Region 2: Energy in the Central Lowland

The use and production of coal is big in this region, providing the majority of power, followed by hydropower and petroleum. The most important sources of coal come from Pennsylvanian period deposits in the Illinois Basin in Southern Illinois and part of southern Indiana (Figure 7.4). Coal from these deposits is relatively sulfur-rich bituminous coal.

The use of coal has declined in recent decades, associated with environmental concerns about acid rain. However, through the widespread use of technology that removes sulfur dioxide at coal-fired plants, mining from these deposits has recently begun to increase again. There are also small Pennsylvanian-age coal deposits in central Michigan.

Figure 7.4: Distribution of coal mining in the Midwest.

Figure 7.5: Distribution of oil and natural gas drilling in the Midwest.

Coal

As leaves and wood are buried more and more deeply, pressure on them builds from overlying sediments, squeezing and compressing them into coal. The coal becomes gradually more enriched in carbon as water and other components are squeezed out: peat becomes lignite, bituminous and eventually anthracite coal, which contains up to 95% carbon. Anthracite has the fewest pollutants of the four types of coal, because it has the highest amount of pure carbon. By the time a peat bed has been turned into a layer of anthracite, the layer is one- tenth its original thickness.

The Carboniferous period takes its name from the carbon in coal. A remarkable amount of today’s coal formed from the plants of the Carboniferous, which included thick forests of trees with woody vascular tissues.

The largest producer of oil in the region is also the Illinois Basin, which generates about 12,000 barrels a year (Figure 7.5). Michigan increased its gas production in the late 1990s with extraction from Late Devonian period sedimentary rocks of the Antrim Shale, which is part of the Michigan Basin. Michigan produces about 1% of the US total, extracting 300 billion cubic feet of natural gas per year. Natural gas is also produced in Illinois, Indiana, and western Ohio, but not to a significant degree.

Biofuels (from biomass) also represent a significant energy resource in this region, with production and consumption on the rise. The Central Lowland is also a major oil-refining region. The Chicago area has one of the largest oil refineries in the country, with a capacity of nearly one million barrels a day.