Tag Archives: oil spill

exxon valdez oil

Oil Spill Du Jour

This week connects several events. The 25th anniversary of the Exxon Valdez oil spill, the first anniversary of the Pegasus pipeline rupture in Mayflower Arkansas, and a brand spanking new oil spill in the Houston Shipping Channel of coastal Texas.

On March 24th, just after midnight the Exxon Valdez, loaded with over 50 million gallons of crude oil steamed out of Prince William Sound. Before the supertanker cleared the sound however, the ship collided with a reef which tore open the single walled hull releasing about 20 million gallons of crude oil. Twenty five years later oil can be found under rocks around the beach of the sound.

Exxon Valdez attempted cleanup

Exxon Valdez attempted cleanup

In a very short time hundreds of thousands of seabirds, thousands of sea otters, hundreds of sea lions and whales, and even 47 bald eagles were killed. A robust herring fishery has yet to recover. Damage to the local economy was devastating. Bankruptcies of both businesses and individuals shot up, and many families had to leave their ancestral communities for lack of jobs.

On March 29th an ExxonMobil pipeline ruptured and began spewing crude oil into the yards and streets of Mayflower Arkansas. The estimated quarter of a million gallons of crude, actually a substance known as dilbit, came from the Tar Sands of Alberta Canada. It is a mixture of tarry crude oil known as bitumen and and a diluent of lighter hydrocarbons, hence the name dilbit. Over a score of homes were evacuated. The dibit ran down the streets and intimately into Lake Conway. The pipeline has been closed and my not be reopened due to it’s passage through sensitive areas such as the Lake Maumelle Watershed.

Mayflower, AR

Mayflower, AR

On March 22nd a barge tow was struck by another vessel, releasing just under a quarter million gallons of a material know as bunker fuel – essentially heavy crude oil. The material is so viscous that it requires heating to flow threw fuel lines to burn in ship’s engines. Because of the spill, one of the busiest shipping lanes in north America was closed. This shut down oil refineries that produce over ten per cent of the oil refined in the United States.

Oil covered Shore Bird

Oil covered Shore Bird

So what connects the events besides late March? Human error. Every one of these events were due to multiple errors. Double walled hulls on the Exxon Valdez, and better navigation could have prevented the disaster in Alaska. The closure of the Houston shipping channel could have been avoided by better management of shippers involved. The ship which collided with the barge was already under probation for other problems. Replacement of aging pipelines and more frequent inspections could have prevented the Mayflower spill.

There are over 20,000 oil spills reported annually to the EPA. Some are minor and some not so minor, but they point out just how common the events are. In aggregate the economic and personal losses are large and generally unaccounted for when we look at the price of fossil fuels. The level of collateral damage we are willing to accept to avoid changing our lifestyle is staggering.

Mayflower Oilspill and its Connection to the Keystone XL Pipeline

The ruptured pipeline and the expanding environmental disaster in Mayflower, Arkansas has a back story that began in Athabasca, Alberta. First the local story. To date Exxon has removed about a half a million gallons of a crude oil/water mixture from the area. News photos show that not only has the oil fouled numerous homes in the area but also run into nearby wooded areas and Lake Conway. Several families were evacuated, and clean-up of the affected neighborhood may take months or more.



If that was all to the story it would be bad enough, but the source of the crude oil adds a much larger degree of environmental degradation in Canada and a greater risk of degradation here in the United States. The oil flowing through (or out of) the pipeline in Mayflower began as a tarry substance known as bitumen. The stuff could only be described as a relative of crude oil. It is thick as cold molasses and is commingled with sand in vast beds in Northeastern Alberta, Canada.

Production of crude oil from the sands begins with a huge strip mining operation. The gunk is excavated and then trucked to processing facilities where it is heated with steam to lower the viscosity so it can be separated from the sand and clay. It is still too viscous to send through a pipeline so the bitumen is chemically processed with hydrogen.

The total process from strip mining, steam heating, and hydrogenation requires a large amount of energy and local environmental degradation , making this source of crude oil costly and inefficient. In fact this whole process would be near impossible were it not for a source of natural gas to provide energy for the processing. It makes one wonder why we just don’t buy the natural gas, instead of the oil resulting from the process?

The processed crude oil then makes its way through a network of pipes including the Exxon pipeline in Mayflower, to refineries in the midwest and gulf coast region. A measure of just how inefficient the production and shipment of the oil can be seen in a calculation called the EROEI, or the energy returned on energy invested. The higher the ratio the more efficient the process. For the tar sands the ratio is less than three to one.

The production of fossil fuels as an energy source is absolutely and completely dependent on the energy returned on energy invested (EROEI). If it takes more energy to obtain a fossil fuel than the fossil fuel delivers on use, then it is not an energy source. It is a waste of energy.

Consider the EROEI of some other fuel sources. In the earlier decades of the 20th century, the EROEI for crude oil in the U.S. was close to 100:1, that is to say one barrel of oil invested in exploration/production produced about 100 barrels of oil. Conventional crude oil today has an EROEI of about 20:1. Compare this to the EROEI for tar sands at less than 3:1.

Paraphrasing a late-night infomercial, BUT WAIT, THERE’S MORE. Lower EROEIs mean greater amounts of greenhouse gases emitted for useful energy produced. Fuels such as natural gas have relatively low greenhouse gas emissions compared to conventional crude oil, which has less than coal. The low EROEI means that bitumen processing and use makes it as bad as coal in terms of greenhouse gas emissions.

Additionally, a lot of water is required to process the tar sands. Roughly 5-10 barrels of potable water are converted to oil fouled waste for each barrel of oil produced. Although there are tar sands in Utah and thereabouts, the resource may never be extracted due to the lack of process water.

The tar sands of Alberta is the raison d’etre for the proposed Keystone XL pipeline, which will be ten times the size of the ruptured pipeline in Mayflower. We really don’t need the additional pipeline capacity, it causes environmental degradation where it is extracted, and has the potential for more damage due to spills such as is occurring here, and its use will greatly contribute to global warming.