Electricity mix based on coal and gas

Electricity mix based on coal and gas – Since the late nineteenth century, coal has been a dominant source for electricity generation. Natural gas entered the energy mix of many countries in the 1920s, and since the 1960s has become increasingly important. Today all the large economies of the world are dependent on these two fuel sources for the majority of their power. The exceptions are a few nuclear and hydro-powered nations. For example, France is over 70% dependent on nuclear power, and Brazil is over 85% dependent on hydro. 

Electricity mix based on coal and gas

The main reason for coal and gas-powered economies across the world is their truly low cost, high energy content, and because we can easily store them and generate power when we want where we want. The highest-quality coals contain 26-33 MJ per kg, and natural gas contains 34-39 MJ per kg in energy value. Today the retrieval of 1,000 kilograms of coal and their conversion into electricity provides enough energy to power 10 refrigerators for an entire year, at a labor cost of less than a single hour.

Electricity mix based on coal and gas
Figure 1.

Natural gas has become the main source of cheap power in countries where large gas fields have been discovered, including the United States, Russia, northern Europe, and the Middle East. With nearly no processing or labor needed, its cost is extremely low. The price of natural gas in the US market fluctuated between $30 and $50 per 1,000 m3 in the twentieth century prior to the oil crises. It grew four-fold to $180 per 1,000 m3 during the oil crises, and stayed high until the rock bottom $50 per 1,000m3 price, as a consequence of the US shale revolution. Similar price trends can be observed in other countries (figure 1). Still today, a 1,000 m3 of natural gas, obtained with less than an hour of labor, can supply heat for a single household for close to an entire year in colder climates. 

The rise of natural gas as a global source for power generation started in the 1960s. The first large-scale pipeline export of natural gas was established in the 1970s from Norway to northern Europe as well as Russia via Ukraine, and from Canada to the United States, and in the 1980s from northern Africa to southern Europe. Today these are still the biggest pipeline systems, through which nearly 70% of all pipeline-exported natural gas flows.

Since the 1990s, cross-continent transport of natural gas has also become possible thanks to the liquefaction of natural gas. In this process, the gas is cooled down to -162 degrees Celsius (- 260 degrees Fahrenheit) so that it becomes a liquid, after which it can be pumped onto a special storage vessel called a Liquified Natural Gas (LNG) tanker. As the tanker sails across the oceans it burns some of the gas to power the engines, and arrives at a facility where in turn the liquid is converted back into gas by gradual heating. 

Once gaseous, the natural gas can be transported to a power plant in the country of destination. Today about 10% of produced natural gas is exported to other countries via LNG transport, and 20% is exported by pipeline.

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