Energy is an integral part of a society and plays a pivotal role in its socio-economic development by raising the standard of living and the quality of life. The state of economic development of any region can be assessed from the pattern and consumption quality of its energy. Energy demand increases as the economy grows bringing along a change in the consumption pattern, which in turn varies with the source and availability of its energy, conversion loss and end use efficiency. Through the different stages of development, humankind has experimented with various sources of energy ranging from wood, coal, oil and petroleum to nuclear power. But indiscriminate exploitation of resources and unplanned developmental activities has led to serious ecological and environmental problems.
The threat posed to sustainability by greenhouse gas emissions and deterioration of the natural resource base (e.g., oil crisis, etc.) has caused worldwide concern. The natural resource base has deteriorated considerably due to the rapid growth in population coupled with unplanned developmental activities including industrialization and urbanization. This also has resulted in exponential increase in fossil fuel consumption. Post-oil crises shifted the focus towards renewable resources and energy conservation. An energy resource that is renewed by nature and whose supply is not affected by the rate of consumption is often termed as renewable energy. The need to search for renewable, alternate and non-polluting sources of energy assumes top priority for self-reliance in the regional energy supply. Sustainable development of a region depends on the health of renewable energy resources like water, vegetation, livestock, etc. The integrated development of all these components is essential for environmentally sound development of the region. Examples for renewable energy are solar, wind, hydroenergy, tidal, geothermal, biomass and energy from organic wastes such as biogas, etc.
ENERGY SCENARIO IN KARNATAKA
Karnataka does not have any coal deposits. It gets its coal from external sources. Electrical energy for Karnataka was purely hydro, but with the commissioning of the Raichur thermal power station, it also gets electrical energy from coal. The other major source of commercial energy - oil - is also not available in Karnataka. Hence the main source of commercial energy for the state comes from hydroelectric plants. These plants have large reservoirs to store rainwater throughout the year, the dams being built in prime forest areas thereby submerging sizable areas of forest. It is shown by a study that we can obtain a comparable quantity of energy from forest biomass instead of water from the submerged areas. An ideal solution would be to go in for a set of peaking power plants with minimum storage, which utilises rainwater during the monsoon period and supplemented by firewood-based thermal power plants. It can be seen that Karnataka State depends both on commercial and non-commercial forms of energy. Non-commercial energy provided over half the supply from sources such as firewood, agricultural residues, charcoal and cow dung. Commercial energy provided the rest, mainly through electricity, oil and coal.
SOLAR ENERGY
The Sun is by far the largest object in the solar system and contains more than 99.8% of the total mass of the solar system. From the Sun’s surface, the radiation is then transferred to the whole of the solar. An annual energy of 1.5 1018 kWh is obtained from the Sun to the earth. This is about 10,000 times larger than the current annual energy consumption of the world. The surface temperature of the Sun is around 5503.85 1C. Energy is continuously released from the Sun by a fusion reaction, which produces 3.94 1023 kW of power. Radiation from the Sun takes about 91.3 min to cover 93 million miles to the earth. The earth receives only a small fraction of the total power emitted by the Sun, an amount of 1.73 1014kW or 340W/m2 averaged over the whole earth surface. Approximately 30% is reflected back to space and 20% is absorbed by clouds, dust and ‘‘greenhouse’’ gas such as water vapour, carbon dioxide and ozone. The annual global radiation in India varies from 1600 to 2200kWh/m2, which is comparable with radiation received in the tropical and sub-tropical regions. The equivalent energy potential is about 6000 million GWh of energy per year (Feller, 2003).
The annual global radiation in India varies from 1600 to 2200 kWh/m2, which is comparable with radiation received in the tropical and sub-tropical regions. The daily average global radiation is around 5kWh/m2 day with the sunshine hours ranging between 2300 and 3200 per year. Though the energy density is low and the availability is not continuous, it is now possible to harness this abundantly available energy very reliably for many purposes by converting it to usable heat or through direct generation of electricity.
Ramachandra and Subramanian (1997) assessed the solar energy potential of Uttara Kannada district by using radiation data for radiation stations at Goa and Mangalore and climatological data of the meteorological observatories at Karwar, Honnavar, and Shirali. Karwar was found to be having GR range of 5.5-6.5 during January-May and was in the minimum range of 4-5 during the monsoon months, July-September whereas at Honnavar, the GR range during January-May was found to be 5.47-6.5 kWh/m2. This demonstrated that the coastal area of the Western Ghats region had a good solar energy potential available during most months of the year.
Ramachandra (2007) used the geographical information system (GIS) to map the solar potential of the Karnataka state and identified the regions suitable for tapping solar energy on the basis of global solar radiation data. Their analysis revealed that the coastal parts of Karnataka had a higher global solar radiation and was ideally suited for harvesting solar energy. Maximum global solar radiation was also found to be high in Uttara Kannada and Dakshina Kannada districts.
WIND ENERGY
Wind energy is another form of solar energy. Sunlight falling on the ocean and continents causes air to warm and rise, which in turn generates surface winds. Wind is affected significantly by topography, weather conditions with seasonal, daily and hourly variation, and land use pattern. The total annual kinetic energy of air movement in the atmosphere is estimated to be around 3 106TWh or about 0.2% of solar energy reaching the earth (Wilbur, 1985). Windmills are used to harness wind energy. The power of wind blowing at 25.6 km/h is about 200W/m2 of the area swept by windmill. Approximately 35% of this power can be captured by the windmill and converted to electricity. Maximum amount of wind energy can be harnessed only in windy locations like on mountaintops and coasts. Such places are suitable for the economic generation of electricity by wind power. According to initial estimates, India’s wind power potential was assessed at around 20,000MW. It has been re-assessed at 45,000MW, assuming 1% of land availability for wind power generation in potential areas.
Ramachandra et al (1997) assessed the availability of wind energy and its characteristics for Kumta and Sirsi taluks of Uttara Kannada district of Karnataka based on primary data collected at these sites for a period of 24 months and found that the coastal taluks like Kumta and Karwar had good wind potential and if exploited, could be useful for local industries and areca and coconut plantations.
Initially, the analyses of wind speed across the agro-climatic gradients of Karnataka state by Ramachandra and Shruthi (2003) showed that the Northern dry zone in Karnataka had good wind potential, which if exploited could help the local industries and agriculture. Later, Ramachandra and Shruthi (2005) employed the geographical information system (GIS) to map the wind energy potential of Karnataka state and identify the potential sites for tapping the wind energy potential. They found that the areas of Chikkodi, Horti, Kahanderayanahalli and Kamkarhatti had wind velocities greater than 5 m/s during most of the months, i.e. the wind energy potential was high in these locations and hence, it was suitable for construction of wind farms in these areas.
BIOENERGY
Biomass energy is a result of solar energy converted to biomass energy by green plants. s per an estimate, photosynthesis produces 220 billion dry tonnes of biomass per year globally, with 1% conversion efficiency (Johansson et al, 1993). Bioenergy is the most developed renewable energy, providing 38% of the primary energy needs of developing countries. The total bioenergy potential in India is about 19,500MW, including 3500MW of exportable surplus power from bagasse-based cogeneration in sugar mills and 16,000MW of grid quality power from other biomass resources. Quality of life in rural areas can be improved through the efficient use of locally available bioenergy sources by recovering the energy from cattle dung, human waste and non-woody organic wastes without losing their manurial value through biogas plants. Against an estimated potential of 12 million biogas plants, about 3.44 million family type plants have been set up so far, representing coverage of over 28% of the potential. In the developing world as a whole, about 2 billion people rely solely on fuelwood as their energy source for water heating and cooking. In order to achieve sustainable, selfreliant and equitable development of a region, it is imperative to focus on efficient production and use of bioenergy to meet both traditional and modern fuel requirements.
Ramachandra et al (2000) examined the role of biomass in Uttara Kannada district’s energy supply and calculated the potential for future biomass provision. Based on the investigations of biomass resource availability and demand, they categorized the district into two different zones – (1) Biomass surplus zones which included the taluks mostly from the hilly area and (2) Biomass deficit zones consisting of thickly populated coastal taluks such as Bhatkal, Karwar, Honawar, Kumta and Ankola. They also found that most of houses in the study area depended upon fuelwood for cooking and used the traditional stoves with efficiency less than 10%. Thus, they suggested that the dependence on fuel consumption could be brought down by the use of fuel-efficient stoves.
Ramachandra et al (2007) carried out a study in Linganamakki reservoir catchment of Sharavathi river basin to assess the impacts of developmental work on the local energy resources and demands. A questionnaire based stratified random sampling of households was done in a cluster of selected villages to collect the data of energy consumption pattern, resources available, and social, economical and cultural aspects. It was observed in the study that majority of the households (92.17%) still depended upon the fuelwood for their cooking energy needs due to availability of forest resources in the immediate vicinity at zero cost with the per capita fuel wood consumption of 1.2 tonnes per year which is higher than national average (o.7 tonnes per year). The study also pointed out that there was enormous potential for development of biogas technology over the study area to replace the usage of fuelwood in domestic energy for cooking.
Ramachandra (2007) also estimated the talukwise bioresource availability based on the compilation of data on the area (land use) and productivity of agriculture and horticulture crops, forests and plantations and carried out talukwise mapping of bioenergy potential using Geographical Information System (GIS) for the Karnataka state. The bioresource availability analysis showed that horticulture constituted the major share of 43.6%, followed by forests (39.8%), agricultural residues (13.6%), animal residues (3.01%) and plantation (0.15%). Few taluks in the southern transition zone, hilly zone and coastal zone of Karnataka were found to be having surplus bioresource.
HYDROENERGY
Hydropower owes its position as a renewable resource, as it depends ultimately on the natural evaporation of water by solar energy and precipitation. Hydropower, large or small, remains by far the most important of the ‘‘renewables’’ for electrical power production worldwide, providing 19% of the planet’s electricity. The exploitable hydroresources in the world are enormous and the total estimated hydroelectric resources in the world are 2,261,000MW (Johansson et al, 1993). Hydroelectric power plants are generally located near dams or river barrages. The capacity of hydropower plants can vary between a few kW and thousands of kW. Depending on this, hydropower plants are classified as micro (up to 100 kW), mini (up to 3MW) and small (up to 25MW) plants.
Ramachandra et al (1999) assessed the potential of the streams of Aghanashini and Bedthi river basins in the Western Ghats of Uttara Kannada district in Karnataka by carrying out an exploratory survey in all the streams satisfying the prescribed criteria and measuring the catchment area and stream discharge for a substantial period of time. The hydro energy potentials of streams in the Bedthi and Aghnashini river catchments were estimated to be about 720 and 510 million kWh, respectively. The study indicated that the regional energy requirements could be met by developing an integrated approach system such as harnessing hydro power in a decentralized way during the monsoon season, and meeting lean season requirements through small storage, solar or other thermal options.
Ramachandra et al (2000) proposed a model for minimizing the submergence of bioresources during construction of hydroelectric projects and maximizing the net energy in a region with seasonal power generation, reservoir storage capacity and installed generation capacity as the decision variables. The net energy analyses incorporating the biomass energy lost in submergence that maximization of energy at a site is possible if the hydroelectric generation capacity is adjusted according to the seasonal variation in river’s water discharge. The net energy computed for various dam heights showed that a reservoir with a dam height of 67m stores enough water to meet the region’s lean season’s electricity requirement and the area saved has a bioresource potential of 319 million kWh that can cater to the domestic thermal energy demand of 312 million kWh.
ENERGETICS IN AGRICULTURE
The agriculture sector represents both consumers and producers of various forms of energy. Valuable byproducts of agriculture, like crop residues, are used as animal feed, cooking fuel and as raw material in industries. The level and pattern of energy use in agriculture, as well as its contribution to energy supplies, depends on a variety of agronomic and socio-economic factors.
Ramachandra and Nagarathna (2001) gave an insight into the energetic associated with the rainfed paddy cultivation in the Uttara Kannada district of Karnataka. a detailed questionnaire based survey was conducted in 90 villages spread over the coast, interior and hilly zones of Kumta taluk, covering all categories of landholdings and the operationwise energy flow patterns were studied to find the energy consumption. The paddy cultivation was found to be mainly dependent upon farm yard manure (FYM) with different levels of inputs in different zones and different land holdings. However, the paddy yield showed a decline from 3.3 (1980–1981) to 1.9 (1992–1993) ton/ha in spite of continued use of HYV and greater application of inorganic fertilizer and pesticides. Thus, it was highlighted through the study that it was not necessary always to increase the energy inputs in agriculture to get higher production but it is necessary to practice environmentally sound management practices for sustainable agriculture without affecting other components of the ecosystem.
ENERGY CONSUMPTION IN THE DOMESTIC SECTOR
Energy use patterns are closely linked to agro-climatic and socio-economic conditions. Energy problems in rural areas are closely linked to soil fertility, landholding, livestock holding, etc. Energy planning of any region should be based on the existing levels of energy consumption. However, existing programs of development lack a disaggregated information base. Regional developmental activities have to be based on detailed information from each sector. Sustainable development of a region depends critically on the health of renewable resources such as soil, water, vegetation, livestock and genetic diversity. The integrated development of all these components is essential for environmentally sound development. This necessitates promotion of conservation activities among local communities and application of traditional environmentally sound technologies.
Ramachandra et al (2000) conducted a detailed exploratory survey to understand the energy use patterns in various agro-climatic zones and seasons in Uttara Kannada district of Karnataka. The results indicated that the average energy consumption for cooking and water heating varied significantly in various seasons across the zones. A detailed energy consumption investigation in Kumta taluk showed that most of the households used the traditional stoves for cooking and water heating with the average consumption of cooking ranging from 2.01±1.49 (coastal) to 2.32±2.09 (hilly) kg/person/day. . Analysis of other sources of energy for domestic purposes shows that kerosene is used for cooking and lighting in the coast. However, the surplus availability of bioresources in the hilly regions was main reason for less consumption of kerosene as compared to the coastal regions. The fuel efficiency studies indicated the scope for saving 27.45 to 42% fuel wood by switching to improved stoves.
Ramachandra et al (2000) analyzed the household energy consumption patterns in five taluks of Uttara Kannada district and discussed strategies to minimize the potentially negative impacts of energy systems on natural and human systems. They found that the per capita fuel wood consumption in the study locality was quite high, in the range of 2.5–4.25 kg/day and most of this requirement was met by minor forests, leaf forests (soppinabettas) and partly by areca and coconut residues. the end use efficiency experiments conducted in some households of Masur village showed that there was good scope for saving 27–42% of energy by switching to improved devices.
References:
- Ramachandra T.V. and Subramanian D. K. (1997), Potential and Prospects of Solar Energy in Uttara Kannada, District of Karnataka State, India. Energy Sources, 19(9): 945-988.
- Ramachandra T.V., Subramaniyan D.K. and Joshi N.V. (1997), Wind energy potential assessment in Uttara Kannada district of Karnataka. Renewable Energy, 10(4): 585-611.
- Ramachandra T.V., Subramaniyan D.K. and Joshi N.V. (1999), Hydroelectric resource assessment in Uttara Kannada district, Karnataka state. Journal of Cleaner Production, 7(3): 195-211.
- Ramachandra T.V., Subramaniyan D.K. and Joshi N.V. (2000), Optimal design of hydroelectric projects in Uttara Kannada, India. Hydrological Sciences, 45(2): 299-314.
- Ramachandra T.V., Subramaniyan D.K., Joshi N.V, Gunaga V. and Harikantra R.B. (2000), Domestic energy consumption patterns in Uttara Kannada district, Karnataka state, India. Energy Conversion and Management, 41(8): 775-831.
- Ramachandra T.V., Subramaniyan D.K., Joshi N.V., Gunaga S.V. and Harikantra R.B. (2000), End use efficiencies in the domestic sector of Uttara Kannada district. Energy Conversion and Management, 41(8): 833-845.
- Ramachandra T.V. and Nagarathna A.V. (2001), Energetics in paddy cultivation in Uttara Kannada district. Energy Conversion and Management, 42(2): 131-155.
- Ramachandra T.V. and Shruthi B.V. (2005), Wind energy potential mapping in Karnataka, India, using GIS. Energy Conversion and Management, 49(9-10): 1561-1578.
- Ramachandra T.V., Sreekantha and Purnima G.B. (2007). Bioenergy Status of Sharavathi river basin, Western Ghats, India, Energy and Environment, 18(5): 591-613.
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- Ramachandra T V, Rishabh Jain, Gautham Krishnadas, 2011. Hotspots of solar potential in India, Renewable and Sustainable Energy Reviews 15 (2011) 3178–3186, doi:10.1016/j.rser.2011.04.007.
