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1. INTRODUCTION


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Energy is considered as the prime mover of a region’s development. In India, more than 70% of the total population inhabits rural areas and 85–90% of energy requirement is being met by bioresources. In the context of energy crisis due to dwindling of fossil fuel based energy resources, the importance of biomass as a renewable energy resource has increased in recent years. Although biomass energy is predominantly used in rural areas, it also provides an important fuel source for the urban poor, and many rural, small and medium scale industries. Field investigations reveal that most of the rural population still depends on the traditional devices (which are energy inefficient) for cooking and water heating, etc. leading to excess consumption of local resources. Lack of information about the resources and technologies may be cited as the reason for this situation.

Bioresources are diverse solid carbonaceous material ranging from fuelwood collected from farmlands and natural woodland, to plantation crops grown specifically for energy purposes, agricultural and forestry residues, food and timber processing residues, animal residues and aquatic flora. The energy released from the reaction of these materials with oxygen is known as bioenergy and it is being used in various ways to meet daily energy needs of the society. Bioenergy is the most developed renewable energy, providing 38% of the primary energy needs of developing countries. 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.

The rural energy scenario in India is dominated by the domestic sector, which accounts for 75% of the total energy consumed. The fuel consumption pattern of the domestic sector in rural areas is characterized by higher dependence on bioresourcebased fuels such as fuelwood, agricultural residues, etc. Cooking and water heating (for bathing and washing) are the prime end-uses in domestic sector accounting for over 90% of the energy. Rural population still depends on the traditional devices for cooking and water heating, etc., which are energy inefficient leading to excess consumption of local resources. This is mainly due to the lack of knowledge of energy efficient devices and renewable energy technologies. According to the recent National Sample Survey (NSS) data, about 36.5% of fuel needs in urban and 17.2% fuel needs in rural area is met by sources like kerosene and electricity. All other cooking is done either with fuelwood or dung cakes. This reveals the higher dependence on bioresource to meet the energy requirement that is mainly due to availability of biofuels at zero private cost and also non-availability of other sources of energy (high costs and unreliable supply network).

The estimate done at regional level for Karnataka (a federal State in India) shows that 8.5 million tonnes of fuelwood is required annually for cooking purpose in Karnataka. Inclusion of additional domestic demands such as water heating, space heating, etc., pushes it to 11.2 million tonnes annually. The demand for fuelwood is continuously rising along with increase in population. The State has only 16.9% of the area under forests (38,724 km2 of the total area of 191,791 km2).

The burgeoning population coupled with unplanned developmental activities based on ad-hoc decisions has led to bioresource scarcity in many parts of Karnataka. Present fossil fuel potential is unable to meet the growing demands of the society. There is a need to look for viable alternatives to meet the scarcity. Thus, there is a requirement for interventions particularly in rural development and in general, the energy system to boost the energy potential at disaggregated levels to balance demand and availability. This necessitates the understanding of the present energy consumption pattern and exploring locally available alternative energy sources in order to ensure resource sustainability.

Alternatives like biogas technology has made inroads in rural economy in some districts like Uttara Kannada,Udupi, Shimoga, etc. in Karnataka State (with higher literacy among women) during the last two decades due to economic viability, ecological soundness, technical feasibility and social acceptance. Biogas from biomass and animal wastes is an excellent technology that provides an alternate source of fuel in rural areas with an output of both energy and manure by using locally available resources like animal dung and other organic material.India is a pioneer in the field of developing technology for biogas production from animal dung (Srinivaran, 1979). Animal dung is a potentially large biomass resource and dried dung has the same energy content as wood. When burned for heat, the efficiency is only about 10%. About 150 million tonnes of cow dung (dry) is used for fuel each year across the globe, 40% of which is in India (UNEP, 1980). Biogas is produced by biological decomposition of organic material in the absence of air. The efficiency of conversion of animal residues could be raised to 60% by digesting anaerobically (to produce biogas). Biogas production will also resolve the conflict between energy recovery and nutrient utilisation as the effluent from the digester could be returned to the fields.

For 2002–03, a target of setting up of 0.12 million family type biogas plants had been allocated to States and agencies. About 70,440 plants have been completed during the period April to December 2002, which is almost 117% over the target of 60,000 plants planned for the corresponding period (MNES, 2003).

Current study was carried out in the Linganamakki reservoir catchment of Sharavathi river basin, Western Ghats, India to assess the impacts due to developmental work (in the form of hydroelectric power stations with reservoir) on local energy resources and demand. This region is considered to be one of the biodiversity hotspots as it harbours rich flora and fauna. The people residing in this area are largely dependent on these forests for daily energy needs (fuelwood) and sustenance. It is observed that the boundary of the energy flow extends beyond the sub-basin limit of the Sharavathi River. Hence a river basin-hydrological unit is considered for this investigation as energy movement is related to geographical features and shows similar trends in relatively homogenous features.

Karnataka State mainly depends on hydroelectricity (67%) of which Sharavathi river basin’s share is about 48%. It is one of the west flowing rivers of India, which traverses over a length of 132 km through undulating terrain in the Western Ghats with rich biodiversity and joins the Arabian Sea. The study area is situated at latitude 74°67’11” to 75°30’63” east and longitude 14°7’27” to 13°77’08” north with an area of 1992 sq. km. This river is extensively utilized for hydroelectric power generation (1450 MW). The Karnataka Power Transmission Corporation Limited (KPTCL) has constructed a dam at Linganamakki towards meeting the electricity requirement of the State.

The Linganamakki reservoir is about 105 km west of the district headquarter, Shimoga. Figure 1 provides the location of the study area while; Figure 2 is the remote sensing composite image that was used to assess the bioresource availability in various land use categories.The mountainous terrain of Western Ghats binds the western part of the study area, which has rich vegetation cover of evergreen to semi-evergreen type. The vegetation richness gradually recedes towards east. The hills slope towards east and transition between Maidan and Malnad can be seen on eastern part of the study area. It is further divided in to sub-basins based on major tributaries and associated streams as given in Figure 3.

Assessment of the energy consumption pattern and bioresources availability was done in order to quantify the energy demand and to understand the present status of energy supply and prospects for alternate policies and technologies along with management strategies to ensure the sustainability of the ecosystem. The Ministry of Environment and Forests, Government of India through the forest departments in each State has implemented the JFPM (Joint Forest Participatory Management) programme through a participatory approach involving village communities and voluntary agencies in the conservation and regeneration of forests. The performance of this programme in the river basin has been explored to assess the efficacy in resource management. Presently under JFPM, about 23 Village Forest Committees (VFCs) are active.

The National Commission on Agriculture (NAC) in 1976 projected the fuelwood demand up to the year 2000 (Kumar, 1999). The net per capita fuelwood consumption was estimated at about 194 kg/year. The demand projections estimated on that basis for fuelwood was 157.5 million tonnes in 2000. The Commission did not project an appreciable shift away from non-commercial fuels.

Comparative analysis of village level domestic energy consumption patterns across coastal, interior, hilly and plain zones considering regional and seasonal variations was done for Uttara Kannada District in 1999. Average consumption (kg/capita/day) of fuel wood for cooking ranges from 2.01 ± 1.49 (coastal) to 2.32 ± 2.09 (hilly). Season wise cooking fuel wood requirement for coast and hilly zones, ranges from 1.98 and 2.22 (summer) to 2.11 and 2.51 (monsoon) respectively, while for water heating (for bathing and washing), it ranges from 1.17 ± 0.02 (coast) to 1.63 ± 0.05 (hilly). Examination of present role of biomass in the energy supply of Uttara Kannada district, Karnataka and the potential for future biomass provision and scope for conversion to both modern and traditional fuels reveals that fuel wood was mainly used for cooking, and horticultural residues from coconut and areca nut trees were used for water heating purposes. Most of the households in this region still use traditional stoves whose efficiency is less than 10%. Energy from various crop residues was calculated: paddy husk-170.12 million kWh, bagasse-136.3 million kWh, groundnut-11.64 million kWh and maize-1.66 million kWh. The total residues available for the district were calculated to be 42020.37 tonnes. The total energy available from horticultural residues is: areca-540.58 million kWh, coconut-247.04 million kWh and cashew–38.365 million kWh. The total biogas available was calculated to be 46.29 million m3, which could meet 30% of the population’s energy demand. The fodder requirement was estimated to be 1.09 million tonnes of which 0.21million tonnes could be met by agro-residues. The improved cook stoves (ASTRA stoves-designed at ASTRA, Indian Institute of Science) were distributed under an ecodevelopment programme, which was done through local people’s active participation and after consultations with the villagers and local NGOs (Non-Governmental Organizations). These stoves are characterized by complete fuel combustion with as little excess air as practicable to generate the highest temperature of flue gases. The efficiencies of these stoves are in the range of 32–41%.The study also reveals that grazing in forests as well as removal of fuelwood (for domestic and small scale industries) has affected the sustainability of the forests, as there is large-scale degradation in many localities (Ramachandra et al, 2000).

Centre for Sustainable Technologies (formerly known as ASTRA), Indian Institute of Science conducted a detailed survey in six villages in a dry arid zone that revealed:

  1. fuelwood is a dominant energy source (81.6%) used mainly for household activities,
  2. cooking is a major activity consuming human and fuelwood energy and efficiency of improved stoves are in the range of 5.08%,
  3. human energy in h/day/household (especially women and children) was inefficiently used in fuelwood gathering (2.6), cooking (3.68), carrying food to farms (1.82), fetching water (1.53), taking cattle for grazing (5.54) etc.,
  4. kerosene consumption for lighting is about 4.3l% non-electrified house (78% of the houses being non-electrified) and
  5. industrial consumption is very small.
Essential factors determining biomass availability for energy are:
  1. The future demand for food, determined by the population growth and the future diet;
  2. The type of food production systems that can be adopted world-wide over the next 50 years;
  3. Productivity of forest and energy crops;
  4. The (increased) use of bio-materials;
  5. Availability of degraded land;
  6. Competing land use types, e.g. surplus agricultural land used for reforestation. The focus has been put on the factors that influence the potential biomass availability for energy purposes.
Six biomass resource categories for energy are
  1. energy crops on surplus cropland,
  2. energy crops on degraded land,
  3. agricultural residues,
  4. forest residues,
  5. animal manure and
  6. organic wastes.

The amount of re-circulating biomass is the key variable for controlling nutrient availability within an ecosystem. In this regard, recycling of biomass, rotation of crops, and biomass-producing strips inter-cultured with crop areas maintain the nutrition balance in agricultural lands. Part of the biomass is locally consumed in providing fodder to the draught animals. It can be used as a layer to suppress evaporation and as organic input for crop production, satisfying part of the nutrient requirements enhancing soil fertility and improving its moisture holding and permeability characteristics (Datye, 1997).

Even though forests cater most of the daily energy needs in rural areas, there is a need to focus on viable energy alternatives to cater to the growing demand of the burgeoning population. In this context, biogas generators lessen the dependence on forest and increases green areas leading to improved environment. More than 2 million biogas plants have been built in India so far. With a potential market for 30 plants attached to households with 3 cattle or more, the social and environmental advantages of biogas are just beginning to be explored. In rural areas, where there is generally no electricity supply, the introduction of biogas has given women a sense of self-worth and time to engage in more activities outside the home (Rene and Gunnar, 1997). Important sociological issues that have prevented widespread adoption of Biogas generators in India (during the evolution of biogas) are scarcity of animal residues, asphyxiation, fire explosion, kitchen fire, digester bursting or cracking and hazardous developments with respect to human safety (Goswami and Sutar, 1993).

Stall-feeding instead of field grazing is one of the best ways to circumvent the scarcity of animal residues and it facilitates increased production of biogas. Also, it would aid the regeneration of forests as the damages to saplings are minimised. However, stall-feeding is a labour-intensive activity demanding high labour inputs during the growing season. Cutting and carrying grass and carrying water to the cattle absorb 60–75% of the total labour. Slurry of biogas plant serves as manure and supply humus to soils, thereby helps in soil conditioning (John, 1986).

However, certain barriers hinder the overall potential of community biogas plants for cooking. Compared to biogas, fuel wood is available at zero cash cost and the cost of a stove is still high and acts as a deterrent, especially for the poor. Scarcity of large funds hinders the installation process of biogas plants. NGOs are suffering with improper incentive facilities for construction and maintenance, and also with unavailability of technology packages and adequate demonstration units. No organization at village level is willing to take leadership and accept responsibility of biogas plants. Inadequate funding and scarcity of skilled personnel for construction and maintenance affect the full potential use of biogas plants. Maintenance of biogas plants in some areas is affected by scarcity of water. Women and children play a dominant role in most of the household activities (like gathering of fuelwood, cooking etc.), but lack of representation of women in decision-making has also contributed to the problem.

The barriers for improved cooking technologies could be grouped as financial, technical and institutional from both supply and demand perspective. The improved stove cost varies with the design and is expensive compared to the traditional stoves. The government provides subsidy for improved stoves, which the households claim after the installation. Some households still consider the cost as high due to lack of knowledge of certain direct and indirect benefits, and also availability of fuel wood, dung cakes and crop residues with no cash expenditure. Inaccessibility of the improved stove accessories along with the scarcity of the trained builders and service facilities in rural areas hinder the diffusion of devices. The distance from the nearest urban centre and availability of transportation facilities also plays a dominant role in adopting the alternate energy technologies (Ravindranath and Hall, 1995).

The entire study area falls under two taluks namely, Sagar and Hosanagara of Shimoga District. Talukwise bioenergy available in the study area from agricultural residues, forests, horticultural residues, plantation and livestock is tabulated in Table 1.This shows that despite good resource potential in the region, growing demand for fuelwood would threaten the sustainability of the resources. In order to understand the impacts at local scale, the entire upper river basin is divided into eight sub-basins based on the major tributaries and their respective watershed areas. The central part does not fall under any of the major tributaries and was considered separately (central zone). The western part of the river basin has three sub-basins, southern part has two sub-basins and the eastern part has three sub-basins.

Bioresource availability and energy demand assessments were done through primary and secondary data collections. The primary data collection mainly aimed at quantifying the energy needs, identifying the technological options, selection of the best options and integrating the optimal mix of technologies. Secondary data collected from government departments at district and taluk head quarters included villagewise demography and occupational and infrastructural facilities data, land holding particulars of the individual households (agriculture, horticulture, landless, etc.), household list of each village, village level data on livestock population, landuse data, cropping pattern, productivity and the daily rainfall data for the last 50 years.

In this regard, 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. Forty-two villages were selected which are distributed over the entire study area and based on factors such as per capita forest area, per capita agricultural area, etc., which have a role in the energy consumption pattern in a village.

Land holding by a family is considered as the primary criterion for selection of households for energy survey. Households were selected covering all communities from all land holding (small/medium/large) and land less categories. Totally 447 households in 42 villages were covered, which comprises households of 90 landless labourers. Affordability to advanced technologies is determined by the household income and agriculture is the main income source in the rural area. The social and cultural aspects of the households lead to their own fuel preferences. Thus, community-wise variation in the fuel type and quantity in use can be expected.

Representation of energy consumption data in terms of per capita consumption and standard adult equivalents are useful to visualize the consumption pattern and for easier comparison. Hence the analysis was done through the computation of per capita fuel consumption (PCFC) and is given by ‘eqn (1)’.

PCFC = FC/P
(1)

Where, FC ( fuel consumed in kg/day, P = number of adult equivalents.
The adult equivalents for computation of PCFC are listed in Table 2, depending on the age and sex. The total demand for a sub-basin was computed based on the total population and the annual per capita fuelwood requirement.

Quantification of the source-wise bioresources potential (sub-basin wise) was done through land cover and land use analysis using remote sensing data-IRS 1C MSS (Multi Spectral Sensor) data of 1999 and 2003. The land cover analysis shows that 70% of river basin is under vegetation indicating the predominance of bioresources. The bioresource availability under each category was obtained by multiplying the spatial extent of each land use type with the annual productivity. The annual availability is based on aggregation of biomass productivity for each type of forest patches. In the present case, the productivity of evergreen to semi-evergreen forests was considered as 3.6–6.5 tonnes/ha/year. The deciduous forests have biomass productivity of 3.9–13.5 tonnes/ha/year. The homogenous plantations were considered as 3.6–6.5 tonnes/ha/year in terms of annual biomass productivity.