. Under the core analysis and with a 3% real discount rate, the net benefits from historical federal wind energy research investments are found to equal $31.4 billion, leading to an 18 to 1 benefit-to-cost ratio and an internal rate of return of 15.4%. Avoided carbon dioxide emissions are not valued in monetary terms, but are estimated at 1510 million metric tons. Alternative methods and input assumptions yield benefit-to-cost ratios that fall within a relatively narrow range from 7-to-1 to 21-to-1, reinforcing in broad terms the general finding of a sizable positive return on investment. Unsurprisingly, results are sensitive to the chosen discount rate, with higher discount rates leading to lower benefit-to-cost ratios, and lower discount rates yielding higher benefit-to-cost ratios.

Energy recovery through natural gas turboexpander and solar collectors: Modelling and thermoeconomic optimization

This paper presents a novel dynamic simulation model for the analysis of a hybrid turboexpander system coupled with innovative high-vacuum solar thermal collectors. The model is developed in MatLab and it is able to dynamically calculate the energy, exergy, environmental, and economic performances of the investigated system, by taking into account the hourly fluctuation of thermodynamic and economic parameters (e.g. electricity cost, natural gas temperature, and flow rates, etc.). In addition, a computer-based Design of Experiment (DoE) approach was implemented for achieving the optimal design of the proposed system.A suitable case study is presented in order to show the capabilities of the developed simulation tool. Conventional and non-conventional decompression systems located in the weather zone of Messina (South-Italy) are investigated with the aim of assessing the optimal system configuration. By means of the computer-based DoE analysis, the optimal values of several design parameters (such as the number of solar thermal collectors, the volume of the hot water storage tank, and the size of the water loop pump) are calculated. Numerical results show significant primary energy savings (1.36 TWh/year) and avoided carbon dioxide emissions (348 tCO2/year). From the economic point of view, a feasible simple pay-back period of 4.51 years is achieved. The destroyed exergy of the system components are calculated, obtaining the highest value for the turbo-expander, equal to 12.0 TWh/year.

Experimentation, modelling and applications of a novel low-cost air-based photovoltaic thermal collector prototype

This paper focuses on the design of an innovative low-cost air-based photovoltaic/thermal collector prototype, for which a novel dynamic simulation model is suitably developed in order to investigate its energy performance and economic feasibility under different operating conditions. The main novelty of this photovoltaic/thermal collector is the low-cost heat extraction system, implemented to reduce the photovoltaic cells temperature and to recover thermal energy. The prototype is tested under different operating conditions and the experimental data are used to validate the presented simulation model. The developed tool, implemented in a MatLab code, is used for analysing a suitable case study. The photovoltaic/thermal collectors are coupled to an air-to-air heat pump for space heating of a sample building. A novel performance map of such a coupled system is built with the aim of linking the heat pump coefficient of performance to both the outdoor air temperature and incident solar radiation. In addition, the system energy effectiveness and economic feasibility, compared to those of a traditional system, are assessed for the climate of 8 different European weather zones. Simulation results highlight the effectiveness of the proposed system, estimating primary energy savings (11.0–19.7 MWh/year corresponding to 52–80%), avoided carbon dioxide emissions (4.64–10.4 tCO2/year), and simple pay-back periods (3.2–4.8 years).

Evaluation of greenhouse gas emissions avoided by wind generation in the Brazilian energetic matrix: A retroactive analysis and future potential

In recent years, wind power generation has grown exponentially in Brazil. The Brazilian Ten-Year Plan for Energy Expansion predicts an installed wind capacity about of 22.4 GW by 2023. This study evaluates the potential of avoided carbon dioxide emissions due to wind power development in Brazil. First, the emissions avoided by using wind power until the year 2017 were analyzed retrospectively. The future growth projections of wind power in Brazil were then analyzed, using magnitude growth projection models, and the impact of avoided carbon dioxide emissions on the energy matrix was assessed, under various scenarios. The results show that the avoided emissions may correspond to 5.8% of the carbon dioxide emissions in 2030 for the entire Brazilian energy matrix.

Vinasse biogas for energy generation in Brazil: An assessment of economic feasibility, energy potential and avoided CO2 emissions

Energy recovery from waste is one of the strategies that can assist the expansion of renewable energy in Brazil. Among the various types of waste, vinasse, which is a residue that contains a high organic load, originates from the sugarcane industry, which is a very important industry for the Brazilian economy. Due to high levels of sugarcane harvesting in the country and the production of large amounts of ethanol, vinasse is produced at high levels in Brazil. In this context, this paper presents an energy analysis of the avoided carbon dioxide emissions and economic viability associated with the combustion of biogas produced by the anaerobic digestion of the vinasse that results from the use of sugar cane planted in Brazil. Based on the literature review, data related to the process of biogas production from anaerobic digestion of the vinasse were collected and used for the calculation of the energy potential associated. The results show that to achieve economic viability for the use of this waste for energy, the following plantation areas would be required, considering their processed sugarcane equivalents: 14,580 ha (if considering the processing of sugarcane in attached plants), and 6000 ha (if considering the processing of sugarcane in autonomous plants). The total energy potential of this use may reach 3.26 TWhe/y, which represents 0.52% of all domestic energy consumption in 2014. The potential to avoid emissions from the same use could reach 1.9 Mt CO2/y, which is approximately 2.1% of the emissions for the whole industry in Brazil in 2014. These results demonstrate the environmental and energy benefits that can be obtained via power generation from biogas produced by the anaerobic digestion of vinasse and highlight the need to include the use of such residue for energy in expansion plans for the Brazilian energy matrix.

Raum und Verkehr – ein Feld komplexer Wirkungsbeziehungen. Können Interventionen in die gebaute Umwelt klimawirksame Verkehrsemissionen wirklich senken?

The image of an integrated urban and transport planning is linked to the hope for a turnaround in the mutual interrelations between the built environment and transport that have actually induced more transport to date. Planning interventions in location structures and transport supply should therefore effectively contribute to reduce transport-related climate emissions. However, the targeted design of mixed land-use and compact location structures on the local and regional level is superimposed by societal and spatial trends that make large-scale mobility politically desirable or necessary. Against this background, the hopes mentioned before appear widely overstated. In this paper we put well-known empirical findings in new contexts of interpretation, and we point to other – from our perspective, more important – drivers of transport trends that are beyond the scope of integrated urban and transport planning. We conclude that integrated urban and transport planning should not be justified by avoiding carbon dioxide emissions, but remains reasonable for other reasons.

An assessment of two environmental and economic benefits of ‘Cash for Clunkers’

This research aims to provide a more comprehensive, life cycle accounting of two categories of environmental and economic benefits associated with the $3billion US “Cash for Clunkers” vehicle scrappage program. First, using a life cycle emissions methodology developed in Lenski et al. (2010), we find that about 29,000metric tons of criteria pollutant emissions were avoided, for a benefit of about $23million; avoided carbon dioxide emissions, by comparison, provided a benefit worth $90million. Second, we compare the market value of scrapped vehicles to the rebates provided, calculating the consumer surplus or “gift” to participants to be up to $2billion (about $2000 to $3000 per vehicle). This is significantly more than offered in previous vehicle scrappage programs, and suggests opportunities to get more environmental and economic “bang for the buck.” Finally, these two categories of benefits are found to be heavily concentrated geographically around urban centers. About 2% of US counties (50 counties) received 50% and 30% of the aggregate benefits from avoided criteria pollutant emissions and consumer surplus from the rebates, respectively.

Biomasfor: an open-source holistic model for the assessment of sustainable forest bioenergy

This paper presents an open-source spatial analysis model (Biomasfor) that can quantify the availability of forest wood-energy biomass in the light of ecological and economic sustainability. Several multi-functionality parameters were evaluated to highlight the potential impact of biomass extraction on different forest functions. The multistep approach used and the model’s internal structure permit the use of the model with highly differentiated input datasets. The introduction of biomass demand evaluation allows the quantification of the wood-energy supply/demand. The analysis is focused on the province of Trento (northeastern Italian Alps). The results are based on a scenario evaluation characterised by several degrees of biomass extraction and by a sensitivity analysis of biomass price, as well as on a typology of mechanisation. The model outputs define a reduction in biomass availability with the introduction of technical, economic and multi-functionality parameters. Furthermore, considerations on territorial characteristics outline the importance of woodchip production as a means of avoiding carbon dioxide emissions and achieving low-impact reductions of the risk of fires. The model appears to be an effective tool in bioenergy planning, particularly for the following purposes: (i) the estimation of the biomass supply/demand ratio under different scenarios; (ii) a preliminary analysis of biomass quality; and (iii) the influence of local environmental, economic and logistical characteristics on biomass production.

Avoiding mangrove destruction by avoiding carbon dioxide emissions

Tens of millions of tons of CO2 emissions from mangrove deforestation may be avoided each year at an average cost of less than $10 per ton CO2, conclude Siikamaki et al. in their study (1) in PNAS. Avoiding CO2 emission from mangroves would have the beneficial side effect of protecting biodiversity. With careful selection of areas to be protected, increased protection of biodiversity could be obtained at relatively little additional cost. However, a major challenge to mangrove protection is the availability of good governance. It is one thing to pay for mangrove protection and another thing entirely for those mangroves to be protected in practice.

Sustainable Development through Policy Integration in Latin America: A comparative approach

‘Greening’ the economy requires the creation of new markets in ecological goods and services, and there exist today many different payment mechanisms that differ significantly in terms of their distributional outcomes. Laura Rival compares three case studies: a forest conservation scheme involving payments for ecosystem services (PES) in the state of Amazonas, Brazil; Ecuador's government-led PES aimed at avoiding carbon dioxide emissions by keeping oil in the ground; and a ten-year grassroots project in the state of Minas Geiras, Brazil, which combats social exclusion with the dissemination of agroecological practices among poor small-scale farmers to provide viable economic alternatives to out-migration. The three programmes result from the efforts of social actors who have sought to create innovative sustainability-enhancing institutions in order to achieve environmental and social policy integration.

A Sustainable Nuclear Fuel Cycle Based on Laser Inertial Fusion Energy

The National Ignition Facility (NIF), a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, will soon be completed at the Lawrence Livermore National Laboratory. Experiments designed to accomplish the NIF’s goal will commence in 2010, using laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 35 MJ are expected soon thereafter. We propose that a laser system capable of generating fusion yields of 35 to 75 MJ at 10 to 15 Hz (i.e., ≈ 350- to 1000-MW fusion and ≈ 1.3 to 3.6 x 1020 n/s), coupled to a compact subcritical fission blanket, could be used to generate several GW of thermal power (GWth) while avoiding carbon dioxide emissions, mitigating nuclear proliferation concerns and minimizing the concerns associated with nuclear safety and long-term nuclear waste disposition. This Laser Inertial Fusion Energy (LIFE) based system is a logical extension of the NIF laser and the yields expected from the early ignition experiments on NIF. The LIFE concept is a once-through, self-contained closed fuel cycle and would have the following characteristics: (1) eliminate the need for uranium enrichment; (2) utilize over 90% of the energy content of the nuclear fuel; (3) eliminate the need for spent fuel chemical separation facilities; (4) maintain the fission blanket subcritical at all times (keff <0.90); and (5) minimize future requirements for deep underground geological waste repositories and minimize actinide content in the end-of-life nuclear waste below the (the lowest). Options to burn natural or depleted U, Th, U/Th mixtures, Spent Nuclear Fuel (SNF) without chemical separations of weapons-attractive actinide streams, and excess weapons Pu or highly enriched U (HEU) are possible and under consideration. Because the fission blanket is always subcritical and decay heat removal is possible via passive mechanisms, the technology is inherently safe. Many technical challenges must be met, but a LIFE solution could provide a sustainable path for worldwide growth of nuclear power for electricity production and hydrogen generation.