Hydro, wind and solar power as a base for a 100% renewable energy supply for South and Central America.

Power systems for South and Central America based on 100% renewable energy (RE) in the year 2030 were calculated for the first time using an hourly resolved energy model. The region was subdivided into 15 sub-regions. Four different scenarios were considered: three according to different high voltage direct current (HVDC) transmission grid development levels (region, country, area-wide) and one integrated scenario that considers water desalination and industrial gas demand supplied by synthetic natural gas via power-to-gas (PtG). RE is not only able to cover 1813 TWh of estimated electricity demand of the area in 2030 but also able to generate the electricity needed to fulfil 3.9 billion m3 of water desalination and 640 TWhLHV of synthetic natural gas demand. Existing hydro dams can be used as virtual batteries for solar and wind electricity storage, diminishing the role of storage technologies. The results for total levelized cost of electricity (LCOE) are decreased from 62 €/MWh for a highly decentralized to 56 €/MWh for a highly centralized grid scenario (currency value of the year 2015). For the integrated scenario, the levelized cost of gas (LCOG) and the levelized cost of water (LCOW) are 95 €/MWhLHV and 0.91 €/m3, respectively. A reduction of 8% in total cost and 5% in electricity generation was achieved when integrating desalination and power-to-gas into the system.

Synthesis of trigeneration systems: sensitivity analyses and resilience.

This paper presents sensitivity and resilience analyses for a trigeneration system designed for a hospital. The following information is utilized to formulate an integer linear programming model: (1) energy service demands of the hospital, (2) technical and economical characteristics of the potential technologies for installation, (3) prices of the available utilities interchanged, and (4) financial parameters of the project. The solution of the model, minimizing the annual total cost, provides the optimal configuration of the system (technologies installed and number of pieces of equipment) and the optimal operation mode (operational load of equipment, interchange of utilities with the environment, convenience of wasting cogenerated heat, etc.) at each temporal interval defining the demand. The broad range of technical, economic, and institutional uncertainties throughout the life cycle of energy supply systems for buildings makes it necessary to delve more deeply into the fundamental properties of resilient systems: feasibility, flexibility and robustness. The resilience of the obtained solution is tested by varying, within reasonable limits, selected parameters: energy demand, amortization and maintenance factor, natural gas price, self-consumption of electricity, and time-of-delivery feed-in tariffs.

Efeito do nível de energia digestível no desempenho de suínos da raça Piau nas fases de crescimento e terminaçäo / Digestible energy levels on performance of growing-finishing Piau pigs

Estudou-se o efeito de níveis de energia digestível (ED) sobre o desenvolvimento ponderal, consumo e conversäo alimentar de suínos da raça Piau, dos 12 aos 85 kg de peso vivo. O experimento utilizou 32 machos castrados e 32 fêmeas, recebendo quatro níveis de energia (3.100, 3.250, 3.400 e 3.550 kcal ED/kg), em raçöes fareladas e isoprotéicas por faixa de peso. O delineamento experimental foi o inteiramente ao acaso, com quatro níveis de energia, dois sexos e dois animais por parcela, em arranjo fatorial. O ganho de peso diário e a conversäo alimentar aumentaram (P<0,05) proporcionalmente ao aumento do nível de energia, até o limite de 3.400 kcal ED/kg, quando se estabilizaram. Näo houve diferença entre machos castrados e fêmeas em quaisquer das variáveis estudadas, assim como näo houve interaçäo entre sexo e nível de energia. O padräo de resposta do porco tipo banha à variaçäo do nível de energia da dieta mostrou-se semelhante ao relatado para suínos tipo carne. O melhor desempenho do porco Piau foi obtido com a concentraçäo de 3.400 kcal ED/kg de raçäo