Prospect and advancement of solar irrigation in Bangladesh: A review
Bangladesh is an agrarian country where rice is the main food of nearly 161 million population and about two-third of the total population directly or indirectly involves with agriculture. Agricultural sector of the country contributes about 16% of the gross domestic product. In average, 1.9 million people are being added every year which creates additional rice demand of over 350 thousand metric tons. On the other hand, due to rapid urbanization and industrialization, the country is significantly losing its cultivable land. In 2015, the cultivated land for rice was about 10.7 million hectares which will be reduced to 10.28 million hectares by next 5 years. At present, about 1.43 million diesel-based pumps and 320,557 electricity-based pumps are in operation for irrigation, which consume more than 1.06 million tons of diesel and near about 1400 MW electrical power, respectively. The irrigation pumps emit about 7 million tons of carbon dioxide every year which significantly pollutes the environment. Bangladesh is one of the energy starving countries, only 60% of its population has access to electricity. A huge amount of diesel fuel is required to import to mitigate the country's energy demand as the country has very limited fossil fuel resources. In the year 2011-2012, the total imported diesel fuel was 2,884,614 metric tons. In order to maintain a reasonable diesel price, the government had to subsidy around USD 0.3/L of diesel in recent years. However, the geographical position of Bangladesh is ideal for solar energy utilization which can be harvested from everywhere of the country. The annual solar radiation is as high as 1700 kWh/m2 with the variation of daily average solar radiation of 4-6.5 kWh/m2. Therefore, solar irrigation may be an alternative way to increase production of crops without creating extra pressure on grid power or diesel fuel, and also helps to keep the environment clean. Bangladesh government has taken an initiative to replace 18,700 diesel based irrigation pumps by solar irrigation pumps with average capacity of 8 kWp each. More than 300 solar pumps have already been installed all over the country. In order to enhance the solar irrigation program, Bangladesh government has given attractive incentives, e. g. providing 50% subsidy and arranging 35% soft loan with the aid of donor agencies. Under the program, owners or individual investors require to invest only 15% of the total cost. This paper aims to review the prospect, necessity and technical challenges of solar irrigation in Bangladesh. A comprehensive review of current research and developmental activities taken by governmental and nongovernmental organizations, and possible future directions of research to develop a reliable and cost-effective solar irrigation system are also presented in this article. In addition, the review points out the way of investment opportunities in agricultural sector for sustainable development of the country.