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Re: Gas or Electric
The discussion here is very educational, thanks. Let me add my take.
In the public and school seminars I have given on making good environmental
choices, there is often a "bedrock" below which the public doesn't seem to
want to go, however well intentioned and informed they are. They very often
get lost in the details on issues like this. They want to know if something
is good or bad, right or wrong, because they have dozens of other things to
Discussions on good choices are also often short circuited by issues like "I
have to mow my lawn, and I want you to mow yours, because of property
values. No I DON'T want scraggly native plants in your front yard or mine,
thanks, because then I can't sell my house."
I continue to believe we have to keep pushing the economic side of P2,
proving the benefits where necessary, because once it is an economic issue
and not an environmental or "goodness" issue then everyone will play, even
those who don't believe in it.
I'm waiting for (and working toward) the day when property values are
figured on how energy efficient and low-maintenance a house is.That way the
public makes good choices automatically for economic reasons, and no
convincing is required on any of our parts!
Best regards to all. What a great group.
WASTREN, Maryland Office
22 Executive Park Court
Germantown, MD 20875
----- Original Message -----
From: "Brady, Bernard" <bbra461@ECY.WA.GOV>
To: "'Estes, Laura'" <email@example.com>; <P2Tech@great-lakes.net>
Sent: Thursday, January 10, 2002 1:20 PM
Subject: RE: Gas or Electric
> It's always interesting to see that in these discussions, we attempt to
> support the alternative we like by leaving out or overlooking some of its
> negatives while loading up the alternative we don't like with all the
> imaginable negatives. I agree with Howard Haines' points about the real
> justifications for preferring electric mowers (cord or cordless) over
> gasoline-powered being geographically specific. Outside LA, maybe, this is
> tempest in a teapot. However, there are a couple of Howard's comments that
> need correction. One is that gas turbine power plants are not more energy
> efficient than thermal plants ... BTW: I assume he means coal-fired
> Gas turbine, coal-fired, and nuke all get electricity by converting from
> heat. If typical coal-fired efficiency is 33 to 35% (Howard's Montana
> example), they're a lot less efficient than a gas-fired turbine at 52 to
> ... I assume we're both talking about the ratio of the power output to
> heat value. And as for emissions, Howard suggested looking at the back end
> of jet engines (for those who don't know it, gas turbines are jet engines
> bolted down). That ain't fair. Gas turbines in power plants are now
> to have selective catalytic and carbon monoxide catalyst control systems
> that reduce NOx and CO (and some VOC) emissions to small fractions of what
> comes out the back end of an uncontrolled jet engine.
> The second comment is that fuel cells are 80% efficient. That's only true
> for the conversion of hydrogen heat value to power output. Unfortunately,
> there ain't no uncombined hydrogen around. Natural gas and coal are used
> a form not greatly different from the way they come out of the ground.
> Gasoline is distilled from petroleum along with some reforming reactions
> break too big molecules down to gasoline range. Some energy value is lost
> that process. But, you can only get hydrogen with a net energy value by
> reforming it from a fossil fuel. So, you really start with something like
> gasoline before you get to the fuel cell. Yes, you can get hydrogen
> electrolytically from water, but you get no net heating value. You have to
> use just as much energy (actually more) to separate hydrogen from oxygen
> you'd bet back by re-combining it at the fuel cell. Anyway, when you
> the fossil fuel, say methane (the simplest), you lose the heat value of
> carbon part of the molecule. If I remember correctly, the net efficiency
> a reformer - fuel cell combo is about 50%. On the other hand, at the
> emissions source, the emissions are only water and carbon dioxide.
> Not that I expect anyone will really have read this far, but I finally
> a compulsion to offer my "what to do" suggestion: Keep using your
> gas-powered mower 'til it wears out. Then replace it with whatever is most
> cost effective and useful for you. Take care of it. Service it: Change the
> oil, clean the filter, clean and/or replace the spark plug, drain and
> dispose of the gas in the tank at the end of the mowing season. Set the
> mower for the highest grass length. Cut the grass frequently enough to
> your neighbors happy, but don't try for Better Homes and Gardens awards.
> Water enough in the summer to keep the whole lawn from turning brown, but
> not so much that your yard looks like a field of emerald green. Kill the
> lawn weeds: By hand if you have time, or spot spray. Replace your lawn
> a vegetable or flower garden if you like. But, that'll be a lot more work
> than the lawn, so be realistic. Don't worry. Be happy.
> -----Original Message-----
> From: Estes, Laura [mailto:firstname.lastname@example.org]
> Sent: Thursday, January 10, 2002 9:30 AM
> To: 'P2Tech@great-lakes.net'
> Cc: 'email@example.com'
> Subject: FW: Gas or Electric
> This information from a colleague who has done quite a bit of engine
> emissions work.
> -----Original Message-----
> From: Haines, Howard [mailto:firstname.lastname@example.org]
> Sent: Wednesday, January 09, 2002 4:28 PM
> To: 'Estes, Laura'; Tomas Vinson (E-mail)
> Subject: RE: Gas or Electric
> Dear Laura and Tomas,
> I am not on the P2Tech, but you can post it there. This reads like someone
> should have shown up at one of my workshops with the Health and Air
> Impacts of Bio-based Fuels and Lubes in Small Engines slide show. These
> given in Montana, Minnesota (2), Michigan (7), New York, Washington D. C.,
> and are now being done in parts of Canada.
> As of January 2002, the newer lawnmowers would be the most efficient
> mechanical units in terms of energy, CO2 emissions, and reduced pollution
> for areas that do not have air quality problems.
> Newer lawnmowers are almost all 4-stroke engines (see the EPA report at
> OTAQ), and some have electronic fuel injection-quite a bit cleaner than
> older 2-strokes, and more energy efficient (less CO2 emissions). For
> look at a number of reports by CARB and Southwest Research Institute.
> In most of the data I have seen, the reasoning behind electric lawn mowers
> (and vehicles) is to move the pollution out of an air shed that has poor
> (exceeding regulated pollutant levels), and away from people, to an air
> where the electricity is produced. The idea is to reduce pollution at the
> site of use so that other pollution sources (like industries that have
> energy options) can operate in the same air shed. In most cases when you
> think about it, electric mowers don't make much sense except for the
> companies. True, a coal-steam plant in Montana may be 33 to 35 percent
> efficient, but it looses (rule of thumb) about ten percent to move it down
> to California. With that size of operation, the typical battery and
> recharge losses (30 to 45 percent) would cut the efficiency or increases
> emissions even more. From an energy or emissions standpoint, an electric
> lawn mower is like cutting butter with a chainsaw.
> Gas turbines for electric production are not all that efficient compared
> the large thermal plants, but they are cheap. As for emissions, just look
> out the back of any turbojet airplane and see the difference.
> Fuel cells where the heat can be used can get up to 85 percent efficiency,
> but they are just now starting to come down in price. If you don't think a
> fuel cell-powered mower is possible, then I won't worry you with the one I
> saw at a unit of the Department of Defense in Utah. They also have a fuel
> cell-powered utility vehicle (bigger than a golf cart, smaller than an
> that has an overall efficiency of somewhere in the mid-40s. There are
> for a fuel cell-powered snowmobile as well, but that is still on paper for
> the time being.
> For a specific comparison of fuel economy, CO, HC, and PM emissions
> 2- and 4- stroke small engines, see the fourth, sixth, and seventh slides
> (titled Emissions of 2-stroke vs 2-stroke Engines) in the Health and Air
> Quality Impacts of Bio-based Fuels and Lubes in Small Engines slide show
> http://www.deq.state.mt.us/CleanSnowmobile/montana/hpp.pdf ). In the
> slide, a comparison of CO and HC is done for two 2-stroke snowmobile
> circa 1995 and 1998, a 1998 personal water craft engine, a 4-stroke engine
> is a utility-type engine (a bit bigger, but not unlike a lawn mower), and
> advanced 4-stroke engine (with emission controls similar to an automotive
> engine). The sixth slide down compares fuel consumption, and the seventh
> illustrates particulate matter emissions. The data were all developed at
> Southwest Research Institute, some of which was paid for by this
> Information on cleaning up these small engines also on the web site
> (www.deq.state.mt.us\cleansnowmobile or www.cleansnowmobilefacts.org .
> by using an ethanol blend fuel and low emissions lube oil in a two-stroke
> engine, we measured reductions of CO by 9 to 38 percent, HC reductions of
> to 27 percent, and particulate matter reductions of 25 to 70 percent. NOx
> was not affected, and NOx emissions from 2-stroke engines are low-so low
> that they produce ammonia. A number of colleges have also been looking
> cleaning up and quieting down 2-stroke engines as illustrated in the
> from the SAE Clean Snowmobile Challenge (also on the web site). Catalytic
> converts are available and used (in Europe, Asia, and some places here)
> engines as small as chain saws. It would not be a problem to put one on a
> lawn mower.
> I suspect many on the P2Tech list will not have to worry about snowmobile
> emissions, but the same principles apply to jet skis, personal watercraft,
> small marine engines, and ATVs. This site represents over $1 million in
> research done in or for the greater Yellowstone (as in National Park)
> Back to the first topic of keeping the area around buildings trimmed in a
> acceptable (pollution-prevention) method.
> I would suggest a more efficient way to keep the grass short-use a drought
> resistant grass variety (like buffalo grass) and/or your neighbors' horses
> (or sheep) to periodically mow it. I also limit watering. If I don't
> water, I don't have to mow here in Montana. I keep it dry enough to where
> dandelions don't grow, but it stays green to keep the dust down. I know
> some places in this country it rains (Seattle, WA, Beaumont TX, New
> New York, Michigan), so other methods might be needed. Like possibly not
> growing any grass at all: put in a vegetable garden with mulch, or do
> something a bit more natural.
> This was less than 15 minutes of thought/typing, and I apologize if it was
> boring. Just know that someone has been working on the problem of
> engine emissions because once you are out the U. S., almost all the
> use either diesel or 2-stroke engines.
> Howard Haines
> Bioenergy Engineering Specialist
> Montana Department of Environmental Quality