As a fossil fuel, natural gas is much cleaner than oil and coal in terms of carbon dioxide, soot and other pollutants after burning. The US has one of the largest gas deposits in the world known as the Marcellus Shale under the Appalachian region in the northeast. This carries the prospect of significant reduction of US dependence on foreign energy. At present, more than 60% of US oil consumption comes from foreign countries, most of which are not friendly, whereas nearly all natural gas comes from domestic sources.
The following statistics show great potential for natural gas in the US: only 25% of electricity generation is derived from burning gas, 21% for residential heating, and merely 1% for transportation. The biggest potential lies in the transportation sector where natural gas directly competes with oil for land and sea transports as a conventional fossil fuel.
Despite being abundant, cleaner and cheaper, why is the usage of natural gas so low? The reason is that the competitors are difficult to beat. Although being dirty fuels, oil and coal have established stronger infrastructure and political support. Worse, a new alternative recently appears on the scene, which is bio-fuel generated from corn. Although clean and renewable, this bio-fuel compels people to choose between food and oil that doesn’t make any sense at all, but has managed to receive billions of dollars of government subsidy. Due to strong political lobby, these competitors enjoy favorable terms in taxation, subsidy, and misplaced priority.
On the other hand, the combined pressures of national security, spiraling oil prices, climate change due to CO2, and rising corn prices will increase the appeal of natural gas as the best fossil fuel. As time passes, natural gas will replace more and more oil, coal, and corn-based bio-fuel, while green energy such as solar and wind continue to develop. Three factors determine the growth of usage of natural gas: adaptation, infrastructure, and extraction.
Adaptation is most relevant for the transportation sector. On land, car engines must be modified to run on natural gas. The investment is not expensive. There already exist 10 million cars worldwide that run on compressed natural gas (CNG) costing 40% less compared with gasoline. In the US there are only 110,000 CNG vehicles consisting mainly of city buses and garbage trucks. However, corporations have seen the low cost and are switching over to natural gas for their company fleet, notably, UPS and AT&T. The greatest potential lies in the conversion of heavy commercial trucks and trains that go long distances across statelines, and maybe passenger cars too, in the future.
One area of neglect is sea and river transport. How much tonnage is moving around the world on water including both cargo and humans? It must be comparable to land although it is hard to quote a figure. Since diesel is now used in most water transports, the savings would be tremendous by switching over to natural gas. The adaptation of marine diesel engines to run on natural gas would take place once diesel price has risen to a new threshold level.
Second, a substantial infrastructure already exists in the US for gas transfer in pipelines, and storage in the form of liquefied natural gas (LNG). Some countries, especially Australia, are building more ocean-going vessels to transfer domestic liquefied gas for sale overseas. When demand increases, the existing infrastructure will be upgraded. For land transport, if natural gas is to expand to commercial trucks and passenger cars, a network of storage and refill stations will be required (same is true for electric cars).
Third, extraction presents a challenge if the Marcellus Shale is to be fully utilized. This huge deposit requires drilling deeper into the layer of shale rock where the natural gas is trapped. The drilling then continues horizontally within the shale layer. The horizontal pipe carries explosives to blast open cracks in the rocks. Water, sand and some chemicals are pumped in with high pressure to force out the natural gas through the pipe. This extraction method is known as fracking. The environmental problem is possible contamination of the water table above the shale layer. The drilling companies have been asked about the chemicals being used in the process. So far, they have declined to provide the specifics, thus fueling suspicions about their intention and the toxicity of the chemicals used. Until the pollution issue is settled, the Marcellus deposit remains a great potential only, to the pleasure of the oil and coal industries.
Natural gas is the cleanest of all fossil fuels being used in our established system. While we are moving gradually toward renewable green energy such as solar and wind, natural gas presents itself as the best fossil fuel in many respects. There is no reason to inhibit its substituting oil and coal as an intermediate measure for building a green energy future.