Solar Panels and PHEVs

boulder_bum · 08-31-2007, 03:57 PM

My wife and I might be buying a house soon, and in Colorado, there are some especially nice perks for installing solar panels at the time of purchase.

I anticipate purchasing a PHEV in some form or another when they come out in 2009-2010 (knock on wood). What I'm wondering is how much juice I'd need to support a nightly charge of the car (not counting the rest of the home).

Because of some time-sensitive incentives, it might make sense to prepare for 2010 now.

**efusco** · 08-31-2007, 04:02 PM

You might need to search a little, but if you're considering the Volt or similar there was recently a thread talking about the anticipated capacity. Someone mentioned that it would take 5 200Wh panels charging 8 hours a day to fully charge the Volt PHEV40 battery.

mgipe · 08-31-2007, 04:16 PM

I suspect that an infinite number of solar panels would not charge your electric car overnight.

---No sun!---

Sufferin' Prius Envy · 08-31-2007, 04:33 PM

<div class='quotetop'>QUOTE(mgipe @ Aug 31 2007, 01:16 PM) [snapback]505115[/snapback]</div>

Quote:

I suspect that an infinite number of solar panels would not charge your electric car overnight.
---No sun!---

[/b]

The OP needs to check with their utility company.

Not all do net metering - whereby the car could be recharged at night with credits from daytime solar production.

The other thing to find out is if, at the end of the year, the utility will pay you for any extra solar power credits which you did not use. Most utilities DON'T . . . which is really unfortunate. They will gladly take your extra power without paying you for it . . .

. . therefor, in designing your system, if you go over 100% of your yearly need, you are spending money you will never see a return on. <_<

EricGo · 08-31-2007, 05:47 PM

Boulder, this is a two part question

1. How much energy will the car use ? about 200 - 250 watt-hour per mile. Multiply this by miles driven per month ..

2. How much energy will a 1000 watt panel produce per month in your area ? That information should be forthcoming from your installer. Cross check their numbers with your local solar energy groups.

----
As an aside, a couple bits of advice

1. Heat your water with solar heating, not PV
2. First spend money decreasing your home energy energy use. Smart choices regarding lighting, insulation, conservation, shading and light, and AC can be quite a bit less expensive then PV. As an example, a clothesline instead of a dryer for my kid's incessant clothes washing will save over 100 kWh per month in drying 10 months of the year.

I'm guessing you will install a tie-in to grid with net metering ? It's the best way to go.

All the best !

Lywyllyn · 08-31-2007, 05:53 PM

We have netmetering (meter spins backwards if we generate more then use) and also use TOU (time of use) metering. The TOU really makes a big difference. Basically we have a peek time 12 - 7pm where electricity is at its most expensive. The other times it is cheap(er) Weekends are 24hr at the same low rate. So I recommend that you look into getting appliances with timers. We do our dishes at midnight, laundry starts at 6:00 am and we stop using the dryer before noon and resume after 7:00pm. I also put all our entertainment stuff on a powerstrip and turn that off when we go to bed. the standby power sucks up to 25% of running power on some electronics.

so with a bit of change in schedule you should be able to get away with 3KW system (provided you don't have more then 2200sq ft) else I would aim at a 5K system. With current rebates you can probably expect to get half of the cost back and then a approx $1800.00 tax benefit

boulder_bum · 08-31-2007, 06:01 PM

<div class='quotetop'>QUOTE(efusco @ Aug 31 2007, 02:02 PM) [snapback]505109[/snapback]</div>

Quote:

You might need to search a little, but if you're considering the Volt or similar there was recently a thread talking about the anticipated capacity. Someone mentioned that it would take 5 200Wh panels charging 8 hours a day to fully charge the Volt PHEV40 battery.
[/b]

Okay, I'll look for that. I've never had much luck with the site's search feature, but I'll give it a whirl.

<div class='quotetop'>QUOTE(mgipe @ Aug 31 2007, 02:16 PM) [snapback]505115[/snapback]</div>

Quote:

I suspect that an infinite number of solar panels would not charge your electric car overnight.

---No sun!---

[/b]

My utility company gives you credits for the energy you collect during the day.

<div class='quotetop'>QUOTE(Sufferin' Prius Envy @ Aug 31 2007, 02:33 PM) [snapback]505127[/snapback]</div>

Quote:

The OP needs to check with their utility company.

Not all do net metering - whereby the car could be recharged at night with credits from daytime solar production.

The other thing to find out is if, at the end of the year, the utility will pay you for any extra solar power credits which you did not use. Most utilities DON'T . . . which is really unfortunate. They will gladly take your extra power without paying you for it . . .

. . therefor, in designing your system, if you go over 100% of your yearly need, you are spending money you will never see a return on. <_<
[/b]

Locally, I think the energy company not only gives you credits, but pays for up to 60% of the system to help meet state laws for building renewable energy systems. I don't understand the details, but it sounds like a pretty sweet deal though the funding is limited.

Because the utility company will only help pay for the system for a limited time and because I think there's some state incentive that lets you roll the cost of the solar system into the home loan, it may make sense to install a beefier-than-I-currently-need system even if I'm giving the utility company a little free electricity for awhile.

<div class='quotetop'>QUOTE(EricGo @ Aug 31 2007, 03:47 PM) [snapback]505152[/snapback]</div>

Quote:

Boulder, this is a two part question

1. How much energy will the car use ? about 200 - 250 watt-hour per mile. Multiply this by miles driven per month ..

2. How much energy will a 1000 watt panel produce per month in your area ? That information should be forthcoming from your installer. Cross check their numbers with your local solar energy groups.
[/b]

1. I actually don't entirely know (which is why I'm asking for help). For the Volt, someone directed me to these specs: http://www.chevy-volt.net/chevrolet-volt-specs.htm, but I honestly don't know how to interperet them.

2. Not sure on that either, though I can definately check.

tripp · 08-31-2007, 06:30 PM

Darreldd might be able to give you some ideas, as he does this with his EV. He hasn't been around for a while though. If you have an AC, rip it out and put in a swamp cooler. You'll save loads on electricity. In CO we get a $2.50/watt rebate from Xcel Energy and a $2.00/watt rebate from the state. There's also the $2000 fed tax credit. Shop around, there are many installers in our area. One of my friends is installing an 8.1 kW system and the cost to him is gonna be around $33K. A 2.5 kW system will cost you around $12K out of pocket. A prius sized car will go about 4 mi on a kWh so factor that in along with the size of the array and your monthly household consumption and you'll get an idea.

ohershey · 08-31-2007, 06:43 PM

<div class='quotetop'>QUOTE(tripp @ Aug 31 2007, 03:30 PM) [snapback]505169[/snapback]</div>

Quote:

If you have an AC, rip it out and put in a swamp cooler. You'll save loads on electricity.[/b]

True, but I found the swamp cooler to pretty darn ineffective if we got above 92-93 F. I'm currently planning a heat-pump geothermal system for next year. We get triple digits too often, and if I wanted to be that hot and humid, I'd live in Texas.

EricGo · 08-31-2007, 06:49 PM

Apologies boulder if this stuff is obvious, but your response makes me think a primer may be useful:

1 kilowatt (kW) = 1000 watts. This is a power measure
1 kWh (kilowatt*hr) is an energy measure

power * time = energy.

You buy PV by the watt, but decide how to size your system by matching energy production to consumption.

08-31-2007, 05:47 PM	#5
EricGo Three cats, one Prius, and assorted humans Join Date: Apr 2005 Location: Albuquerque, NM (SouthWest US) Posts: 1,810 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Boulder, this is a two part question 1. How much energy will the car use ? about 200 - 250 watt-hour per mile. Multiply this by miles driven per month .. 2. How much energy will a 1000 watt panel produce per month in your area ? That information should be forthcoming from your installer. Cross check their numbers with your local solar energy groups. ---- As an aside, a couple bits of advice 1. Heat your water with solar heating, not PV 2. First spend money decreasing your home energy energy use. Smart choices regarding lighting, insulation, conservation, shading and light, and AC can be quite a bit less expensive then PV. As an example, a clothesline instead of a dryer for my kid's incessant clothes washing will save over 100 kWh per month in drying 10 months of the year. I'm guessing you will install a tie-in to grid with net metering ? It's the best way to go. All the best ! __________________ R2-E2: 2004 Prius, 37K miles, lifetime MPG 57.1 as of 8/2006. Rolling 12 month average: 61.05

08-31-2007, 05:53 PM	#6
Lywyllyn Senior Member Join Date: Mar 2007 Posts: 199 My Car: 2001 Prius Model: Package: N/A Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	We have netmetering (meter spins backwards if we generate more then use) and also use TOU (time of use) metering. The TOU really makes a big difference. Basically we have a peek time 12 - 7pm where electricity is at its most expensive. The other times it is cheap(er) Weekends are 24hr at the same low rate. So I recommend that you look into getting appliances with timers. We do our dishes at midnight, laundry starts at 6:00 am and we stop using the dryer before noon and resume after 7:00pm. I also put all our entertainment stuff on a powerstrip and turn that off when we go to bed. the standby power sucks up to 25% of running power on some electronics. so with a bit of change in schedule you should be able to get away with 3KW system (provided you don't have more then 2200sq ft) else I would aim at a 5K system. With current rebates you can probably expect to get half of the cost back and then a approx $1800.00 tax benefit __________________ "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." Douglas Adams, "Last Chance to See"

08-31-2007, 06:30 PM	#8
tripp Which it's a 'ybrid, ain't it? Join Date: Oct 2005 Location: Denver, CO Posts: 4,323 My Car: 2005 Prius Model: Package: #3 Thanks: 0 Thanked 2 Times in 2 Posts Friends: 6	Darreldd might be able to give you some ideas, as he does this with his EV. He hasn't been around for a while though. If you have an AC, rip it out and put in a swamp cooler. You'll save loads on electricity. In CO we get a $2.50/watt rebate from Xcel Energy and a $2.00/watt rebate from the state. There's also the $2000 fed tax credit. Shop around, there are many installers in our area. One of my friends is installing an 8.1 kW system and the cost to him is gonna be around $33K. A 2.5 kW system will cost you around $12K out of pocket. A prius sized car will go about 4 mi on a kWh so factor that in along with the size of the array and your monthly household consumption and you'll get an idea. __________________ Cheers, Tripp 2005 Silver Pkg 3, OEM Block Heater, Coastal Tech EV mod, BT Tech Chassis Stiffener, hell damned infernal reverse beep disabled Boulder Real Estate Howay the Toon! "Sometimes when you aim for the stars, you hit the moon." -- Ian Holloway

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08-31-2007, 03:57 PM	#1
boulder_bum Senior Member Join Date: Mar 2007 Location: Castle Rock, CO Posts: 1,293 My Car: 2007 Prius Model: Package: N/A Thanks: 1 Thanked 23 Times in 6 Posts Friends: 5	My wife and I might be buying a house soon, and in Colorado, there are some especially nice perks for installing solar panels at the time of purchase. I anticipate purchasing a PHEV in some form or another when they come out in 2009-2010 (knock on wood). What I'm wondering is how much juice I'd need to support a nightly charge of the car (not counting the rest of the home). Because of some time-sensitive incentives, it might make sense to prepare for 2010 now.

08-31-2007, 04:02 PM	#2
efusco Troll Slayer Join Date: Nov 2003 Location: Nixa, MO Posts: 17,250 My Car: 2004 Prius Model: Package: #9 Thanks: 50 Thanked 261 Times in 157 Posts Friends: 37	You might need to search a little, but if you're considering the Volt or similar there was recently a thread talking about the anticipated capacity. Someone mentioned that it would take 5 200Wh panels charging 8 hours a day to fully charge the Volt PHEV40 battery.

08-31-2007, 04:16 PM	#3
mgipe Member Join Date: Jun 2007 Posts: 50 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	I suspect that an infinite number of solar panels would not charge your electric car overnight. ---No sun!---

08-31-2007, 06:49 PM	#10
EricGo Three cats, one Prius, and assorted humans Join Date: Apr 2005 Location: Albuquerque, NM (SouthWest US) Posts: 1,810 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Apologies boulder if this stuff is obvious, but your response makes me think a primer may be useful: 1 kilowatt (kW) = 1000 watts. This is a power measure 1 kWh (kilowatthr) is an energy measure power time = energy. You buy PV by the watt, but decide how to size your system by matching energy production to consumption.