Mirai gets 67 MPGe - official

uh-oh.

 

Not gonna repost but 67 MPGe Mirai is as efficient as 115 MPGe EV (both using domestic natural gas as source fuel) or a 53 MPG hybrid -- well to wheel.

 

we need better measuring metrics.

 

How a bout a yardstick?

 

exactly. or at least a hockey stick.

 

Renewable is the future and US is slowly shifting. Currently in the US, average grid efficiency is about 33% (a third from coal).

 

I don't think we can get better metrics given that we don't know the source of the hydrogen or how it is transported and stored. The same goes for electricity is produced.

We have 5 metrics
MPG(e) from the fueling station
cost per mile (km) (varies wildly based on cost of fuel)
ghg source to wheel (uses mpg(e) in calculation
percent domestic fuel
cafe (gives bonuses for not being oil based)

As the plug-in haters have demonstrated efficiency is a poor measure as it is so corruptible.

One of the key talking points of fuel cell lobby is how much more efficient fcv would be than gasoline vehicles. Here they were talking about 3x more efficient in MPG(e). Somehow in epa testing they don't come close, so we can now give a better measure.

Mirai might be compared with a camry or a prius when it comes to comparison, If fuel is $4/gallon (higher than today) and hydrogen is $10/kg (probably lower than today but toyota estimate) we can do the first 2
Compare Side-by-Side
Mirai $0.15 fuel/mile

camry xle hybrid 40 mpg, 168% of mirai consumption, $0.10 fuel/mile
prius 50 mpg, 134%, $0.08
lexus ct200h 42 mpg, 159%, $0.095
camry I4 28 mpg, 239%, $0.14

As you can see there is not that much of a mpg(e) gain over hybrids. The 3x claims came out before the second generation prius, and people thought fcv would be much more efficient than they are, but now its time to put them to bed. The tucson fcv does a little better than mirai when it comes to its class, but the rav 4 hybrid isn't out yet.

 

In 2014 about 2 kwh of fossil energy were used to produce each kwh at the plug using 2013 plant efficiency figures.

What is U.S. electricity generation by energy source? - FAQ - U.S. Energy Information Administration (EIA)
SAS Output
SAS Output

39% was coal @33% efficiency
27% was natural gas @43% efficiency (new ccgt over 55% efficiency but ccgt as a whole @45% efficiency)
1% was petroleum @32% efficiency.

The rest was non-fossil with 19% nuclear, 6% hydro, and 7% other renewable.

Combined fossil fuel counting non fossil as 100% efficient (not counting really) is 54% efficiency. After a 7% grid loss this is approximately 50% (2 units fossil fuel energy for every unit at the plug).

Many think coal,big hydro, petroleum and nuclear should not be counted as these are stable or declining in the face of increased electrical demand. But if you are looking at average you have all the 2014 and 2013 efficiency figures to make your own calculation.

 

Good ground work.

I wouldn't say nuclear power plants are 100% efficient. Neither for the renewable sources. For example, solar panels are 15-20% efficient.

Leaving nuclear and renewables alone, average fossil power plant efficiency after transmission and distribution loss is 34.4% efficiency and it makes up 67% of the power.

We have to be very careful not to act like all the electricity is from renewable when overwhelming majority is at 34% efficiency.

 

Its all about how you count non-fossil. EPA included figures for nuclear in that chart. It was 33% efficient on fuel consumed on average in 2013. Then again most of the fuel is not consumed before it is disposed of. Solar panels actually are less efficient than that when you get to ac compared to energy hitting them, but again what does solar efficiency mean here, its a tiny part of the grid (<1%). Wind efficiency is also low because we don't put up lots of turbines, it is installed for lower cost per kwh, not highest efficiency. These non-fossil efficiencies are not really key to anything, as the fuel is plentiful and does not produce ghg. On nuclear the amount of fuel disposed of without being reacted is a much bigger problem (nuclear waste) then the small heat losses.

Let's call it 34% (I got 33.8% when I did the calculation) efficiency for 67% of electricity at the plug, with 33% non-fossil.

Well I thought I was pretty clear it was 67% not 0, but I'll try to be more clear in the future.

New net power coming onto the grid is ccgt natural gas and renewable. Percentage for each on the margin for new demand from plug-ins is up for debate. Net new steam generated electricity is not coming on-line for plug-ins but its possible that it will retire faster or slower for plug-ins. As a data point roughly 39% of plug-in buyers in california (largest US plug-in market) installed solar around the time of their plug-in.

Coal, nuclear, petroleum, large hydro make up 65% of power produced today, but this share is shrinking. Net power percentage from each will be flat or decline from each of these sources in the future US mix.

 

As Bisco says, " uh-oh. " ... because the U.S. is a mix of coal - oil - natural gas - nuke - as well as various minor non-carbon renewables.
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B.S. You convert CNG to hydrogen, fill a thousand Diesel tanker trucks with said hydrogen, have them drive to a thousand different gas stations, and wasting precious fossil fuel in the process. Plus make FCV drivers divert to said stations to refill, which wastes 1-2 miles of fuel each time.

That is in NO way more efficient than a CNG pipeline direct to a power plant, and then shipping the weightless electrons to homes & into the battery car.

 

wow.

 

On Fuel Economy website, Mirai is listed as 66 MPGe.

Compare Fuel Cell Vehicles

 

Call me whacked - & considering the author of the chart at its bottom - but I'd find a lot more comfort in data that doesn't come from a source that has become notorious for skewing data against plugins & in hydrogen's favor.

Consider for example the chart calls the fuel cell car an "advantage" yet failed to even mention their own plug in Prius' EPA. Of course that's because the PiP's EPA rating is much higher ..... never mind that it costs less, & infrastructure for both its fuel sources are already in place.
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That slide has been debunked many times. Perhaps in 2008 Toyota actually believed it.

The biggest problem is it assumes plug-ins will receive none of their power from wind, solar, geothermal, hydro, or nuclear. Using any of these sources a plug-in car is much more efficient than a car running on 10,000 psi hydrogen. Toyota's own claim to "greeness" for the mirai is that it will when built use a big enough of these non-fossil sources. You can't really look at these low ghg claims without also thinking about the cost of all the non-fossil sources.

Better measures of fuel comparison of these two diverse sources are ghg/mile and $/mile. For the same ghg/mile a plug-in has much less cost per mile of unsubsidized fuel. To get these equal you would need to subsidize the hydrogen fuel much more.

Now some would argue that fuel cell cars running on SMR (natural gas and renewable methane) and off peak wind, is better than running them on gasoline and diesel, and I would agree here. There may also be breakthroughs to photo catalyst or other methods that bring down the price of efficient hydrogen.

On the numbers, things have changed. If you base the plug-in off the 50 mpg hybrid prius, the plug-in should be 106 mpge - that's about the same as the volt, but the 114 mpge leaf and 117 mpge i3-rex do better. Still not far off. But when you do the same with the fcv you get 74 mpge 10% higher than the 67 mpge mirai and even more off on the 59 mpge clarity. mirai to i3-rex has a 21% error in efficiency in that chart compared to the real world.

In 2008 when that chart was written ccgt on the grid to plug may have been 39% efficient, but the 2013 eia numbers are 41.4% and new plants are over 50% efficient. The 67% for natural gas smr to pump assumes much more efficient storage and dispensing than California is dispensing today. NREL does say if you have 1200kg/day stations with high utilizations maybe with reasearch by 2020 they can build refueling at 69% efficient. At least 50 of the 57 now exisiting or planned can dispense 200kg or less per day, meaning they will use the much less efficient compression that is planned today. Those using smr for hydrogen will be less than 60% efficient. But screw it, lets use the prius as the key, the possible 69% efficient in 2020 smr, and 2013s ccgt to compare.

Plugging the new numbers in current grid for the i3-rex gets us 38.8% efficiency on existing natural gas infrastruture, it should go up in effiiciency as more of the current tech is built. Plugging in future hydrogen efficiency if their are breakthroughs that NREL thinks are possible in the next 5 years the mirai is 37.0% on smr distributed natural gas. Leaving the gen III prius at 34% efficient on gasoline.

Btw: the nrel report came out last year so it is recent and understands that what is being built in california doesn't have this efficiency. A humbolt station uses 18 kwh of electricity on average to dispense each kg of hydrogen. DOE hopes that in 2020 the hydrogen tanks on fcv will go down to $1800/vehicle

 

does that include btu energy for reforming & trucking to delivery sites? Or is this just the compression energy.
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