Balance Of Greenhouse Gas Emissions Research Articles

Carbon Footprint Assessment: Case Studies for Hemp-Based Eco-Concrete Masonry Blocks

In recent times, climate change has become more evident than ever, and measures to slow down its negative effects are imperative for the future of the world. The scientific and economic communities of countries around the world, under the force of international climate agreements, are identifying solutions to reduce greenhouse gas (GHG) emissions by establishing appropriate measures and developing new strategies. In the context of these objectives, the effort to identify eco-sustainable practices for the construction industry is growing significantly. Recently, much research has focused on solutions for producing green building materials, as well as applying circular economy principles to achieve a balance between anthropogenic emissions and absorptions by greenhouse gas absorbers. The relevant indicators of the level of achievement of these major objectives can be identified, already from the construction design phase, with the help of Life Cycle Assessment (LCA) analysis. This paper presents a series of environmental impact analyses for an eco-friendly solution of precast concrete masonry blocks. Ecological concrete is manufactured with aggregates from biological waste resulting from hemp crops. Impact assessments were performed with the SimaPro 9.5 software application. Research has shown that in the production chain, which includes the materials resulting from the recycling and reuse of hemp concrete blocks, the contribution to the effort to achieve neutrality in terms of global warming is significant. The Cradle-to-Cradle scenario revealed that the recycling of hemp concrete masonry blocks at the end of their use, for a functional unit of 0.5 m3, has a GHG emission of 33.5228 [kg CO2-eq] and CO2 uptakes can reach the negative value of −53.8397 [kg CO2-eq]. Thus, the balance of GHG emissions is negative, with values of approximately −20.3169 [kg CO2-eq]. The LCA analyses also reflect a decreased damage to human health, natural resources, and biodiversity when hemp concrete is used for masonry blocks.

Going Green: The Green House Gas Emissions Balance for Selected Climate Smart Agriculture Practices

Going Green: The Green House Gas Emissions Balance for Selected Climate Smart Agriculture Practices

Forecast Assessment of Achieving Carbon Neutrality in the Russian Federation in View of Changes in Forestry and Land Use

The article analyzes the problem of reducing greenhouse gas emissions in the Russian Federation by 2030 to 70% relative to the 1990 level. It is shown that the Russian Federation is one of the world’s leaders in reducing greenhouse gas emissions, while the goals set forth by the European Union to achieve carbon neutrality are currently not confirmed by the availability of resources and actually taken efforts. The Russian and foreign approaches to the formation of input data for calculating and accounting the absorption capacity of forestry are analyzed; the results of carbon dioxide absorption estimates performed using different techniques are given, and the balance of greenhouse gas emissions in the Russian Federation is evaluated taking into account land use, and changes in the land use and forestry. The results of the assessment of carbon dioxide absorption performed on the basis of the methodology developed by the Center for Ecology and Forest Productivity of the Russian Academy of Sciences are several times lower than those obtained using other techniques. The absorption capacity of Russian forests calculated by an international group of scientists exceeds the emission of greenhouse gases in the Russian Federation. According to calculations made by the Russian Research Institute for Silviculture and Mechanization of Forestry (VNIILM) and IIASA, the absorption capacity of forests is slightly less than the greenhouse gas emissions. The problems and prospects of accounting the reserve lands and forests that have grown on abandoned agricultural lands are described. The prospects for reducing greenhouse gas emissions owing to the development of solar and wind power plants are estimated, and the capital costs for the construction of wind and solar power plants are shown with and without taking into account energy storages. It has been determined that the reduction of greenhouse gas emissions through the development of wind and solar power plants entails significant financial costs and yields a smaller effect than in taking into account the absorption of carbon dioxide by forests grown on abandoned agricultural lands. Recommendations for achieving greenhouse gas emission targets are formulated, including full-valued consideration of the absorption capacity of reserve forests and farmlands overgrown with forests and shrubs after updating the information of the state forest register.

GHG action zone identification at the local level: Emissions inventory and spatial distribution as methodologies for policies and plans

Climate change mitigation and adaptation policies play a role in the political agendas of local authorities. The number of monitoring tools and experiences is progressively increasing also due to improvement in standardization of methods and proliferation of research and accounting experiments, which bring about increase in awareness of political subjects and the general public. Coherently with its Sustainable Energy Action Plan (SEAP), in 2018 the Municipality of Grosseto (central Italy) decided to build a greenhouse gas (GHG) emissions inventory integrated with Geographic Information Systems (GIS)-based maps, to visualize the spatial distribution of the GHG balance results.A bottom-up GHG emissions inventory at the sub-national level has been elaborated, following the most recent Intergovernmental Panel on Climate Change (IPCC) Guidelines, with the aim of creating site-specific knowledge and supporting policies. GHG gross emissions corresponded to 395,558.59 t carbon dioxide equivalents (CO2eq), i.e. five time higher than CO2 absorption, determining an abatement percentage of 17.09%. The emissions came mainly from road transport (47.57%), heating (15.01%), and consumption of imported electricity (14.57%). The GHG emissions balance results have been translated into five geo-referenced GIS-based maps, which help localize the areas under stress and categorize the territory into GHG action zones, able to stimulate environmental policies and monitor their efficacy. Beside policies inspired by the key categories of the GHG emissions inventory (e.g., mobility, import of electricity, heating), the spatial visualization of results stimulates considerations and measures regarding the localization of activities and infrastructures, urban and environmental planning, and land use change, which are not always supported by adequate information in the case of sub-national administrative systems. Moreover, by virtue of reliability and replicability, the obtained results (i.e., climate-altering emission maps and GHG action zones identification) should be incorporated into the so-called Baseline and Monitoring Emission Inventories, required in the Sustainable Energy and Climate Action Plan (SECAP) of the municipalities that join the Covenant of Mayors.

Cropland intensification mediates the radiative balance of greenhouse gas emissions and soil carbon sequestration in maize systems of sub-Saharan Africa.

Sub-Saharan Africa (SSA) must undertake proper cropland intensification for higher crop yields while minimizing climate impacts. Unfortunately, no studies have simultaneously quantified greenhouse gas (GHG; CO2 , CH4 , and N2 O) emissions and soil organic carbon (SOC) change in SSA croplands, leaving it a blind spot in the accounting of global warming potential (GWP). Here, based on 2-year field monitoring of soil emissions of CO2 , CH4 , and N2 O, as well as SOC changes in two contrasting soil types (sandy vs. clayey), we provided the first, full accounting of GWP for maize systems in response to cropland intensifications (increasing nitrogen rates and in combination with crop residue return) in SSA. To corroborate our field observations on SOC change (i.e., 2-year, a short duration), we implemented a process-oriented model parameterized with field data to simulate SOC dynamic over time. We further tested the generality of our findings by including a literature synthesis of SOC change across maize-based systems in SSA. We found that nitrogen application reduced SOC loss, likely through increased biomass yield and consequently belowground carbon allocation. Residue return switched the direction of SOC change from loss to gain; such a benefit (SOC sequestration) was not compromised by CH4 emissions (negligible) nor outweighed by the amplified N2 O emissions, and contributed to negative net GWP. Overall, we show encouraging results that, combining residue and fertilizer-nitrogen input allowed for sequestering 82-284 kg of CO2 -eq per Mg of maize grain produced across two soils. All analyses pointed to an advantage of sandy over clayey soils in achieving higher SOC sequestration targets, and thus call for a re-evaluation on the potential of sandy soils in SOC sequestration across SSA croplands. Our findings carry important implications for developing viable intensification practices for SSA croplands in mitigating climate change while securing food production.

Evaluating the Effectiveness of Catch Crops and Tillage Systems for Carbon Farming

In modern agriculture, it is necessary to identify strategic steps that will reduce greenhouse gas emissions: on the one hand, reducing emissions by cutting down fuel consumption, reducing soil interference, limiting nitrogen losses when using fertilisers, and on the other hand – increasing the efficiency of carbon extraction from the atmosphere through plant photosynthesis and sequestration as organic matter of the soil. The purpose of this study is to figure out the influence on the carbon balance of such elements of the agricultural system as the system of tillage and the use of intermediate cover crops in a model 4-field crop rotation in the Steppe zone of Ukraine. This work was performed using the method of empirical calculations based on the online calculator of greenhouse gas emissions Cool Farm Tool. The influence of intermediate crops in two fields of crop rotation (after the early grain predecessors – wheat and winter barley) and tillage systems (traditional, reduced, and no-till) on the balance of carbon emissions and sequestration in the model 4-field crop rotation was analysed. According to the results, it was found that during the model 4-field crop rotation under the conditions of the classical system of tillage for sunflower and maize without intermediate crops and reduced processing for wheat and barley, the total greenhouse gas emissions amount to 4015 kg/ha of CO2 -eq. in 4 years. Switching to a reduced tillage system has been shown to reduce emissions by 30.1%. The addition of two intermediate crops in two crop rotation fields before spring crops allows obtaining a negative balance of greenhouse gas emissions of -377 kg/ha of CO2 -eq. during this period, and when switching to no-till for all crops -1221 kg/ha of CO2 -eq. for a 4-year rotation period. This study will help identify strategic steps and their potential contribution to the development and implementation of agricultural systems with minimal greenhouse gas emissions

Assessing the climate impacts of oat straw as a raw material

Straw is an interesting renewable feedstock for various high-value products, such as textile fibers. However, straw encompass to soils maintains a good soil structure, fertility, and carbon storage. Despite the availability of previous research on this topic, uncertainties remain regarding the climate and soil impacts of straw collection. This study aims to show the carbon footprint (CF) of straw collection compared with that of soil encompass. The goal is to demonstrate uncertainties related to initial data and methodological assumptions on whether straw is regarded as a waste or a coproduct and illustrate where more measured data is needed. Life cycle assessment method was used to conduct this study and the data therein were gotten from literature. The results show that straw removal can lead to reduced greenhouse gas emissions in comparison to soil encompass because of reduced nitrogen fertilizing needs and subsequent N2O emissions. However, there is high uncertainty related to soil organic carbon (SOC) and N2O emission changes because of straw removal. It is also possible that greenhouse gas emissions increase due to straw removal. Straw seems to have a relatively low CF, especially when it is regarded as a waste. Coproduct interpretation significantly increases the emissions allocated for straw. Straw also stores carbon, and its total CF can be negative. The life cycle length of the straw-based end products determines how long carbon can be stored before it is released back into the atmosphere. Total greenhouse gas emission balance at a system level can be defined only when also straw refining and manufacturing of replaced final products are considered. Additional information is needed, especially on soil emissions (N2O and CH4) and impacts on SOC storage, to ensure the sustainability of straw-based products.

Bioethanol production from short rotation S. schwerinii E. Wolf is carbon neutral with utilization of waste-based organic fertilizer and process carbon dioxide capture

The sustainability of transportation biofuel production value chains is under discussion as a consequence of the implementation of the European Union Bioeconomy Strategy and renewable energy production. Greenhouse gas emissions from the biomass produced for biofuel, and the energy required during the production process are, in many cases, greater than the emission reductions from the biofuels that are produced and used to replace fossil fuels. In this study, the sustainability of bioethanol production from short rotation coppice Salix schwerinii was considered from cultivation and harvesting to biofuel production and distribution. The sustainability of the full value chain was evaluated according to the European Union Renewable Energy Directive and calculations of greenhouse gas emission savings (%) from biofuel production were compared to a reference fossil fuel (gasoline). For comparison, four bioethanol production scenarios were developed, and specific attention was focused on the utilization of waste-based organic fertilizers (for biomass production) and on carbon dioxide capture at the fermentation stage, and their effects on value chain greenhouse gas emissions. Based on our evaluation, Salix bioethanol production achieved 60% emission savings compared to the fossil reference (requirement for installations that will commence operations until end of December 2020). When waste based organic fertilizers were used in the Salix biomass production, 65% emission savings were achieved (requirement for the installations that will commence operations from 2021). Moreover, the value chain sustainability and greenhouse gas emissions balance were improved by the carbon dioxide captured during the bioethanol fermentation stage.

Carbon metrics for cities: production and consumption implications for policies

The estimated cities’ contribution to climate change varies depending on the methods chosen by a given city for compiling its greenhouse gas (GHG) emission inventory. This study provides an interpretative synthesis of existing research to explore the differences of three emerging approaches to city-level GHG emissions accounting, based on methodological dimensions: boundary-setting, the categorisation of emissions and the type of emissions. The policy relevance and implications of selecting different system boundaries are explored: each approach can reveal important information which the others fail to identify. This suggests the value of using different and complementary approaches to address as many policy questions and relevant actors possible in climate action planning. Next, key methodological considerations that arise in target-setting approaches involving bringing the emissions balance to zero are presented. An analysis of actual ‘net-zero emission’ concepts used by eight cities reveals that their precise meaning and applicability remain ambiguous. Finally, to improve both the transparency about such metrics and their usability for policy and decision-making, this paper synthesises all key considerations occurring from the analysis of inventorying approaches and net-zero targets into a reporting and communication framework. Policy relevance Many cities are assuming responsibility for measures to mitigate climate change, but they need greater clarity on ‘climate neutral’ or ‘net-zero’ approaches. Each city’s intended purpose needs careful alignment with a choice of methods. The diverse accounting and target-setting landscape and the associated policy implications are elucidated. This can empower more cities to select appropriate methods and set ambitious targets. Calculation of a GHG emission balance is a means to an end and not the end itself. Its purpose is to show the options for action and measure success. Non-transparent methods involve reputational and ethical risks for city governments. A framework to improve transparency is presented. Dual-accounting approaches involving both production and consumption are now the new trend. Individual actors must be able to identify their influence and potential action scope for mitigating climate change. Agreement is needed on how to approach consumption-based accounting and create more city-specific data.

Feasibility analysis for reduction of carbon footprint in a wastewater treatment plant

This study presents an integrated feasibility analysis approach to reduce the carbon footprint in the largest Italian wastewater treatment plant (WWTP). Firstly, a model-based feasibility analysis was carried out to assess the applicability of upgrading scenarios, for an ongoing anaerobic sludge digestion process. Application of dynamic sludge thickener, as well as hybrid thermo-alkali pre-treatment of waste activated sludge, were assessed to enhance the biogas production in the WWTP. Further, an implementation of the selective membranes was proposed and studied to upgrade the produced biogas in sludge treatment units to biomethane with an average efficiency of 98.6%. Model-based sludge pre-treatment and biogas upgrading strategies were developed and evaluated in terms of mass, energy, and greenhouse gas emission balance. The obtained results prove that practicing the proposed upgrading scenario can lead to an 18% improvement in biogas production and a significant reduction of thermal energy auto-consumption and total greenhouse gas emissions. In the second phase, the laboratory-based feasibility analysis was performed about the integration of microalgae technology into the current process of the WWTP. A planar photobioreactor was built to estimate the volumetric mass transfer coefficient (KLa) and CO2 consumption of the reactor. By the use of 44 and 76 μmol/m2/s light intensities, the results show 80% and 70% reductions in total CO2, respectively. The tested configuration guaranteed 11.763 and 27.943 mg/l/h CO2 consumptions, as well as 0.5775 h−1 and 17.7 h−1 KLa values. Overall, the results prove that applications of the technologies proposed in this study can significantly reduce the carbon footprint of the WWTP.

Simulating Long-Term Development of Greenhouse Gas Emissions, Plant Biomass, and Soil Moisture of a Temperate Grassland Ecosystem under Elevated Atmospheric CO2

The rising atmospheric CO2 concentrations have effects on the worldwide ecosystems such as an increase in biomass production as well as changing soil processes and conditions. Since this affects the ecosystem’s net balance of greenhouse gas emissions, reliable projections about the CO2 impact are required. Deterministic models can capture the interrelated biological, hydrological, and biogeochemical processes under changing CO2 concentrations if long-term observations for model testing are provided. We used 13 years of data on above-ground biomass production, soil moisture, and emissions of CO2 and N2O from the Free Air Carbon dioxide Enrichment (FACE) grassland experiment in Giessen, Germany. Then, the LandscapeDNDC ecosystem model was calibrated with data measured under current CO2 concentrations and validated under elevated CO2. Depending on the hydrological conditions, different CO2 effects were observed and captured well for all ecosystem variables but N2O emissions. Confidence intervals of ensemble simulations covered up to 96% of measured biomass and CO2 emission values, while soil water content was well simulated in terms of annual cycle and location-specific CO2 effects. N2O emissions under elevated CO2 could not be reproduced, presumably due to a rarely considered mineralization process of organic nitrogen, which is not yet included in LandscapeDNDC.

Understanding the timing and variation of greenhouse gas emissions of forest bioenergy systems

Forest-based bioenergy plays an important role in climate mitigation for limiting global mean temperature increase to below 2 °C. The greenhouse gas (GHG) impact of three forest-based bioenergy systems from the USA, Canada and Spain supplying wood pellets for electricity in the UK were evaluated by conducting lifecycle assessments and forest carbon modelling of the three forest systems. Cumulative emissions were analysed by calculating the forest carbon stock change and net GHG emissions balance of the forest-based bioenergy electricity. The analysis considered both the replacement of the existing electricity mix with bioenergy electricity and forest management with and without bioenergy use. The supply chain emissions and forest carbon balances indicated that GHG emission reductions are possible. However, the cumulative net GHG balance at forest landscape scale revealed that the reduction potential is limited, potentially with no GHG reductions in fast growing forests with shorter rotations, while slow growing forest systems with longer rotations result in greater GHG reductions. This means that the maximum climate benefit is delivered at a different point in time for different forest systems. To evaluate the climate change mitigation potential of forest-based bioenergy it is therefore necessary to consider the management, utilisation and relevant counterfactual of the whole forest and its products. In terms of climate change mitigation potential and minimising possible negative impacts that would require multi-level governance.

Methane emissions in grazing systems in grassland regions of China: A synthesis

The effects of grazing on methane (CH4) budgets are important for understanding the balance of greenhouse gas emissions and removals in grassland ecosystems. However, the CH4 budgets of grazing systems, that is simultaneously considering CH4 uptake by grassland soils and emissions from ruminant enteric fermentation, livestock folds and animal feces, are poorly investigated, particularly for Chinese grasslands, and thus, remained unclear currently. Here, a synthesis of 43 individual studies was carried out to assess the grazing season/annual CH4 budgets and their responses to grazing in grassland ecosystems of China. The results showed that heavy grazing (HG) significantly decreased, while light grazing (LG) and moderate grazing (MG) had no significant effects soil CH4 uptake, as compared to un-grazing sites. Grazing has shifted Chinese grasslands from a sink to source for atmospheric CH4, and the grazing season/annual CH4 budgets increased with increasing grazing intensity, while the offset of CH4 uptake by grassland soils to total CH4 emissions from sheep, sheepfolds and feces were exponentially decreased with increasing grazing intensity. Moreover, the herbage biomass (HBM), organic matter intake (OMI) and live weight gain (LWG) were decreased while CH4 emission intensities (i.e., CH4 emission per HBM, OMI, and LWG) were linearly increased with increasing grazing intensity. Our results demonstrate that mediating grazing intensity, e.g., from HG to LG, could yield the optimal balance between maintaining productive grasslands and meanwhile mitigating CH4 emissions. This study could help for building strategies with implications for grassland management in China with similar CH4 emission problems.

Modelowanie emisji podtlenku azotu i amoniaku w skali regionalnej oraz w Polsce

Celem badań była weryfikacja przyjętych w krajowych inwentaryzacjach emisji gazów cieplarnianych współczynników emisji bezpośredniej N2O i NH3 oraz oszacowanie emisji bezpośredniej i pośredniej N2O w systemach uprawy zwiększających sekwestrację węgla. Symulacje wykonywano przy użyciu modelu DNDC dla województw i Polski z użyciem dwudziestoletnich serii danych meteorologicznych. Stwierdzono, że symulowana emisja bezpośrednia podtlenku azotu dla Polski była zgodna z przyjętym współczynnikiem emisji. Symulowana emisja amoniaku była większa od przyjętego współczynnika emisji. Zastosowanie w symulacjach systemów uprawy zwiększających sekwestrację węgla organicznego, takich jak uprawa konserwująca oraz nawożenie obornikiem, zwiększało: wymycie i spływ powierzchniowy azotu oraz emisję bezpośrednią i pośrednią N2O. Wzrost tych emisji powinien być skompensowany z naddatkiem przyrostem ilości sekwestrowanego węgla organicznego w glebie, jeśli bilans emisji gazów cieplarnianych ma być ujemny.

Pyrolysis of switchgrass in an auger reactor for biochar production: A greenhouse gas and energy impacts assessment

A life cycle approach was used to assess greenhouse gas (GHG) emissions and energy balances of switchgrass pyrolysis in an auger reactor for biochar production, with bio-oil and syngas as co-products. The system boundaries included the cultivation of switchgrass on marginal lands, harvesting, transport, conditioning, pyrolysis, the amendment of biochar in soil to sequester carbon (C) and to reduce N2O emissions, and the valorisation of bio-oil and syngas as energy sources. Two pyrolysis scenarios were evaluated. Scenario A involves a lower pyrolysis temperature and a shorter solid residence in the reactor as compared to scenario B. A negative GHG emissions balance of −2110 and −2561 kg CO2e Mg−1 biochar was obtained for scenarios A and B, respectively. Biochar C sequestration contributed the most to the reduction of GHG emissions in scenario B due to the high C content and stability in biochar. However, scenario B resulted in a higher energy consumption (13,563 MJ Mg−1 biochar) than scenario A (2925 MJ Mg−1 biochar) due to a higher energy consumption of the pyrolysis unit. These results confirm that pyrolysis of switchgrass for biochar and bio-oil production can be a negative emission technology, but pyrolysis operating parameters should be selected carefully.

Climate-smart cropping systems for temperate and tropical agriculture: mitigation, adaptation and trade-offs

Climate-smart cropping systems should be designed with three objectives: reducing greenhouse gas (GHG) emissions, adapting to changing and fluctuating climate and environment, and securing food production sustainably. Agriculture can improve the net GHG emissions balance via three levers: less N2 O, CH4 and CO2 emissions, more carbon storage, and green energy production (agrifuels, biogas). Reducing the application of mineral N fertilizer is the main option for reducing N2 O emissions either directly or by increasing the proportion of legumes in the rotation. The most promising options for mitigating CH4 emissions in paddy fields are based on mid-season drainage or intermittent irrigation. The second option is storing more carbon in soil and biomass by promoting no-tillage (less fuel, crop residues), sowing cover crops, introducing or maintaining grasslands and promoting agroforestry. Breeding for varieties better adapted to thermal shocks and drought is mainly suggested as long-term adaptation to climate change. Short-term strategies have been identified from current practices to take advantage of more favorable growing conditions or to offset negative impacts: shifting sowing dates, changing species, cultivars and crop rotations, modifying soil management and fertilization, introducing or expanding irrigation. Some crops could also move to more suitable locations. Model-based tools and site-specific technologies should be developed to optimize, support and secure farmer's decisions in a context of uncertainty and hazards. Most of the adaptation and mitigation options are going in the same way but trade-offs will have to be addressed (e.g. increasing the part of legumes will be possible only with significant breeding efforts). This will be a challenge for designing cropping systems in a multifunctional perspective.

Influence of PV technology and system design on the emission balance of a net zero emission building concept

This paper presents an analysis of how the design of a photovoltaic (PV) system influences the greenhouse gas emission balance in a net zero emission building (nZEB). In a zero emission building, the emissions associated both with the energy required in the operation of the building (operational emissions) and the energy used to produce the building materials (embodied emissions) are offset by renewable energy generated on-site (avoided emissions). The analysis is applied to a nZEB concept for a single-family building, developed by the Norwegian Research Centre on Zero Emission Buildings. Previous analyses have shown that the installation of a PV system accounts for a significant share of the embodied emissions of a nZEB. The objective of this paper is to assess how the PV system design choices influence the embodied and avoided emissions, in order to determine how the environmental impact can be minimised. Four different PV technologies (Si-mono, poly-Si and CIS, and high-efficiency Si-mono) in four different system designs for flat roofs are evaluated using two different grid emission factors. The installations are compared by means of net avoided emissions, greenhouse gas payback time (GPBT), greenhouse gas return on investment (GROI), and finally the net emission balance of the building. The results show that the system with the largest area of high-efficiency Si-mono modules achieves the best lifetime emission balance, but that the greenhouse gas return on investment is highest for the optimally oriented CIS modules.

Balance and saving of GHG emissions in thermochemical biorefineries

Abstract In this study, a simplified methodology for the calculation of the balance of greenhouse gas (GHG) emissions and corresponding saving compared with the fossil reference is presented. The proposed methodology allows the estimation of the anthropogenic GHG emissions of thermochemical biorefineries (net emitted to the atmosphere). In the calculation of the GHG balance, all relevant factors have been identified and analyzed including multiproduction, emissions from biogenic carbon capture and storage (Bio-CCS), co-feeding of fossil fuels (secondary feedstock) and possible carbon storage in biomass-derived products (chemicals). Therefore, it is possible to calculate the balance of GHG emissions of a hypothetical thermochemical biorefinery considering different alternatives of land-use, biomass feedstock, co-feeding of fossil fuels, Bio-CCS incorporation and final use of the products. The comparison of the estimated GHG balance with the corresponding fossil reference for each product is of special relevance in the methodology since it is the parameter used in European regulation for the fulfillment of sustainability criteria in biomass-derived fuels and liquids. The proposed methodology is tested using a previously assessed set of different process concepts of thermochemical biorefineries (techno-economic analysis). The resulting GHG balance and saving are analyzed to identify uncertainties and provide recommendations for future regulation. In all process concepts, the GHG savings are above the minimum requirement of GHG emissions for 2018. In the case of incorporating Bio-CCS, cradle-to-grave negative GHG emissions are obtained. However, in order to assess the role of chemical co-production from biomass, they need to be included in future regulation.

Algogroup: Towards a Shared Vision of the Possible Deployment of Algae to Biofuels

Algogroup: Towards a Shared Vision of the Possible Deployment of Algae to Biofuels

Changes in greenhouse gas balance and resource demand of biogas plants in southern Germany after a period of three years

For five agricultural biogas plants with a high share of energy crops in the input material, a detailed balance of greenhouse gas emissions (GHG) and cumulated energy demand (CED) was calculated for the years 2007 and 2010. The results vary considerably between plants and over time. In 2010 compared with 2007, all of the five biogas plants reduced their impact on climate change and four of them also reduced their consumption of fossil energy. The strongest influence was from the enhanced utilization of surplus heat energy, whereas variations of environmental impact due to direct emissions from the biogas plants were less distinctive. Compared with a reference system based on fossil resources, electricity production in the biogas plants avoided GHG emissions of 603 g to 940 g carbon dioxide equivalents (CO2-eq)•kilowatt hours electrical energy (kWhel (-1)) and saved 2.48 to 3.23 kilowatt hours primary energy from fossil energy carriers (kWhfossil)•kWhel (-1) CED (results for 2010).