Treibhausgas-Emissionen zukünftiger Erdgas-Bereitstellung für Deutschland

Background

Natural gas makes a significant contribution to the current energy supply and its importance, in relation to both the German and worldwide energy supplies, will increase further in decades to come. In addition to its high degree of efficiency, the low level of direct GHG combustion emissions is also an advantageous factor. However, around 90% of natural gas is methane (CH₄), which is the second most significant GHG due to its high greenhouse potential (21 times higher than CO₂). Therefore, high levels of direct gas losses of natural gas in its production, processing, transport and distribution could neutralise its low emission advantages. This is particularly apparent when considering the growing distances between production and use, the demanding production processes and the upcoming worldwide market for LNG (liquefied natural gas).

Aim

This paper aims to analyse and illustrate the future GHG emissions of the whole process chain of natural gas (indirect emissions) to be supplied to the German border over the next 2 decades. This should allow the comparison of total GHG emissions (indirect and direct) of natural gas with the GHG emissions of other fossil fuels. By considering likely changes in gas origin as well as dynamic changes in the infrastructure and technology of gas production, processing and transport until 2030, all relevant factors are included. The study focuses on the emissions of Russian natural gas as Russia is already, and will be in the future, the most important gas supplier to the German and European gas markets.

Results and Discussion

The analysis illustrates a significant change in the gas supply over the next two decades. The EU Gas Fields are in decline and it is predicted that these will run dry. In parallel the share of Russian and Norwegian natural gas, and also the levels of LNG production (e.g. from Algeria or Egypt), will increase. Although the potential for GHG emissions tends to grow as a result of greater transport distances and demanding production and processing activities, high investment in necessary mitigation options (e.g. through replacing older and inefficient technology; updating to state-of-the-art technology) may neutralise the increase. The overall result of these counteracting trends will be to decrease GHG emissions, in a range of around 12% per TJ of direct emissions of natural gas, depending on the level of investment in the modernisation of the Russian gas infrastructure and the improvements of the LNG process. In the two given scenarios the indirect emissions of the natural gas used in Germany will decrease from about 23 million t CO₂-eq (2005) to 19.5 or 17.6 million t CO₂-eq in the year 2030. In spite of a significant higher gas consumption the emissions are reduced in the first scenario due to technical modifications. In the second scenario the emission reduction is based on the lower gas consumption.

Conclusions

At present, the indirect GHG emissions of the natural gas process chain are comparable to the indirect emissions produced by oil and coal. The emission trend of the natural gas process chain will markedly decrease if the mitigation options are followed consistently. However, in order to ensure the long-term security of natural gas supply for future decades, a high level of investment is essential. With regard to future emissions, the best available technology and, therefore, that which is most economically feasible in the long term, should be used. Under these conditions natural gas — as the fossil fuel with the lowest levels of GHG emissions — can play a major role in the transition to a renewable energy supply for the future.     

Evaluation of greenhouse gas emissions from wetland and agriculture ecosystems in Sanjiang Plain

Carbon dioxide (CO₂), nitrous oxide (N₂O) and methane (CH₄) are important greenhouse gases (GHGs). The objective of this study is to quantify the aggregate GHG (CH₄, N₂O and CO₂) emissions and estimate economic losses of three ecosystems (marsh, paddy field and upland) in the Sanjiang Plain, excluding the Muling-Xiangkai Plain, south of Wanda Mountain. The results indicate the economic losses from GHG emissions of marshes were from 6.40 to 7.75?×?10⁹ CNY (Chinese Yuan), those of paddy fields were from 1.41 to 3.20?×?10⁹ CNY; and from uplands were from 0.26 to 0.49?×?10⁹ CNY. Using linear trend analysis, the economic losses through GHG emissions of marshes fell between 1982 and 2005, but those from paddy fields and uplands increased. In our study, the sequence in magnitude of the economic losses from GHG emissions was: marshes > paddy fields > uplands. In fact, the economic value of GHG emissions was negative because of these adverse impacts on the environment. This article could provide a reference for calculation of GHG exchange. The results suggest that improvement of fertiliser use efficiency for more precise agricultural management and returning straw to cropland could mitigate GHG emissions and would help to achieve sustainable development.     

Ökologische Optimierungspotenziale der energetischen Nutzung von Palmöl

Aim and Background The use of palm oil for bioenergy has become increasingly important for Europe in the last years because of its favourable proportion of yield to area under cultivation. Thus, palm oil presents a low-priced alternative to other energy sources, e.?g. rapeseed oil. Currently, however, palm oil gets a bad press due to new studies about the negative environmental consequences of cultivation practices. Due to the high demand for palm oil, land is becoming scarce. This results in the clearing of primary forests and consequently in the loss of biodiversity and in an increase of greenhouse gas emissions. To reduce the latter, not only the process of oil palm cultivation has to be optimised but also the practice of establishing new plantations by clearing natural forests has to be questioned. The aim of this article is to disclose potentials for greenhouse gas reductions in existing as well as in newly-planned oil palm plantations. Results and Discussion For existing oil palm plantations, two main fields for possible optimisation can be identified: one is improving the plantation management, the other is increasing the efficiency of the utilisation of waste products such as fibres and husks or oil mill effluents. For newly-planned oil palm plantations alternative land use scenarios have to be considered. The results show a big potential for optimisation. Thus, the greenhouse gas balance improves slightly if plantations are run more efficiently. If the waste products are used to generate energy, there are significantly positive effects on the greenhouse gas balance, especially through the reduction of methane emissions. By running a plantation in a professional best-practice way, 4.8 t of greenhouse gases can be saved annually per hectare cultivation area, expressed as CO₂ equivalents. If newly-planned oil palm plantations are established on fallow land, greenhouse gas emissions can be further reduced by an additional 4.8 t of CO₂ equivalents per hectare and year. From an economic perspective, this may be more costly than clearing primary forest but it is advantageous for both the greenhouse gas balance and the biodiversity of the concerned areas. All in all, exploiting the whole potential for optimisation could result in the saving of 10.2 t CO₂ equivalents per hectare and year more than it is the case in the existing mode of cultivation. Conclusions and Perspectives Due to the high demand of palm oil by the world market, cultivation areas for oil palms are becoming increasingly scarce. Thus, it is vital to exploit the full potential of oil palm cultivation in an environmentally and economically sustainable way. The management of plantations has to be optimised and a generally valid waste management system must be implemented in existing and future plantations. New plantations should preferably be established on fallow land, not by the clearing of primary forests. It is essential for a sustainable palm oil production to tap the full potential for optimisation. This, however, is currently not happening due to the high start-up investments. It is thus recommended to introduce an internationally valid certification system which may provide an incentive for more sustainable and effective production methods.     

Quantification of energy related industrial eco-efficiency of China

Improving eco-efficiency is propitious for saving resources and reducing emissions, and has become a popular route to sustainable development. We define two energy-related eco-efficiencies: energy efficiency (ENE) and greenhouse gas (GHG) emission-related eco-efficiency (GEE) using energy consumption and the associated GHG emissions as the environmental impacts. Using statistical data, we analyze China??s energy consumption and GHG emissions by industrial subsystem and sector, and estimate the ENE and GEE values for China in 2007 as 4.871×10⁷ US$/PJ and 4.26×10⁸ US$/TgCO₂eq, respectively. Industry is the primary contributing subsystem of China??s economy, contributing 45.2% to the total economic production, using 79.6% of the energy consumed, and generating 91.4% of the total GHG emissions. We distinguish the individual contributions of the 39 industrial sectors to the national economy, overall energy consumption, and GHG emissions, and estimate their energyrelated eco-efficiencies. The results show that although ferrous metal production contributes only 3.5% to the national industrial economy, it consumes the most industrial energy (20% of total), contributes 16% to the total industrial global warming potential (GWP), and ranks third in GHG emissions. The power and heat sector ranks first in GHG emissions and contributes one-third of the total industrial GWP, although it only consumes about 8% of total industrial energy and, like ferrous metal production, contributes 3.5% to the national economy. The ENE of the ferrous metal and power and heat sectors are only 8 and 2.1×10⁷ US$/PJ, while the GEE for these two sectors are 9 and 4×10⁴ US$/GgCO₂eq, respectively; these are nearly the lowest ENE and GEE values among all 39 industry sectors. Finally, we discuss the possibility of ecoefficiency improvement through a comparison with other countries.     

Effect of biochar addition on short-term N<Subscript>2</Subscript>O and CO<Subscript>2</Subscript> emissions during repeated drying and wetting of an anthropogenic alluvial soil

Agricultural soils are an important source of greenhouse gases (GHG). Biochar application to such soils has the potential of mitigating global anthropogenic GHG emissions. Under irrigation, the topsoils in arid regions experience repeated drying and wetting during the crop growing season. Biochar incorporation into these soils would change the soil microbial environment and hence affect GHG emissions. Little information, however, is available regarding the effect of biochar addition on carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions from agricultural soils undergoing repeated drying and wetting. Here, we report the results of a 49-day aerobic incubation experiment, incorporating biochar into an anthropogenic alluvial soil in an arid region of Xinjiang Province, China, and measuring CO₂ and N₂O emissions. Under both drying–wetting and constantly moist conditions, biochar amendment significantly increased cumulative CO₂ emission. At the same time, there was a significant reduction (up to ~20 %) in cumulative N₂O emission, indicating that the addition of biochar to irrigated agricultural soils may effectively slow down global warming in arid regions of China.     

Embodied energy and emergy evaluation of a typical biodiesel production chain in China

Biodiesel from non-grain feedstock has been considered as one of the proper substitutes for fossil fuels associated with a series of activities emerging in China in order to meet the resource shortage and develop the energy crops. This paper presents an ecological accounting framework based on embodied energy, emergy, and CO₂ emission for the whole production chain of biodiesel made from Jatropha curcas L. (JCL) oil. The energy and materials invested in and CO₂ emission from the whole process, including cropping, transportation, extraction, and production, are accounted and calculated. Also, E_mCO₂, the ratio of real CO₂ released to the emergy-based sustainability indicator per joule biodiesel, is proposed in this paper to present a new goal function for low-carbon system optimization. Finally, the results are compared with those of the bioethanol (wheat) production in Henan Province, China, and bioethanol (corn) production in Italy in view of the indices of embodied energy, emergy and CO₂ emissions and E_mCO₂.     

Effect of flue gas recirculation on nitric oxide (NO) emissions during the coal grate-fired process

Flue gas recirculation (FGR) is a low nitrogen oxide (NO_X) combustion technology. The present study used standard gas to simulate the cycle gas (the main ingredients of which are oxygen (O₂), nitrogen (N₂), and carbon dioxide (CO₂)). The coal grate-fired process was divided into three zones, namely (1) volatilization zone, (2) main combustion zone, and (3) char combustion and burn-out zone. The effects of FGR on coal combustion and NO emissions were investigated in these zones of a unit-boiler experimental system. An industrial test was then conducted on a chain boiler that previously used FGR. Data showed that if the cycle gas was directed into the furnace from the volatilization zone, the curve of the coal surface temperature moved backwards, the temperature peak increased, and coal ignition was delayed. When the FGR rate was 20%, NO emissions/g coal was 41.8% less than in the absence of FGR, in the overall combustion process except for the volatilization zone. An industrial test demonstrated that FGR decreased the NO emissions and incomplete-combustion loss of gas. NO and carbon monoxide (CO) emissions were reduced by 26.9 and 38%, respectively. These observations may prove to be beneficial in reducing ambient air pollution and saving energy.     

Urea formation from carbon dioxide and ammonia at atmospheric pressure

Urea synthesis, currently the largest use of carbon dioxide in organic synthesis, is conventionally operated at high pressure and high temperature. Here, we report for the first time that urea forms at atmosphere and ambient temperatures by negative corona discharge in gas phase. The conversion of CO₂ and yields of a solid mixture of urea and ammonium carbamate, which was identified by the ¹³C NMR spectrum, rise with reducing temperatures and increasing molar ratios of NH₃/CO₂ and discharge frequencies. The conversion of carbon dioxide was found to be 82.16?% at 20?°C and 1?atm with a molar flow ratio of n(NH₃)/n(CO₂) of 2.5. High pressure and high temperature as energy inputs are not necessary.     

Economic and environmental performance of electricity production in Finland: A multicriteria assessment framework

Meeting environmental, economic, and societal targets in energy policy is complex and requires a multicriteria assessment framework capable of exploring trade-offs among alternative energy options. In this study, we integrated economic analysis and biophysical accounting methods to investigate the performance of electricity production in Finland at plant and national level. Economic and environmental costs of electricity generation technologies were assessed by evaluating economic features (direct monetary production cost), direct and indirect use of fossil fuels (GER cost), environmental impact (CO₂ emissions), and global environmental support (emergy cost). Three scenarios for Finland's energy future in 2025 and 2050 were also drawn and compared with the reference year 2008. Accounting for an emission permit of 25 €/t CO₂, the production costs calculated for CHP, gas, coal, and peat power plants resulted in 42, 67, 68, and 74 €/MWh, respectively. For wind and nuclear power a production cost of 63 and 35 €/MWh were calculated. The sensitivity analysis confirmed wind power's competitiveness when the price of emission permits overcomes 20 €/t CO₂. Hydro, wind, and nuclear power were characterized by a minor dependence on fossil fuels, showing a GER cost of 0.04, 0.13, and 0.26 J/J_e, and a value of direct and indirect CO₂ emissions of 0.01, 0.04, and 0.07 t CO₂/MWh. Instead, peat, coal, gas, and CHP plants showed a GER cost of 4.18, 4.00, 2.78, and 2.33 J/J_e. At national level, a major economic and environmental load was given by CHP and nuclear power while hydro power showed a minor load in spite of its large production. The scenario analysis raised technological and environmental concerns due to the massive increase of nuclear power and wood biomass exploitation. In conclusion, we addressed the need to further develop an energy policy for Finland's energy future based on a diversified energy mix oriented to the sustainable exploitation of local, renewable, and environmentally friendly energy sources.     

Teil VI: Die Ökobilanz der Universität Osnabrück

Within the development of the “Osnabrück Environmental Management Model for Universities,” an environmental audit for the university has been carried out for the first time. It was implemented by way of a Life Cycle Assessment (LCA) based on ISO 14 040. Following this, an LCA includes the four steps:goal and scope definition, inventory analysis, impact assessment andinterpretation. The impact assessment phase of the LCA was carried out following the ”UBA-Method” of the German Federal Environmental Agency (UBA) which is based on the method of impact categories described in ISO 14 040 and implemented in the software Umberto^®. The most significant results are that the University contributes “considerably” towards both categories, “Depletion of fossil energy resources” and “Climate change”. The main causes of this are electricity and heat consumption as well as traffic. In order to improve its environmental situation, the university has been recommended to reduce its CO₂ emissions, its consumption of fossil energy resources and its methane emissions.     

Decomposition analysis of energy-related carbon dioxide emissions in the iron and steel industry in China

This work aims to identify the main factors influencing the energy-related carbon dioxide (CO₂) emissions from the iron and steel industry in China during the period of 1995–2007. The logarithmic mean divisia index (LMDI) technique was applied with period-wise analysis and time-series analysis. Changes in energyrelated CO₂ emissions were decomposed into four factors: emission factor effect, energy structure effect, energy consumption effect, and the steel production effect. The results show that steel production is the major factor responsible for the rise in CO₂ emissions during the sampling period; on the other hand the energy consumption is the largest contributor to the decrease in CO₂ emissions. To a lesser extent, the emission factor and energy structure effects have both negative and positive contributions to CO₂ emissions, respectively. Policy implications are provided regarding the reduction of CO₂ emissions from the iron and steel industry in China, such as controlling the overgrowth of steel production, improving energy-saving technologies, and introducing low-carbon energy sources into the iron and steel industry.     

Long-run dynamics of renewable energy consumption on carbon emissions and economic growth in the European union

This paper examines long-run and short-run dynamics of renewable energy consumption on carbon dioxide (CO₂) emissions and economic growth in the European Union. This study employs cointegration tests, Granger causality tests and vector error correction estimates to examine the direction of Granger causality, the long-run dynamics of economic growth and energy variables on carbon emissions. This study analyses time series data from the World Development Indicators over the period from1961 to 2012. The results of this study support a link between renewable energy consumption, economic growth, industrialization, exports and CO₂ emissions in the long-run and short-run. The results support that the sign of the long-run dynamics from the endogenous variables to the CO₂ emissions variable is negative and significant, which implies that the energy and environmental policies of the European Union aimed at curbing CO₂ emissions must have been effective in the long-term. Furthermore, renewable energy consumption and exports have significant negative impact on CO₂ emissions in the short-run. However, industrialization and economic growth have positive impact on CO₂ emissions in the short-run. The results suggest that both economic growth and industrialization must have been achieved at the cost of harming the environment. The finding suggests that the increasing consumption of renewable energy tends to play an important role in curbing carbon emissions in the region.     

Efficient adsorption of carbon dioxide and methane on activated carbon prepared from glycerol with potassium acetate

In the context of global warming and the energy crisis, emissions to the atmosphere of greenhouse gases such as carbon dioxide (CO₂) and methane (CH₄) should be reduced, and biomethane from landfill biogas should be recycled. For this, there is a need for affordable technologies to capture carbon dioxide, such as adsorption of biogas on activated carbon produced from industrial wastes. Here we converted glycerol, a largely available by-product from biodiesel production, into activated carbon with the first use of potassium acetate as an activating agent. We studied adsorption of CO₂ and CH₄ on activated carbon. The results show that activated carbon adsorb CO₂ up to 20% activated carbon weight at 250 kPa, and 9% at atmospheric pressure. This is explained by high specific surface areas up to 1115 m²g⁻¹. Moreover, selectivity values up to 10.6 are observed for the separation of CO₂/CH₄. We also found that the equivalent CO₂ emissions from activated carbon synthesis are easily neutralized by their use, even in a small biogas production unit.

     

An optimized policy for the reduction of CO2 emission in the Brazilian Legal Amazon

The Brazilian government has already acknowledged the importance of investing in the development and application of technologies to reduce or prevent CO₂ emissions resulting from human activities in the Legal Brazilian Amazon (BA). The BA corresponds to a total area of 5 × 10⁶ km² from which 4 × 10⁶ km² was originally covered by the rain forest. One way to interfere with the net balance of greenhouse gases (GHG) emissions is to increase the forest area to sequester CO₂ from the atmosphere. The single most important cause of depletion of the rain forest is cattle ranching. In this work, we present an effective policy to reduce the net balance of CO₂ emissions using optimal control theory to obtain a compromising partition of investments in reforestation and promotion of clear technology to achieve a CO₂ emission target for 2020. The simulation indicates that a CO₂ emission target for 2020 of 376 million tonnes requires an estimated forest area by 2020 of 3,708,000 km², demanding a reforestation of 454,037 km². Even though the regional economic growth can foster the necessary political environment for the commitment with optimal emission targets, the reduction of 38.9% of carbon emissions until 2020 proposed by Brazilian government seems too ambitious.     

Reduction of carbon dioxide into tetraiodomethane at 1?atm

We here report that by using electronegative gas of iodine and CO₂ under negative corona discharge, tetraiodomethane could be synthesized at 70?°C and 1?atm without any catalyst, despite thermodynamically infeasible at ambience without electron discharge. The conversion of carbon dioxide reached 88.71?% at a gas flow rate of 0.06?L/min and a discharge frequency of 9.608?kHz. The anion-involved CO₂ reduction process could be implemented efficiently under mild conditions, avoiding high temperature and high pressure.     

Challenge of global climate change: Prospects for a new energy paradigm

Perspectives on the challenge posed by potential future climate change are presented including a discussion of prospects for carbon capture followed either by sequestration or reuse including opportunities for alternatives to the use of oil in the transportation sector. The potential for wind energy as an alternative to fossil fuel energy as a source of electricity is outlined including the related opportunities for cost effective curtailment of future growth in emissions of CO₂.     

The dynamic causal links between CO2 emissions from transport,real GDP,energy use and international tourism

This study examines the dynamic causality relationship between international tourism and carbon dioxide (CO₂) emissions from transport, real gross domestic product and energy use. The vector error correction model and Granger causality test approach have been used to investigate these relationships for the top ten international tourism destinations spanning the period 1995–2013. Results reveal a unidirectional causality running from CO₂ emissions to economic growth without feedback; a bidirectional causality between economic growth and energy use; a bidirectional causality between international tourism and economic growth; and a bidirectional causality between international tourism and energy use. They also suggest that energy use and international tourism both contribute to the decrease of emissions level coming from transport sector, while economic growth leads to the increase of CO₂ emissions. This study can be used in policy recommendations by encouraging countries to use clean energy and to stimulate tourism sector for combating global warming.     

Responses of marine benthic microalgae to elevated CO2

Increasing anthropogenic CO₂ emissions to the atmosphere are causing a rise in pCO₂ concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO₂ levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO₂ gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO₂ concentrations increased. CO₂ enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO₂ levels increased. The responses of benthic microalgae to rising anthropogenic CO₂ emissions are likely to have significant ecological ramifications for coastal systems.     

Carbon sequestration in Taiwan harvested wood products

This study, with FAOSTAT and Taiwan data sources, estimates Taiwan carbon dioxide (CO₂) emissions in harvested wood products (HWP) by applying the three accounting methods suggested by the 2006 IPCC Guidelines. The investigation also explores impulse responses of CO₂ emissions to economic factors. Results from FAOSTAT and Taiwan data demonstrate an inconsistent production approach (PA) in the signs of the estimated CO₂ emissions. Average contributions of HWP from 1990 to 2008 for the stock change approach (SCA), PA and atmospheric flow approach (AFA) in Taiwan are ?3.195 Tg, 0.412 Tg and 10.632 Tg CO₂ emissions, respectively. SCA has determined the Taiwan HWP as a carbon reservoir; in contrast, PA and AFA have determined Taiwan HWP as a CO₂ emission. The net forest products imports into Taiwan induce the inconsistent signs of HWP carbon sequestration among SCA, PA and AFA. The vector autoregressive model (VAR) results also indicate that real GDP per capita is crucial for SCA CO₂ emissions, followed by exchange rate.     

29 % N2O emission reduction from a modelled low-greenhouse gas cropping system during 2009–2011

Atmospheric concentration of nitrous oxide (N₂O), a greenhouse gas (GHG), is rising largely due to agriculture. At the plot scale, N₂O emissions from crops are known to be controlled by local agricultural practices such as fertilisation, tillage and residue management. However, knowledge of greenhouse gas emissions at the scale of the cropping system is scarce, notably because N₂O monitoring is time consuming. Strategies to reduce impact of farming on climate should therefore be sought at the cropping system level. Agro-ecosystem models are simple alternative means to estimate N₂O emissions. Here, we combined ecosystem modelling and field measurements to assess the effect of agronomic management on N₂O emissions. The model was tested with series of daily to monthly N₂O emission data. It was then used to evaluate the N₂O abatement potential of a low-emission system designed to halve greenhouse gas emissions in comparison with a system with high productivity and environmental performance. We found a 29 % N₂O abatement potential for the low-emission system compared with the high-productivity system. Among N₂O abatement options, reduction in mineral fertiliser inputs was the most effective.