No. 6 December 1994
The power sector in India has been growing rapidly, registering an annual growth rate of 8 to 10 percent. Thermal power, most of which is generated using coal, accounted for about 70% of the total installed capacity of about 77,000 MW in 1994. Coal is a highly polluting fuel, responsible for emissions of CO2, NOx, SO2 and particulates. Therefore, the use of environmentally sound technologies in the power sector can make a substantial contribution to addressing pollution problems in India. This study covers Maharashtra State Electricity Board, which is the biggest state utility in India with an installed capacity of 7,400 MW (in Dec 1993). Environmentally sound technological options for the both supply and the demand side have been considered in the study.
On the supply side, options to reduce auxiliary consumption (that is the electric power consumed by power plant auxiliaries) in the power plant have been explored. Auxiliary consumption in MSEB power plants varies between 8 to 12 percent. Several factors contribute to high auxiliary consumption in a power plant. These include external factors outside of plant-level control, and plant-specific factors that are controllable at plant level. External factors include poor coal quality and coal shortages, backing down of units and reactive generation requirements. Plant-specific factors include operating practices, technology upgrading of auxiliaries and minimising waste of energy.
A detailed study of the power plants at Nasik and Parli shows that substantial energy savings are possible through technical upgrading of auxiliaries. Variable speed drives for ID fans and boilers feed pumps, pulse energising for electrostatic precipitators (ESP) and utilisation of waste steam to substitute the electric power used for air conditioning in the plant through a vapour absorption system were identified as viable options to reduce energy consumption and associated pollution. Of these measures, ESP modification has already been initiated at both the plants. In addition to these measures, improvements in the cooling tower area were identified for Nasik.
Alternative energy-efficient ash handling systems are also recommended as these both save electricity and allow dry ash to be used for other purposes. Energy savings alone may not justify this option but since the measure also saves CO2, inclusion of global benefits in the analysis may make it an attractive option. Overall about 72 and 50 GWh (million kWh) of annual savings are expected at Nasik and Parli, respectively, on adoption of all the suggested measures.
The 210 MW units at Nasik and Parli constitute about 40% of the total capacity of 210 MW sets of the same vintage with MSEB. In addition to this there is some scope for energy and emission savings from the upgrading of auxiliaries of older units of lower ratings, wherever modernisation of the sets has not already been carried out.
Transmission and distribution (T& D) losses are relatively low in the State of Maharashtra: 16.4 percent against the all-India average of 21.8 percent losses in 1992-93. Nevertheless some scope for improvement still exists. Large reactive loads, overloading of distribution transformers, and pilferage of power are present in MSEB system also. A preliminary study of typical peak-period load data of the transmission system was carried out. Significant voltage drops were observed at some sub-stations due to high reactive loads and inadequate reactive compensation. The inadequacy of reactive compensation was observed for both 400 kV and 220 kV level transmission. This results in higher T & D losses. For a study of distribution losses, a detailed investigation through field experiment is recommended.
Demand-side management (DSM) options are yet to be explored thoroughly in India. A study of industries using high tension electricity (HT industries) in Maharashtra indicated substantial scope for capacity and energy savings through DSM. Energy savings of about 8500 GWh and demand savings of about 760 MW can be achieved by 1998 through various options identified for HT industries in Maharashtra. The detailed savings for various options are included in Table 1.
There are several barriers against the implementation of these options. These barriers include a lack of appropriate institutional and financial mechanisms. At the power plant level, we recommend the formation of a task force to examine issues related to plant upgrading. At corporate level we recommend an expert group consisting of in-house and outside experts to look into short term and long term measures. An active utility role and a consortium approach consisting of utility, equipment manufacturers and consumers for implementation of DSM options is necessary. The State Government needs to support MSEB to formulate and adopt a pricing policy that would facilitate implementation of DSM programmes.
Rationalisation of power tariffs and introduction of time-of-day tariffs are important requirements for a successful DSM programme. Pilot projects involving various agencies like utility, consumer, equipment manufacturers, financial institutions, governmental agencies (like the Energy Management Centre) and other experts should be initiated by the MSEB. Funding for such projects could be sought from national and international organisations involved in issues related to greenhouse gas emission reductions.
The study was carried out in collaboration with, and with the support of the UNEP Centre. A full report on the study will be published early in 1995.
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