http://news.engineering.utoronto.ca/where-you-live-could-mean-greener-alternatives-do-more-harm-than-good/
[images and links in on-line article]
March 4, 2015 | RJ Taylor
Where you live could mean “greener” alternatives do more harm than good
Whether it’s swapping your car for an electric vehicle, or your natural
gas furnace for geothermal heating, transitioning from fossil fuels to
electric-powered technology is widely believed to be the best way to
lower carbon emissions.
But according to U of T civil engineer Chris Kennedy (CivE), knowing
where the electricity comes from to power those “eco-alternatives” is
critical. If that electricity comes from burning oil and coal, it might
mean that green alternatives aren’t that green after all.
Kennedy’s study, published in the journal Nature Climate Change,
proposes a new decision-making threshold for when to move from fossil
fuel technology to electric power (called electrification), and at what
point that move may increase or lower carbon emissions.
Although regions may welcome “green” technology like electric vehicles,
high-speed rail and geothermal heating, they aren’t green if the
electricity to power them creates even more carbon emissions than their
oil-driven counterparts.
For electrification to lower emissions, Kennedy says that a region needs
to produce its electricity at a rate below his threshold: approximately
600 tons of carbon dioxide equivalent per gigawatt hour (GWh). This
means that for every gigawatt hour of electricity generated (the power
needed to run about 100 homes for a year), less than 600 tons of
greenhouses gases (measured as “CO2 equivalent”) can be emitted.
If a region’s electricity production exceeds this 600-ton threshold,
such as in countries like India, Australia and China (as shown below in
Figure A), electrification could actually increase carbon emissions and
accelerate climate change.
Countries such as these generate much of their electricity using coal,
which he says produces about 1,000 tons of CO2 equivalent per GWh—nearly
double the suggested threshold. Natural gas, on the other hand, produces
600 tons, and hydropower and nuclear energy produce nearly zero.
“You could speculate that incorporating electrified technologies such as
high speed rail in China may not lower overall emissions,” says Kennedy.
“It might even be more carbon friendly to fly.”
Kennedy employed an industrial ecology approach to dig into the data
from four previous studies—including one from the International Energy
Agency and others from Canada, the U.S. and countries in Europe.
As a nation, Canada’s electricity does not produce very much carbon in
comparison to other regions. It ranks low on the list, at just under 200
tons of CO2 equivalent per GWh. “Despite that many believe our power is
generated using fossil fuels from Alberta, most of Canada’s electricity
mix comes from hydropower and nuclear facilities,” Kennedy says.
But when he zoomed in on certain regions in Canada, some of this good
news changed. In a previous study, he compared the use of “green”
geothermal heat pumps (used in homes) versus natural gas furnaces across
different provinces. He found that the pumps were more eco-friendly in
Ontario and British Columbia—owing to nuclear and hydropower—but in
coal-dependent Alberta, it was greener to stay with a natural gas furnace.
In his recent paper, Kennedy also cites a study that found using plug-in
electric vehicles emitted less carbon when used along the west coast of
the United States, but produced the same, if not more, carbon when used
in the Midwestern U.S.
Why does this threshold matter?
“Looking at overall carbon emissions of one country or a group of
countries can only get you so far,” says civil engineering PhD student
Lorraine Sugar (CivE MASc 1T0, PhD 1T8), who worked as a climate change
specialist for the World Bank for nearly five years. “It’s hard to track
progress and set goals internationally, while holding regions
accountable. Having a specific and measurable target like this threshold
is incredibly important, especially leading into the United Nations
Climate Change Conference in Paris later this year.”
According to Kennedy, this threshold puts a marker down in a policy
arena where none has existed before—and it isn’t just valuable for
government.
“It reframes part of the climate change debate by encouraging
individuals around the world to better understand where their
electricity is coming from before they adopt supposedly eco-friendly
technologies,” he says. “And even more, it incites them to understand
how much carbon is emitted during the entire life cycle of those
technologies—from their ongoing operation to their manufacture and
disposal.”
He recommends people search for their local government energy agencies
to find out how electricity is generated. If it is largely coal, then
electric-powered technologies like ground-source heat pumps or electric
vehicles may not be the most eco-friendly alternatives. On the national
and international stage, he hopes governments do the same research when
developing environmental policies and incentives.
“Canada’s three largest cities—Toronto, Montreal and Vancouver—have some
of the lowest carbon emissions from electricity generation in the
world,” says Daniel Hoornweg (CivE PhD), an associate professor at the
University of Ontario Institute of Technology and a current U of T
engineering PhD student.
“This threshold helps politicians make smarter energy decisions,” says
Hoornweg, who recently retired from the World Bank after nearly 20 years
in the urban sector. “Why aren’t we making better use of these
advantages to electrify our transportation modes? And why are we so
focused on one or two energy projects (like a pipeline) instead of
working on a more comprehensive U.S.-Canada energy agreement that could
better leverage our energy strengths?”
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