It is more than six weeks since the Deepwater blowout and notwithstanding the truly sad pictures of birds covered in oil, loss (unseen) of marine life and serious environmental damage, I think it important that people should reflect a little more on how society's demand for oil (and not just BP's) have brought this disaster upon the Gulf.
Monetary and Ecosystem Losses
Monetary costs incurred by BP include containment and clean-up of the spill, future settlement of claims against the company and a major fall in the value of its shares that will hurt investors, as well as employees. Other parties liable to losses include service companies who will see a significant fall in earnings as a result of the moratorium on deep water drilling in US waters, as well as those 
whose livelihoods depend on tourism and produce from the sea, shorelines and estuaries now contaminated by oil. Although I don't have any figures to hand, I would not be surprised to learn that more people in the region rely on the drilling industry for a living than those who depend on the Gulf for its environmental productivity - see for example a recent news item that Anadarko the oil independent has invoked force majeure and terminated offshore drilling at 3 separate locations.
It is difficult to quantify the impact that large amounts of crude will have on the wealth generating capacity of the Gulf's biotic resources. Unlike the rapid and controlled combustion of petrol in an engine, the direct release of crude into the sea overwhelms the natural environment's ability to oxidise the pollutant by biological means. It can and will recover with time, but for the moment parts of the Gulf are witness to the destructive power of the chemical energy stored in hydrocarbons.
Further information on the potential impact of pollutants and their interaction with the environment can be found in the work of the late Howard T. Odum, amongst whose many publications is a book titled Environmental Accounting. Deserving of detailed study, page 130 of the book includes an 'emergy' analysis of the Exxon Valdez oil spill of 1989 (similar in magnitude to the quantity of crude that could eventually be released by Deepwater Horizon) which suggests that the loss of biological productivity was considerably less than the gain to the local economy after damages had been awarded and other financial assistance had flowed into the area. Of course, such an analysis overlooks the incremental loss of environmental productivity across the globe arising from such incidents, but in the short term the economic gain from exploiting the stored energy content of hydrocarbons including oil, gas and coal continues to outweigh that generated by the productivity of a coastal zone such as the Gulf's.
A Few GHG Numbers
Whilst many have expressed anger and concern about the impact that continued leakage of crude is having on the Gulf's ecology, it's seashore and the salt marshes of the Mississippi delta, I imagine few have stopped to reflect on the potential impact this same crude would have if it had been collected without leak, refined to produce gasoline and then burnt in people's cars before dispersal to the atmosphere. In such circumstances, few would perceive any impact on the environment, probably because there would be no visual imagery to provoke any sense of outrage.
Surprisngly, the quantity of greenhouse gas released directly by the blow-out appears to be relatively small as the following estimate reveals. Some of the numbers I have used are based on values from the Oil Drum which has provided detailed and excellent coverage of the incident these last few weeks and from a respondent (Paul K2) who posted some figures (now amended by this author) to the following New York Times article about BP agreeing to stream live video of the blowout. The calculation also assumes that all the gas contained in the crude rises to the surface from the blow-out preventer (BOP) which is located on the sea floor at a depth of some 1,560 meters. In practice, this may not occur if the oil containing gas (as a liquid) remains at depth or if the gas released forms hydrates before it reaches the surface.
- Estimated rate of leakage = 20,000 barrels of oil per day (bopd).
- Apparent gas to oil ratio = 2,000 standard cubic feet per barrel (SCF/bbl)
NB: The pressure of water at the depth of the blow-out is high (156 atmospheres) and sufficient to keep gas in a liquid state. This means that the flow of 'liquids' shown leaking from the damaged BOP is a mix of crude and 'supercritical' gas. At the surface (atmospheric pressure) this gas would occupy a volume of 2,000 cubic feet (ft3) for every barrel of oil produced, but at the depth of the blow-out it occupies somewhere closer to 13 ft3. The volume of one barrel of oil is typically around 5.6 ft3 and on this basis close to 70% of the 'liquid' seen escaping from the well may actually be pressurised / liquid gas. This may be the reason for the apparent mismatch between leakage rates that BP has quoted and the public's perception of flowrates based on webcams of the damaged well. - Total gas capable of reaching the surface = 20,000 x 2,000 = 40 million standard cubic feet a day = 1,070,000 Nm3/day or approximately 870 tonnes per day, assuming the average density of natural gas = 0.8 kg/Nm3.
- Assumed methane content of gas = 85%
- Methane (greenhouse gas) released = 740 tonnes per day.
- Equivalent 100 year greenhouse warming potential = 18,500 tonnes of carbon dioxide (CO2e) per day. NB: Combusting / oxidising 740 tonnes of methane would generate approx 2,000 tonnes of carbon dioxide a day.
Blame and Response
I may be accused of downplaying the seriousness of the leak, but an estimated 20,000 barrels of oil per day (bopd) is small in comparison to a World daily production rate currently running at some 73 million barrels (10 million tonnes) of crude. This total is accompanied by any number of environmental leaks and incidents of pollution.
It is early days, but the final amount released could be less than other historic spills that include the Ixtoc blowout of 1979 which occurred in the Mexican sector of the Gulf or the wanton opening of wellheads and destruction of platforms in the Persian Gulf by the Iraqis upon their invasion of Kuwait in 1991. At the same time, the incident shows how we are reaching the limits of extractive technology and that we can expect to pay an increasingly higher price in terms of the capital and energy expended, as well as risk to the environment in seeking to discover and retrieve the hydrocarbons that sustain our life styles. Quite when society will make the connection and accept some responsibility for an occurrence such as this is not at all certain. For now, people continue to drive their cars and imagine that the problem can be solved simply by sueing, vilifying and bringing criminal charges against BP, designing better BOPs and revamping the government agencies that failed to supervise the industry.
The Financial Times in an article published in early May also questioned how US society would respond to the Deepwater incident. It concluded that it was unlikely to hasten any transition to alternative fuels for reasons that included:
- Any legislation that suggested some measure of austerity or self-sacrifice would have an uphill climb in the US. Voters will only accept 'new era' environmentalism and a focus on climate change so long as it is free. There is also a temptation to ditch 'old era' environmentalism with its focus on visible pollution, acid rain, ozone and smog, etc.
- Greening the economy, like innovations in the finance industry, involves trade-offs. However the modern voter, like the modern consumer and the modern investor does not like trade-offs. He wants windfalls.
- Companies and governments present technological innovations as pure gains. This is paid for by rounding the risk down and taking it off the balance sheet until such time as the inevitable incident (blow-out, refinery explosion, tanker spill, etc.) occurs. As others have noted in a similar accusation against companies in the financial sector, the World sanctions the privatisation of profit, but increasingly has to socialise the risk and the cost of failure.
