Total Net Emissions Research Articles

Identifying the main crops and key factors determining the carbon footprint of crop production in China, 2001–2018

Agriculture affects climate change and contributes directly and indirectly to greenhouse gas (GHG) emissions. However, no reports have fully quantified the GHG emissions from different crop systems in China. In this study, the carbon emission and carbon sequestration inventories and the carbon footprint (CF) of 16 major crop systems in China from 2001 to 2018 were analyzed with a cradle-to-farm gate life cycle analysis approach for the first time. The results showed that the largest farm CF and product CF were vegetables (11.9 t CO2 eq ha−1) and tea (4.6 t CO2 eq t−1), respectively. From the perspective of crop emissions and processes, the main crop systems influencing the national total net carbon emissions (NTCE) from crop production are rice, maize, wheat, fruits and vegetables, accounting for 87.3–90.4%; the key emission processes for NTCE are fertilization and irrigation, accounting for 73.7–76.8%. The NTCE has increased by 410.4 Mt CO2 eq from 2001 to 2018, of which maize, fruits and vegetables were the main crops that explained 99.0%, while fertilization and irrigation were the key factors and explained 91.9% of these increases. Scenario analysis indicated that increasing the straw return rate and partially replacing chemical fertilizers with manure have a minimal impact on NTCE. In contrast, reducing the loss of reactive nitrogen is the most effective single strategy to alleviate agricultural GHG emissions in the future. Our results will provide a fresh perspective for the development of more effective GHG emission reduction strategies for agricultural green development.

Developing a spatially explicit modelling and evaluation framework for integrated carbon sequestration and biodiversity conservation: Application in southern Finland

The challenges posed by climate change and biodiversity loss are deeply interconnected. Successful co-managing of these tangled drivers requires innovative methods that can prioritize and target management actions against multiple criteria, while also enabling cost-effective land use planning and impact scenario assessment. This paper synthesises the development and application of an integrated multidisciplinary modelling and evaluation framework for carbon and biodiversity in forest systems. By analysing and spatio-temporally modelling carbon processes and biodiversity elements, we determine an optimal solution for their co-management in the study landscape. We also describe how advanced Earth Observation measurements can be used to enhance mapping and monitoring of biodiversity and ecosystem processes. The scenarios used for the dynamic models were based on official Finnish policy goals for forest management and climate change mitigation. The development and testing of the system were executed in a large region in southern Finland (Kokemäenjoki basin, 27,024 km2) containing highly instrumented LTER (Long-Term Ecosystem Research) stations; these LTER data sources were complemented by fieldwork, remote sensing and national data bases. In the study area, estimated total net emissions were currently 4.2 TgCO2eq a−1, but modelling of forestry measures and anthropogenic emission reductions demonstrated that it would be possible to achieve the stated policy goal of carbon neutrality by low forest harvest intensity. We show how this policy-relevant information can be further utilized for optimal allocation of set-aside forest areas for nature conservation, which would significantly contribute to preserving both biodiversity and carbon values in the region. Biodiversity gain in the area could be increased without a loss of carbon-related benefits.

Planular-vertical distribution and pollution characteristics of cropland soil Hg and the estimated soil–air exchange fluxes of gaseous Hg over croplands in northern China

As an important reservoir of mercury (Hg), cropland play an important role in the Hg cycle, but it was poorly understood in northern China. The major objectives of this study are to ascertain the distribution characteristics of soil Hg and then assess its pollution level and potential risk, and further evaluate the role of cropland in northern China in the global soil–air exchange of Hg based on the simulation experiments and regional survey. The average Hg concentration in surface soils of the 30 sites in northern China was 116.1 ± 135.8 ng g−1, which was significantly higher than background values. The surface soils show a significant spatial heterogeneity in Hg concentration, and the Hg levels near provincial capitals were higher than those at corresponding prefecture-level cities, revealing that the soil Hg levels were closely associated with the local industrial and economic development. Profile data shows that topsoil Hg concentration was significantly higher than those in deeper layers at most of sites, indicating the more serious pollution situation in recent years. Generally, the higher the surface soil Hg concentration, the more obvious this top-bottom decreasing trend. The planular-vertical distribution patterns of TOM share similar trends as those of soil Hg concentration, indicating Hg concentration was closely associated with TOM content. Statistical results show that the mean CF, Eri, and Igeo values were 4.0 ± 5.0, 161 ± 198, 0.76 ± 1.34, respectively, and more than two thirds of sampling sites were moderately and considerably polluted. The mean annual accumulative flux of Hg in the northern China was 20.9 ± 43.8 μg m−2 yr−1, and the total net emission fluxes of Hg from the croplands in six provinces were 8.37 ton yr−1. This indicates that although the cropland occasionally acts as a sink, it represents an important natural source of atmospheric Hg as a whole.

Carbon Emissions and Sequestration Due to Land Conversion In The Padang Watershed, North Sumatera (incomplete)

Land conversion activities cause changes in the area of vegetation and carbon storage in the air. These changes can lead to emissions (reduction of carbon stocks) or sequestration (addition of carbon stocks). This study aims to calculate stored carbon in the Padang watershed in 2009 and 2019 and to determine the dynamics of emissions and carbon sequestration due to land conversion in the Padang watershed, North Sumatra Province from 2009 to 2019. The method used in this research is spatial data processing using software Arc Gis. Processing, interpretation and classification of land cover are obtained from land cover data for 2009 and 2019 from the Ministry of Environment and Forestry. Furthermore, the analysis of emissions and carbon sequestration in the Padang watershed was carried out using the REDD Abacus SP software. The results showed that the total carbon stored in 2009 was 5,168,464.09 tons. Meanwhile, the total carbon stored in 2019 was 5,150,784.81 tons. This means that there is a decrease or carbon emission during the 2009-2019 period of 17,679.28 tons. The total net emissions and sequestration that occurred in the Padang watershed due to changes in land use from 2009 - 2019 were 22,851,751.43 tonnes CO2-eq / year and 3,100,199.00 tonnes CO2-eq / year, respectively. Efforts to reduce emissions include planting and developing forests and community-based forest management.

Mitigating Curtailment and Carbon Emissions through Load Migration between Data Centers

Summary As the share of variable renewable energy (VRE) grows in the electric grid, so does the risk of curtailment. While energy storage and hydrogen production have been proposed as solutions to the curtailment problem, they often pose technological and economic challenges. Here, we analyze the potential of data center load migration for mitigating curtailment and greenhouse gas (GHG) emissions. Using historical hourly electricity generation, curtailment, and typical data center server utilization data, we simulate the effect of migrating data center workloads from the fossil-fuel-heavy PJM to the renewable-heavy CAISO. The results show that load migration within the existing data center capacity during the curtailment hours in CAISO has the potential to reduce 113–239 KtCO2e per year of GHG emissions and absorb up to 62% of the total curtailment with negative abatement costs in 2019. Our study demonstrates the overlooked role that data centers can play for VRE integration and GHG emissions mitigation.

Economic assessment of high renewable energy penetration scenario in 2030 on the interconnected Irish power system

The Irish Government has set very ambitious targets for the penetration of renewables into the Integrated Single Electricity Market (I-SEM), aiming for 40% electricity generation by 2020. This renewable share is expected to increase further in the I-SEM, British Electricity Trading and Transmission Arrangements (BETTA) and French electricity market by 2030. This research presents a case study testing the various levels of renewable energy integration in the three regions and assessed the economic impacts and benefits at elevated renewables penetration. To measure the economic and environmental sustainability, four indicators, i.e. annual wholesale system marginal prices (SMPs), total generation costs, total generation net revenues and CO2 emissions were selected. The results showed that the I-SEM 2030 wholesale electricity market pricing would range from €101.26/MWh to €50.77/MWh with the increase of renewable integration from 44% to 75%. In the BETTA and French market, the addition of the renewable generation contributes to reductions to SMPs by 51.10% and 51.61% at most, respectively. It was also found that these enhanced renewable targets for 2030 could lower consumers’ electricity bills and expand the total social welfare.

Quantifying the effects of general waste reduction on greenhouse-gas emissions at public facilities

ABSTRACTGlobal municipal solid waste (MSW) amounts to approximately 1.3 billion tons per year and is expected to increase to approximately 2.2 billion tons per year by 2025. The greenhouse gas (GHG) emissions from landfills contribute to global climate change. Emissions from this sector contribute around 3% of total net emissions in Australia. Although responsible for a minor portion of Australia’s emissions, the sector provides the opportunity for low-cost sources of abatement. This research study aimed to identify new opportunities for reducing GHG emissions from the landfill waste stream in public facilities in Blacktown City in New South Wales, Australia. For this purpose, two public facilities of different types were selected, a library and an aquatic center. The results of the study show that removing organic food waste from the landfill stream at 10 public facilities of the Council could reduce GHG emissions compared with landfilling the food waste by about 0.805 tCO2e/year. However, separately transporting that waste would emit 7.13 tCO2e/year. Therefore, the separated food waste would need to be processed on-site, for example, through worm farms. Removing coffee cups from the landfill waste stream could reduce the associated landfill GHG emissions by around 0.275 tCO2e/y for the 10 public facilities. The study also recommended separating plastic bags from the landfill waste stream of these facilities to reduce 1.10 tonnes of plastic bags from landfill each year.Implications: Potential opportunities for general waste reduction and GHG emission mitigation in public facilities has been studied in this paper. Removing coffee cups and organics food from the waste stream are the main potential opportunities for reducing general waste with possible GHG emission reduction of 0.275 tCO2e/y and 0.161 tCO2/y respectively for 10 public facilities. Removing plastic bags from the waste stream would offer another solution for waste reduction by jointing with the large program running in Australia and creating a collection point for them with 1.1 tonne/y mitigation in general waste at 10 studied public facilities.

Economic and Environmental Optimization of the Forest Supply Chain for Timber and Bioenergy Production from Beetle-Killed Forests in Northern Colorado

Harvesting mountain pine beetle-infested forest stands in the northern Colorado Rocky Mountains provides an opportunity to utilize otherwise wasted resources, generate net revenues, and minimize greenhouse gas (GHG) emissions. Timber and bioenergy production are commonly managed separately, and their integration is seldom considered. Yet, degraded wood and logging residues can provide a feedstock for bioenergy, while the sound wood from beetle-killed stands can still be used for traditional timber products. In addition, beneficial greenhouse gas emission (GHG) savings are often realized only by compromising net revenues during salvage harvest where beetle-killed wood has a relatively low market value and high harvesting cost. In this study we compared Sequential and Integrated decision-making scenarios for managing the supply chain from beetle-killed forest salvage operations. In the Sequential scenario, timber and bioenergy production was managed sequentially in two separate processes, where salvage harvest was conducted without considering influences on or from bioenergy production. Biomass availability was assessed next as an outcome from timber production managed to produce bioenergy products. In the Integrated scenario, timber and bioenergy production were managed jointly, where collective decisions were made regarding tree salvage harvest, residue treatment, and bioenergy product selection and production. We applied a multi-objective optimization approach to integrate the economic and environmental objectives of producing timber and bioenergy, and measured results by total net revenues and total net GHG emission savings, respectively. The optimization model results show that distinctively different decisions are made in selecting the harvesting system and residue treatment under the two scenarios. When the optimization is fully economic-oriented, 49.6% more forest areas are harvested under the Integrated scenario than the Sequential scenario, generating 12.3% more net revenues and 50.5% more net GHG emission savings. Comparison of modelled Pareto fronts also indicate the Integrated decision scenario provides more efficient trade-offs between the two objectives and performs better than the Sequential scenario in both objectives.

CO2 emissions embodied in trade: Evidence for Hong Kong SAR

Abstract Cities play an important role in carbon emissions reduction and climate change mitigation. In this study, we examine the CO2 emissions embodied in the imports and exports of the Hong Kong special administrative region (SAR) from 1990 to 2015 using the emissions embodied in bilateral trade (EEBT) method. The results show that Hong Kong SAR has been a net CO2 importer and Mainland China plays a dominating role in the embodied CO2 emissions of Hong Kong SAR. The sectors with high imported CO2 emissions are mainly the energy sectors, such as electricity, heat, gas and water production and supply. Population density, GDP per capita, and trade openness have significantly positive effects on net CO2 emissions increases in Hong Kong SAR, with population density taking the leading role. Population density increases by 1%, total net CO2 emissions increase by 4%. Population slowdown scenario simulation results show that net CO2 emissions of Hong Kong SAR could be reduced by 5.5%. Whereas, net CO2 emissions of Hong Kong SAR could increase by 8.7% in the accelerated economic development scenario. Therefore, to reduce CO2 emissions, Hong Kong SAR need control its population, develop the circular economy, and promote green lifestyle and consumption patterns.

Transport sector carbon linkages of EU's top seven emitters

This study estimates total, inland, water and air transport net forward, backward and internal carbon linkages of EU's top seven emitters from 1995 to 2011. Moreover, it also reports direct emissions and intensities. Direct emissions of the seven for all four sectors mostly increased with varying proportions, while direct intensities followed a downward trend. Total, inland, water and air net backward emissions were reasonably stable excluding Germany who's total and inland net backward emissions sharply declined during 2000 while water and air emissions increased sharply. Although some nations witnessed a decrease, overall total, inland and air transport net forward emissions increased. While water transport net forward emissions had huge fluxes in the middle, stabilised towards the end. Total, inland, and air transport internal emissions for most of the nations increased over time. However, water transport internal emissions except for the UK were reasonably stable. ‘Electricity, Gas and Water Supply’ was the top source of German; Polish; Italian; British and Dutch net backward emissions. France and Spain's highest carbon imports were from ‘Coke, Refined Petroleum and Nuclear Fuel.’ Highest destinations of net forward emissions keep changing over time. The paper also discusses policy implications.

Multi-objective optimization framework of a photovoltaic-diesel generator hybrid energy system considering operating reserve

This paper presents a new multi-objective optimization framework to design a photovoltaic/diesel generator (PV/DG) power generation system for an isolated community in the presence of operating reserve. Operating reserve is the safety margin to ensure the system reliability despite variability in load and PV power supply. For this aim, three objectives, namely, total net present cost (TNPC), CO2 emission and loss of power supply probability (LPSP) have been considered to have a cost-effective, clean and reliable power generation system. In order to solve the optimization problem, multi-objective version of a recently developed meta-heuristic method, crow search algorithm (CSA), has been proposed. To validate the results obtained by multi-objective CSA (MO-CSA), the sizing problem is also solved by multi-objective particle swarm optimization (MOPSO). Simulated results show that by considering operating reserve, the size (correspondingly the cost) of the system increases significantly. Moreover, in comparison with MOPSO, the Pareto front obtained by MO-CSA is well-distributed and widely spread.

Optimal Design of Ship’s Hybrid Power System for Efficient Energy

The International Maritime Organization regulations on the reduction of greenhouse gas emissions (GHGs) from ships require efficient dealing with this complex techno-economic and highly political problem through joint efforts of all major stakeholders from the shipbuilding industry and ship operations. The key problems of any research in the field of renewable energy, including power generation, storage, transformation and distribution, and the issues associated with limited power generation for specific loads, are the same issues that are experienced in the implementation of electric distribution technologies onboard ships. This paper analyses the effects of efficient shipping using the solar panel system and batteries to ensure continuous power supply, regardless of the weather conditions. The logistics chain of this control architecture is modelled by Colored Petri Nets. The economic analysis examines the annual costs of fuel consumption, the initial capital cost, total net cost and CO2 emissions.

Contribution of volatile organic compound fluxes to the ecosystem carbon budget of a poplar short-rotation plantation.

Biogenic volatile organic compounds (BVOCs) are major precursors of both ozone and secondary organic aerosols (SOA) in the troposphere and represent a non‐negligible portion of the carbon fixed by primary producers, but long‐term ecosystem‐scale measurements of their exchanges with the atmosphere are lacking. In this study, the fluxes of 46 ions corresponding to 36 BVOCs were continuously monitored along with the exchanges of mass (carbon dioxide and water vapor) and energy (sensible and latent heat) for an entire year in a poplar (Populus) short‐rotation crop (SRC), using the eddy covariance methodology. BVOC emissions mainly consisted of isoprene, acetic acid, and methanol. Total net BVOC emissions were 19.20 kg C ha−1 yr−1, which represented 0.63% of the net ecosystem exchange (NEE), resulting from −23.59 Mg C ha−1 yr−1 fixed as CO 2 and 20.55 Mg C ha−1 yr−1 respired as CO 2 from the ecosystem. Isoprene emissions represented 0.293% of NEE, being emitted at a ratio of 1 : 1709 mol isoprene per mol of CO 2 fixed. Based on annual ecosystem‐scale measurements, this study quantified for the first time that BVOC carbon emissions were lower than previously estimated in other studies (0.5–2% of NEE) on poplar trees. Furthermore, the seasonal and diurnal emission patterns of isoprene, methanol, and other BVOCs provided a better interpretation of the relationships with ecosystem CO 2 and water vapor fluxes, with air temperature, vapor pressure deficit, and photosynthetic photon flux density.

Effects of land-use changes on city-level net carbon emissions based on a coupled model

ABSTRACTShanghai is a rapidly developing metropolitan area and concentrations of greenhouse gases are high. Carbon-sink and carbon-source estimation are of significance for carbon-emissions reduction. This paper describes the effect of land-use change on the variation of urban net carbon emissions, and discusses the probable spatiotemporal impact on the dynamics of carbon emissions using coupled SD (system dynamics) and CLUE-S (the conversion of land use and its effects at small regional extent) models. The results show that: increase in construction land and decrease in agricultural land have positive and negative effects on land-use emissions, respectively; under the Basic Policy scenario, total net carbon emissions will continue to increase, from 39.43 to 80.28 Mt, with a decreasing growth rate; the increase/decrease in carbon emissions occurs mainly in urban–rural fringes and source water areas; the conversion of all land-use types to construction land is the main carbon source, while the conversion of agricultural land to ecological land is the main carbon sink. Two land-use strategies are suggested for the mitigation of carbon emissions in Shanghai. It is also shown that the coupled models are suitable for simulating and predicting spatiotemporal city-level net carbon emissions and are applicable to similar cities in developing countries.

Effects of biochar and maize straw on the short-term carbon and nitrogen dynamics in a cultivated silty loam in China

Application of maize straw and biochar can potentially improve soil fertility and sequester carbon (C) in the soil, but little information is available about the effects of maize straw and biochar on the mineralization of soil C and nitrogen (N). We conducted a laboratory incubation experiment with five treatments of a cultivated silty loam, biochar produced from maize straw and/or maize straw: soil only (control), soil + 1% maize straw (S), soil + 4% biochar (B1), soil + 4% biochar + 1% maize straw (B1S), and soil + 8% biochar + 1% maize straw (B2S). CO2 emissions, soil organic C, dissolved organic C, easily oxidized C, total N, mineral N, net N mineralization, and microbial biomass C and N of three replicates were measured periodically during the 60-day incubation using destructive sampling method. C mineralization was highest in treatment S, followed by B2S, B1S, the control, and B1. Total net CO2 emissions suggested that negative or positive priming effect may occur between the biochar and straw according to the biochar addition rate, and biochar mineralization was minimal. By day 35, maize straw, irrespective of the rate of biochar addition, significantly increased microbial biomass C and N but decreased dissolved organic N. Biochar alone, however, had no significant effect on either microbial biomass C or N but decreased dissolved organic N. Mixing the soil with biochar and/or straw significantly increased soil organic C, easily oxidized C and total N contents, and decreased dissolved organic N content. Dissolved organic C contents showed mixed results. Notably, N was immobilized in soil mixed with straw and/or biochar, but the effect was stronger for soil mixed with straw, which may cause N deficiency for plant growth. The application of biochar and maize straw can thus affect soil C and N cycles, and the appropriate proportion of biochar and maize straw need further studies to increase C sequestration.

A Worldwide Assessment of Greenhouse Gas Emissions from Drained Organic Soils

Despite the importance of organic soils, including peatlands, in the global carbon cycle, detailed information on regional and global emissions is scarce. This is due to the difficulty to map, measure, and assess the complex dynamics of land, soil, and water interactions needed to assess the human-driven degradation of organic soils. We produced a new methodology for the comprehensive assessment of drained organic soils in agriculture and the estimation of the associated greenhouse gas emissions. Results indicated that over 25 million hectares of organic soils were drained worldwide for agriculture use, of which about 60% were in boreal and temperate cool areas, 34% in tropical areas, and 5% in warm temperate areas. Total emissions from the drainage were globally significant, totaling nearly one billion tonnes CO2eq annually. Of this, the CO2 component, about 780 million tonnes, represented more than one-fourth of total net CO2 emissions from agriculture, forestry, and land use. The bulk of these emissions came from a few tropical countries in Southeast Asia, and was linked to land clearing and drainage for crop cultivation. Geospatial data relative to this work were disseminated via the FAO geospatial server GeoNetwork, while the national aggregated statistics were disseminated via the FAOSTAT database.

Nitrate and flooding induce N2O emissions from soybean nodules

Nitrous oxide (N2O) is one of the three main biogenic greenhouse gases (GHGs) and agriculture represents close to 30 % of the total N2O net emissions. In agricultural soils, N2O is emitted by two main microbial processes, nitrification and denitrification, both of which can convert synthetic nitrogen fertilizer into N2O. Legume-rhizobia symbiosis could be an effective and environmental-friendly alternative to nitrogen fertilization and hence, to mitigate soil N2O emissions. However, legume crops also contribute to N2O emissions. A better understanding of the environmental factors involved in the emission of N2O from nodules would be instrumental for mitigating the release of this GHG gas. In this work, in vivo N2O emissions from nodulated soybean roots in response to nitrate (0, 1, 2 and 4 mM) and flooding have been measured. To investigate the contribution of rhizobial denitrification in N2O emission from nodules, plants were inoculated with B. japonicum USDA110 and napA and nosZ denitrification mutants. The results showed that nitrate was essential for N2O emissions and its concentration enhanced N2O fluxes showing a statistical linear correlation, being the highest N2O fluxes obtained with 4 mM nitrate. When inoculated plants grown with 4 mM nitrate were subjected to flooding, a 150- and 830-fold induction of N2O emission rates from USDA110 and nosZ nodulated roots, respectively, was observed compared to non-flooded plants, especially during long-term flooding. Under these conditions, N2O emissions from detached nodules produced by the napA mutant were significantly lower (p < 0.05) than those produced by the wild-type strain (382 versus 1120 nmol N2O h−1 g−1 NFW, respectively). In contrast, nodules from plants inoculated with the nosZ mutant accumulated statistically higher levels of N2O compared to wild-type nodules (2522 versus nmol 1120 N2O h−1 g−1 NFW, p < 0.05). These results demonstrate that flooding is an important environmental factor for N2O emissions from soybean nodules and that B. japonicum denitrification is involved in such emission.

Methane Emissions from United States Natural Gas Gathering and Processing.

New facility-level methane (CH4) emissions measurements obtained from 114 natural gas gathering facilities and 16 processing plants in 13 U.S. states were combined with facility counts obtained from state and national databases in a Monte Carlo simulation to estimate CH4 emissions from U.S. natural gas gathering and processing operations. Total annual CH4 emissions of 2421 (+245/-237) Gg were estimated for all U.S. gathering and processing operations, which represents a CH4 loss rate of 0.47% (±0.05%) when normalized by 2012 CH4 production. Over 90% of those emissions were attributed to normal operation of gathering facilities (1697 +189/-185 Gg) and processing plants (506 +55/-52 Gg), with the balance attributed to gathering pipelines and processing plant routine maintenance and upsets. The median CH4 emissions estimate for processing plants is a factor of 1.7 lower than the 2012 EPA Greenhouse Gas Inventory (GHGI) estimate, with the difference due largely to fewer reciprocating compressors, and a factor of 3.0 higher than that reported under the EPA Greenhouse Gas Reporting Program. Since gathering operations are currently embedded within the production segment of the EPA GHGI, direct comparison to our results is complicated. However, the study results suggest that CH4 emissions from gathering are substantially higher than the current EPA GHGI estimate and are equivalent to 30% of the total net CH4 emissions in the natural gas systems GHGI. Because CH4 emissions from most gathering facilities are not reported under the current rule and not all source categories are reported for processing plants, the total CH4 emissions from gathering and processing reported under the EPA GHGRP (180 Gg) represents only 14% of that tabulated in the EPA GHGI and 7% of that predicted from this study.

Optimal design of hybrid renewable energy systems in buildings with low to high renewable energy ratio

We develop a simulation-based meta-heuristic approach that determines the optimal size of a hybrid renewable energy system for residential buildings. This multi-objective optimization problem requires the advancement of a dynamic multi-objective particle swarm optimization algorithm that maximizes the renewable energy ratio of buildings and minimizes total net present cost and CO2 emission for required system changes. Three proven performance metrics evaluate the quality of the Pareto front generated by the proposed approach. The obtained results are compared against two reported multi-objective optimization algorithms in the related literature. Finally, an existing residential apartment located in a cold Canadian climate provides a test case to apply the proposed model and optimally size a hybrid renewable energy system. In this test application, the model investigates the potential use of a heat pump, a biomass boiler, wind turbines, solar heat collectors, photovoltaic panels, and a heat storage tank to produce renewable energy for the building. Furthermore, the utilization of plug-in electric vehicles for transportation reduces gasoline use where all power is generated by the building, and the utility provides the means to match intermittent renewable generation from solar and wind to the building electrical loads. Model results show that under the chosen meteorological conditions and building parameters a wind turbine, and plug-in electric vehicle technologies are consistently the optimal option to achieve a target renewable energy ratio. In particular, the optimization result shows that the renewable energy ratio can achieve near 100% by installing a 73 kW wind turbine, a 200 kW biomass boiler, and using plug-in electric vehicles. This option has a net present cost of C$705,180 and results in total CO2 emission of 2.4 ton/year. Finally, a sensitivity analysis is performed to investigate the impact of economic constants on net present cost of the obtained non-dominated solutions.

Carbon benefits of wolfberry plantation on secondary saline land in Jingtai oasis, Gansu – A case study on application of the CBP model

The largest global source of anthropogenic CO2 emissions comes from the burning of fossil fuel and approximately 30% of total net emissions come from land use and land use change. Forestation and reforestation are regarded worldwide as effective options of sequestering carbon to mitigate climate change with relatively low costs compared with industrial greenhouse gas (GHG) emission reduction efforts. Cash trees with a steady augmentation in size are recognized as a multiple-beneficial solution to climate change in China. The reporting of C changes and GHG emissions for sustainable land management (SLM) practices such as afforestation is required for a variety of reasons, such as devising land management options and making policy. The Carbon Benefit Project (CBP) Simple Assessment Tool was employed to estimate changes in soil organic carbon (SOC) stocks and GHG emissions for wolfberry (Lycium barbarum L.) planting on secondary salinized land over a 10 year period (2004–2014) in the Jingtai oasis in Gansu with salinized barren land as baseline scenario. Results show that wolfberry plantation, an intensively managed ecosystem, served as a carbon sink with a large potential for climate change mitigation, a restorative practice for saline land and income stream generator for farmers in soil salinized regions in Gansu province. However, an increase in wolfberry production, driven by economic demands, would bring environmental pressures associated with the use of N fertilizer and irrigation. With an understanding of all of the components of an ecosystem and their interconnections using the Drivers-Pressures-State-Impact-Response (DPSIR) framework there comes a need for strategies to respond to them such as capacity building, judicious irrigation and institutional strengthening. Cost benefit analysis (CBA) suggests that wolfberry cultivation was economically profitable and socially beneficial and thus well-accepted locally in the context of carbon sequestration. This study has important implications for Gansu as it helps to understand the role cash trees can play in carbon emission reductions. Such information is necessary in devising management options for sustainable land management (SLM).