More on the Tesla electric car

[Malcolm2]

Quote:

Originally Posted by ERD50 First things first... 2) Right. I'm sure some would, but as clifp says, the forums seem to have a lot of comments from proud owners of a performance vehicle. And that's fine, but (insert boring subsidy rant here ). -ERD50

Sometimes reality about the true green marginal economics of an electric car are not convenient if you own one, or plan to. Better to refer to truth as a 'boring subsidy rant' than to simply say I like the car and thats why I bought it, even at a premium shared by the taxpayer. The Tesla looks sharp and is fine for a niche market who can afford it. Not sure about the long term future for the company though. Technology changes rapidly.
It is OK, really to buy a Tesla or Prius for the reason that you like the look and wish to try to be an early adopter and don't plan to drive much outside of a few metro areas. It is just not accurate to simply equate no/less gas needed post purchase with a true 'green' product. That would be a boring and inaccurate rant all by itself - and simple marketing.

[ERD50]

Quote:

Originally Posted by Animorph It's probably not productive to compare efficiencies between different energy sources. We have coal available, at some point, even if it's just because it's the last source of energy on Earth, we'll need to use it. It's not really important if EV's use coal energy more efficiently than ICE's use oil energy. What matters is can EV's use coal energy more efficiently than some other automobile coal-energy engine?

I agree, the comparison is of limited usefulness. I went down that road, because after seeing the ghg numbers, clifp said he thought BTU eff% was important. Those didn't look so impressive after taking generation and conversion losses into account.

That's why this gets complex - how do you weight the various pros and the various cons? I sure don't know.

Quote:

Originally Posted by Animorph Regarding how much gas equals how much electricity and energy efficiency... The energy available to us on Earth is available in many forms, oil, natural gas, coal, nuclear, solar, wind, wave, and more. ICE engines probably won't be using all of those with a high efficiency. EV's should be able to use more forms of energy with reasonable efficiency. We will eventually want to use all sources available to us. ... Of course that's just the energy side of things. We might want to delay additional coal energy use until we can clean it up some more.

Yes, EVs have an advantage that they can use anything that can be turned into electricity. But my point, and it goes along with your comment on possibly delaying coal until it is clean, is we need to measure EVs on where the grid is today (or the near-term future). If it's really a lot cleaner in 20 years, maybe EVs make great sense then.

A little aside, but in my readings, I saw a chart that showed new hydro power actually increased GHG for the first 60 years (!!!) I guess the effect of the concrete and of drowning plants in the lake that is formed behind the dam.

-ERD50

[Midpack]

Related topic:
DW is considering a plug-in hybrid, but we expect to move in two years or less. IF* we decide we'd like to install a 240V charger in our garage, are they easily moveable? I assume I have to install a 240V line to the garage, and would have to do so in the new house, but I can move the charger itself which is most of the expense?

The above is what I gather from Google and the Leviton site, but I am not sure at all, hence the question here for Tesla owners and knowledgeable others.

*not looking for merits/need re: 120V vs 240V charging stations, I understand all that.

[yakers]

Some 240V chargers are movable and some are not. We had ours hard wired in, the best way if you are going to actually use 30+ AMPS or if have it set up outside, like I do. You could just get a 240V plug and plug in model. Also good for taking with you when camping or visiting and have 240V available.

[rodi]

We're seriously considering a plug in hybrid or EV car when my husband's 18 year old truck eventually becomes unreliable. (We can't justify replacing it - it runs well and we don't put a lot of miles on it.)

When we do - we'll put on solar panels. We're currently light electrical users - barely into the 2nd tier... so solar doesn't pencil out. But if we're charging a car - it makes a LOT more sense. We live in a year round sunny place - and even though we're semi-coastal and deal with the dreaded "June Gloom" and "May Gray"... solar will still make sense.

Neighbors bought a leaf and got solar - they love that they're charging their car in a "clean" way.

I currently drive a hybrid highlander. It's 8 years old so I'm not as concerned about warranty. I'd consider modifying it to be plug in when we get solar panels.

Hopefully, when we pull the trigger, the solar panel technology will have improved that much more.

[ERD50]

Quote:

Originally Posted by rodi Hopefully, when we pull the trigger, the solar panel technology will have improved that much more.

If solar PV prices come down as they have been, I think it makes sense to wait. It seems that the prices are coming down at about the same rate as payback, so why not just wait?

Quote:

Originally Posted by rodi Neighbors bought a leaf and got solar - they love that they're charging their car in a "clean" way.

While that sounds good, too bad that it is just not the case. It's repeated so often in the various EV forums I've been reading, it really needs to be straightened out. I covered this in an earlier post, in a 'truth table' format, I'll re-post that here, but I think I'll add a 'narrative format', that might make the point better -

Quote:

For simplicity, let's assume a household consumes one 'unit' of electrical power average per month. And assume if they purchased an EV, that would consume one 'unit' of electrical power average per month. And that they could install PV solar that would produce one 'unit' of electrical power average per month. Now consider each possibility: 1) NO EV; NO PV; - status quo - consume ONE unit electrical, consume X gallons gas 2) NO EV; YES PV; - consume ZERO units electrical, consume X gallons gas 3) YES EV; NO PV; - consume TWO units electrical, consume ZERO gallons gas 4) YES EV; YES PV; - consume ONE unit electrical, consume ZERO gallons gas

As a narrative -

Take that first paragraph above, then assume they add solar first. You can see that they now consume no electricity on average, and their allocation of the pollution that the power plant generates is zero. So this is great enviro-wise.

Now they add their EV. Adding the EV means they now draw one more electrical unit from the grid (and the allocated pollution) than they were w/o the EV. The EV undid the good they did by adding PV!

Or you can turn it around, and they add the EV first. At that point they are consuming two units of electricity on average, and their allocation of the pollution that the power plant generates is twice what it was before.

Now they add solar. Adding the solar means they now draw one less electrical unit from the grid (and the allocated pollution) than they were w/o the solar. The solar undid the draw/pollution from adding EV!


So we can see, adding solar cuts their grid pollution, and adding an EV increases the grid pollution. It makes no difference if they are done together or separately, one before the other or vice-versa. As I said earlier, they each need to stand on their own, there is no multiplier effect.

So there is no justification for saying that having solar means they are charging their EV in a 'clean' way. The EV must be measured against other available vehicles. I can buy a pure hybrid and buy solar too. So compare apples-apples.

Will you be able to break this news to your neighbors?

-ERD50

[eridanus]

Quote:

Originally Posted by ERD50 I covered this in an earlier post, in a 'truth table' format,

The logical fallacy of the above "truth table" is, of course, that one unit of grid energy for an EV puts out the same pollution as one unit of gasoline energy in an ICE. We know this isn't true where the early adopters are buying EVs (more than 60% of Leafs were sold to CA residents in 2011, the latest number I could find).

It's the whole apples-to-apples thing given the efficiency and pollution of those EV drivers, who, realistically, mostly reside in California (at least in 2011), where the fuel mix is far cleaner than the average US fuel mix (those pesky averages again!).

Quote:

So we can see, adding solar cuts their grid pollution, and adding an EV increases the grid pollution. It makes no difference if they are done together or separately, one before the other or vice-versa. As I said earlier, they each need to stand on their own, there is no multiplier effect.

If a new EV owner puts in PVs to power their EV, the grid change is zero, nada, zip because, well, the PV supplies the EV. The EV owner also wouldn't be using X gallons of gas. So the real truth table would look like,

Before the EV and PV:
House electricity from grid + X gallons of gas

After the EV and PV:
House electricity from grid + 0 gallons of gas

After obviously uses less external energy once the PV panel pays for itself.

What we're missing is whether an EV buyer would have bought PVs without buying an EV. In other words, are they two independent events or are they linked? As you stated yourself, "[I]t's repeated so often in the various EV forums I've been reading" that it seems like they're linked. Buying an EV is an impetus to buy PVs because, damn, wouldn't it be cool to power the car without gas or grid power?

[clifp]

Quote:

Originally Posted by ERD50 OK, so here's my stab at calculating an 'mpge' number that actually includes the generation of the electricity, with delivery and charging losses. I got the conversion eff% (kWh of electrical power generated, divided by the kWh content of fuel) for coal & Nat Gas plants from this link, and the current fuel mix from 'State of Charge'. So I weight the mix with the eff% to determine how many units in for units out, and the total gives this as an eff%. Then multiply by distribution eff%, and by charging eff%. All this multiplied by the 'battery draw mpge' figure, gives you the adjusted mpge. As we see, this comes down to ~ 43 mpge of fossil fuel used, right around a good hybrid. Next, I plugged in some numbers for assumed 'greening' of the grid. So I moved NG up to 40% from 24%, coal down from 45% to 25%, and non-fossil up 4 points to 35%. All that change gets us to ~ 48 mpge adjusted.I guess we are still right around a good hybrid in terms of fossil Yes, as discussed earlier, there should be some factor for delivery of gasoline to the gas station, and maybe some for refining (coal and NG have to be processed and delivered to power plants also). I'll see if I can find the numbers, but somehow I doubt they would add back the > 2 mpge I 'gave' the EV with the generous charging eff% assumption. Summary so far - the mpge number is pretty useless. It can be used to compare the efficiency of one EV to another, but only from the battery on. It doesn't tell you anything about the charge efficiency and phantom power. And it really isn't useful to compare to an ICE/hybrid. So GHG doesn't seem like any great shakes for an EV. Fossil fuel consumption isn't great in comparison. Other pollutants are from several times higher to hundreds of times higher for an EV. Are EVs really something that environmentalists should be rallying around? I honestly think there are better paths to take. But I bet clifp is having a 'gas' in his Tesla S right about now! -ERD50

I first thought I'd check with a reputable source and looked to see what David McKay had to say. From Chapter 20 Sustainable Energy:Without the Hot Air (SE:WTHA)

Quote:

What if we demand more – more acceleration, more speed, and more range? At the other end of the spectrum is the Tesla Roadster. The Tesla Roadster 2008 has a range of 220 miles (354 km); its lithium-ion battery pack stores 53 kWh and weighs 450 kg (120 Wh/kg). The vehicle weighs 1220 kg and its motor’s maximum power is 185 kW. What is the energy-consumption of this muscle car? Remarkably, it’s better than the G-Wiz: 15 kWh per 100 km. Evidence that a range of 354 km should be enough for most people most of the time comes from the fact that only 8.3% of commuters travel more than 30 km to their workplace. I’ve looked up the performance figures for lots of electric vehicles – they’re listed in this chapter’s end-notes – and they seem to be consistent with this summary: electric vehicles can deliver transport at an energy cost of roughly 15 kWh per 100 km. That’s five times better than our baseline fossil-car, and significantly better than any hybrid cars

It is also worth looking at the first technical chapter Cars II as he discusses the benefits of electric cars.

I followed your calculations fairly well, but then looked for alternatives on the web.

The section from a pretty detailed wiki on MPG

Quote:

Petroleum-equivalency factor (PEF) — a CAFE metric In 2000 the United States Department of Energy (DOE) established the methodology for calculating the petroleum-equivalent fuel economy of electric vehicles based on the well-to-wheel (WTW) gasoline-equivalent energy content of electricity (Eg). The methodology considers the upstream efficiency of the processes involved in the two fuel cycles, and considers the national average electricity generation and transmission efficiencies because a battery electric vehicle burns its fuel (mainly fossil fuels) off-board at the power generation plant.[8] This methodology is used by carmakers to estimate credits into their overall Corporate Average Fuel Economy (CAFE) for manufacturing electric drive vehicles.[7] The equations for determining the petroleum equivalent fuel economy of electric vehicles are the following:[8] PEF = Eg * 1/0.15 * AF * DPF where: PEF = Petroleum-equivalent fuel economy Eg = Gasoline-equivalent energy content of electricity factor 1/0.15 = "Fuel content" factor or incentive factor. DoE selected this value to keep consistency with existing regulatory and statutory procedures, and to provide a similar treatment to manufacturers of all types of alternative fuel vehicles AF = Petroleum-fueled accessory factor DPF = Driving pattern factor The gasoline-equivalent energy content of electricity factor, abbreviated as Eg, is defined as: Eg = gasoline-equivalent energy content of electricity = (Tg * Tt * C) / Tp where: Tg = U.S. average fossil-fuel electricity generation efficiency = 0.328 Tt = U.S. average electricity transmission efficiency = 0.924 Tp = Petroleum refining and distribution efficiency = 0.830 C = Watt-hours of energy per gallon of gasoline conversion factor = 33,705 Wh/ga lEg = (0.328 * 0.924 * 33705)/0.830 = 12,307 Wh/gal PEF = Eg * 1/0.15 * AF * DPF = 12,307 Wh/gal/0.15 * AF * DPF PEF = 82,049 Wh/gal * AF * DPF The petroleum-fueled accessory factor, AF, is equal to 1 if the electric drive vehicle does not have petroleum-powered accessories installed, and 0.90 if it does. The driving pattern factor, DPF, is equal to 1, as DoE considered that electric vehicles eligible for inclusion in CAFE will offer capabilities, perhaps excepting driving range, similar to those of conventional vehicles. In the example provided by the US DoE in its final rule, an electric car with an energy consumption of 265 Watt-hour per mile in urban driving, and 220 Watt-hour per mile in highway driving, resulted in a petroleum-equivalent fuel economy of 335.24 miles per gallon, based on a driving schedule factor of 55 percent urban, and 45 percent highway, and using a petroleum equivalency factor of 82,049 Watt-hours per gallon.[8]

At first glance I thought ERD was way off. Until I noticed the DOE did a tricky thing they multiply MPGe of Electric cars by 6.667 and hybrids by 6 for CAFE purposes. However for energy equivalents we can just divide by the incentive factor. Meaning this car has Well to wheel MPG of 50 and my Tesla with 284 wH/mile is 43 MPGw.

The main thing ERD calculations are missing is the factor for refining oil into gasoline (which is pretty energy intensive) and the energy cost of distributing gasoline. DOE says that is .83 which is almost exactly equal to the transmission losses .92 * the power lost due to charging .9. A factor which DOE didn't include.

Simplifying, what this says the EV will be more energy efficient the ICE for pretty simple reasons. Braking regeneration provides a roughly 20% increase in efficiency plus the greater energy efficiency of power plants. There is significant increase in energy efficiency from going to coal to natural gas (25%+) and the switch over it is a good opportunity to make our power plant more efficient. Both hybrids and electric cars benefit from regenerative breaking. The big disadvantage to me of a hybrid is that it combines all the complexity and maintenance of an ICE car plus the addition of a expensive battery, and electric motor. I look how few moving parts the Tesla has I think no reason, lots of cars can't be built this way.

You maybe right that hybrids are currently are almost as good environmentally as EVs. But what you can't say is the Hybrids are better. 43 MPGw for a car the size and performance of the Tesla is just more impressive than the same MPG from a Prius.

Now it is perfectly understandable to complain about the over hyping of the how green EVs. Hybrids are good green cars also, and maybe they will end up as the dominate cars, and EV just relegated to niche. On the other hand it is possible that EV could be ~1/3 to 1/2 the fleet and that a two car house has an EV for commuting and Hybrid for long trips. But what makes hybrids efficient is the electric motor and the batteries. So the subsidies for EV result in better batteries, more efficient electric motors, and better charging solutions.

[ERD50]

Quote:

Originally Posted by clifp ... At first glance I thought ERD was way off. Until I noticed the DOE did a tricky thing they multiply MPGe of Electric cars by 6.667 and hybrids by 6 for CAFE purposes. However for energy equivalents we can just divide by the incentive factor.

The DOE did a "tricky thing"? A factor of six is just "tricky"? Sounds more like "lying" to me! Or as Elwood said to Jake - "I took the liberty of bullshittin' ya."

From what I've found, this is a totally made up number in order to make alternatives appear more attractive to the consumer. Is this the same govt that has set "Truth in Advertising" laws? Am I living in Bizzaro-World? Are we on Htrae?

Why are the VOLT and LEAF EVs measured in Miles Per Gallon? | Electric Vehicle News

Quote:

Fudge Factor This 'utility factor' or 'Driving Pattern Factor' is just one variable in what the DoE/EPA officially call the 'petroleum-equivalency factor' (PEF) which has been on the books since July 2000. The background is that Congress wanted to allow auto manufactures to quote high equivalent 'fuel economy' for electric vehicles as an incentive to help accelerate the commercialization of electric vehicles.

So what if Intel decided to do a 'tricky thing' and multiply a key spec by a factor of six? After all, people benefit from computers, and if they think they are better than they really are, they will buy more and it's all good, right? The ends justifies the means? Hmmmm, if you did that as a private business, you might be experiencing the "8x10, three squares and a cot" Federal FIRE program.

Am I allowed a "WTF" on this one? Peeling back the layers of this onion is making my eyes water. Holy Cow!

Quote:

The main thing ERD calculations are missing is the factor for refining oil into gasoline (which is pretty energy intensive) and the energy cost of distributing gasoline. DOE says that is .83 which is almost exactly equal to the transmission losses .92 * the power lost due to charging .9. A factor which DOE didn't include.

Yes, I acknowledged that in that post. I'm trying to find a good number, and I think that .83 is probably good for refinery losses. But obviously, any DOE number needs to be taken with a salt mine full of salt

I also mentioned, coal, NG, and fuel-grade uranium don't magically appear at the power plant all ready to jump into the fire/core either. While I'm sure those losses are less than petroleum refinery losses, those losses are not zero. I'd like to find out what they are. And I have not yet found a good comparative analysis of the embodied energy in the EV battery, controller, and motor, versus the propulsion system and associated components in a high mpg hybrid.

Quote:

Simplifying, what this says the EV will be more energy efficient the ICE for pretty simple reasons. Braking regeneration provides a roughly 20% increase in efficiency plus the greater energy efficiency of power plants. There is significant increase in energy efficiency from going to coal to natural gas (25%+) and the switch over it is a good opportunity to make our power plant more efficient. Both hybrids and electric cars benefit from regenerative breaking. The big disadvantage to me of a hybrid is that it combines all the complexity and maintenance of an ICE car plus the addition of a expensive battery, and electric motor. I look how few moving parts the Tesla has I think no reason, lots of cars can't be built this way.

And I've been comparing to a high mpg hybrid with regenerative braking, not a plain ICE. I think that is the right comparison if we are looking to a practical, mass market vehicle with the lowest enviro-harm.

I totally agree that the simplicity of an EV is attractive. It is one of the reasons I wish I could have been driving one for the past thirty years. But in practical terms, it appears that the Prius has had a very good record for reliability. It's not something that is keeping a significant number of people from buying hybrids, range anxiety is keeping a significant number of people from buying EVs. But EVs should have an advantage here, and no oil changes, etc provide a (probably small? ) enviro-benefit.

Another thing I've thought of regarding the idea that urban areas will benefit from shifting the other pollutants away from the populated city. I'm only familiar with Chicago, but many cars are parked on the street - no access to 110V, let alone 220V. And the garages I'm familiar with are detached, out back along the alley. I doubt any significant number have 220V, and I think it would be an expensive upgrade, involving running new wiring from house/meter out and through/over the back-yard to a detached structure. 110V charging is less efficient, and probably not practical for daily commutes. So how many EVs can a city support, w/o major infrastructure changes? This will slow adoption, but is not a factor for a hybrid.

Quote:

You maybe right that hybrids are currently are almost as good environmentally as EVs. But what you can't say is the Hybrids are better. 43 MPGw for a car the size and performance of the Tesla is just more impressive than the same MPG from a Prius.

OK, from a BTU of fossil fuel POV, EV is probably somewhat better. But my question all along has been - so much better that they should be 'pushed'? And can we ignore the 'inconvenient truths' of NOx, SOx, mercury, particulates, etc?

Quote:

So the subsidies for EV result in better batteries, more efficient electric motors, and better charging solutions.

This is debatable, but not today

Hey, keep us up to-date on how much you are enjoying the new Tesla. Just because I'm questioning the enviro-benefits of EVs doesn't mean I don't think the Tesla is an awesome vehicle and an impressive engineering feat, because I do think it's awesome. Details!

-ERD50

[samclem]

Quote:

Originally Posted by ERD50 I'm only familiar with Chicago, but many cars are parked on the street - no access to 110V, let alone 220V. And the garages I'm familiar with are detached, out back along the alley. I doubt any significant number have 220V, and I think it would be an expensive upgrade, involving running new wiring from house/meter out and through/over the back-yard to a detached structure.

This is easy to solve. Just start 'er up when you park the car, the charging will be done at the efficient 220V. Bonus: Make a little trailer for it and the range problem is also solved.
Honda EB650X1. Other models burn diesel or NG.



Price:
$2,749.95
SKU:
EB6500X1
Weight:
220.00 LBS
Availability:
Ships in 3-5 days.
Shipping:
Free Shipping in the Continental U.S.

[ERD50]

First eridanus, I'll agree with you that on a relatively clean grid, the EV is better by some measures than a high mpg hybrid. And still worse by others.

Quote:

Originally Posted by eridanus The logical fallacy of the above "truth table" is, ...

I've reviewed my 'truth table' and I stand by it.

Quote:

Originally Posted by eridanus The logical fallacy of the above "truth table" is, of course, that one unit of grid energy for an EV puts out the same pollution as one unit of gasoline energy in an ICE. We know this isn't true where the early adopters are buying EVs (more than 60% of Leafs were sold to CA residents in 2011, the latest number I could find).

I didn't claim it did or didn't. It isn't part of my 'truth table', because it is a separate issue from the EV/PV calculus. Let me re-state it:

EEU = Electrical Energy Unit from Power Plant					
GU  = Gasoline Unit to propel a Hybrid

					
 EV + Home          = 2 EEU and ZERO GU			 
 Hybrid + Home 	    = 1 EEU and 1 GU			 

 EV + Home + PV     = 1 EEU and ZERO GU
 Hybrid + Home + PV = 0 EEU and 1 GU

So, w/o solar, an EV adds 1 EEU and eliminates 1 GU, compared with a hybrid.
And with solar, an EV adds 1 EEU and eliminates 1 GU, compared with a hybrid.

Solar washes out. With or w/o solar, the EV adds a 1 EEU draw from the power plant, and saves 1 Gasoline Unit. So the decision is still - is an EV 'better' than a hybrid? Solar has nothing to do with it. Solar does not make the EV 'greener', solar is 'greener' on its own.

Your conclusion does not conflict with mine, you just injected the EV versus hybrid into the EV w&w/o solar question, and it is separate.

Quote:

What we're missing is whether an EV buyer would have bought PVs without buying an EV. In other words, are they two independent events or are they linked? As you stated yourself, "[I]t's repeated so often in the various EV forums I've been reading" that it seems like they're linked. Buying an EV is an impetus to buy PVs because, damn, wouldn't it be cool to power the car without gas or grid power?

I can't quantify how many EV owners would be pushed over the edge to purchase PV due to the EV. But if they are doing it on a false premise, I think that's a problem. We're back to 'the ends justify the means' arguments, and that opens up those tactics to your opposition (what's good for the goose...). And then it is who is the best (or best funded) liar. I think it is better to act on truthful statements rather than distortions from one side or the other. Facts are facts.

-ERD50

[ERD50]

Quote:

Originally Posted by samclem This is easy to solve. Just start 'er up when you park the car, the charging will be done at the efficient 220V. Bonus: Make a little trailer for it and the range problem is also solved. Honda EB650X1. Other models burn diesel or NG.

Brilliant! I knew we'd be able to solve this problem if we just put all these smart minds on er-org to the task!

What should we tackle next - world hunger, AIDS, malaria? Watch out Gates Foundation, you've got competition from er-org, we have time on our hands, and all the answers!

-ERD50

[rodi]

Quote:

Originally Posted by ERD50 If solar PV prices come down as they have been, I think it makes sense to wait. It seems that the prices are coming down at about the same rate as payback, so why not just wait? While that sounds good, too bad that it is just not the case. It's repeated so often in the various EV forums I've been reading, it really needs to be straightened out. I covered this in an earlier post, in a 'truth table' format, I'll re-post that here, but I think I'll add a 'narrative format', that might make the point better - As a narrative - Take that first paragraph above, then assume they add solar first. You can see that they now consume no electricity on average, and their allocation of the pollution that the power plant generates is zero. So this is great enviro-wise. Now they add their EV. Adding the EV means they now draw one more electrical unit from the grid (and the allocated pollution) than they were w/o the EV. The EV undid the good they did by adding PV! Or you can turn it around, and they add the EV first. At that point they are consuming two units of electricity on average, and their allocation of the pollution that the power plant generates is twice what it was before. Now they add solar. Adding the solar means they now draw one less electrical unit from the grid (and the allocated pollution) than they were w/o the solar. The solar undid the draw/pollution from adding EV! So we can see, adding solar cuts their grid pollution, and adding an EV increases the grid pollution. It makes no difference if they are done together or separately, one before the other or vice-versa. As I said earlier, they each need to stand on their own, there is no multiplier effect. So there is no justification for saying that having solar means they are charging their EV in a 'clean' way. The EV must be measured against other available vehicles. I can buy a pure hybrid and buy solar too. So compare apples-apples. Will you be able to break this news to your neighbors? -ERD50

What you don't account for is that we'd size the PV to include the car use. We're NOT getting PV until we have enough use (with the car). It doesn't make sense since we're already low consumers and it doesn't pencil out till we add the consumption with the car.

So it would be 2PV units, to provide 1 house unit and 1 car unit. = Net zero on the grid.

And being cheap - we'll also time it with the roof replacement. Should be due for a new roof about the same time-frame that DH's truck needs replacing and PV is cheap enough. His truck is running fine now, despite it's age... It should be good for another 5-7 years... which is when our roof comes out of warranty.

[Elbata]

How come you don't see this stuff on motorcycles or scooters?

My scooter gets 85MPG and I'd be really happy at 200MPG.

[Running_Man]

Quote:

Originally Posted by Chuckanut +1 As much as I like the idea of fully electric vehicles whose power comes from very low polluting sources, I do think the subsidy would be far better spent on something else - like cleaning up a coal fired plant, or refitting holder buildings to be more energy efficient. The greenest car is the one that stays parked.

Tesla is setting up charging stations that are solar powered , so that if your desire was to be truly green it is surely possible. Long term I would think that would be the eventual use of the Tesla technology and is the goal of the company.

Supercharger | Tesla Motors

[Running_Man]

Quote:

Originally Posted by mikefixac How come you don't see this stuff on motorcycles or scooters? My scooter gets 85MPG and I'd be really happy at 200MPG.

It certainly is available, put a windmill on your home and your are using no pollutants!
ZERO MOTORCYCLES ? The Electric Motorcycle Company - Official Site

[ERD50]

Quote:

Originally Posted by mikefixac How come you don't see this stuff on motorcycles or scooters? My scooter gets 85MPG and I'd be really happy at 200MPG.

Because going from 85 mpg to 200 mpg saves only a small amount of gasoline. It is hard to pay back the investment. MPG is a bad measure to use, it's hard to work with. A better way to do it is in consumption per 10,000 miles, then multiply by your annual miles factor.

85 to 200 is a 2.35x improvement, but at 10,000 miles saves only 118-50 = 68 gallons ($338 @ $5/g). But the same 2.35x improvement from 17 mpg to 40 mpg saves 588-250 = 338 gallons ($1691 @ $5/g).

Quote:

Originally Posted by rodi What you don't account for is that we'd size the PV to include the car use. We're NOT getting PV until we have enough use (with the car). It doesn't make sense since we're already low consumers and it doesn't pencil out till we add the consumption with the car. So it would be 2PV units, to provide 1 house unit and 1 car unit. = Net zero on the grid. ...

OK, so you are on a tiered billing system, and your rate is too low w/o the extra consumption with the EV to justify solar? That's a wrinkle I hadn't considered or heard of prior to this - that would seem to bring a connection between the EV and PV, but I have no idea how many are affected by this. Interesting.

Quote:

Originally Posted by Running_Man Tesla is setting up charging stations that are solar powered , so that if your desire was to be truly green it is surely possible.

I disagree for the reasons stated before. Those PV panels will be feeding the grid when no EVs are being fed. There's your 'green'. And we're back to - is an EV enviro-better than a high mpg hybrid?

-ERD50

[Running_Man]

Quote:

Originally Posted by ERD50 I disagree for the reasons stated before. Those PV panels will be feeding the grid when no EVs are being fed. There's your 'green'. And we're back to - is an EV enviro-better than a high mpg hybrid? -ERD50

If a car that is only charged by solar power from specifically made solar stations by the manufacturer of for those cars and the manufacturer maintains the stations for the benefit of the car owners does not count as green, then there is no green. The idea that first TESLA would have to create enough solar energy to power the entire country before any credit can go to TESLA being green does not seem at all rational to me.

[ERD50]

Quote:

Originally Posted by Running_Man If a car that is only charged by solar power from specifically made solar stations by the manufacturer of for those cars and the manufacturer maintains the stations for the benefit of the car owners does not count as green, then there is no green. The idea that first TESLA would have to create enough solar energy to power the entire country before any credit can go to TESLA being green does not seem at all rational to me.

That would be irrational, and it isn't at all what I am saying.

On one level, this is actually very simple, but I completely understand having a mental block on it. I did for a while, and had to go through this myself to understand and be able to explain it. I'll try another illustration, but I'm afraid I'm out of ammo after that. You'll need some specifics to defend an opposing view. Here goes...



Keep in mind, when the solar PV is not charging an EV, it will be feeding the grid.

Picture a small local grid. Each day, 1000 EEU are produced and consumed.

One day, the town installs an EV solar powered charging station (EV-SPCS) that produces an average 1 EEU of solar power per day. So now, the local grid only needs to produce 999 EEU. So we can give the EV-SPCS 1 EEU 'green credit' per day. You agree so far, right?

Then a local buys a Tesla S. He charges it at home each day, using 1 EEU. So now the grid is back to needing to produce 1000 EEU/day. We just lost our 1 EEU 'green credit', we are back to status quo.

On another day, he charges the 1 EEU from the EV-SPCS. So the 1 EEU that the EV-SPCS produces goes to the Tesla instead of to the grid. So the grid still needs to produce the normal 1000 EEU per day. There is no difference whether the Tesla charges from the grid, or from the EV-SPCS - same 1000 EEU is produced by the grid.

The EV-SPCS gets the 'green credit', the EV doesn't.

OK, I hear you - what about the gas savings from the EV? It's a separate issue, and I'll cover that now...

Some time later, clifp this guy develops whiplash from giving rides to hot girls and impressing them with the acceleration, so he sells his Tesla to someone outside this grid, and replaces it with a Prius. So let's look at the effect on the grid and on gasoline consumption.

The EV-SPCS is still there, so the grid is back to producing 999 EEU, and the EV-SPCS produces 1 EEU to meet the original 1000 EEU demand. So the EV-SPCS is still earning that 1 EEU 'green credit' per day.

But this guy has to fill his Prius with gasoline, so gets 1 'Gasoline Unit demerit' to go along with the 1 EEU green credit from the power the EV-SPCS provides to the grid. See where this is going? It all washes down to the original question:

Is the overall environmental impact from 1 Gasoline Unit significantly better/worse than 1 EEU unit? Which is the same as saying, is the overall environmental impact from an EV significantly better/worse than a high mpg hybrid?

edit/add: A slightly different way to state that - consider the grid plus PV to be status quo. The EV consumes an added 1 EEU, and zero Gasoline Units. The Prius consumes zero EEU, but 1 Gasoline Unit. So again, we compare a GU to an EEU. The solar PV is green, but it is green with or without an EV.

I'll repeat an earlier statement you may have missed - the optimal use of an EV and PV would be to charge the EV from the cleanest grid around, and install the PV on the dirtiest grid around (adjusting for solarisation differences).


Whew!


-ERD50

[ERD50]

That was long, in summary form - heh, heh:

		Grid    PV 	Gasoline
		Power	Power 	Power

1) Before PV:	1000	  0	  0

2) After PV:	 999	  1	  0

3) No Car Yet:	 999      1       0

4) Buy an EV:	1000	  1	  0

5)Sell EV - 
  add Prius:	 999	  1	  1

In step 2, the PV lowers EEU produced by the relatively dirty grid by 1 EEU. So 1 EEU green credit for PV.

In step 4, buying an EV consumes an added 1 EEU, and zero added Gasoline Units. One EEU demerit.

In step 5, buying a Prius instead, he consumes zero added EEU, but 1 added Gasoline Unit. One GU demerit.


So again, we compare a GU to an EEU. The solar PV is green, but it is green with or without an EV.

-ERD50