Agricultural Biomass-Based Power Generation Potential in Sri Lanka: A Techno-Economic Analysis

Abstract

Worldwide energy costs have grown in recent years due to the dwindling global fossil fuel resources and the increased reliance on them for global energy production. This is a common scenario in many nations, including Sri Lanka. As a developing country, Sri Lanka should encourage the diversification of its renewable energy supplies using locally available resources. In this regard, Sri Lanka can promote the use of agricultural residues for energy generation. The present work explores the energy potential of the solid waste generated by the rice industry: rice straw (RS) and rice husk (RH). A new approach was developed using statistical data on rice production and paddy cultivation in each district of the island. The obtained data were integrated into a geographic information system (GIS) to provide geo-referenced results. A physico-chemical characterization of the RS and RH was conducted to correlate the properties of raw materials to their potential energy generation. As an energy generation technology, the grate-fired combustion boiler accompanied by steam turbine cycle (GFC/ST) was selected. Our findings show that the total energy capacity using by-products of the rice industry is estimated to be 2129.24 ktoe/year of primary energy, with a capacity of 977 Mwe, producing 5.65 TWh of electricity annually. An economic analysis shows ten districts have a high profit index (PI > 1). The districts with the highest PI values are Anuradhapura, Ampara, Polonnaruwa, and Kurunegala, with annual energy potentials of 286 ktoe, 279 ktoe, 231 ktoe, and 160 ktoe, respectively. This work aims to aid future policy decisions by identifying potential districts in which to develop infrastructure for energy generation using agricultural waste, thus reducing net greenhouse gas emissions (GHG) of Sri Lanka.

Preparation and Modification of Biochar Derived from Agricultural Waste for Metal Adsorption from Urban Wastewater

“…The DTG curve shows the highest degradation rate in this temperature range. The fourth step (400 • C-1000 • C) accounts for 11.9% wt of mass loss and occurs due to the continuous elimination of different types of carbonaceous components [75][76][77]. The obtained TGA profile of the RH is similar to those found in the literature for RHs [78,79].…”

“…This peak shifts toward higher temperatures for the RHB HCl sample because this sample was subjected to a second heat treatment after HCl impregnation, which already allowed for the degradation of a larger organic component amount with respect to the other samples. Finally, RHB, RHB NaOH , and RHB HCl had a third mass loss peak starting at 800 • C, which corresponds to the additional elimination of various carbonaceous components [75][76][77].…”

“…This biomass component begins to decompose at around 160 • C, but the process is sluggish, and the decomposition continues until the temperature reaches 900 • C [73]. The third stage of weight loss (48.9%) occurs from 250 • C to 400 • C and is due to the degradation of lignin and cellulose [73][74][75]. The DTG curve shows the highest degradation rate in this temperature range.…”

“…Biochar is a carbon material produced by the thermal decomposition of biomass in an oxygen-free atmosphere [27][28][29][30][31][32][33]. It is a highly aromatic compound, made up of layers of graphene and graphite structures and edge carbon atoms containing functional groups, such as carboxylic, hydroxyl, and carbonyl units [33][34][35]. It is an environmentally friendly adsorbent that can be produced from agricultural, forest, and sewage wastes [36].…”

Thermochemical Characterization of Rice-Derived Residues for Fuel Use and Its Potential for Slagging Tendency

“…It is the most important renewable feedstock (e.g., rice straw, rice husk), thus indicating considerably cheap, clean and environment-friendly (carbon-neutral) features as compared to fossil fuels such as coal [2]. As a result, there is increased interest in developing biomass-derived fuels for direct energy use [3][4][5][6][7] or converting them into higher energy density biofuels via thermochemical processes [8][9][10][11], including torrefaction [1,12,13], pyrolysis [1,14,15] and gasification [1,16,17]. Although the contents of sulfur and ash in lignocellulosic biomass are relatively lower than those of coal [1], the so-called slagging, fouling or agglomeration often causes challenges during direct energy use (i.e., combustion) and/or co-firing with coal in boilers and power plants [5][6][7].…”