POTENTIAL AND PROSPECTS OF SOLAR-ENERGY IN UTTARA-KANNADA, DISTRICT OF KARNATAKA STATE, INDIA

Solar energy can meet a large variety of the small-scale decentralized energy needs of a region. The design of solar devices depends on the global and diffuse solar radiation data. Estimation of solar radiation for Uttara Kannada district is done on the basis of solar and other c limatological data available at stations located at Karwar, Honnavar, Shirali, Mangalore, and Goa. A variety of empirical equations for esti mating monthly global solar radiation exist in the solar energy litera ture. The most commonly used empirical formula is the one that relates sunshine duration and global radiation, also referred to as Angstrom' s equation. We have used this relationship to estimate global radiatio n based on 20 years of data at Mangalore and 25 years of data at Goa p rovided by the India Meteorological Department It is seen that compute d and measured values (actual values) of global radiation (GR) agree w ithin the range of 2-5% for most months. Data at Goa and Mangalore hav e been analyzed in order to improve accuracy and to establish the role of other climatological parameters, such as mean daily temperature, r elative humidity, specific humidity, minimum and maximum temperature, and rainfall. Based on the R-2 value and the least value of the standa rd error of the Y estimate, the empirical formula consisting of mean t emperature, sunshine duration, and specific humidity is the best relat ionship to estimate GR with the available climatological information. The computed and estimated values are within the range +/- 5%. With th is empirical relationship, GR is estimated (kWh/m(2)) for Karwar (with 37 years of climatological data), Honnavar (with 50 years of climatol ogical data), and Bhatkal (Shirali, with 15 years of climatological da ta). Karwar has a GR range of 5.5-6.5 for January-May and is in the ra nge of 4-5 during the monsoon months, July-September, while at Honnava r the GR range during January-May is 5.47-6.5 and is minimum during th e monsoon months. Thus this study, covering five locations of the coas tal belt of the western Ghats region, demonstrates that good solar ene rgy potential is available in this region during most months of the ye ar. The amount of solar energy that could be harnessed by utilizing 5% of the present wasteland in coastal taluks as a solar collector area, is found to be of the order of 95.72 million units (mkWh) annually fr om the coastal belt of the Uttara Kannada district alone. That means t he solar energy can meet at least 32.5% of the present electricity dem and of Uttara Kannada. This study suggests that solar conversion techn ologies have considerable potential for application, provided that que stions of storage and the monsoon season requirement can be adequately addressed through other options. The abundance of solar resources can be illustrated by comparing the land requirements of solar projects ( thermal or photovoltaic) with those of hydro or energy plantation proj ects. Except for run-of-river projects and for high head sites in deep gorges, the land requirements for hydel projects at today's conversio n efficiencies average around 25-45 times that required for solar proj ects. This means that solar energy is capable of supplying 5-10 times the electricity demand of Karnataka State while occupying a land area less than that currently used by hydel projects.