AIR POLLUTION DEFINED
Air pollution is any harmful substance (such as chemicals, particulates or biological matter) contained in the Earth's atmosphere that is harmful to living organisms (people, plants and wildlife). Prolonged exposure to these substances is known to cause death or disease.
SOURCES OF AIR POLLUTION IN CANADA
The most common sources of air pollution in Canada are (in order of magnitude):
- carbon monoxide (CO)
- nitrogen oxides (NOx)
- sulphur oxides (SOx)
- particulate mater (PM)
- ammonia (NH₃)
- volatile organic compounds (VOCs)
SOURCES OF AIR POLLUTANTS
- CO & NOx: mainly from fuel combustion in vehicles (cars, trucks & airplanes)
- SOx: mainly from power generation, heating & oil & gas production
- PM: from wood burning fireplaces & forest fires
- NH₃: mainly from the agricultural industry (livestock & fertilizer)
- VOC: mainly from the oil & gas industry and the use of paints & solvents
CARBON AS A POLLUTANT
Since carbon dioxide is exhaled by humans and inhaled by plants, carbon and carbon dioxide are not pollutants since they do not pose a hazard to living things. However, many governmental agencies, such as the US EPA (Environmental Protection Agency), have recently re-classified carbon dioxide as a regulated gas since it is believed to have a warming effect on the atmosphere.
GREENHOUSE GASES DEFINED
A greenhouse gas (GHG) is an atmospheric gas that absorbs & emits radiation, thereby trapping heat in the atmosphere. The most common GHGs in the atmosphere include:
- water vapour (H₂O)
- carbon dioxide (CO₂)
- methane (CH₄)
- nitrous oxide (N₂O)
- ozone (O₂)
- chlorofluorocarbons (CFCs)
GREENHOUSE GASES: NATURAL VERSUS MAN-MADE
GHGs that naturally occur in the atmosphere are called atmospheric GHGs, such as water vapour & ozone. GHGs that are man-made are termed anthropogenic GHGs, such nitrous oxide and CFCs. Some GHGs such as CO₂ and methane originate from both naturally occurring and man-made sources.
SOURCES OF MAN-MADE GREENHOUSE GASES IN THE EARTH'S ATMOSPHERE
- Power generation (CO₂): 25%
- Deforestation (CO₂ + methane): 20%
- Road transport (CO₂): 13%
- Oil & gas Industry (CO₂): 6%
- Fertilizer (methane): 6%
- Livestock (methane): 5%
- Cement production (CO₂): 4%
- Air travel (CO₂ & N₂O): 3%
- Iron & steel making (CO₂): 3%
- Garbage & waste (methane): 3%
GHG EMISSIONS - NOT ALL THE SAME
Nitrous oxides (N₂O) are 300 times more potent as warming agents than CO₂. Methane is 20 times more powerful than CO₂. Also, different GHGs have a different life span in the atmosphere.
MAN-MADE SOURCES OF CO₂ IN THE ATMOSPHERE
- Coal burning power plants
- Natural gas extraction & combustion
- Oil production & combustion
CO₂ EMISSION TRENDS: DEVELOPED VS DEVELOPING NATIONS
Global CO₂ emission have doubled in the past 40 years. Most of this increase has come from the expanded use of coal in developing nations (particularly China) which has been increasing exponentially since the year 2000.
THE LARGEST EMITTERS OF GREENHOUSE GASES
- 60% of the world’s CO₂ emission originate from China, the US and the European Union.
- Canada accounts for 2% of global CO₂ emissions.
GHG EMISSIONS AND THE OIL SANDS
Canada's oil sands emit about 60 million tonnes of GHGs per year. This represents:
- 8.5% of Canada's GHG emissions
- less than 1% of North America's GHG emissions
- less than 0.15% of global GHG emissions
PRODUCTION VERSUS CONSUMPTION: CARBON DIOXIDE (CO₂) EMISSIONS?
- Oil and gas production and combustion account for approximately 55% of global man-made CO₂ emissions.
- Approximately 25% of the carbon contained in crude oil is released in the production phase, though oil extraction and refining.
- The balance (75%) is emitted during the combustion of the oil products (manly by railcars, trucks, automobiles, motorcycles, power generation, power tools and marine transport).
PRODUCTION THROUGH COMBUSTION: SOURCES OF AIR EMISSIONS
1. BITUMEN EXTRACTION: In order to extract bitumen, a significant amount of steam or heat is required to reduce the viscosity of the bitumen, particularly when extracted in-situ. Also, surface mining operations require a large fleet of mining vehicles to transport the oil sands to the main processing plant. These vehicles are typically diesel-fired which adds to the total emissions from bitumen extraction. Extraction emissions are the highest in thermal in-situ oil sands operations and the lowest in conventional light-oil production.
2. FLARING & VENTING: Some crude oil deposits contain a significant amount of dissolved natural gas, which is typically separated, recovered and sold to market. However, some countries lack the infrastructure to capture this gas and therefore opt to flare (or burn) the dissolved gas. Emissions from natural gas flaring is particularly high in Russia, Iran, Nigeria, the US and Angola. Flaring emissions are relatively low in Canada, where flaring is monitored, reported and tightly regulated.
3. FUGITIVE EMISSIONS: Fugitive emissions are defined as the unintended or uncontrolled release of gasses through valves, fittings, seals or flanges. Fugitive emissions tend to be higher in older refineries (which use older equipment and piping) and lower in newer facilities.
4. TRANSPORTATION OF CRUDE OIL: All forms of oil transportation require some form of energy (rail, pipeline, tanker or transport trucks). Air emissions during transport are a function of distance, API gravity and mode of transport. As a general rule, transport by ship is twice as carbon intensive as transport by pipeline for a given distance and volume.
5. UPGRADING & REFINING: Emissions from upgrading and refining is a function of API gravity, sulphur content and the process configuration. Heavier oils require more energy to refine than lighter crude supplies. Refineries release emissions into the atmosphere when cracking the heavy hydrocarbon molecules and during the removal of sulphur.
6. COMBUSTION: The combustion of hydrocarbons (fuel oils or natural gas) releases carbon dioxide (CO₂) and water. Combustion is where 70-80% of the total carbon content contained in the fuel is released to the atmosphere.
WHERE GHG EMISSIONS ARE RELEASED
- 75-80% of GHGs contained in a barrel of oil are emitted during combustion of the fuel by the end user
- 12-15% are emitting during upgrading & refining
- 7-10% are emitted during extraction & oil production
- 1-2% are emitted during crude oil transportation.
BITUMEN VERSUS THE AVERAGE CRUDE OIL BASKET
The life-cycle carbon footprint of the Canadian oil sands is on average 3-9% greater than the average US imported crude oil blend. This difference is attributed to greater emissions during bitumen extraction. However, significant technological advancements are helping to improve operating efficiencies and reduce this gap. Currently, the carbon footprint of fuels produced from oil sands is on par or better than heavy oil production form Venezuela, Mexico and California. The carbon footprint of oil produced from the oil sands has been steadily declining in recent years.
BITUMEN VERSUS LIGHT CONVENTIONAL CRUDE
- Extraction of bitumen from the oil sands is more carbon intensive than conventional light crude due to the higher amount of steam required to reduce bitumen viscosity, particularly for in-situ operations. This heat is generated from the burning of natural gas, which adds to the total carbon footprint.
- Surface mining requires a large fleet of diesel-powered trucks and shovels to haul the oil sands and overburden. The combustion of diesel adds to the carbon footprint of bitumen extracted from oil sands mining operations.
- Bitumen produced from the oil sands sometimes requires the added step of upgrading to break down the heavy hydrocarbons into lighter components. This adds to the energy intensity of oil sands.
PUTTING IT IN PERSPECTIVE
- Canada's total greenhouse gas emissions for 2011 was about 700 million tonnes. This is down from a peak emission of 750 million tonnes emitted in 2008.
- Canada's oil & gas sector accounted for 163 million tonnes emitted in 2011. In 2013, about 62 million tonnes was specifically from oil sands.
- In 2011, Canada's oil sands accounted for 55% of total Canadian oil production. That number has been steadily rising while GHG emissions have been relatively flat.
- Globally, the oil sands account for 0.13% of the world's GHG emissions.
SEPARATING FACT FROM FICTION: ALBERTA'S "TAR" SANDS NOT AS DIRTY AS ADVERTISED
Anti-oil sands groups have labelled the Alberta oil sands the "dirtiest fuel on Earth", often proclaiming oil produced from the oil sands to be over 30% more carbon intensive than oil produce elsewhere in the world. In fact, bitumen produced from the oil sands is only slightly more carbon intensive than the average crude and actually less carbon intensive than other streams of heavy crude from around the world. Here are some things to consider:
- About 75-80% of the carbon contained in a barrel of oil is emitted during combustion by the end user (mostly through the burning of gasoline & diesel in vehicles). This is equivalent for all types of crude regardless of source. Oil combustion is sometimes omitted from carbon emission calculations in order to magnify the differences in emissions from the different sources of oil.
- Canadian oil sands (and Canadian oil production in general) have very low flaring rates. Flaring is exceptionally high in countries which lack the infrastructure to capture the natural gas contained in the oil reservoir. These sources of oil supply (including Russia, Iran, Nigeria, Angola and the US) are very carbon intensive, often higher than production from the oil sands. However, flaring rates are not widely reported in most countries and are sometimes omitted from carbon intensity calculations.
- Alberta's oil sands produce excess electricity from their co-generation power plants. This excess electricity (produced by burning natural gas) is sold back to the Alberta power grid, which offsets electricity production from coal. As co-generation plants become more and more common in Alberta, this is helping to reduce the carbon footprint of the oil sands.
- Crude oil produced from Alberta's oil sands is generally transported to the North American market by pipeline, which is 50% less carbon intensive than transportation by crude oil carrier. For example, oil supply to BC is pipelined from Alberta. This method of transport is far less carbon intensive than Middle Eastern oil shipped to Eastern Canada by crude carrier. Also, pipelines which operate in regions with hydroelectric or nuclear power (such as Quebec, Ontario and BC) have zero carbon emissions.
REDUCING EMISSIONS FROM THE OIL SANDS: ACTION PLAN
There are countless initiatives being undertaken in the oil sands all in an effort to reduce greenhouse gas emissions and air pollutants. Some examples include:
STATE-OF-THE-ART MINING FLEET: As with all commercial & industrial vehicles (such as cars, trucks and airplanes), newer vehicles tend to be much more fuel efficient and clean-burning than older vehicles. Oil sands mining operators strive to use the latest and greatest mining equipment, particularly heavy haulers which transport the oil sands to the main plant site. This ensures the maximum fuel efficiency and lowest emissions from the mining fleet.
LOWER TEMPERATURE PROCESS WATER: By lowering the temperature of the oil sands slurry water, oil sands mining facilities can reduce the amount of natural gas required to burned. Oil sands operators have learned to minimize water temperature without compromising bitumen recovery rates. This reduces the steam load for the overall facility.
BETTER HEAT INTEGRATION IN UTILITY PLANTS: Waste heat generated by the cooling of bitumen products is used to warm the process water used at the front end of the process plant. Heat integration helps mining facilities reduce the heating load for the Utility Plant and lowers overall natural gas consumption.
TAILINGS THICKENERS FOR WARM WATER RECOVERY: Tailings streams produced by oil sands mining facilities are generally 50 to 60ºC, containing a significant amount of heat which is typically lost in the tailings ponds. Some oil sands operators have successfully installed thickeners in their tailings circuit; these thickeners recover the warm water in the tailings stream and recycle this water (and this heat) back to the front end of the plant for use as process water. This reduces the overall heating requirement for the mining facility and lowers GHG emissions.
MORE CO-GENERATION PLANTS: A co-generation (CoGen) plant burns natural gas to simultaneously produce steam (required for the process) and electricity (required to power the process equipment). Co-generation plants reduce the load on the Alberta electricity grid, which uses coal-fired power plants. Excess electricity can be sold back to the grid. This helps offset the carbon footprint of the overall process. Almost all full-scale oil sands facilities in Alberta use co-generation power plants for the production of both power and steam.
SOLVENT-ASSISTED THERMAL IN-SITU EXTRACTION: In-situ extraction of bitumen from oil sands requires a large amount of steam to reduce the viscosity of the bitumen; this allows the oil to flow to the production well and be pumped to the surface. In order to reduce the volume of steam required, the use of solvents (such as propane or butane) and/or chemical agents can be used to reduce the viscosity of the bitumen. Bitumen heating by combustion is also being tested to eliminate or reduce steam requirements. These initiatives will all improve the efficiency of oil extraction and reduce natural gas consumption.
CARBON CAPTURE & STORAGE (CCS): There are 2 CCS projects currently under construction in Alberta. CCS involves capturing the CO₂ produced by the process plant, compressing it and injecting it deep underground. The first operation is scheduled to start-up in 2016. Once operational, these facilities will remove 28 million tonnes of CO₂. This is equivalent to taking 550,000 cars off the road.