Because of the high energy efficiency of the coupled production of thermal and electrical energy, cogeneration is a key technology of the German climate protection plan. This paper focuses on the optimized use of cogeneration plants with a low scale of thermal and electrical power output (micro-cogeneration units) to supply residential buildings with thermal and electrical energy. The operating behavior of microcogeneration units depends on the concept of the heating system, the operating mode and the building's load profile. Different operating modes are developed, analyzed and compared in terms of energy efficiency and economic efficiency. A special heat and electricity driven operating mode is introduced and compared to existing alternatives like operating the cogeneration unit with a thermal storage unit or using the ability to modulate the power output. In addition, the energy efficiency and economic efficiency potential of preheating service water of washing machines and dishwashers is evaluated.The simulations and evaluations are executed for a poorly insulated apartment building in the Ruhr area in Western Germany.
The increasing feed-in of Renewable Energy Sources (RES) and the coupling of electricity markets fundamentally change the European energy system. To investigate the impact of these developments, models are necessary which provide regionally disaggregated load and generation time series as an estimate of future system states. With the Model of International Energy Systems (MILES), this paper presents a market model for simulating demand and supply of electrical energy under consideration of generation and transmission constraints. Previous versions of MILES have already been applied in several energy system studies. As important characteristics, the model enables to generate spatially high-resolution feed-in time series of RES as well as Combined Heat and Power (CHP) plants and to perform one-year simulations for determining costminimal hourly generation schedules of thermal and pumped storage power plants. MILES is validated by the comparison of simulation results for the ENTSO-E region for the year 2013 with published historical data.
Network development planning is a central task during the next decades due to the extension of renewable energy generation all over the world. In most countries, the geographic locations of renewable energy systems are not planned by any authority -the process is decentralized.The following analysis shows the effects of regional distribution of smaller power generation units on network development planning. Two different ways of regionalization of wind and photovoltaic power capacity are compared using an AC load flow calculation of the German transmission system. A special effort was made in collecting and structuring all input data for the analysis. This paper aims to sensibilize all those who are responsible to consider the input data intensely and with due diligence.
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