Yahoo – AFP,
March 20, 2015
 |
| Electric cars combat urban heat problem: study |
Paris (AFP)
- Electric vehicles are a useful tool for fighting sweaty city summers,
according to a study published on Thursday.
Switching
from vehicles powered by fossil fuels to plug-in equivalents would ease a
phenomenon called urban heat island, it said.
The term
describes what happens when city temperatures are driven higher by heat from
traffic and air conditioners and by warmth, stored during the day in roads and
buildings, which is released at night.
In some
places, the buildup combines with a summer heatwave to inflict sweltering
discomfort and heat stress.
Writing in
the journal Scientific Reports, specialists in China and the United States said
urban heat island creates a vicious circle.
The hotter
it is, the more people crank up their air conditioning, which in turn disgorges
more heat into the street, and so on.
The team
calculated what would happen in Beijing if petrol- and diesel-powered cars and
light trucks were replaced by their electric equivalent.
Their
simulation was based on the weather in the Chinese capital in the summer of
2012, when the city was three degrees Celsius (5.4 degrees Fahrenheit) warmer
than the surrounding countryside.
Switching
vehicles would have caused this to fall by 0.94 C (1.7 F), according to their
model.
"Heatwaves
kill, and in terms of climate change, even one degree can make a
difference," said Jianguo Liu of Michigan State University, who took part
in the study.
The
theoretical switch would also save the city 14.4 million Kilowatt-hours in
electricity each day -- the daily equivalent of 10,686 tonnes of carbon dioxide
(CO2) emissions.
The
calculation took into account heat from the extra fossil fuel that would have
had to be burned at local power plants to charge the electric cars.
Electric
vehicles emit only about a fifth of the heat of conventional cars.
"The
replacement can mitigate heat island intensity, which can reduce the amount of
electricity consumed daily by air conditions, benefitting the local and global
climate," the study said.
The
researchers sounded a note of caution, pointing out that urban heat island has
a basket of factors, some of which are sketchy.
Particulate
pollution, city layout, building design, energy efficiency and parks are also
believed to play a part in worsening or mitigating it.
The
computer simulation focused only temperature change and energy savings.
It was not
designed to factor in the cost of introducing electric vehicles and their
charging infrastructure, nor did it estimate the health benefits from less
pollution.
No comments:
Post a Comment