ot particularly, but debate has erupted lately that maybe
they are. A major determining factor is the energy we use to mine the iron,
lithium (Li) and rare earth elements (REEs), to smelt and process the raw
materials, and to transport all these materials in order to manufacture the
cars, the batteries and everything associated with them.
But the most important question is how you charge them once
they’re made. Even more important is how you charge 100,000,000 of them 20
years from now. If it’s not with nuclear and renewables, then things get dicey.
I guess you can get pretty depressed about this if you’re
not careful. Ozzie Zehner has become quite bummed out about electric vehicles,
as he wrote for the Institute of Electrical and Electronics Engineers (Unclean
at Any Speed). He referenced a 2010 National Academy of Science (NAS) assessment
of the Hidden Costs of Energy, and stated that the lifecycle health and
environmental damages of an electric vehicle are actually greater than
that of a gasoline-powered car…discounting climate change effects.
Of course, one of the most important issues facing us is
climate change, so I’m not sure what his conclusions really mean. He does bring
attention to the toxic compounds used in manufacturing, but that issue cuts
across all industries, especially computers, batteries and electronics.
Eliminating, recycling or addressing these compounds is a major focus of
building any sustainable future.
Still after reading this, I felt a sudden urge to throw out
my computer and dust off my typewriter.
Then I read that same NAS study. But I didn’t come away with
the same conclusion. Like most discussions of this topic, the NAS study states
that the power grid must produce a majority of electricity from non-fossil fuel
in order to realize the potential of electric vehicles.
Yes, everyone knows that unusual metals are needed for
awesome batteries, not to mention that the solvents and process chemicals
required for their manufacturing release greenhouse gases like sulfur
hexafluoride (SF6). SF6 is over 20,000 times as effective in global warming
potential as CO2. SF6 gas also decomposes to form some pretty nasty things
like sulfur/metal-fluoride gases, sulfur-oxyfluorides and hydrofluoric and
sulfuric acids.
But the effects are small compared to the billions of tons
of CO2 emitted from coal, oil and gas.
If we’re going to build hundreds of millions of electric
vehicles, toxic compounds will become an issue and we will have to deal with it
like all other industrial processes. Still, it all comes down to the energy
sources we use, which themselves have health and environmental concerns, and is
the reason we’re having this debate nationally.
In the end, Zehner recommends focusing on major societal
changes like walking, bicycling, and using mass transit as a replacement for
driving, all great things that we should do, but difficult without completely
restructuring society like urban infrastructure and job-domicile relative
locations.
Everyone should instead read the more recent NAS study from
2013, Alternative Vehicles and Fuels, which concludes that, while the
environmental costs of an electric vehicle depends on many things, how you
power it is still the most important.
It is correct to raise awareness that high-tech fixes like
wind turbines and electric vehicles use more toxic compounds and processes in
their manufacture than is generally understood, but we’ve known this problem
since computer technology skyrocketed fifteen years ago as they have exactly
the same problems.
But mining for thousands of tons of rare earth
elements a year does not compare with mining for billions of tons of
coal a year. From an environmental and health perspective, the amount of heavy
metals, like mercury, uranium and thorium, emitted from burning coal in
the U.S. alone exceeds by a thousand times the total amount of lithium and rare
earth elements mined in the entire world (USGS; Treehugger).
Contrast Zehner’s take with the one of the Union of
Concerned Scientists (State of Charge) that lays out how different regional
power grids provide different emissions levels relative to operating an
electric vehicle, again because of how each energy mix is comprised.
The United States is carved up into different electric grid
regions with substantially different energy mixes. The dirtiest grid regions
have over three times the CO2 emissions than the cleanest region. The
coal-dominated regions of the Rockies, Upper Plains, and parts of the Midwest
have the highest CO2 emissions per kWhr while the regions that include
California, New York, and the Pacific Northwest have the lowest emissions per
kWhr.
The State of Washington is over 80% non-fossil fuel,
primarily because of hydro, nuclear and a little wind, so electric vehicles
charged in this region are fairly “green”, yielding emission-equivalents
similar to gasoline-powered vehicles getting over 70 mpg. But cars charged in
Indiana, where coal exceeds 90% of the electricity production, are not much
greener than cars with internal combustion engines getting less than half of
that.
Fortunately, about half of Americans live in the best grid
regions.
Even so, we will still need lots of baseload electricity for
this super-charged future.
So what will be baseload and what will be renewable? If it’s
coal and gas, things get worse fast. If it’s gas and renewables, then
atmospheric CO2 concentrations will continue to rise, albeit more slowly. If
it’s a combination of gas, nuclear and renewables, then atmospheric CO2 could
actually decrease.
The simple evaluation is to compare the CO2 emissions from
burning gasoline to those emitted by the power plants to produce the energy to charge
the battery to drive the same distance. We’ll be nice to internal combustion
engines and say they get 40 miles to the gallon. Similarly, we’ll be
conservative and say electric vehicles get only 40 miles to every 10 kWhrs.
A gallon of gasoline produces 8,887 grams of CO2 when burned
in a vehicle (EPA vehicle emissions). Producing the equivalent of 10 kWhrs of
electricity, including the total life-cycle from mining, construction,
transport and burning, emits about 9,750 g of CO2 when generated in a coal-fired
power plant, 6,000 g when generated in a natural gas plant, 900g from a
hydroelectric plant, 550 g from solar, but only 150 g each from wind and
nuclear (UK Office of Science and Technology 2006).
So using coal-generated electricity really does make it a
wash with respect to electric vehicles, although either efficient new gasoline
engines or bad old ones alter it accordingly. Using natural gas plants to
produce the electricity to charge you car is a little better, but not great.
All the others are significantly better, especially nuclear and wind, although
wind’s requirement for gas to buffer the intermittency increases the CO2 output
somewhat, but it’s still better than anything except nuclear.
Since the 100,000,000 electric cars in America in 2040 will
drive a trillion miles that year, they will require 250 billion kWhrs, or the
equivalent of thirty GenIII 1,000-MW nuclear plants, 75 combined cycled 800-MW
gas plants, or 250,000 of the big 1-MW wind turbines.
That is a lot of energy, but still only about 5% of the
total electricity production in the U.S. And powering that many electric
vehicles from nuclear, hydro or renewables alone would eliminate over 10% of
our GHG emissions.
Yes, we need better battery technology. Yes, we need to
recycle metals. Yes, we need to put in place all of the conservation and
efficiency strategies we have, but electric vehicles can be a major benefit in
our quest to reign in our worst of our effects on this planet.
I think I’ll leave the typewriter at the storage space.
Article Credit: www.forbes.com
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