The Expected Perimeter in Eden and Related Growth Processes

Following Richardson and using results of Kesten on First-passage percolation, we obtain an upper bound on the expected perimeter in an Eden Growth Process. Using results of the author from a problem in Statistical Mechanics, we show that the average perimeter of the lattice animals resulting from a very natural family of "growth histories" does not obey a similar bound.Comment: 11 page

Modelling Effects of Agricultural Policies on Regional Greenhouse Gas Emissions From Cattle Raising Production Systems in Baden-Württemberg (Southwest Germany)

In the light of the anthropogenic climate change and the resulting need to mitigate greenhouse gas (GHG) emissions, policies are needed which efficiently abate GHG emissions in the agricultural sector. However, reliable estimates of regional GHG abatement potentials in the agricultural sector are rare because the models do not integrate the economic and environmental effects of different agricultural policies and are generally restricted to a single-gas approach. Coupling an economic sector model with a process-oriented ecosystem model can overcome this gap and thus provide realistic exante information of socioeconomically and environmentally sustainable agricultural policies

Greenhouse gas emissions and energy use in UK-grown short-day strawberry (Fragaria xananassa Duch) crops

Original article can be found at: http://journals.cambridge.org/ Copyright Cambridge University PressReducing greenhouse gas emissions and optimizing energy consumption are important for mitigating climate change and improving resource use efficiency. Strawberry (Fragaria xananassa Duch) crops are a key component of the UK soft fruit sector and potentially resource-intensive crops. This is the first study to undertake a detailed environmental impact assessment of all methods of UK strawberry production. A total of 14 systems with six additional sub-systems grown for between 1 and 3 years were identified. They were defined by the growing of short-day (Junebearer) or everbearer varieties, organic production, covering with polytunnels or grown in the open, soil-grown (with or without fumigation) or container-grown (with peat or coir substrate) and summer or spring planted. Pre-harvest, the global warming potential varied between 1·5 and 10·3 t CO2 equiv/ha/crop or 0·13 and 1·14 t CO2 equiv/t of class 1 fruit. Key factors included the use of tunnels, mulch and irrigation, sterilization of soil with fumigants and the use of peat substrate. Seasonal crops without covers grown where rotation of sufficient length reduced Verticillium (system 4) were the most efficient. System 4a (that did not use mulch) emitted 0·13 t CO2 equiv/t of class 1 fruit. A second or third cropping year in soil-grown systems prolonged the effect of mulch and soil fumigants. Greenhouse gases from system 4 (with mulch) averaged 0·30 t CO2 equiv/t of class 1 fruit after 3 years of cropping compared to 0·63 and 0·36 t CO2 equiv/t after 1 and 2 years, respectively.Peer reviewe

Strategy For A Large Scale Introduction Of Solar Energy In Central Asia

In spite of the significant need for energy and the large power of solar radiation (insolation) available in Central Asia the use of solar energy is still in a starting phase. In this paper a strategy is lined out how this deficit may be overcome, start-ing from a large number of affordable small and medium-sized photovoltaic solar plants. Details for various types of multi-purpose and dedicated solar plants are explained. Investment costs may be significantly lowered by the assembly of solar panels and the production of connectors, wiring and special accumulators within Central Asia. PV solar panels produce a much lower amount of greenhouse gases than Diesel generators resulting in a significant contribution to cli-mate change mitigation

Ecobalances of Heat Supply through Whole Grain Crops: Effect of Cereal Species and N Rate at Two Locations

Ziel der Untersuchungen war es, den Einfluß der Getreideart (Winterweizen, -roggen und -triticale) und der Stickstoff (N)-Düngung an zwei verschiedenen Standorten auf den Energieertrag, die Qualität der Biomasse, die Entstehung von Treibhausgasemissionen (CO2-Äquivalente) und Emissionen mit versauernder Wirkung (SO2-Äquivalente) zu untersuchen. Hierzu wurden Feldversuche angelegt und der Ganzpflanzenertrag sowie die Biomassequalität gemessen. Die CO2- und SO2-Äquivalente wurden anhand einer Ökobilanz ermittelt. Die meisten CO2-Äquivalente waren der Phase der Pflanzenproduktion zuzurechnen. Ein wesentlicher Beitrag resultierte hier aus der N-Düngemittelproduktion. Demgegenüber wurden die SO2-Äquivalente primär in der Phase der Verbrennung gebildet und waren auf die Konzentrationen der Elemente N, Chlor (Cl) und Schwefel (S) in der Biomasse zurückzuführen. Grundsätzlich führte die Erhöhung der N-Düngung zum Ansteigen der auf die bereitgestellte Nutzenergie bezogenen Emissionen an CO2- und SO2-Äquivalenten, gleichzeitig nahmen jedoch die flächenbezogenen Nettoenergieerträge sowie die flächenbezogenen CO2-Äquivalente, die durch Verbrennung von Wintergetreideganzpflanzen anstatt von Heizöl eingespart werden könnten, zu. Bezüglich der CO2- Äquivalente wurde für jede Variante eine Umweltentlastung im Vergleich zur Nutzung fossiler Energieträger ermittelt. Bei den SO2-Äquivalenten kann dagegen die Verbrennung von Winterweizen, der intensiv mit N gedüngt wurden, zu einer Mehremission an SO2-Äquivalenten gegenüber der fossilen Referenz Heizöl führen. Aufgrund seines hohen Ganzpflanzenertragspotentials und der niedrigen N- und Cl-Konzentrationen erwies sich Wintertriticale in den vorliegenden Versuchen als das günstigste Energiegetreide.The objective of the study was to determine the effect of cereal species (winter wheat, winter rye and winter triticale) and nitrogen (N) fertilisation at two locations on energy yield, biomass quality, formation of greenhouse gas emissions (CO2 equivalents) and emissions with acidifying effects (SO2 equivalents). Therefore field experiments were performed and biomass yield and quality assessed. The CO2 and SO2 equivalents were calculated using an ecobalance. The largest share of CO2 equivalents was determined for the phase of plant production. Here a substantial contribution resulted from the production of the N fertilisers. SO2 equivalents were released primarily during the phase of combustion. The amount depended on the contents of N, chlorine (Cl) and sulphur (S) in the biomass. In general, emissions of CO2 and SO2 equivalents, determined relative to utilisable energy, increased with increasing level of N fertilisation. However, at the same time net energy yields and the CO2 saving potentials increased on a per hectare basis. In terms of CO2 equivalents each experimental treatment implied an environmental benefit in comparison to fuel oil (the reference fossil fuel). In contrast, in some variants emission of SO2 equivalents from whole grain crops were equal to or exceeded those from fuel oil when N-rich biomass was combusted. High N concentrations in the biomass were related to intensive N fertilisation particularly in the case of winter wheat. In the present trials winter triticale proved to be the most favourable energy crop due to its high whole crop yield potential and its low N and Cl concentrations

Energy Policy at Crossroad: potentials for sustainable energy transition in the Middle East and North African region

Countries of the Middle East and North African (MENA) region such as Morocco, Jordan and Tunisia, are facing challenges which require systems analysis. These challenges are connected with the growing energy demand and the need to diversify energy supply while addressing targets of climate change mitigation and energy security policies. At the same time the countries of the MENA region are also facing challenges of socio-economic development, such as the need in creation of jobs and multiplier effects for national economies as well as of further technological development and political transformation. Deployment of new and upgrading of existing electricity infrastructure, including generation, transmission and distribution systems, is an important prerequisite for sustainable development and economic growth. Energy policy solutions are needed for further upgrading of electricity system, which should be cost efficient, should support multiple development objectives and be based on compromise solutions involving a variety of views as well as perceptions of risks and benefits of various technologies from different stakeholders’ groups. The goal of this research was to explore economic, social, political and environmental effects on national and local levels of different electricity pathways for the period of up to the year 2050 in three countries of the MENA region. The methodology of this research was based on integrated and interdisciplinary approach while applying various methods of stakeholders’ dialogue such as multi criteria decision analysis, participatory modeling and others

Survey of Photovoltaic Industry and Policy in Germany and China

As building-integrated photovoltaic (PV) solutions can meet around one-third of electricity demand in Germany and China, both countries are interested in exploring this potential. PV technologies have demonstrated significant price reductions, but large-scale global application of PV requires further technology improvements and cost reductions along the value chain. We analyze policies in Germany and China, including deployment support, investment support for manufacturing plants and R&D support measures, and we survey the industrial actors they can encourage to pursue innovation. While deployment support has been successful, investment support for manufacturing in these nations has not been sufficiently tied to innovation incentives, and R&D support has been comparatively weak. The paper concludes with a discussion of the opportunities for global policy coordination

Setting priorities for land management to mitigate climate change

<p>Abstract</p> <p>Background</p> <p>No consensus has been reached how to measure the effectiveness of climate change mitigation in the land-use sector and how to prioritize land use accordingly. We used the long-term cumulative and average sectorial C stocks in biomass, soil and products, C stock changes, the substitution of fossil energy and of energy-intensive products, and net present value (NPV) as evaluation criteria for the effectiveness of a hectare of productive land to mitigate climate change and produce economic returns. We evaluated land management options using real-life data of Thuringia, a region representative for central-western European conditions, and input from life cycle assessment, with a carbon-tracking model. We focused on solid biomass use for energy production.</p> <p>Results</p> <p>In forestry, the traditional timber production was most economically viable and most climate-friendly due to an assumed recycling rate of 80% of wood products for bioenergy. Intensification towards "pure bioenergy production" would reduce the average sectorial C stocks and the C substitution and would turn NPV negative. In the forest conservation (non-use) option, the sectorial C stocks increased by 52% against timber production, which was not compensated by foregone wood products and C substitution. Among the cropland options wheat for food with straw use for energy, whole cereals for energy, and short rotation coppice for bioenergy the latter was most climate-friendly. However, specific subsidies or incentives for perennials would be needed to favour this option.</p> <p>Conclusions</p> <p>When using the harvested products as materials prior to energy use there is no climate argument to support intensification by switching from sawn-wood timber production towards energy-wood in forestry systems. A legal framework would be needed to ensure that harvested products are first used for raw materials prior to energy use. Only an effective recycling of biomaterials frees land for long-term sustained C sequestration by conservation. Reuse cascades avoid additional emissions from shifting production or intensification.</p