Reduce Charging Costs

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FiddlerJohn

Well-known member
Joined
Jan 7, 2012
Messages
244
Location
Bowie, Maryland
How To Reduce Electric Car Charging Costs:
http://www.edmunds.com/fuel-economy/how-to-reduce-electric-car-charging-costs.html
... electricity is cheap (particularly compared to gasoline)...
Wrong! The energy cost is about the same.
The EPA says a Gallon of Gas has the energy of 33.7 kWh which I now call a "Gallon of Electricity."

$0.11/kWh x 33.7 kWh = $3.70 for a "Gallon of Electricity"

So the energy cost is about the same. The difference is in the efficiency of use NOT the cost of energy.

About half of SCE's customers with plug-in vehicles haven't bothered to call to inquire about rate plans, says Bob Graham, manager of the utility's plug-in vehicle readiness program.

BGE installed a "Smart Grid" meter on my house last month. I should be getting plan options soon.

DC Region Not Prepared for Increased Electric Vehicle Usage:
http://bethesdagreen.wordpress.com/tag/metropolitan-washington-council-of-governments/
http://www.mwcog.org/store/item.asp?PUBLICATION_ID=449

Maryland MVA has reported the addresses of all EV owners to the electric companies.
 
Some people have all the luck. my electric rate, including all taxes comes out to be 26 cents per kwh. When I called my utility company and asked if they had a special rate for EV owners, they said, "Well if we gave you a discount for an EV, them the public would be subsidsing your transportation costs."

We do have a cheaper time of use plan where the night rate is cheaper, but they raise your daytime rate, so you take a calculated risk, and you would have to move more of your electric use to night time...which is near impossible.
 
Hi Fjpod,
It is a bit complicated and it may not be economical depending on how the feed in rates are, but assuming the power returned to the grid is at the rate of 25 cents, and say the night rate is 12 cents and the day rate is say 30 cents, then if one was to buy a grid tied inverter, used the imiev as as a power storage by charging at night on the cheap rate and then used the power during the day in the house or feed it back to the grid, you could even make money, perhaps.

As you might want to use the iMiEV during the day, one could get a battery pack and use that for the house instead and charge that on the cheaper night rate, saving the day rate power use.


The cost of inverters and battery packs might not make it worthwhile though.


Our office here uses 30 Kw per 24 hours, most of it after the cheap night rate comes on, and that will increase by about 8 to 16 kw per night when we recharge the imiev.

Current power costs are NZ 15 cents at night and 27 cents at daytime. 7 am to 9 pm for day, 9 pm to 7 am for night.

Feeding power back to the grid is on a one for one basis, so 1 Kw sent back at daytime gives a day rate meter refund, and a night sent back gives a night rate refund, using a meter for each as the new meters here don't go backwards I think.

So one meter for night rate, coming into the house, one for outgoing to the grid for night rate, and the same for day rate. 4 Meters in total.

So if a office draws power during the night to charge a battery, then uses a grid tied inverter to return that power during the day, then a credit is given for the day units.


Assuming the 5 Kw grid tie charger inverter is $ 5, 000 NZ and the Battery is $ 5, 000 for the 5 Kw capacity, then the power drawn at night , not allowing for losses, is 5 Kw, and cost is 15 x 5 = 75 cents.

The refeeding back at daytime, earns , again not counting power losses, 25 cents x 5 = 125 cents.

Profit is 50 cents. Kw to resend to gain the repayment of the $ 10, 000 spent is 10 Kw = $ 1 , so 100,000 Kw would need to be resent to achieve this.

@ 5Kw per night, this would take 2, 000 nights or 5.5 years, then the battery and the inverter would be free, again assuming no losses, power price increases or interest on money spent.

After that, using it to recharge the imiev would be @ 16 Kw at night, 16 x 15 = 2. 40.

If we used the day rate, it would be 25 x 16 = $ 4. 00 or a constant anytime rate of 22 cents, then it would be $ 3. 52.

Ideally though, solar during the day for office use and night rates for iMiEV and office use at night after 9 pm. It is 2 am as I write this and I'd Like to wish everyone a Happy New Year for 2013 from New Zealand !.
 
FiddlerJohn said:
... electricity is cheap (particularly compared to gasoline)...
Wrong! The energy cost is about the same.
The EPA says a Gallon of Gas has the energy of 33.7 kWh which I now call a "Gallon of Electricity."

$0.11/kWh x 33.7 kWh = $3.70 for a "Gallon of Electricity"

So the energy cost is about the same. The difference is in the efficiency of use NOT the cost of energy.
I've read this before, but it still doesn't 'compute' for me, so lend me your wisdom here, if you will

I know the 'efficiency of use' plays a BIG part. I've read that an ICE uses only about 15% of the energy in a gallon of gasoline to actually move the car - Much of the other 85% is either wasted with the engine running when the car isn't moving, or when the slow movement of the car isn't using the engine's output efficiently, but most of it just goes up as wasted heat, heating the atmosphere for no gain

Does your 'gallon of electricity' represent the electric power needed to heat something (a 100 ton crucible of molten steel for instance) as compared to heating it with a petroleum product?

For transportation usage, my 'gallon of electricity' is actually equal to only .15 gallons of gasoline, isn't it? This 'gallon of electricity' correlation isn't going to help us sell the idea of driving electric to the general public, is it?

Don
 
A gallon of gas costs me about $3.80 right now. In my Prius, I get at least 50 mpg. If my calculations are correct, at 25 cents per kwh, it costs me about $4.00 for a full charge. ($.25 x 16). This charge gives me about 80 miles in warm weather, but only about 55 miles in the cold. So, the miev is still "economical"...not that all decisions are made on being the most economical.
 
Don said:
FiddlerJohn said:
... electricity is cheap (particularly compared to gasoline)...
Wrong! The energy cost is about the same.
The EPA says a Gallon of Gas has the energy of 33.7 kWh which I now call a "Gallon of Electricity."

$0.11/kWh x 33.7 kWh = $3.70 for a "Gallon of Electricity"

So the energy cost is about the same. The difference is in the efficiency of use NOT the cost of energy.
I've read this before, but it still doesn't 'compute' for me...Don

Here's the answer to your question Don:

One important point that somewhat clouds the practical utility of a GGE for comparing different fuels to each other is that machines which run on them produce usable energy from different fuels at different efficiencies. For example a 2012 Nissan Leaf has a battery capacity of 24 kWh, or a GGE size of 0.72 gallons. A standard small gasoline-powered car with 25 MPG efficiency can go 18 miles on this much fuel. But the higher efficiency Nissan Leaf can go 80-100 miles on this much battery charge.

That quote comes from here: http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

As this article implies the "gasoline gallon equivalent" is useless when you have an inefficient machine using one fuel and an efficient machine using another. That's why the EPA came up with mpge because a gallon of gas does not get you the same distance as the equivalent energy from electricity and that's why the MiEV has an mpge of 112. Since the average compact car gets 27 mpg it takes over 4 gallons to go the same distance as "one gallon" of electricity. So, in this sense the Edmunds article was accurate, the electricity cost is 1/4 the cost of gasoline.
 
Yes, a gallon of (E10?) gasoline equals about 33.7kWh of electricity. But the Leaf battery has a DOD of about 93% so it has about 22.3kWh of usable power.

Does anybody know what the DOD / usable capacity there is in the i MiEV's battery pack?

Also, an EV is about 85% efficient plug-to-wheels. An ICE car is only about 25% efficient pump-to-wheels. So, if your costs are the same for 33.7kWh as it is for a gallon of gasoline, then by definition the energy costs at ~3.4X higher on an ICE car. Then you need to add about 25% *more* for regular maintenance cost - so that means driving an ICE costs 4.25X more than driving an EV.

I think it goes without saying that you cannot make your own gasoline. Because you can make your own electricity - especially if you live in a place where you can take advantage of incentives to install solar PV panels on your home, then you can pay 3-5¢ / kWh for all your electricity. In other words, you can lower your current electric bill by 25-60% as you drive your EV. Kewl!
 
I wonder if it could also be thought of another way...When we were working out how to recharge on a remote road, away from houses we could pop in and ask to borrow some electricity, grin, we came up with the Kipor IG 2600 petrol powered one, and worked out the fuel usage per Kw hour so we could estimate the ecconomy of the generator compared to the mains power.

The Generator at rated load of 2, 300 watts which is 240 volts at 9.6 amps uses roughly 5 litres over five hours for a per Kw hour usage of approx 0.5 litres per Kw. http://www.kipor.co.nz/products/inverter/main.html The Imiev ESEV here draws 9. 5 amps.

In New Zealand the petrol price is about $ 2. 20 NZ This makes the 1 Kw that is made by the generator using 0. 5 litres to be about $ 1. 10 per Kw.

The mains pricing for the day rate is about 25 cents per Kw. So the Generator is about 4 times more expensive to refuel the imiev than the main.

So the Imiev, if charged on the Kipor generator solely, would get 8 Kw a gallon which I think is about 3. 78 litres per USA Gallon, so equivalent to:

3. 78 litres, say 4 litres, produces 8 Kw hours for the imiev to recharge with. The imiev gets about 50 km per 8 Kw in testing here, so the MPGe via generator I think would be in Kms per Gallon, 50 Kms. I think that is about 30 Miles.


So Miles Per Gallon via Generator equivalent = 30 MPGeVG

Putting that another way, that is 7. 5 litres per 100 km.

The Prius C, I test drove here gave a return of between 5.7 Litres per 100 km in a long drive at 100 km / hour and 10 litres per 100 km was the best around town if I remember correctly.

The V8 Adventra we have, uses 12 litres per 100 km at 100 km/ hr.

On a 100 Km trip @ 100 KM hour, the imiev would be cheaper than the Prius C, on mains, but if recharged via the Kipor Generator it would be more expensive.

Imiev recharged via mains = 16 kw x 25 cents per Kw = $ 4.00 NZ

Imiev recharged via Kipor generator = 16 Kw = 8 liters x $ 2. 20 per litre = $ 17.60 NZ

Pirus C @ 5.7 litres per 100 Km = 5.7 litres x $ 2.20 per litre = $ 12.50

Adventra V8 = 12 litres = $ 26.40

Grin.
 
Another thought on the cost of recharging, at least here for NZ, where the night rate is cheap, but the day rate is higher is to consider the payback cost for the idea of solar and a dedicated inverter for daytime charging.

This would mean no large battery costs, say just a 1 Kw battery as a buffer for clouding on a otherwise sunny day, and if the travel was say only 50km per day then the 8 Kw needed, on a summer's day of good 8 hours of sunshine, would only be around 1 kw of panels needed.

A 2.5 Kw inverter here is about $ 2, 500 NZ, and @ the 2. 3 Kw the imiev charges here with the standard ESVE would charge it from zero to 50 % full in around four hours, so if we get a upgraded ESVE and have it set to say 1 Kw or less, then over the 8 hour day it should give the iMiEV a 50 % charge solely from the solar panels.

Of course there are inefficiencies so it would require a larger array, but as an idea it seems like it has some good points.


For a at work carpark, with no shading, and reasonable security, a set of quick connection points to attach the painted alloy poles that support the array to the car, and a lead into the boot via a connector socket, to the solar controller and buffer battery and inverter, then to the imiev upgraded ESEV, then to the J1772 socket in the boot and secure solar charging is on.

If we used say 10 x 120 watt panels, it would shade the imiev on hot days, and provide some allowance for the inefficiencies.

Assuming it all worked and there was plenty of good solar days and you kept a buffer in the main battery of say 20 % then it should work out.

Cost of Panels 10 x $ 250 = $ 2, 500 NZ
Cost of poles and frame = $ 500
Cost of Battery for 1 Kw for a lithium one. = $ 1, 000
Cost of solar controller = $ 900
Cost of 2. 5 Kw inverter = $ 2, 500


Total Cost of system, for free power with a 10 year depreciation to zero value est. = $ 7, 400

Est payback at 50 km per day, based on day mains power pricing, with 8 Kw = 8 x 25 cents = $ 2.00.

$7, 400 / 2 = 3, 700 days. = 10. 2 years.

So after 10 years fuel for the imiev is free. Or thinking another way, it cost the same as mains, but no power point instalation cost and no problems if someone is already in the EV recharging space.

But taking the set up and pack up time into consideration, to save $ 2, hmmm maybe not. But unless I am being paid for my time like at work, my non paid time is well, free so gaining $ 2 or $ 700 per year is cool.


Already thinking about a Campervan with electric motor and a 2 Kw array !


But seriously, a house or building mounted solar array for recharging the imiev, that already has the inverter for running other items, and perhaps a storage battery for cloudy days would be the more practical and ecconomical way of running the imiev.
 
Selling the power generated by your array to the grid at daytime rates and then recharging from the grid at night makes far more sense . . . . plus it would pay for your system much faster

Don
 
Don said:
Selling the power generated by your array to the grid at daytime rates and then recharging from the grid at night makes far more sense . . . . plus it would pay for your system much faster

Don

I was about to say that... If you install the solar panels yourself on your house or property, the cost is as little as 79 cents (USD) per watt. Get a "grid-tie" inverter and make sure you have the right type of meter, and the meter will simply run backwards during the day (assuming the air conditioner is off most of the time), and that will act like charging a "money battery" without the actual cost of a battery!

I figure the payback might be as little as 5 or 6 years, depending on whether the tax rebates expire this year or not, and which type of Grid-Tie inverter you get. I've heard that the Sunny Boy's are better than the no-name Chinese grid-tie inverters, but cost like twice as much. Plus in most areas you probably have to have a building permit, and the wiring probably has to be inspected or actually done by a licensed electrician, which might cost half as much as the solar panels themselves. :shock:

FYI, here's where I saw the solar cells for 79 cents/watt - They are Chinese of course, but most of the US makers are out of business now anyway: http://www.civicsolar.com/solar-panels . I'm seeing some on eBay for 99 cents/watt now.

Oh - It would be kinda neat if the MiEV were big enough to hold enough of the flexible peel-and-stick UniSolar panels - Imagine every metal surface on the car coated with flexible solar panels :)

Unfortunately UniSolar just filed for bankruptcy too a few months ago, so the flexible panels are just leftover stock. :(
 
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