Distributed and Dispersed Generation:
Distributed Generation (DG) using many small generators of 2-50 MW output, installed at various strategic points throughout the area, so that each provides power to a small number of consumers nearby. These may be solar, mini/micro hydel or wind turbine units, highly efficient gas turbines, small combined cycle plants, since these are the most economical choices. Dispersed generation referes to use of still smaller generating units, of less than 500 kW output and often sized to serve individual homes or businesses. Micro gas turbines, fuel cells, diesel, and small wind and solar PV generators make up this category.
Dispersed generation has been used for decades as an emergency backup power source. Most of these units are used only for reliability reinforcement. Now-a-days inverters are being increasingly used in domestic sector as an emergency supply during black outs.
The distributed/dispersed generators can be stand alone/autonomous or grid connected depending upon the requirement.
At the time of writing this (2001) there still is and will probably always be some economy of scale favouring large generators. But the margin of economy decreased considerably in last 10 years. Even if the power itself costs a bit more than central station power, there is no need of transmission lines, and perhaps a reduced need for distribution equipment as well. Another major advantage of dispersed generation is its modularity, portability and relocatability. Dispersed generators also include two new types of fossil fuel units—fuel cells and microgas turbines.
The main challenge today is to upgrade the existing technologies and to promote development, demonstration, scaling up and commercialization of new and emerging technologies for widespread adaptation. In the rural sector main thrust areas are biomass briquetting, biomass-based cogeneration, etc. In solar PV (Photovoltaic), large size solar cells/modules based on crystalline silicon thin films need to be developed. Solar cells efficiency is to be improved to 15% to be of use at commercial level. Other areas are development of high efficiency inverters. Urban and industrial wastes are used for various energy applications including power generation which was around 17 MW in 2002.
There are already 32 million improved chulhas. If growing energy needs in the rural areas are met by decentralised and hybrid energy systems (distributed/ dispersed generation), this can stem growing migration of rural population to urban areas in search of better living conditions. Thus, India will be able to achieve a smooth transition from fossil fuel economy to sustainable renew-able-energy based economy and bring “Energy for all” for equitable, environment-friendly, and sustainable development.