Supertankers drafted in to store glut of crude oil

A supertanker off Jurong Island in Singapore
A supertanker off Jurong Island in Singapore. The island state and the US gulf coast are harbouring scores of tankers just to store oil | Image: Edgar Su/Reuters

Giant oil tankers are being used to hold record amounts of crude at sea due to a global oversupply that threatens to overwhelm the world’s storage facilities

A record 160m barrels of oil has so far been stored in “Supergiant” oil tankers. An oil glut has followed the deepest fall in oil demand in 25 years because of the Coronavirus pandemic.

The Supertankers, which can each hold up to 2m barrels of oil, are in high demand by oil traders as land-based oil storage facilities have quickly filled up.

Oil storage facilities near a dock
Oil storage facilities

Charter rates for giant vessels that can be used to store oil have more than doubled in the last month to reach highs of $350,000 a day as traders scramble to find space for crude that cannot be sold on to refineries.

60 supertankers have so far been chartered to store oil, mostly off the coast of Singapore and in the US gulf coast. Commodity traders are hunting for extra space to store their crude as demand for oil collapses by 29m barrels per day in April compared with last year, falling to lows not seen since 1995.

Oil tanker
Oil tanker | Image: Hellenic Shipping News

Global storage facilities are predicted to be full to the brim by May. What happens when the world’s oil tanks and tankers fill up? Global oil storage capacity has an upper limit of 1.2 billion barrels*. There is virtually no optimistic scenario about oil demand so in order to avoid filling tanks and tankers to the brim, producers would have to cut production by approximately 10 million barrels per day.

It’s likely an agreement to cut production will be arrived at eventually, but storing so much extra oil at sea increases the risk of a serious pollution incident. As the cost of storing oil at sea rises and becomes more lucrative, Ocean Desk will be looking for signs of physical oil dumping at sea in the following weeks.

*IHS Markit data cited by Forbes’ Sharma

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10 facts about oil tankers…

  1. The first modern oil tanker was the Zoroaster, designed and built in 1878 by Ludvig Nobel of Sweden.

2. Oil tankers fall into two basic categories, crude tankers and product tankers. Crude tankers are bigger, they move unrefined oil from where it’s pumped out of the earth to the refineries. Product tankers are smaller and move processed petroleum products to markets.

3. Due to their immense size, oil tankers only costs around two to four cents per gallon to transport oil.

4. Without oil tankers, it would be impossible to enjoy the mobility many of us take for granted. Yet, some of the worst man-made environmental disasters resulted from oil tanker accidents.

5. In 1989 one of history’s most environmentally destructive oil spills occurred in Alaska’s Prince William Sound. The tanker Exxon Valdez ran aground and gushed out nearly 11 million gallons of oil. The slick killed countless birds, sea otters and other marine life over 120 square miles of pristine wilderness and ocean.

A burning oil tanker with flaming oi spilling into the sea

6. Double-hull construction is a mandatory design feature on newly built oil tankers, partly as a result of the Exxon Valdez spill. It means the ship has two hulls, one inside the other. This offers an extra layer of protection against damage that might otherwise result in catastrophic oil spills.

7. Even in an empty oil compartment, a single spark can turn fumes into an inferno. That’s why bigger tankers have systems installed that take gas from the ship’s boiler flue, and pump it into empty oil tanks. This inert gas makes the air within those spaces nearly impossible to ignite.

An oil tankere

8. Seawater jets were used to clean the toxic oil tanks and the mixture of seawater and residue (called ‘slops’) discharged into the sea. The 1954 OILPOL Convention attempted to reduce the harm by prohibiting such discharges within 50 miles of land. Crude oil washing has fortunately replaced this practice on most larger ships today.

9. Vessels belch out vast quantities of pollutants into the air, principally in the form of sulphur dioxide, nitrogen oxides and particulate matter, which have been steadily rising and endangering human health along key shipping routes. They also create between 2 and 3 per cent of the world’s total greenhouse gas emissions.

10. Recycling oil tankers can be really hazardous. Recycling any large ship in developed world is strictly regulated and very costly, so this work is mainly done in Bangladesh, India and Pakistan. This is one of the most dangerous professions in the world since each tanker can constitute of mass toxic, dangerous chemicals and asbestos.

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10 ways to clean up an oil spill…

1. Oil Booms

The use of oil booms is a very simple and popular method of controlling oil spills. Equipment called containment booms acts like a fence to prevent the oil from further spreading or floating away.

2. Skimmers

Once the oil has been confined by using oil booms, skimmers or oil scoops can be deployed onto boats to remove the contaminants from the water surface. Skimmers are machines specially designed to suck up the oil from the water surface like a vacuum cleaner.

3. Sorbents

Sorbents are materials that soak up liquids by either absorption (pulling in through pores) or adsorption (forming a layer on the surface). Both these properties make the process of clean-up much easier. Materials commonly used as oil sorbents are hay, peat moss, straw or vermiculite.

4. Burning In-situ

In this method, the oil floating on the surface is ignited to burn it off. This in-situ burning of oil can effectively remove up to 98% of an oil spill, which is more than most of the other methods. The toxic fumes released from the burning can cause significant damage to the environment as well as marine life.

5. Dispersants

When the spilled oil cannot be contained by using booms, the only option left is to accelerate the disintegration of oil. Dispersal agents, such as Corexit 9500, are chemicals that are sprayed upon the spill with the help of aircraft and boats, which aid the natural breakdown of oil components.

They allow the oil to chemically bond with water by increasing the surface area of each molecule. This ensures that the slick does not travel over the surface of the water, and is easier to degrade by microbes. The toxicity of dispersants can affect marine organisms, especially the non-mobile ones such as corals and seagrass.

Workers high-pressure washing a rocky shore of oil

6. Hot Water and High-Pressure Washing

This procedure is mainly used in situations where the oil is inaccessible to methods of mechanical removal such as using booms and skimmers. It is used to dislodge the trapped and weathered oil from locations which are generally inaccessible to machinery.

Water heaters are used to heat up water to around 170°C, which is then sprayed by hand with high-pressure wands or nozzles. The oil is thus flushed to the water surface, which can be collected with skimmers or sorbents.

7. Manual Labour

As the name suggests, the method requires hand-held tools and manual labour to clean up the contaminants. It involves the use of manual means like hands, rakes, shovels etc. to clean the surface oil and oily debris and place them in special containers to be removed from the shoreline.

8. Bioremediation

Bioremediation refers to the use of specific microorganisms to remove any toxic or harmful substances. There are various classes of bacteria, fungi, archaea and algae that degrade petroleum products by metabolizing and breaking them into simpler and non-toxic molecules (mostly fatty acids and carbon dioxide). This process is generally not used when the spill has happened in the deep seas and is gradually put into action once the oil starts to approach the shoreline.

9. Chemical Stabilisation

Right after an oil spill, the immediate concern is to prevent the oil from spreading and contaminating the adjacent areas. While mechanical methods like using oil booms effectively contain the oil, they have certain limitations to their use.

Quite recently, experts have been using compounds like ‘Elastol’, the compound gelatinizes or solidifies the oil on the water surface and thus keeps it from spreading or escaping. The gelatin is easy to retrieve, and this makes the process highly efficient.

10. Natural Recovery

The simplest method of dealing with the oil spill cleanup operation is to make use of the vagaries of nature like the sun, the wind, the weather, tides, or naturally occurring microbes. It is used in certain cases when the shoreline is too remote or inaccessible, or the environmental impact of cleaning up a spill could potentially far outweigh the benefits.

The treatments follow a general rule: (All distances measured from the shoreline)

  • 200 nautical miles and beyond – No treatment is used, unless the case is very severe.
  • Between 20 and 200 nautical miles, booms and skimmers may be used.
  • Between 20 and 10 nautical miles, dispersants are used.
  • For areas very close to the shoreline, biological agents are used.

These are only general rules and can be altered based on the type of oil that has been spilt and the prevailing weather conditions. No two oil spill cases are the same, so each one is evaluated individually based on its own merit.


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