At the request of a California consortium of regulators and oil
companies, two scientists at the Ernest Orlando Lawrence Berkeley National
Laboratory, Donald Lucas and David Littlejohn, have developed a method to
measure air pollution emissions from oil storage tanks.
The new method requires a simple device fashioned from parts available at
local hardware stores for less than $20. Using this device, they are studying
how emissions from these tanks contribute to air pollution in southern
Thousands of oil storage tanks dot the landscape of oil-rich counties in
southern and central California. Typically 30 feet high and 40 to 50 feet
across, they store the crude oil extracted by pumps scattered throughout
numerous oil fields that are sometimes as small as a few acres. Drivers on
Interstate 5, one of the state's most heavily used north-south routes, are
familiar with some of these tanks, but many more lie unseen in the back
country, out of view of the state's roadways.
Trying to meet the goals of the Clean Air Act in their districts, regulatory
agencies began to develop rules that would affect heavy oil storage tanks for
the first time. However, no one has good measurements of the magnitude of air
pollution emissions from these tanks. Reducing storage tank emissions could
cost the oil industry tens of millions of dollars.
"Air quality districts have to reduce hydrocarbon emissions, and these tanks
are an obvious source that they can regulate to help meet the Clean Air Act's
requirements," says Lucas, a scientist at Berkeley Lab's Environmental Energy
Technologies Division. "But the standard method used to test emissions from
tanks, the Reid method, was designed for lighter oil products, mainly gasoline.
It doesn't work for the thicker, heavier crude oil."
The oil industry, represented by the Western States Petroleum Association,
told regulatory agencies that they would need a new method capable of
determining the actual emissions levels from these tanks. WSPA offered to fund
a scientific study.
Regulators and industry decided to band together to work out a solution to
their problem, and HOST, the Heavy Oil Storage Tank Working Group, was born. A
unique collaboration of industry and government, HOST originally consisted of
the California Air Resources Board, the Monterey Unified Air Pollution Control
District (MUAPCD), the San Joaquin UAPCD, the Santa Barbara UAPCD, the U.S.
Environmental Protection Agency and WSPA.
"HOST came to Berkeley Lab first, but it was not clear initially that there
was a scientific problem to solve. Then HOST released a request for proposals
to 17 commercial testing labs in search of one willing to develop the new
procedure and test other methods but only one submitted a proposal, and it was
over budget," says Lucas. "We became interested when we realized during
discussions with program officers at the Department of Energy that the project
offered the chance to solve a scientific problem underlying environmental
regulations with a wide impact on the oil industry."
WSPA funded $50,000 and DOE came up with an additional $75,000. DOE and
Berkeley Lab became HOST members. "The group has an unusual way of operating,"
according to Lucas. "HOST makes decisions by consensus. We meet once a month to
discuss our results. No one in the group has veto power. Berkeley Lab takes a
leadership role in conducting the research but we don't mandate any approaches.
A trained mediator helps make sure that our meetings are productive."
Accompanied by safety personnel from HOST member companies, and by a CARB
representative, Lucas and Littlejohn visited several tanks in southern
California. Using parts bought at a local home improvement store for under $20,
they devised a rugged sampler capable of transferring a little of the crude oil
from the tank to a standard analytical laboratory without exposing the oil to
the atmosphere or losing any emissions from the sample. The old Reid method
required a $500 canister.
"The sampler's design is not radically new," explains Lucas, "but we had to
prove that it could work here. The Reid method only measures the total pressure
of the vapors above the gasoline. We measure the total vapor pressure, as well
as how much water vapor, carbon dioxide, methane, ethane, and the heavier
components of the crude oil, the so-called reactive organic compounds are in
the sample. This is important because only the reactive organic compounds are
covered by emission standards and contribute to urban air pollution."
In addition to the sampler, the researchers also tested and developed other
procedures for testing the crude in the lab, and on-site at the oil field.
Using a mobile laboratory facility, it is possible to run continuous emissions
tests of a tank 24 hours a day.
With oil companies providing logistical cooperation such as running power
lines, and renting trailers and lifts, Lucas and Littlejohn made measurements
at six tanks. These published results show that the measured tanks emit less
than a pound of reactive organics per day, much less than was expected.
Thanks to an additional year of funding by DOE and WSPA, they are now testing
more tanks over a wider area of southern California, to get a better idea of
the magnitude of emissions. "Also, we are moving toward certifying the test
procedure with the American Society of Testing and Materials," says Lucas. ASTM
certification would give air quality districts and regulated entities
throughout the U.S. a standard test of the tanks.
"This is an example of how industry and the government can work cooperatively
to solve problems with both scientific and political issues," concludes Lucas.
"Berkeley Lab's contribution was to bring independent, scientific credibility
to the project."
The researchers presented their work at the Society of Petroleum
Engineers/Environmental Protection Agency Exploration and Production
Environmental Conference, and have published their account in SPE's
Berkeley Lab is a U.S. Department of Energy national laboratory located in
Berkeley, California. It conducts unclassified research and is managed by the
University of California.