In Jordan, energy resources are almost nonexistent, and the country imports most of its energy. The unstable imported supply consumes a significant proportion of the GNP. Consequently, research in the renewable energy sector has emerged. Jordan produces a large volume of olive cake (OC) annually, which has a high potential as an energy source. This study involves burning OC in pulverized form in a vertical tube furnace with equivalence ratios from 0.8 to 1.4. The furnace design proved acceptable, and the pulverized OC burned efficiently. The maximum thermal and combustion efficiencies were 69% and 82%, respectively. The maximum flame temperature reached 980 degrees C, and the cooling water temperature gradient was about 20 degrees C. Exhaust gas analyses showed that the concentration of CO was below 1.61%, while the NOx emission was within 550 ppm and the SOx maximum concentration was 30 ppm. (c) 2005 Elsevier Ltd. All rights reserved.