This paper covers the hydrogen technologies regarding the role of hydrogen as an energy carrier and the possibilities of its production and use. It is initially presented the modalities and the efficiency of the current technologies of obtaining hydrogen, detailing its obtaining by the electrolysis of the water, the electrochemical efficiency and the specific consumption of electricity as well as the thermodynamics of the electrochemical processes. The following paragraph addresses hydrogen conversion possibilities. This paragraph details the thermodynamic analysis of the fuel cell, the external characteristic of the fuel cell and the types of fuel cell. The last paragraph addresses the possibilities of using the fuel cells for electrical vehicles and cogeneration systems for buildings.In this context, the traditional transport and distribution grid will have to adapt to the new realities as they will need to actively participate in the internal energy market by the transformation of the traditional electricity grid in energy flow, from unidirectional to bidirectional through the production of hydrogen offering the same facilities as the gas grid.

This paper approaches in a didactic manner the Life Cycle Assessment (LCA) methodology for wind turbines, starting from the definition of the purpose and limits of the LCA system, continuing with the Life Cycle Inventory—LCI, and Life Cycle Impact Assessment (LCIA). This methodology is applied as an LCA case study to a 15 MW wind farm, consisting of 5 3 MW turbines, mounted in south-eastern Romania. The purpose of the study was to evaluate the embodied energy, emissions (air), environmental impacts, Energy and GHG intensity, Energy and GHGs payback time without using LCA softwares. The quantities of component materials of the wind farm established on the basis of the life cycle inventory (LCI) show that a percentage distribution of materials of concrete of 60%, followed by iron with 34%, a difference of 6% being of the other materials. Based on the selected Environmental Product Declarations (EPD) of the materials and the quantities of materials necessary to build the wind farm, were determined on the energy side, the Energy Intensity and Energy Pay Back Time (EPBT) and of course from the environment point, was calculate the GHG payback time and the GHG intensity, last expressed in gCO_2-eq/kWh as a normalized value for 1kWh energy delivered to the grid. Energy Pay Back Time (EPBT) was calculated based on Energy Intensity, and the latter quantifying the energy consumed in the production, operation, and maintenance of a wind farm relative to the total energy produced by the wind turbines over their entire lifecycle, obtaining the EPBT value of 6.1 months. The GHG emissions produced during the construction and operation of a wind farm lead to a GHG payback period of 7.8 months. Finally, it must be mentioned that Empirical Life cycle analysis (LCA) of wind turbines is a useful tool for training young beginners (master's and doctoral students), in the understanding and analysis of the environmental impact of renewable energies.

Renewable energy sources and the economy of energy from classical sources are subjects of many research studies. The goal of this paper is to identify a topology of trigeneration (CCHP) system with a higher efficiency. For this purpose are compared two structures of CCHP systems, depending on the prime mover used: fuel cells or Stirling engine. The analysis are made on two integrated micro-scale combined cooling, heating and power (mCCHP) trigeneration systems dedicated for isolated residents with energetic independence.

This paper refers to an integrated mCCHP systems dedicated for isolated residents with energetic independence. The only energy sources are wood pellet and solar energy. The proposed trigeneration system is based on Stirling engine, photovoltaic panels, thermal solar collector and boiler. Nowadays the mCHP systems use conventional fuel least partial. In addition these systems do not offer an adequate correlation between power to heat ratio of the consumer demands and this ratio of the mCHP systems. Moreover, in summer period the energetic efficient is quite low. This paper removes the above disadvantages by using only renewable energy sources including for the prime thermal mover. The proposed mCCHP system utilizes the exceeding amount of heat in the summer for producing the necessary cooling. The global models simulation aiming performances assessment of the mCCHP-SE system shows a total energetic efficiency of 86%, an average ratio power to heat of 0,25, and a fuel saving of 31,61% for medium size home. This project is realized by a consortium of Romanian and Norway partners and supported by EEA Grant no. RO-0054/2009.

This paper shows the experimental realization of a complete autonomous cogeneration system comprising of a fuel cell unit and a gas condensing device. Both the electrical and thermal output of the fuel cell is 0.72 kilowatt, while the total thermal output of the fuel cell including the condensing heating device is 25 kilowatts. The present paper also presents all the components and monitoring measurements of the electrical and thermal values. The thermal control strategy is adopted for this system. On the overall, this unit serves as “electricity producing heaters” and offers a highly efficient alternative to conventional heating systems.