Abstract: Unit electric energy pricing in a deregulated economy: a case study of delta thermal power plant in Nigeria is presented in this research. The research became necessary because of the clamour in the need to attain sustainable development without considering the indices that play vital role in nations development politically, socially, infrastructuraly and economically. Thus, for a country not to continuously have depreciated currency one of the parameters that must seriously be guided are the GDP/GNP indices and for the GDP to raise the earned foreign reserve that guarantees imports power, the local resources must be adequately harnessed and sustained, hence the importance of a vibrant power sector that ensures stable unit electric energy cost. The research reviewed, the way forward for power industries in Nigeria in a deregulated economy, the analytical principles guiding GDP/GNP estimations, cost components of electricity generation and tariff were extensively looked at. Findings revealed that index values for the Nigeria GDP/GNP are not encouraging when compared with nations of the world that are not endowed with the natural resources the country is blessed with. The cost of generating electricity in the thermal station for the period presented, considering locational marginal pricing in a competitive market forces, for power industries in Nigeria that generates <2800 MW on daily basis as at June, 2009 to survive in the present day deregulation and provide power in acceptable availability standard close to 99.8% the current subsidy by the Federal Government of Nigeria demands for urgent review with the enacted regulatory bodies in order to improve on the position she currently occupies in the survey conducted by Finfacts Ireland. This stand is important because the station with utilization factor of 62.48:1 in 2006, which has not improved in 2009, if not for government funding the station ought to be bought over by striving power utilities in developed nations. The research also, revealed an average annual unitcost for the period reviewed to be #30.73 K kWh^-1, while Power Holding Company of Nigeria (PHCN) PLC current electricity tariff range from #6.00/-12.00 kWh^-1 depending on the type of load and demand level.