Results of GIS statistical analysis for CO2: (a) eGrid subregion emissions factors (kg CO2/kWh), (b) average emissions factor for each district (kg CO2/kWh), (c) coefficient of variation of CO2 emissions factor by district, and (d) difference between eGrid subregion emissions factor and US average emissions factor, 0.65 kg CO2/kWh (kg CO2/kWh). Credit: ACS, Weber et al. Click to enlarge.

Electricity generation and distribution in the US represents nearly 40% of US CO₂ emissions, as well as large shares of the other pollutants. Assessing the limits of current knowledge about US grid electricity in life cycle assessment and carbon footprinting, however, a team of researchers from Carnegie Mellon University and the University of Pittsburgh have shown that differences in standards, protocols, and reporting organizations—and the use of arbitrary political borders—can lead to important differences in estimates of CO₂, SO2, and NO_x emissions factors, with a corresponding effect on policies.

In a paper published online 4 February in the ACS journal Environmental Science & Technology, Weber et al. discuss the implications of this “considerable divergence” and list recommendations for a standardized approach to accounting for air pollution emissions in life cycle assessment and policy analyses.

The types of electricity generation in a region constitute one of the main drivers in regional greenhouse gas intensity and in region-specific life cycle inventories.
However, despite its importance, the electricity industry is unique for life cycle assessment (LCA) and policy analysis because while it is straightforward to measure electricity usage, it is impossible to trace the electricity generated in a given power plant through the transmission and distribution
system to a specific electricity consumer.

For this reason, it is common in LCA and carbon footprinting to create and utilize emissions factors, or average amount of a pollutant per unit activity, for the use of grid
electricity, such as gCO₂/kWh consumed. These factors are different from the traditional type of emissions factor because they represent not a single point source of emissions but an aggregate estimate of emissions from a broad system of power generators. Thus, an LCA practitioner’s assumption
about the emissions factor of electricity generation involves either an explicit or implicit assumption about the mix of methods used to generate purchased electricity at the given
location and time.

This inability to trace electrons from producer to consumer is similar to the well-known problem of allocation for coproducts in LCA, though in reverse; rather than one process making several different products, several distinct processes produce a single indistinguishable
good.

—Weber et al.

A common assumption is the use of national fuel production mixes to calculate emissions factors for electricity generation. However, the authors point out, changes to this critical assumption can raise or lower the CO₂ emissions associated with a product or service by a factor
of 100 or more.

The authors used 101 combinations of the input parameters in the
continental US (state, subregion, and ISO/RTO), and showed that the boundaries of these
different delineations vary considerably. They labelled each of these combinations a “district” to distinguish these boundaries from those of ISO/RTO and eGrid regional boundaries.

They found that the districts with largest uncertainty are those with smaller
than average or larger than average local or regional emissions factors. The variation in emissions factor is larger in estimates performed at the state level than the larger regional levels of the ISO/RTO, EIA state-based regions, or eGrid subregions, they found, “since although they may be important for policy reasons, political borders have little correlation
with electricity systems.”

The larger the region at which the grid is averaged, the closer the estimate comes to the national
average emissions factor. This simple observation has rather important consequences, as electricity consumers in certain areas of the country have incentives to choose a larger or
smaller area for averaging emission factors to achieve a lower emissions factor. As long as it remains common practice in LCA, carbon footprinting, and GHG reporting to use all these
types of emissions factors, individual electricity consumers will have incentive to pick the lowest emissions factor available for their district, be that the local factor for low polluting
regions or the national or interconnect factor for high-polluting regions.

—Weber et al.

Among the recommendations they make to improve the LCA process for grid electricity are:

• Standards organizations can provide clear guidance to reduce system
  boundary choice in determining emissions from grid electricity. By standardizing how such calculations should be done, such organizations could considerably improve the accounting of electricity emissions through a reduction in comparative uncertainty between different product systems
  and companies. By requiring different analysts to use similar methods and system boundaries, the
  difference between different alternative products or companies
  can be reduced.

• Standards organizations should discourage the use of arbitrary political borders when assessing the carbon intensity of an interconnected electricity system.

• Industry reporting and LCA practitioners should aim to report kWhs used (in addition to assumed grid emissions factor), both on an absolute basis and for a functional unit within an appropriate system boundary. (Since while estimating the carbon intensity of electricity purchased by a firm is challenging, estimating or measuring the kWhs of electricity purchased is fairly straightforward.)

• If reporting indirect emissions from purchased electricity is either required or desired, a range of emissions factors should be used. This range could report at least the
  emissions based on subregion, grid operator, and Interconnect emissions factors. If an
  entity wanted to guarantee emissions reductions or carbon neutrality for electricity purchase, it should assume and plan for the highest of the range of emissions factors.

It is clear from the results presented in this paper that uncertainty in emissions factors of electricity generation in the US can be considerable and could have significant impacts on the results of life cycle studies. Policymakers have traditionally preferred discrete answers rather than characterizing uncertainty and it is understandable that facilities would prefer a standardized
carbon emissions factor rather than deal with complicated ranges. If this is the case, the burden falls on the standards organization for due diligence in characterizing uncertainty and providing clarity on a consistent carbon emissions factor for electricity, including an estimation of upstream impacts,
in different national and world regions.

These organizations should work toward finding the best balance in terms of
accuracy and fairness, though transparency (reporting energy use and assumed factors) and consistency should be stressed above all else, since the uncertainty in emissions factors of electricity used by individual consumers is mostly irreducible. Any consistent choice (e.g., always using national emissions factors or always using regional factors) will be more correct for some regions than others, due to differences in regional electricity markets and transmission constraints. However,
this truth must be accepted if consistent, transparent, and reproducible estimates of life cycle impacts are to be made.

—Weber et al.

Resources

• Christopher L. Weber, Paulina Jaramillo, Joe Marriott and Constantine Samaras (2010) Life Cycle Assessment and Grid Electricity: What Do We Know and What Can We Know? Environ. Sci. Technol., Article ASAP doi: 10.1021/es9017909

Nissan is entering into an agreement with the City of Houston to advance zero-emission mobility in the city by promoting the development of an electric-vehicle charging network and policies to support widespread adoptions of electric cars.

The announcement, made at the Houston stop of the Nissan LEAF Zero Emissions Tour, helps pave the way for the 2010 introduction of Nissan LEAF, the industry’s first all-electric, zero-emission car designed for the mass market. Nissan already has a similar working agreement with Reliant Energy, of Houston, one of the largest competitive electricity providers in Texas. The announcement paves the way for public-private collaboration to foster electric-vehicle growth and development.

As part of the agreement, Nissan and the City of Houston, along with Reliant Energy, will develop plans to promote a charging infrastructure for electric cars that encourages home and workplace charging, as well as a public-charging infrastructure. The partners will work to coordinate the establishment of policies and help streamline charging infrastructure deployment. Nissan also has agreed to make available a supply of electric vehicles to the City of Houston and in and around the metropolitan area.

Houston is one of 14 cities that have joined the Clinton Climate Initiative C40 in a commitment to make their cities more electric vehicle-friendly. To that end, the city intends to add 25 electric vehicles this year, bringing to 40 the total number of plug-in cars in the city’s fleet.

Reliant Energy is working to make the broad adoption of electric vehicles simple by developing an ecosystem of charging infrastructure and services that makes fueling electric vehicles more convenient and affordable than the gasoline alternative.

Nissan has formed more than a dozen partnerships in the United States, in areas including State of Tennessee, the State of Oregon, Sonoma County, San Diego and San Francisco in California, Phoenix and Tucson, Ariz., Washington D.C., Seattle, with the City of Orlando and the Orlando Utilities Commission, with Progress Energy in Raleigh, N.C., and with Houston-based Reliant Energy. Nissan also is working with AeroVironment for the supply and installation of home charging stations, creating a one-stop shop for the Nissan LEAF and its charging equipment.

Rapid melting of the Arctic region could carry a minimum global cost of US$2.4 trillion by 2050, according to a new report, “An Initial Estimate of the Cost of Lost Climate Services Due to Changes in the Arctic Cryosphere”, released by the Pew Environment Group.

We estimate that on an annual basis in 2010, albedo changes from loss of sea ice and
snow cover, along with accelerating methane emissions, are heating the planet at a rate
equivalent to approximately 3 billion metric tons of CO₂. This is comparable to about 42
percent of US global warming emissions. This heating from the melting Arctic will grow
significantly over the coming decades, projected to more than double by 2100 when
expressed in CO2 equivalents.

In economic terms, estimated costs in 2010 from the decline in albedo and increase in methane emissions range from $61 billion to $371 billion. By 2050, this number rises to a
cumulative range of $2.4 trillion to $24.1 trillion. Over the remainder of the century,
cumulative costs to society could range from $4.9 trillion to $91.2 trillion. The large
range of the estimate reflects: uncertainty associated with the planet’s temperature
sensitivity to increased carbon emissions (climate sensitivity); uncertainty associated with
the actual future impacts from a given increase in temperature; uncertainty associated
with total emissions levels, economic growth and population growth over the coming
decades; and, especially, the choice of discount rate.

—“An Initial Estimate of the Cost of Lost Climate Services Due to Changes in the Arctic Cryosphere”

To arrive at the economic cost of Arctic melting, the report’s authors converted projected trends in snow and ice loss and methane releases into carbon dioxide emissions equivalents. Those were multiplied by the social cost of carbon, an estimate by economists of impacts from climate change on agriculture, energy production, water availability, sea level rise and flooding and other factors. This calculation produced the range of initial dollar estimates cited in the report.

The report notes that this region is warming at twice the rate of the rest of the planet. The loss of heat-reflecting sea ice and snow results in the absorption of more solar energy leading to warming. The thawing of permafrost, or permanently frozen ground, releases methane, a potent greenhouse gas. Increased warming from these effects, in turn, leads to more melting and thawing in a feedback loop.

The preliminary results in this report show that as the Arctic melts we are losing a hidden treasure: the far north’s crucial capacity to cool the earth. We urge the G7 finance ministers to commission a full economic analysis of the global climate services provided by a frozen Arctic and what losing the planet’s ‘air conditioner’ will cost all of us.

—Scott Highleyman, international Arctic director for the Pew Environment Group

The report was released by the Pew Environment Group’s Oceans North campaign which promotes sound stewardship of the Arctic Ocean. The authors are solely responsible for its content, which was reviewed by more than a dozen economists and Arctic scientists.

Resources

• An Initial Estimate of the Cost of Lost Climate Regulation Services Due to Changes in
  the Arctic Cryosphere

The Volvo Group has chosenPennsylvania State University to be the first North American member of Volvo’s Academic Partner Program, which was launched globally in 2009 for research cooperation with selected universities.

Cooperation in Volvo’s Academic Partner Program encompasses research in areas such as production technology, engine development, and automotive safety. Specifically, the partnership with Penn State will target the areas of diesel combustion and efficiency, alternative fuels, intelligent transportation systems and vehicle and driver safety systems.

We are very pleased to add Penn State to our Academic Partner Program, which now covers Sweden, France, and the US. This program shows our commitment to form a long-term strategic partnership that will strengthen the competitiveness of both the Volvo Group and our academic partners. Penn State already had ongoing activities in several areas such as student co-operative assignments, advanced engineering studies, biofuel research and vehicle system testing, so this partnership was very natural.

—Jan-Eric Sundgren, head of public affairs and environmental issues for the Volvo Group

The Volvo Group aims to establish long-term partnerships with the best universities worldwide in the field of automotive research.