EV Pollution

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Sunday April 13, 2008 - EV Pollution - It seem like every time we get some good news on the EV front we get someone, threatened by the idea of being shifted from there comfortable version of reality by electric cars, who trots out the stale old "the electricity comes from coal so EVs are dirtier" argument.

The big trouble with this type of argument is that it has just enough of an element of truth to sound totally credible.  It is true that unless you charge your EV from renewable sources 100% of the time then you do create a certain amount of pollution.  It is not true however that EVs are charged from coal fired plants so they pollute more.

The truth is that our electric grid is fired by a whole bunch of different and ever changing technologies.  In some areas coal makes up a big portion of the electrical grid mix but in other places coal makes up hardly any of the mix.  In the area I live, serviced by Southern California Edison, the mix is down to around 11% coal and about 17% renewable energy while the vast majority of the electricity, close to 50%, is generated from natural gas.

Now, the "dirty coal" crowd make it appear like you plug in your EV and Charlie over at the power plant starts shoveling coal to get it charged.  Well, the situation is a little different.  The power company is going to try and match supply with demand within the constraints of the generation system.  One of the issues they face is that it is sometimes difficult to shut down power generation on demand.  It is pretty easy to shut of hydro.  You simply close the openings to the turbine shafts and open the bypass shafts, the turbines stop running and generation stops.  To start up the turbines again you just reverse the process.  and within ten minutes you can have 400MW on line and at your disposal.  At the other end of the spectrum is nuclear.  Once you shut down the nuclear reactor it can take weeks to get it restarted again.

Coal isn't as bad as Nuclear but it does take about four hours to restart a coal fired turbine once the boiler has been shut down.  Because of this time lag power generation companies don't shut down coal fired plants very often.  That's one of the reasons why the power companies like EVs and PHEVs.  Charging them overnight provides a nice load on the grid that allows them to keep the turbines turning.

Another thing to remember is that most of the "EVs use coal" crowd do a well to wheels analysis for the EV but only a tailpipe analysis for the ICE.  They forget about all the "coal produced" electricity used to refine a gallon of gas.  They also forget the other pollutants put out at the refinery.  Take the refinery in Carson, CA for example.  When I drive passed this refinery just before dawn I see them burning off waste gasses from several tall chimneys.  When the wind is in the wrong direction this often results in a heavy layer of soot on cars in the Manhattan Beach area a few miles away.

Now, another thing that the old "Coal" argument assumes is that things will stay the same.  This is not really likely to be true.  Since modern coal plants are getting much cleaner than the old plants, as old plants move out of service and newer plants take their place the grid becomes cleaner.  

New techniques are also being developed that can be used to sequester green house gas emissions.  It is a big job to go out and fit sequestration equipment on the thousands of coal and gas fired power plants around the country but imagine trying to do that on the over one hundred million tail-pipes spewing out green house gases.  It will also be a lot harder, and therefore more costly, to try and capture GHGs from moving tailpipes than from stationary smokestacks.  

Over the last few days the BEV v FCV debate has sprung up again on the RAV4 EV board.  I am of the opinion that hydrogen fuel cell vehicles are still a long way off and that if we spent the money on development of BEVs instead of trying to push for hydrogen we would be better off in the long term.  I still don't like it when I hear people argue that FCVs pollute more because currently hydrogen is produced by steam reformatting of natural gas.  That might be true at the moment but doesn't mean it has to be true in the future.  There are lots of ways to produce hydrogen including electrolysis of water and using biological entities such as bacteria to break down water into oxygen and hydrogen.  In the long term it is these technologies that will win out if we ever move to a hydrogen economy.

On the other side of the coin I also get fed up of the hydrogen crowed trying to paint hydrogen as being produced from clean renewable energy and BEVs being charged from dirty coal.  The truth is that both of these get their energy from the same grid and the same power mix.  Improve the grid and we can clean up whichever way we find is optimum in the future.

So here is the big plan, clean up the grid, spend our transportation dollars on getting high speed electrified rail and low speed commuter systems such as subways and electric trolley busses up and running to get people out of their cars, invest big time in battery electric technology to get rid of tail pipes.  I have no problem in continuing research on hydrogen technology but I think that we need to acknowledge that this is a long term solution at best and fund accordingly. 

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