the story behind natural gas
So, why is natural gas a better fuel than other hydrocarbon alternatives or electricity? For one, it is efficient to burn. Appliances and residential furnaces are up to 70% more efficient than comparable ones fueled by electricity, as much energy is wasted in the process of converting gas to electricity and transporting it over long distances3.
And, it is also cleaner burning than other hydrocarbon fuels. Because it is composed primarily of methane, which is a very light and simple compound, it releases fewer toxic substances per unit of energy produced.
The chart below shows a relative comparison of the carbon dioxide emissions that come from burning equivalent units of various fossil fuels. Carbon dioxide is the main contributor to global warming. The chart shows that per unit of energy, natural gas emits 25% less carbon dioxide than gasoline, 27% less carbon dioxide than fuel oil, and fully 44% less than even the cleanest coal. And, it also results in lower levels of other pollutants that contribute to other problems such as acid rain.
The picture is not all rosy though. Relative to other fuels, it is clean-burning. But because of our insatiable appetite for energy, the burning of natural gas is a significant contributor to global warming. Historically, natural gas use has produced about 10% of the greenhouse gases that contribute to global warming4. Now, emissions from the burning of natural gas represent over 20% of the annual US carbon dioxide emissions. Annually, the burning of natural gas in the US produces almost 1,200 million metric tons of carbon dioxide, more than the TOTAL carbon dioxide emissions from ALL sources of all but three other countries in the world: China, Russia, and Japan5.
There is another environmental impact as well. To use natural gas, you have to drill the wells and build the pipelines and processing plants needed to carry it safely to our homes. In the US, there are over 297,000 miles7 of natural gas pipelines and their associated easements – enough to cross the United States almost 100 times. And, the over 405,000 producing natural gas wells8 and their associated utilities and access roads eat up land as well. Many areas where gas is found are either pristine natural areas or under the ocean; drilling in both places puts industrial facilities in some of our most sensitive environmental areas.
Last, there is the issue of liquified natural gas, or LNG, tankers. In order to efficiently bring natural gas from overseas locations, it needs to be compressed under very cold temperatures to the point that it turns into a liquid. This liquid is then carried in huge (up to 900 feet long), specially designed tankers to ports where it is converted back into a gaseous form. There is much debate about the merits of such an operation. First, many sensitive coastal areas are being considered for developing these new facilities. Many people, including experts in the field, also see these ships as tempting terrorist targets: if one were to explode, it would incinerate everything within several miles of the ship. Since many ships will pass through populated waterways, any explosion could be devastating. To date, no consensus has been reached about whether the environmental benefits of burning more natural gas are worth the price and risk of bringing it here on LNG tankers.
3 60%-70% losses in generating station, 10% losses in transmission/distribution per http://resources.yesican-science.ca/energy_flow/fuel2electric.html
4 UCS, http://www.ucsusa.org/clean_energy/fossil_fuels/offmen-how-natural-gas-works.html
6 All data taken from the EPA 2006 US Emissions Inventory