With the growth in liberalised electricity markets and the advent of climate change policy imposing a price on emissions, investment in the global future energy mix will be greatly dependent on the expected generation cost of alternate energy sources. The implicit capital, operating and fuel costs of major electricity generation technologies, including the cost of carbon dioxide emissions, are compared for developed and developing nations using a levelised cost of energy approach. This relatively simple analytical tool allows investors to directly compare alternative technologies which have different scales of operation and investment horizons on a stand-alone basis. The analysis demonstrates that fossil fuels will continue to remain competitive relative to nuclear, hydro and wind generation sources over the long term in OECD countries and highlights the large cost advantage of fossil fuel generation relative to renewable technologies in non-OECD nations. The study also shows that the price applied to carbon-dioxide emissions may need to significantly increase to induce behavioural change in power generation investment in the absence of direct regulation.