Oregon’s Greenhouse Gas Emissions: In-Boundary Inventory Update
Key Takeaway: Rising Transportation Emissions
As the data summarized below clearly indicate, Oregon’s greenhouse gas emissions had been declining or holding relatively steady through 2014 but recorded a non-trivial increase between 2014 and 2015. The majority of this increase (60%) was due to increased emissions from the transportation sector, specifically the use of gasoline and diesel. [FN5] The reversal of the recent trend in emissions declines, both in the transportation sector and statewide, likely means that Oregon will not meet its 2020 emission reduction goal (more on the GHG forecast below).
[FN5: Most of the balance of the increase was in residential/commercial emissions, where action taken by the 2016 legislative session to back out coal-by-wire electricity imports and increase the Renewable Portfolio Standard should result in long-term decreased sector emissions. There is no parallel driver to reduce transportation emissions.]
More action is needed, particularly in the transportation sector, if the state is to meet our longer-term GHG reduction goals. In the 2017 session, the Oregon Legislature has an opportunity in the context of discussing a transportation funding package to prioritize policies and programs that will make material differences in the GHG emissions from transportation, and, by extension, the state’s ability to meet its legislatively adopted reduction goals.
The Commission recommends that the 2017 Legislature, in addressing Oregon’s overall transportation and transportation funding needs, use the occasion to devise and adopt measures that will bring transportation GHG emissions under control and aligned with Oregon’s GHG reduction goals.
Oregonians contribute to greenhouse gas emissions in a variety of ways, spanning nearly all of the activities that we engage in. Having a solid understanding of these emissions, including those that occur both in-state and out-of-state and from both production and consumption, is the first step to analyzing what sorts of actions might be required for us to meet our long-term emission reduction goals.
Prior to 2010, Oregon’s GHG inventory was constructed in a “top-down” fashion, using an inventory tool published by the U.S. Environmental Protection Agency (EPA). Beginning in 2010, Oregon’s largest emitters of GHGs began reporting their emissions to the Oregon DEQ as part of the mandatory GHG reporting program. In 2013, the Oregon Departments of Environmental Quality, Energy, and Transportation produced a technical report which utilized both the “top- down” method and the reported data, and provided a greenhouse gas inventory using multiple emission accounting methodologies.
The report analyzed data up to the year 2010 and described three inventories: in-boundary emissions, which are those that occur within Oregon’s borders plus emissions associated with the use of electricity within Oregon; consumption-based emissions, which are those global emissions associated with satisfying Oregon’s consumption of goods and services, including energy; and expanded transportation sector emissions, which evaluated the full life-cycle emissions from fuel use by ground and commercial vehicles, freight movement of in-bound goods, and air passenger travel. The 2015 Oregon Global Warming Commission (OGWC) Biennial Report to the Legislature contained the first update to these inventories.
This 2017 OGWC Biennial Report to the Legislature provides an update to the in-boundary emissions inventory through 2015. Although EPA’s inventory tool only currently contains data through 2013, Oregon DEQ is able to construct a “hybrid” inventory through 2015 using the most recently reported GHG data that it collects along with slightly older GHG data for other sectors available through the EPA’s tool. The data that comprise the in-boundary inventory are contained in the Appendix to this Report.
In-Boundary Emissions Inventory
Oregon’s in‐boundary inventory estimates greenhouse gas emissions that occur within the State’s jurisdictional boundary and those that are associated with the generation of electricity used by Oregonians within that boundary. This inventory includes emissions from the combustion of fuel used in Oregon, the processing and disposal of waste and other materials, the generation and transmission of electricity used in Oregon, agricultural and industrial operations, and a variety of other processes. Most of these emissions occur within the State, though a substantial share of the electricity used by Oregonians is generated out of state, and the emissions from this out of state generation are included in this inventory. Likewise, emissions from electricity generation occurring in Oregon that is used out of state are presented separately and not included in the statewide emission totals of this inventory.
Following is a discussion of the 2015 inventory, how it compares with prior years, and how the estimates of prior year emissions have changed slightly since the last inventory. [FN8] Key economic sectors and their trends are presented, followed by an examination of those sectors in greater detail. Additional information and data on sources of emissions is available in the Appendix. In addition, the Appendix contains data on per capita emissions and the carbon intensity of Oregon’s economy over time.
[FN8: We endeavor to work with state agencies to reduce the time to 1-2 years between when raw data is reported and when the updated state inventory is available.]
Table 1: Oregon Emissions by Sector, 1990-2015 (Million MT CO2e)
1990 1995 2000 2005 2010 2011 2012 2013 2014 2015
|Residential & Commercial||16.6||19.9||23.1||22.0||23.3||22.5||20.8||22.0||21.4||22.2|
Table 1 summarizes greenhouse gas emissions by economic sectors since 1990.
Transportation remains the largest contributor to the State’s in‐boundary emissions. Residential and commercial activity continues to be the second largest contributor. The industrial sector is the third largest contributor, with about half as much emissions as the transportation or the residential and commercial sectors. Finally, agricultural activity is a distant fourth. Overall, emissions declined approximately 15 percent between 2000 and 2014, but increased by 5% in just one year (between 2014 and 2015). A more detailed discussion of this increase is included below and in the sector-specific sections on the pages that follow.
Figure 2 illustrates how the state’s emissions have changed in each economic sector since 1990. Emissions from agriculture have been relatively constant, at slightly above 5 million MTCO2e each year. The transportation sector has failed to show needed emissions reductions, remaining mostly flat since 1990 at just above 20 million MTCO2e, with slight declines in recent years largely erased by increased emissions in 2015. The residential and commercial sector grew through the 1990s, in part due to the retirement of GHG free Trojan Nuclear Plant, but has since declined to approximately 1993 emission levels, likely due to the drop in emissions associated with electricity use over that time. However, similar to the transportation sector, residential and commercial sector emissions increased in 2015 due primarily to increased emissions from electricity use. The industrial sector’s emissions rose gradually through the 1990s to a peak in 1999 of 19.3 million MTCO2e, and declined most years since then, and were 12.8 million MTCO2e in 2015.
Transportation Sector Emissions
Emissions attributed to transportation are primarily from fuel used by on-road vehicles, including passenger cars and trucks, as well as freight and commercial vehicles. This sector also includes aviation fuel and off-road transportation such as farm vehicles, locomotives, and boats.
Figure 3 illustrates how the state’s emissions from transportation fuel have changed since 1990 by the relative contribution of each fuel type. Non-CO2 gases include methane and nitrous oxide that are byproducts of fuel combustion and fluorinated gases with high global warming potential from air conditioning and other auxiliary systems on vehicles. The other fuels category includes propane, natural gas, lubricant emissions and electricity. Aviation fuels include kerosene jet fuel, aviation-grade gasoline, and naphtha jet fuel. Diesel & residuals include all distillate and residual fuels used for transportation.
Total emissions from transportation have fluctuated since 1990 rather than declining consistent with Oregon’s goals. From 2007 to 2014, emissions from transportation were either relatively flat or declining. In 2015, there was a noticeable uptick in emissions from motor gasoline and diesel use which caused emissions from the sector to increase by 1.8 million MTCO2e, an 8 percent increase between 2014 and 2015. It is possible that this is a reflection of the economy rebounding from the recession, and the corresponding increase in driving and purchases of goods. The increase is also likely driven in part by increasing vehicle miles traveled (VMT) which saw a dramatic spike in 2015 compared to 2014 (See Figure 4). [FN9 Note: This chart only shows vehicle miles traveled on Oregon highways and excludes VMT on other types of roads because the rest of the data for 2015 was not available at the time of writing.]
Figure 4: Statewide Highway Vehicle Miles Traveled (Billion)
Residential and Commercial Emissions
Emissions from residential and commercial activities come primarily from generation of electricity and natural gas combustion to meet the energy demand from this sector. Other sources of emissions from this sector include small amounts of petroleum fuels burned primarily for heating, decomposition of waste in landfills, waste incineration, wastewater treatment, fugitive emissions associated with the distribution of natural gas, and from the fertilization of landscaped areas. Fluorinated gases from refrigerants, aerosols, and fire protection are also a small but increasing source of emissions from this sector.
Figure 5 illustrates how the state’s emissions from electricity, natural gas, and petroleum use in residential and commercial activities have changed since 1990. Emissions from residential and commercial electricity use have followed a similar trend during this period, with residential use consistently between one and two million MTCO2e higher than commercial use each year.
Annual variation in weather influences both electricity demand and the supply of renewable energy from wind and hydroelectric sources. Emissions associated with natural gas direct use in residential and commercial applications have increased steadily since 1990 with the exception of 2012.
The annual emissions intensity of Oregon’s electricity is influenced by weather and hydrological conditions that affect hydroelectric generation. The less power that is available from dams, the more electricity Oregon utilities must acquire from other sources, much of which is generated with fossil fuels. So, changes in annual emissions from various uses within each sector may have as much or more to do with annual differences in the emissions intensity of Oregon’s electricity as with changes in demand. Emissions associated with electricity use rose during the 1990s but have been on a downward trend in recent years, although the last few years have seen flat or increasing emissions from electricity.
Similar to residential and commercial activities, emissions from the industrial sector come primarily from electricity generation and natural gas combustion. Emissions from petroleum combustion have declined since the late 1990s largely because many facilities transitioned from distillate fuels to natural gas and from structural changes in Oregon’s industrial base. Emissions from coal combustion are nominal as there are very few industrial facilities in Oregon using coal onsite.
Certain industries emit greenhouse gases from processes other than fuel combustion. In Oregon, these industrial processes are chiefly cement manufacturing, pulp and paper manufacturing, and semiconductor manufacturing. Emissions from these processes collectively account for approximately 2.8 million MTCO2e in 2015.
Agricultural activities have consistently accounted for approximately 5 million MTCO2e since the mid-1990s. In contrast to other sectors, most of these greenhouse gas emissions are from methane and nitrous oxide rather than carbon dioxide. Slightly more than 2 million MTCO2e is from methane that results from enteric fermentation (i.e. digestion of feed from livestock).
About 2 million MTCO2e is from nitrous oxide, estimated from nitrogen-based fertilizers used for soil management. Methane and nitrous oxide from management of livestock manure have accounted for roughly 0.5 million MTCO2e since 2000. Other agricultural sources of emissions, including urea fertilization, liming of soils, and residue burning, produce less than 0.2 million MTCO2e.