SUMMARYThe world of energy has lately experienced a revolution, and new rules are being defined. The climate change produced by the greenhouse gases, the inefficiency of the energy system or the lack of power supply infrastructure in most of the poor countries, the liberalization of the energy market and the development of new technologies in the field of distributed generation (DG) are the key factors of this revolution.It seems clear that the solution at the moment is the DG. The advantage of DG is the energy generation close to the demand point. It means that DG can lower costs, reduce emissions, or expand the energy options of the consumers. DG may add redundancy that increases grid security even while powering emergency lighting or other critical systems and reduces power losses in the electricity distribution.After the development of the different DG and high efficiency technologies, such as co-generation and tri-generation, the next step in the DG world is the interconnection of different small distributed generation facilities which act together in a DG network as a large power plant controlled by a centralized energy management system (EMS). The main aim of the EMS is to reach the targets of low emissions and high efficiency. The EMS gives priority to renewable energy sources instead of the use of fossil fuels. This new concept of energy infrastructure is referred to as virtual utility (VU).The VU can be defined as a new model of energy infrastructure which consists of integrating different kind of distributed generation utilities in an energy (electricity and heat) generation network controlled by a central energy management system (EMS). The electricity production in the network is subordinated to the heat necessity of every user. The thermal energy is consumed on site; the electricity is generated and distributed in the entire network.The network is composed of one centralized control with the EMS and different clusters of distributed generation utilities and heat storage tanks. Each of these clusters is controlled by a local management station (LMS). Every LMS has information about the requirements (heat, cold and electricity) of the users connected to its cluster and the state of the utilities and water level of the storage tanks in its cluster. The EMS receives the information from the LMSs and sets the electricity input or output of every cluster in the network. With the information ordered by the EMS, the LMS set the run or stand-by of the utilities of its cluster.The benefits of the VU are the optimization of the utilization yield of the whole network, the high reliability of the electricity production, the complete control of the network for achieving the main aim of the EMS, the high velocity for assuming quick changes in the demand of the system and high integration of renewable energy sources, plus the advantages of the DG. This paper indicates the state of the art of the VU concept, analyses the projects that are being developed in this field and considers the future of the VU concept.
Limiting the consequences of the climate change means that global CO2 emissions are to be reduced very rapidly. Taking into account that the expected economic growth of developing countries will inevitably be accompanied by a further growth in emissions in these countries, there is a strong necessity that the energy systems in the industrialized world be transformed into emission‐free ones. This level of reduction requires, for example, that the European Union achieves a ‘nearly zero‐carbon power supply’, involving replacing of fossil fuels in most or all buildings and much of the transport sector by nearly zero‐carbon electricity. It is also clear that the current political framework is, especially in Europe, propitiating the large‐scale implementation of renewable energy sources. In order to make this large implementation economically feasible, it is essential that the potential of these sources is maximized, placing them at sites providing the highest possible output. These sites are often located far away from consumption centers, making compulsory the transmission of large amounts of energy from generation to demand. In the global scenario, the necessary capacity of the power infrastructure for doing such exceeds by far the existing infrastructure and therefore new transmission capacity is necessary. Taking into account that large amounts of Renewable Energy Sources (RES) are to be integrated in the current power system and that most of the generation will take place at remote locations requiring new transmission assets, this article answers the question of whether a supergrid is necessary to enable this transformation.
This article is categorized under:
Energy Infrastructure > Systems and Infrastructure
Energy Infrastructure > Climate and Environment
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