"Negawatts" - Preparing for Your New Electric Car

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

indyflick

Well-known member
Joined
Jul 9, 2010
Messages
505
One of the EV FUD talking points circulating presently is that the'll cause your electric bill to shoot through the roof. I first heard that last summer, about the time we decided to purchase a LEAF. As a result, I set a goal to reduce our electrical usage by 1.2 mega watt hours over a 12 month period. That sounds like a lot, but we did achieve the goal and we did it without installing solar panels or fundamentally changing our lifestyle. So to reduce 1.2 mega watt hours in a year, it means you need to reduce an average of 100 kWh per month or 3.3 kWh per day, now that seems more achievable doesn't it? Here's what we did.

  • - Hang clothes to dry on the clothes rack - usie the electric dryer as little as possible
    - Use whole house fan, instead of air conditioner
    - Only run full loads of wash
    - Close vents to all rooms, except the main living area, and only air condition that area (reduced area to cool by 50%)
    - Use air conditioning to reduce humidity to about 50% (you'll need a hygrometer) turn it off regardless of the temperature. Use fans in the rooms you are occupying
    - Use CFL or LED in all lighting you use regularly
    - Check your refrigerator temperature settings. We keep ours at medium. Keep your freezer full but not overstuffed
    - Eliminate vampire power. We unplug the TV at night and no charger is left on after it has charged the batteries.

Tools help. You can't manage what you can't measure. We use an indoor/outdoor wireless digital thermometer/hygrometer. That way we know when we need to shut down the whole house fan, when the temperature outside exceeds the temperature inside. We also have a smartmeter from SDG&E and it's tied into Google Powermeter. So we can see our hourly electrical use and this is summed daily, weekly, and monthly.

Below is a post I read from another blog. It appears this guy was thinking along the same lines. He mentions the term "Negawatts", I think that is a great term!

Charles Whalen on another blog said:
In the 5 and a half years that my wife and I have been driving our Toyota RAV4-EVs, one of the most frequent questions I’ve gotten from people is ... “How much did your electric bill go up when you got your electric cars?”

People are always confounded and have a puzzled look on their face when I answer that our electric bill actually went DOWN after we got our EVs. How could that be possible, they wonder?

Well, the answer is that we undertook a whole series of household energy efficiency upgrades at the same time that we bought our two EVs, with a result that the amount of electricity saved by all the energy efficiency upgrades was greater than that used for charging our two EVs, such that the net effect ended up being a net reduction in electric consumption.

And that’s without having even done any solar (yet).

So, yes, it's actually possible to produce all the electricity needed to charge an electric car solely from "Negawatts".
 
We used about 600 kwh last month. I paid about $60 in variable charges - including some $8 for "green energy".

If I drive 1,000 miles a month I'd use 250kwh. So my electricity bill would go up by $25.

In my current car, 1,000 miles would be 50 gallons or about $150 a month in gas.

So a net saving of $125 per month because of Leaf.

Even if you paid 30 cents / kwh, in some areas, you would still be spending only half the money on electricity compared to gas.

We don't need to be "defensive" on this issue at all.
 
Using my current standard rate the marginal cost is 24 and soon 27 cents KWH
Additional 200Kwh would be $48 to $54. Compare to $150 to $200 in gas for the truck.
With a TOU plan the cost may add little to nothing as we are very off peak users of electric.
 
smkettner said:
Using my current standard rate the marginal cost is 24 and soon 27 cents KWH
Additional 200Kwh would be $48 to $54. Compare to $150 to $200 in gas for the truck.
With a TOU plan the cost may add little to nothing as we are very off peak users of electric.

If we didn't use our pvs, the rate would be .07/kwh (off peak) X 8kwh daily ave.= $ .56/day = $17/mo. = $204/yr. :D
 
The way I look at it that I'm trading efficiencies for LEAF miles. Year over year I've "banked" 1.2mWh in reduced electrical consumption through efficiencies. That 1.2mWh gets me 4800 LEAF miles at 4 miles per kWh. And it's even better on the grid because the 1.2mWh per year I save is predominately during peak times. The 1.2mWh I'll be using to charge the LEAF will be on super off-peak (12:00am to 6:00am) time.
 
I practice similar techniques which reduce the energy use significantly. CFL lights, check. Line drying clothes, check. Keeping the refrigerator full and the temperature not too cold, check. Another thing that helps a lot is opening the windows at night when the temperature gets cooler outside than in, and closing them when the reverse happens in the morning. No whole-house fan here, but everyone has windows - that, and a $10 indoor/outdoor thermometer from W-Mart is all it takes ;) It's amazing how much energy can be saved without any sacrificing comfort just by doing a few smart things. :)

Since I'm already minimizing our electrical usage, when I get my electric car the electric bills will inevitably go up a little ... but the money spent on gasoline will go way down! :cool:
 
In a house like ours with multiple computers (which are relative energy hogs), it really helps to put computers to sleep or "hibernate" when they are not in use. Configure computers to automatically go to sleep when idle, if possible. Doing this has significantly reduced our electric bills. Replacing our old fridge with a new, Energy Star unit also made a very noticeable difference, even though the new fridge is a lot larger.

At this point, we are using about 300 kWh per month ($38 with Southern California Edison), and I'm not sure how much lower we can go. We don't have AC, as our summers are not too hot and our home is relatively well insulated. Our clothes dryer is gas heated. I've been swapping CFL bulbs for LEDs, which are expensive but should still pay off faster than solar panels.

Once we get a LEAF, I anticipate that our electric bills will be close to $100 per month, assuming about 10,000 miles per year of driving. This is roughly based on SCE's plug-in car rate calculator. This does seem expensive, and isn't greatly cheaper than gasoline for our 30 mpg car. The upside is that solar panels will then make economic sense for us (they currently don't).
 
johnr said:
I practice similar techniques which reduce the energy use significantly. CFL lights, check. Line drying clothes, check. Keeping the refrigerator full and the temperature not too cold, check. Another thing that helps a lot is opening the windows at night when the temperature gets cooler outside than in, and closing them when the reverse happens in the morning. No whole-house fan here, but everyone has windows - that, and a $10 indoor/outdoor thermometer from W-Mart is all it takes ;) It's amazing how much energy can be saved without any sacrificing comfort just by doing a few smart things. :)

Since I'm already minimizing our electrical usage, when I get my electric car the electric bills will inevitably go up a little ... but the money spent on gasoline will go way down! :cool:
Looks like you're all set John. The one thing I would say about the whole house fan is that it not only brings the cool air in faster than an open window, but it also exhausts the intense heat from the attic. We have a simple one in our hallway which works very well. I saw a really nice one in an article that was installed in the middle of the attic an had individual ductwork to each room. You could open or close any vent you wanted. Very nice system but like 5x the cost of what mine was. Probably best for new home construction.
 
Already have an electric car and currently" burn" thru about$ 10 a month. The Leaf will play a much bigger. Role so hoping to at least double that to over $20 a month, but even if i went over$ 40 a month that would still be an estimated$ 25 a month cheaper than gas which also does not account for the average of$ 15 a month in other maintenance costs.

Keep in mind, the car being replaced has a lifetime 52 mpg.
 
abasile said:
At this point, we are using about 300 kWh per month ($38 with Southern California Edison), and I'm not sure how much lower we can go. We don't have AC, as our summers are not too hot and our home is relatively well insulated. Our clothes dryer is gas heated. I've been swapping CFL bulbs for LEDs, which are expensive but should still pay off faster than solar panels.
I think I'm in the same boat, I think we are pretty much as low as we can go. Do you have a recommendation on LED bulbs? I bought a 3W for $20 last year and it's basically unusable, it's way to dim.

By the way, not sure if you were using generic terms but in case you weren't aware, "sleep" AKA suspend to RAM does use more power than "hibernate" AKA suspend to disk. This is because in sleep the RAM needs to be powered. The advantage is that returning from sleep is very quick compared to hibernate.
 
We recently replaced a 20 year-old 21 cuft refrigerator with a new Energy Star Tier 2 25 cuft model and we appear to be on track to save at least 700 kWh per year with just that one move. In fact, we may be saving even more than that.

The new fridge has an Energy Star annual usage rating of about 550 kWh (I know that there are some basic models that are rated close to 400).

I don't have a meter or a TED connected to the fridge, so I don't know the actual change in power usage. But my daily whole house usage readings are down more than 4 kWh per day from the same dates last year. I have made some other changes, such as adding more cfl bulbs in my home office since last year, but if only 3 kWh of that savings is due to the fridge, then I'm looking at saving almost a mWh per year with just that one change.

By the way, there are still dollars available in the California Cash for Appliances rebate program. We got a $200 rebate for buying the new fridge from that program and an additional $100 from Southern Cal Edison for buying it and for letting them recycle the old one.
 
Boomer23 said:
We recently replaced a 20 year-old 21 cuft refrigerator with a new Energy Star Tier 2 25 cuft model and we appear to be on track to save at least 700 kWh per year with just that one move. In fact, we may be saving even more than that.
Wow, that's 2800 LEAF miles right there!
 
With respect to LED bulbs, I am unwilling to pay top dollar ($60/bulb). But most of the cheaper ones are too dim and/or too blueish. I finally found some par30 bulbs for $22/each that I like. They are rated at 6W/bulb and can replace 50-60W incandescents (or 13W CFLs). Check out http://www.amazon.com/gp/product/B003LP9660/ref=oss_product
 
smkettner said:
I wish the fridge would come with a timer to keep the compressor off during peak daytime rates.
Well, there is a cheap, effective solution for that (if you don't mind the fridge light being shut off too): http://www.amazon.com/Intermatic-TN311C-Heavy-Grounded-Timer/dp/B00002N5FO/ref=dp_cp_ob_hi_title_1

indyflick said:
Looks like you're all set John. The one thing I would say about the whole house fan is that it not only brings the cool air in faster than an open window, but it also exhausts the intense heat from the attic. We have a simple one in our hallway which works very well. I saw a really nice one in an article that was installed in the middle of the attic an had individual ductwork to each room. You could open or close any vent you wanted. Very nice system but like 5x the cost of what mine was. Probably best for new home construction.
I do like the idea of it. Plus, it could be controlled automatically with an X10 unit and thermo-sensors if I want to go all geeky which I do :p Not sure whether installing one on this particular existing construction would be worthwhile, one of these days I'll look into it. There are still more things I could do. There's this one big window that gets sun in the afternoon, so a window awning is on my to-do list :)
 
johnr said:
smkettner said:
I wish the fridge would come with a timer to keep the compressor off during peak daytime rates.
Well, there is a cheap, effective solution for that (if you don't mind the fridge light being shut off too): http://www.amazon.com/Intermatic-TN311C-Heavy-Grounded-Timer/dp/B00002N5FO/ref=dp_cp_ob_hi_title_1
It is a GE Monogram built-in and harwired to 20a dedicated circuit. The compressor is actually a three phase motor with some sort of converter. All of which is run by a microprocessor to give service error codes etc. I am not comfortable cutting an internal wire and adding a timer. It would be a huge improvement if some sort of compressor control was madated to reduce peak period run time or if a retrofit was available.

For the average fridge that timer would be OK but would still bug me if the water/ice dispensor was off along with the light.

I am just imagining how much it would help if millions of refridgerators that could be off during peak demand.
 
The fridge runs enough to maintain the temps set. If no o.e is home opening the door, the compressor shouldn't be running that much.

Withe the cost of food these days, i think i would look at other areas to save electricity on if u already have an energy saver model
 
For LED lighting, I recommend CREE. There is a lot of exageration in the LED lighting business, and some products that look good in manufacturer's claims do not perform well in real life or independant testing. CREE products tend to outperform rated specs in independant testing.
http://www.creeledlighting.com/index.aspx

You can acutally buy one of their downlights through home depot:
http://www.homedepot.com/Lighting-Fans-Light-Bulbs-LED/h_d1/N-5yc1vZ1xqdZbmg0/R-202240932/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Also, look for Energy Star complianct LED bulbs. The DOE has done a lot of work to set up new standards and testing for LED bulbs, which cuts through a lot of the marketing BS:
http://www1.eere.energy.gov/buildings/ssl/index.html
http://www.energystar.gov/index.cfm?c=products.pr_find_es_products
 
To illustrate further why I like CREE, they advertise their CR6 at 575 Lumens and 10.5W power consumption (55 lumens/W), but DOE tested them at 585 Lumens and 9.1 W of power consumption (64 lumens/W).

http://www.energystar.gov/index.cfm?fuseaction=ssl.display_products_res_html&sortcolumn=LMEF&sortcolumn_order=DESC

In comparison, many other manufacturers in CALiPER testing come nowhere close to their ratings.
 
Back
Top