Who has Cheap/Free Electricity for home charging

[Yinn]

I pay about the national average of $0.139/kwh. But your question is an interesting one that spans across electricity and mpg equivelant. I think the calculator is a bit misleading without getting information on the efficiency because it doesn't give you the empg equivelant. So I actually worked backwards.

Hard Data from the onboard trip meter:
Miles Driven: 34,946
kWh Used: 11,703
wh/mi: 335
Electricity Cost to Me: $0.139
National Avg Cost of Reg Gas: $2.919

Cost to drive 34,946 Miles = 11,703 * $0.139 = $1,626.72
Gas Gallons Equivalent = $1,626.72 / $2.919 = 557.29 gallons
Cost based MPG Equivalent = 34,946 / 557.29 gallons = 62.71mpg

That's based on my electric rate of $0.139. What's interesting is a potential solar investment.

Average miles per year = 34,946 Miles / 3 Years = 11,648 Miles/Year
Average kWh used per year = 11,703 / 3 Years = 3901kWh
PV System Size Needed = 3901kWh / .85 / 1500 = 3.06 kW PV System (Use PV Watts to estimate)
Avg Cost per W in a PV system = $3.14/W
System Cost = $9,607.17
Less Fed Tax Credit = $9,607.17 - 30% = $6,725.02

$6,725.02 is the total cost of the PV system that will cover 100% of the electric consumption of the car. Now obviously the system is useful after you get rid of the car; but assuming you're only buying the system to fuel your car and nothing else. That reverse MPG calculation would look like this...

3 Year Vehicle Lease
Yearly System Cost = $6,725.02 / 3 = $2,241.67/year.
Gas Gallons Equivalent = $2,241.67 / $2.919 = 767.96 gallons
Cost based MPG Equivalent = 34,946 / 3 / 767.96 gallons = 15.17mpg

The $/kwh is actually $0.57/kWh in this situation. It takes just over 12 years to break even on the kWh (excluding state & local incentives) with the solar option; upon which it's "Free" charging. Avg warranties on panels and the such are about 25 years. So it'd amount to about 13+ years of "free" electricity..

*I'm on year 4 of 12 myself, but with state and local incentives; my breakeven point has actually moved to about 7 years total.

 

[israndy]

Yeah, what kills me is my 28¢/kWh means I should be REALLY interested in going solar. Sadly, I am not eligible for Net Metering so a better solution would be, like you say, only putting in enough solar for the car. If I control the charging of the car based on the amps coming off the roof I am not wasting energy going back to the grid, like this guy:

-Randy

 

[mspohr]

Yeah, what kills me is my 28¢/kWh means I should be REALLY interested in going solar. Sadly, I am not eligible for Net Metering so a better solution would be, like you say, only putting in enough solar for the car. If I control the charging of the car based on the amps coming off the roof I am not wasting energy going back to the grid, like this guy:

-Randy

Sounds like a Powerwall might be a good solution for you. You can put solar into the Powerwall rather than the grid and then pull it out at your leisure. Does an end run around the "no net metering".

 

[Yinn]

Yeah, what kills me is my 28¢/kWh means I should be REALLY interested in going solar. Sadly, I am not eligible for Net Metering so a better solution would be, like you say, only putting in enough solar for the car. If I control the charging of the car based on the amps coming off the roof I am not wasting energy going back to the grid, like this guy:

-Randy

Can you clarify on the net metering? Are you going to be connected to the grid? Will they meter month to month but not pay out? Or will they not bank at all?

If you can't bank at all, I'd recommend still going beyond the car. Go to 80-90% of your lowest monthly usage. That way you still cover a large part of your electricity but won't lose any. At 28c/kwh, the payback would likely be under 6 years.

Sounds like a Powerwall might be a good solution for you. You can put solar into the Powerwall rather than the grid and then pull it out at your leisure. Does an end run around the "no net metering".

Depends. If he isn't in need of a backup solution; then the powerwall might actually increase the kwh numbers compared to just slightly undersizing. But if he needs a backup anyway, then this is definitely the solution.

 

[Enginerd]

I just realized I've got a pretty sweet deal with the GA EV rate program:
On-Peak kWh..............20.3217¢ per kWh
Off-Peak kWh............. 6.5865¢ per kWh
Super Off-Peak kWh....... 1.4164¢ per kWh

 

[israndy]

I have heard rumors of power companies that PAY you to take their power at night, programs coming online to let you charge overnight when the POWER company is ready for you. You get a charger from them (or Tesla adds the feature to the car) where when the power company signals that it needs you to stop charging or it's ready for you to start charging the charger/car responds. Since this means the company doesn't need to spin down a generator that takes a long time to spin back up they don't mind losing the power that they otherwise might have just dumped into resistive loads.

But yeah, 1.4164¢ per kWh is CHEAP

-Randy

 

[LCR1]

I pay 7.8c/ kwh no matter how much I use or when I use it.

 

[israndy]

Texas! Jeez

 

[israndy]

Can you clarify on the net metering? Are you going to be connected to the grid? Will they meter month to month but not pay out? Or will they not bank at all?

The power company I have is only responsible for the island I live on. Businesses signed up for solar and put giant farms on their roofs and get paid for the electricity they generate at Net Metering rates so they MAKE money for the next few decades. They maxed out the 5% of capacity that power companies are mandated to provide to solar installs.

PG&E has a much larger service area so, despite large companies like Ikea and Apple putting in really giant farms, there is still a large number of non-solar customer's, more than 95%.

My power company WILL let me hook up, but ANY power that I send to the grid will not be matched. I still buy at the same cost, but any power I send they reimburse me at the rate *they* pay for power, so like 22¢ less per kWh.

Makes paying back the solar system more expensive. With flat-rate power, I could add solar and set my hot tub to heat during the sunny parts of the day and then charge the car with whatever is left over. I usually don't move the car very far each day so I would end up ahead. Then at night, I would still run the heat and lights off the grid. That's not SO bad that I could also pay off a Power Wall. All in all, probably not going to do it.

-Randy

 

[LCR1]

If I could keep my usage withing a narrow margin I could sign up for plans that are as low as 5c all in. But run out of that range and you're paying 10-13c. I can run as low as 1500kwh one month to 4,000 another so any I'd be in the hole even more.

Also, regular gas was 2.38 a gallon and I cringed with how much it's gone up in the past few weeks.