Mitigation of peak oil is another alternative, and combined cycle power generation using natural gas is the cleanest source of power available using fossil fuels, producing about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. The major difficulty in the use of natural gas is transportation and storage because of its low density. Natural gas pipelines are economical, but are impractical across oceans. Due to its high energy density and ease of handling, oil has a unique role as a transportation fuel. There are, however, a number of possible alternatives. Among the biofuels the use of bioethanol and
Environmental impact of hydraulic fracturing life cycle of oil or coal. Until recently, Canadian provinces such as Alberta, Saskatchewan, and Nova Scotia produced over half of their electricity from coal combustion whereas Ontario has already completely phased out coal-powered electricity. Switching from coal- to natural gas-powered electricity can reduce carbon dioxide emissions by ~50% and also decrease the amount of NOx and SOx emitted to atmosphere. Lack of baseline data or before-and-after hydraulic fracturing sample collection and analysis makes it challenging to quantify environmental impacts (if any) resulting from hydraulic fracturing. Hydraulic fracturing fluids include proppants and other substances, which may include toxic chemicals. In