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- ItemWater use indicators at farm scale: Methodology and case study(Hoboken, NJ : Wiley-Blackwell Publishing Ltd, 2012) Prochnow, A.; Drastig, K.; Klauss, H.; Berg, W.Indicators for water use at farm scale can assist farmers in understanding the water flows on their farms and in optimizing water use by adapting agronomic measures and farm management. The objective of this work is to develop a methodology to estimate water flows at the farm scale, to derive indicators for farm water use, and to apply them in a first case study. After the spatial and temporal boundaries of the farm system and the water flows are defined, three indicators to assess water use at the farm scale are developed: farm water productivity, degree of water utilization, and specific inflow of technical water. Farm water productivity describes the ratio of farm output to water input, where the water input is the total of those water inflows into the farm system that can be assigned to the generation of farm output. Farm output is expressed on a mass basis, food energy basis, and monetary basis. The degree of water utilization characterizes the relationship between productive water to the total water inflow into the farm system, where productive water comprises those water flows that directly contribute to biomass generation via plant and animal metabolism. The specific technical water inflow quantifies the water inflow into the system by technical means relative to the farm area. The application of the methodology in a first case study for a mixed crop-livestock farm with 2869 ha in Germany results in a farm water productivity of 2.30 kg fresh mass per mWinput-3, 1.03 kg dry mass per m Winput-3, 5.96 GJ m Winput-3, and 0.25 € mWinput-3. The degree of water utilization is 0.56. The specific technical water inflow is 36.5 m3 ha-1 year -1. Factors that mainly effect these indicators and general approaches to optimize water use in farms are discussed as well as the further research required for practical implementation.
- ItemEnergy intensity and global warming potential of corn grain ethanol production in Wisconsin (USA)(Hoboken, NJ : Wiley-Blackwell Publishing Ltd, 2013) Kraatz, S.; Sinistore, J.C.; Reinemann, D.J.Increasing demand for renewable alternative fuels, such as ethanol, is driven by decreasing availability of fossil resources and increasing attention to climate change. Life cycle assessment (LCA) is the tool used to evaluate environmental impacts, such as energy intensity (EI) and global warming potential (GWP), from ethanol production, but the application of this tool varies greatly. The goals of this study were to enumerate the life cycle EI, net energy value (NEV), and GWP of corn grain ethanol production in Wisconsin, to explore ethanol production scenarios which differ at the treatment of the whole stillage (WS) coproduct, and to evaluate the various solutions to the multifunctionality problem which arises in LCA. In Scenario 1, all suggested solutions to the multifunctionality problem are considered by transforming WS into the animal feed dried distillers grains with solubles (DDGS). Scenario 2 avoids allocation using an integrated system which recycles the WS with an anaerobic biodigester and a combined heat and power (CHP) plant to provide electricity and steam to the ethanol refinery and returns the residue to the land as fertilizer. Based on the Scenario 1 analysis, we recommend the use of the subdivision (SD) solution to the multifunctionality problem because it enables clear comparisons between different ethanol production systems, it distinguishes between the environmental impacts from ethanol production and coproduct processing and it reduces the number of assumptions in the LCA calculations. From the comparison of both scenarios, we find that recycling the WS into electricity, heat, and fertilizer is the most environmentally beneficial coproduct use because it results in a 54% lower EI and a 67% lower GWP than the processing of WS into DDGS.
- ItemCase Study Report "The Renewable Energy Sector: Solar PV Market"(Hamilton, NZ : University of Waikato, 2017-03-26) Gogoi Saikia, Madhumita; Fang, Molly; Deraman, Mohd. Yusoff Bin; Carson, Tayla; Taylor, Wanida; Fang, YixuanThe renewable energy industry is the future of power consumption. Green electricity or renewable energy is generated from natural resources which has less environment impact to our Earth compared to fossil fuel energy. Using renewable energy reduces the amount of carbon dioxide into the atmosphere. These will help to reduce climate change or global warming. Renewable energy sources like solar energy will reduce our dependence on fossil fuels and noble gases which are in a current state of depletion (Uswitch, 2017). The solar photovoltaic (PV) systems harness the solar energy from the sun and convert this to usable electricity. These systems have a huge amount of growth potential with exponential growth in population and a constant need for power supplies. There has been a steady increase in the current growth of solar PV systems with no indication of a future decline. It was found that this technology is more viable in Asian countries due to low production and wage costs for labour. The main variables causing growth in this sector is population growth and increased per capita income. There are also continuous environmental public policies being set which favour the use of renewable energy resources including solar PV systems. Crystalline silica is the most common main component used needed to produce these systems and the changing cost of this will affect the future market. Using Porter’s competitive model, it was found that the rivalry among competitors is medium to high. There is little threat of substitute products entering the market. Suppliers possess medium to high level of power to bargain. There has been an increasing number of installation of solar PV panels which indicates that in the future the bargaining power of customers could be considerably high. The price elasticity for the solar market was found to be relatively high. Overall there is high potential for growth within this industry and no indication that there would be a decline in the years to come.