Energy drove the industrial revolution in the 1800s, and drives
the information technology (IT) revolution of the 21st century.
Today, the world’s population stands at over 7 billion. Energy
usage per capita in developed countries is too high, with 4.4 t of
oil equivalent used per person per annum in the Organisation for
Economic Co-operation and Development (OECD) [1]; and developing countries are catching up. The present primary source of
energy is fossil fuel in the forms of coal, petroleum, and natural
gas. Recent oil price volatility has had a major impact on the energy sector. From mid-2014 to early 2015, the price of oil dropped
from over $100 USD to less than $50 USD per barrel, lowering the
market prices of natural gas and coal [2]. Although worldwide
energy demand is likely to increase, the energy industry cannot
continue sourcing energy from fossil fuels over the long term. A
revealing statistic is that the total global carbon emissions by the
energy sector over the past 27 years is equal to the total for all
previous years, with fossil fuels making up more than 80% of the
primary energy mix [2]. Greenhouse gas emissions have grown