Sources and mitigation of methane emissions by sectors: A critical review

The environmental community rightly recognizes global warming as one of the gravest threats to the planet. Methane (CH₄), one of the greenhouse gases causing global warming, is emitted from a variety of sources and its concentration in atmosphere has increased dramatically over the last few centuries. Therefore, the increasing concentrations of methane are of special concern because of its effects on climate and atmospheric chemistry. Anthropogenic sources of methane can be collected under the titles of agriculture, energy, waste and industry on the basis of sectors. This paper aims at examining the past trends in emissions, the sources and mitigation strategies of the methane. As a result of the study, it is determined that the agricultural sector is the biggest source of methane emissions among the sectors. The energy, waste and industry follow the agricultural sources respectively.     

Analysis of scenarios for the reduction of energy consumption and GHG emissions in transport in the Basque Country

Fossil energy depletion and fight against climate change force humanity to decarbonize the economy. By year 2050 CO₂ emissions will have to reduce globally at least 85%, and probably over 95% in developed countries.The modeling of the transportation of people and commodities in the Basque Autonomous Community (Spain) in year 2008 has allowed us to draw some conclusions about the challenges ahead. The exploration of several scenarios modeled in order to reduce energy consumption in transport shows that mobility in a decarbonized world will have to be more efficient, electrified when moving people and freight on land, based on renewable generation, and organized in such a way that guarantees very high occupancies of vehicles. All these elements will be indispensable, and even not sufficient if they are still not complemented with a reduction of mobility in absolute terms, so that economic transportation intensity—the ratio between transportation and whole economic activity—recovers to levels seen in the world four decades ago, prior to the development of present hypermobility.     

Forecasting based on sectoral energy consumption of GHGs in Turkey and mitigation policies

Recently, global warming and its effects have become one of the most important themes in the world. Under the Kyoto Protocol, the EU has agreed to an 8% reduction in its greenhouse gas (GHG) emissions by 2008–2012. The GHG emissions (total GHG, CO₂, CO, SO₂, NO₂, E (emissions of non-methane volatile organic compounds)) covered by the Protocol are weighted by their global warming potentials (GWPs) and aggregated to give total emissions in CO₂ equivalents. The main subject in this study is to obtain equations by the artificial neural network (ANN) approach to predict the GHGs of Turkey using sectoral energy consumption. The equations obtained are used to determine the future level of the GHG and to take measures to control the share of sectors in total emission. According to ANN results, the maximum mean absolute percentage error (MAPE) was found as 0.147151, 0.066716, 0.181901, 0.105146, 0.124684, and 0.158157 for GHG, SO₂, NO₂, CO, E, and CO₂, respectively, for the training data with Levenberg–Marquardt (LM) algorithm by 8 neurons. R² values are obtained very close to 1. Also, this study proposes mitigation policies for GHGs.     

Simulating the impact of policy,energy prices and technological progress on the passenger car fleet in Austria—A model based analysis 2010–2050

This paper investigates the effects of policy, fuel prices and technological progress on the Austrian passenger car fleet in terms of energy consumption and greenhouse gas (GHG) emissions. To analyse these effects a simulation model is used. We model the car fleet from a bottom-up perspective, with a detailed coverage of vehicle specifications and propulsion technologies. The model focuses on the technological trend toward electrified propulsion systems and their potential effects on the fleet's energy consumption and GHG emissions. To represent the impact of prices and income on the development of the fleet, we combine the fleet model with top-down demand models.     

Ammonia mitigation and induction effects on hydrogen environment embrittlement of SCM440 low-alloy steel

The effect of ammonia (NH₃) contained in hydrogen (H₂) gas on hydrogen environment embrittlement (HEE) of SCM440 low-alloy steel was studied in association with the NH₃ concentration, loading rate, and gas pressure. NH₃ worked as both mitigator of the HEE and inducer of hydrogen embrittlement (HE) depending on the testing conditions. The mitigation of the HEE was achieved by the deactivation of the iron (Fe) surface for H₂ dissociation caused by the preferential adsorption of NH₃ on the Fe surface, which is enhanced by the increase in the NH₃ concentration and decrease in the H₂ gas pressure. NH₃ induced HE was caused due to creating hydrogen by the NH₃ decomposition. Since the NH₃ decomposition rate is low, the induction effect was observed when the loading rate was low. The effect of NH₃ was determined by the competition of the mitigation and induction effects.     

Electric power generation options for the Netherlands to 2000: An evaluation of government's and environmentalists' scenarios

Over the last four years the Netherlands has been involved in a public debate on its energy future, and more narrowly on the role of nuclear power. In this article computer simulation results for two much discussed strateties for the Dutch electric power system are presented and evaluated. A set of four criteria for comparison of these strategies is discussed. It is found that above a critical value further expansion of the nuclear and coal-fired base load capacity is no longer compatible with enhancement of the industrial cogeneration capacity. It is shown that in terms of kWhe-costs both strategies offer rather effective protection against steep oil price increases, though in different ways and with varying implications for Dutch natural gas policy.     

Stream channel and habitat changes due to flow augmentation

A previously ephemeral stream is being used to convey water and create fish habitat as part of mitigation for impacts of a transbasin water diversion project. This stream, the South Fork of Middle Crow Creek, is located in the Medicine Bow National Forest, Wyoming. After two years of increased flow to the 8.8 km study reach, the amount of stream channel had increased 32 per cent and the total area of beaver ponds had more than doubled. Brook trout (Salvelinus fontinalis) stocked into the beaver ponds are surviving and growing. Factors limiting fishery development in the augmented stream include interrupted flow, discontinuous channels, and summer water temperatures exceeding 25°C. Analysis using the Physical Habitat Simulation System indicated that a flow of 0.07m³s^?1 would maximize the amount of weighted usable area for brook trout under the channel conditions present in 1987.     

Indoor Radon Reduction in Crawl-space Houses: A Review of Alternative Approaches

An analysis has been completed of the performance, mechanisms, and costs of alternative technologies for preventing radon entry into the living areas of houses having crawl-space foundations. Sub-membrane depressurization (SMD) is consistently the most effective technique, often providing radon reductions of 80-98% in the living area. It has a relatively high installation cost, but a moderate annual operating cost. Forced crawl-space depressurization is the second most effective, giving reductions of 70-96%. Crawl-space depressurization is less well demonstrated than is SMD, and performance will vary with crawl-space tightness and weather, but it will be a primary option when large radon reductions are needed in buildings with crawl-spaces which are inaccessible for installation of SMD. Crawl-space depressurization has a lower installation cost than SMD, but its operating cost may be three times higher. Natural crawl-space ventilation and forced crawl-space pressurization each typically provides roughly 50% reduction or less in the living area. The lack of a clear benefit of crawl-space pressurization in most installations probably indicates that the crawl space is in fact not being pressurized. Crawl-space sealing and barriers (as stand-alone methods) usually give little or no reduction.     

Loss of flow accident and its mitigation measures for nuclear systems with SCWR-M

Based on a revised version of RELAP5, which can be used for super-critical pressure calculation, a model of mixed spectrum SCWR (SCWR-M) system is established. To analyze the transient behavior of SCWR-M and develop mitigation measures during loss of flow accident (LOFA), some important parameters, e.g. reactor coolant pump (RCP) coast-down time, Reactor Pressure Vessel (RPV) upper water volume and safety injection flow, etc., are chosen for the parametric analysis. The results achieved so far indicate that the SCWR-M system design is feasible and promising. Three important mitigation measures for LOFA of SCWR-M are derived from the results: RCP coast-down time of more than 15 s, RPV upper water volume of more than 27 m³, and safety injection of more than 5% of the system design flow.     

A climate protection strategy for Germany—40% reduction of CO2 emissions by 2020 compared to 1990

This paper presents measures and instruments for Germany to achieve the goal of 40% CO₂-emission reduction until 2020 by reducing energy-related emissions by 224 million tonne (Mt). The most important measures in this regard are cuts in electricity generation (savings of 40 Mt), fuel switching and increased energy conversion efficiency (30 Mt) and an augmented 26% share of renewable energies in the provision of electrical energy (44 Mt). Average cost of the measures are at 50 euro per tonne avoided CO₂, which corresponds to an additional monthly expenditure per household of less than 25 euro.