Abstract
Long term energy sector planning is essential for a country to achieve sustainable development in all its social, economic and environmental dimensions. Furthermore, it will ensure the energy supply security of the country. The energy supply side needs to deal with technical, economic and environmental assessments of all energy supply options such as natural resources, energy imports, energy exports etc. The energy supply side should follow policy directives of the government and should take into account all other related constraints. Similarly, the demand side too has to deal with the assessment of future energy needs of various consumption sectors, policy directives etc. In this study the software MESSAGE was used to model the energy chains associated with petroleum, coal and Natural Gas (NG) in relation to Sri Lanka. The national energy chain was modelled considering the modernizations of the existing refinery through the introduction of NG to the energy sector and the introduction of electric vehicles. In addition, the viability of constructing a urea plant was also explored.