FIRE BOMBS and shootings at German petrol stations, product boycotts across Europe and questions asked at the summit of G7 nations in Canada are all evidence of how badly Shell has misjudged public attitudes to the Brent Spar oil platform. Shell鈥檚 decision to scuttle the floating petrol station marks a milestone in one of the world鈥檚 largest waste disposal operations, as millions of tonnes of hardware from the North Sea oil and gas industries are abandoned. And if Greenpeace鈥檚 campaign of occupying the Spar is anything to go by, disposing of this junk is likely to attract maximum attention.
Last week at the G7 conference, John Major said that deep disposal of the Brent Spar is the best option. But other governments criticised this view at this month鈥檚 North Sea conference. And Ritt Bjerregaard, environment commissioner for the European Union, said: 鈥淚f we allow the dumping of oil installations, we send a political signal that the sea may be used as a rubbish dump.鈥�
The potential for environmental damage in the North Sea is huge. According to Andrew Searle, spokesman for the UK Offshore Operators Association, British companies own 219 large structures in the North Sea, out of a total of 416. These include 155 fixed platforms, weighing in all about 5 million tonnes, which are surrounded by unquantified amounts of other debris and oil-based pollution. Over the next decade, 50 large British platforms will be decommissioned at a cost of 拢1.5 billion, says the UKOOA. The Department of Trade and Industry, which issues licences for decommissioning, is already considering demolition proposals for the first 15. The question is how should they be disposed of?
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So far, nine installations, most of them small floating structures, have been decommissioned and removed entirely. The 14 500 tonne Brent Spar is the tenth and by far the largest. During the 1970s, oil from the Brent field off the Shetland Islands was piped from production platforms to the Spar, where it was loaded into tankers. In 1979 the platform was put on standby, and was finally abandoned in 1991. In February, energy minister Tim Eggar gave permission for Shell to dump the Spar in the deep Atlantic, more than 2 kilometres down and at least 250 kilometres off the West coast of Scotland.
Change of heart
When the first oil rigs arrived in the North Sea 25 years ago, nobody envisaged dumping obsolete rigs on the ocean floor. The law seemed unambiguous. 鈥淎ny installations which are abandoned or disused must be entirely removed,鈥� said the 1958 Geneva Convention on the Continental Shelf, which Britain signed. The government originally told fishermen that all the platforms would be taken away, says Alasdair McIntyre, a marine biologist at the University of Aberdeen. 鈥淣ow, they are angry to discover this is not intended.鈥�
Britain鈥檚 change of heart came after an oil industry study in 1983 estimated that the cost of removing all the hardware in the North Sea would be $7.3 billion. In 1989, the UN鈥檚 International Maritime Organization published new guidelines, which oil companies helped to draft, rejecting the simple logic of the convention. The guidelines state that platforms in water deeper than 100 metres need only be partially removed, so long as there are 鈥�55 metres of clear water above any submerged remains鈥�. But the IMO does not see this as the ideal solution: the guidelines also say that rigs put into operation after 1998 must be designed to be removed.
The Norwegian government rejects the IMO鈥檚 thinking, saying that it will remove all trace of its North Sea platforms. But in a consultation document on decommissioning published last month, the British government embraces the guidelines.
Critics such as Greenpeace say that the British government鈥檚 position as regulator is compromised. Eggar has said that because oil companies can offset the cost of decommissioning against tax, the government will pay 60 per cent of the decommissioning costs. This means, says Greenpeace, that the government is 鈥渓ooking for a cheap option鈥�.
If the IMO guidelines are followed, 鈥�111 of the present 155 fixed offshore structures must be entirely removed and 44 partially removed鈥�, says John Surrey of the Science Policy Research Unit at the University of Sussex, who has studied the problem. Most of those to be entirely removed are smaller gas-field rigs in the southern North Sea. They typically weigh less than 5000 tonnes, and are in water less than 75 metres deep. They can be picked off the seabed and taken onshore for cutting up and disposal.
The 44 candidates for partial removal are the much larger structures sited further north, typically in 200 metres of water. About half of these are made of steel and their legs could be sheared with explosives. They could then be toppled and left on their sides on the seabed, towed away and dumped alongside the Brent Spar, or dismantled on land.
The structure of steel platforms makes toppling them an attractive economic option. They have a pyramid shape, with most of the steel down deep. To remove these lower structures 鈥渨ould require many cutting and lifting operations鈥�, says the UKOOA. But because the top sections are lighter, they are easier to handle. Leaving these sections on the seabed 鈥渨ould in most cases be sufficient to 鈥� ensure safety of navigation鈥�, says the UKOOA.
For the remaining 20 or so platforms, toppling is not practicable. In some cases, the water is not deep enough. Here the industry plans to cut off very large parts of the platforms and tow them away. The remainder includes nine huge reinforced concrete platforms in deep waters, some weighing more than 200 000 tonnes. The concrete platforms are weighed down by seawater held in vast ballast chambers. In theory, these could be pumped full of air and the platforms refloated. But the British consultation document states that this would 鈥減ose particularly complex technical problems鈥�. Such inscrutable language is seen by some to imply that the government intends to support the UKOOA鈥檚 suggestion that these large concrete platforms could be left where they stand. The best alternative to this, the UKOOA says, may be total removal. The Norwegian government says that it will remove its 15 concrete platforms, although engineers in Norway privately doubt that this will be done.
Underwater collision
Partially demolished steel rigs left on the seabed could harbour pollution and snag fishing nets. Greenpeace says that toppling platforms could also disturb toxic drilling muds and chemicals on the seabed beneath the platforms, spreading the waste over wider areas. In a recent report, the environmental group describes one rig that is surrounded by about 25 000 cubic metres of drilling wastes. Recent research suggests that drilling muds containing oil are a far greater hazard to marine life in the North Sea than previously supposed (This Week, New 杏吧原创, 6 May).
Surrey says that oil companies worry that they may lay themselves open to legal liability for an accident involving a partially demolished rig. Their 鈥渨orst case scenario involves a submarine carrying nuclear weapons鈥�, he says.
But what is left on the seabed is only part of the problem. There still remains the question of what to do with what is towed away. Should the scrapped structures join the Brent Spar in the deep Atlantic, or be brought ashore?
International treaties allow ocean dumping. The Oslo Convention on the northeast Atlantic says that 鈥渂ulky waste, which may present a serious obstacle to fishing or navigation, should be dumped in not less than 2 kilometres of water and not less than 150 nautical miles from land鈥�. The convention also warns that dumping should only take place after 鈥渢he removal of all noxious or hazardous substances鈥�. The British consultation document says that decisions on dumping will be taken on a case-by-case basis, but that 鈥渄eep-sea disposal 鈥� is likely to be exceptional鈥�. The UKOOA says that 鈥渢he majority鈥� of what is removed from the North Sea will come ashore. 鈥淭he Brent Spar is a one-off,鈥� says Searle. Greenpeace wants the Spar to be brought to shore and dismantled, and fears that dumping it will set a precedent. The platform still contains 100 tonnes of oily sludges contaminated with heavy metals and low-level radioactivity, and the environmental group says that dozens of other rigs contain similar loads. Shell says 90 per cent of the Spar鈥檚 sludge is sand.
Many marine biologists share Greenpeace鈥檚 worry that sinking the Spar could set a precedent. But, at the same time, they also see deep-sea dumping as the best option in this case. 鈥淭o float [the Brent Spar] to land and dispose of it would be an immense task with many steps and many risks both to workers and to the environment,鈥� says McIntyre. 鈥淚t would be easier and safer to dump it in the deep ocean.鈥�
Martin Angel at the Institute of Oceanographic Sciences in Surrey denies that pollutants on the Spar will damage life in the deep ocean. 鈥淭he radioactivity in the Brent Spar is probably not much more than in a typical granite building in Aberdeen,鈥� he says. 鈥淎s for heavy metals, we now know that hydrothermal vents on the ocean floor are discharging heavy metals.鈥�
Angel does think, however, that Shell should have done more research before deciding to dump the Brent Spar. 鈥淣obody has done a proper environmental cost-benefit analysis of the options,鈥� he says. He also criticises the absence of detailed plans to continue monitoring the dump site.
Some marine biologists prefer to apply lateral thinking to the problem of doing away with the rigs. John Gray of the University of Oslo believes that one or two large platforms could be left intact. 鈥淭hey would make excellent research facilities,鈥� with good accommodation,鈥� he says. Also, toppled oil rigs will attract fish and could make artificial reefs. 鈥淚t is not logical to spend billions of pounds, much of it taxpayers鈥� money, on removing every last remnant of the big rigs,鈥� he says. 鈥淚t is out of all proportion to the risks.鈥� The main risk to ecosystems in the North Sea, he says, comes not from the oil industry but from overfishing. 鈥淪o the obvious thing to do is to leave the rigs behind. If the trawlermen say the rig remains will snag their nets, then so much the better. They will stay away, giving the fish some respite,鈥� he says. 鈥淭he best solution might be to turn the oil fields into no-go areas where fishing is banned.鈥�