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Up to 17 cents cheaper per KWH (22c day, 5c night).

Assuming you blow 10kWh per day, primarily between 6am and 11pm, that's upwards of $2.20/day.

If you move your entire 10kWh load to the battery system and charge it over night, it drops you down to $0.50/day.

$1.70 savings per day. That's 2058 days to recoup the $3500 expenditure, or just a bit over 5 1/2 years. Over the ten year warranty period you'll save ~$3000, assuming electricity prices remain constant.

-Rick

You are assuming that it takes 10kW to charge the 10kWh battery and that the conversion from the DC battery voltage to AC house power is 1:1 as well. Tesla didn't publish charging efficiency specs unfortunately, but what is more likely is that charging the battery is 80% efficient (or less) and converting the battery power out to 220/120VAC is 80% efficient as well. Which means you are saving less than $0.80 per day. So, if you're lucky, you will just break even with the purchase price of the battery a year or so after the warranty runs out (if it doesn't die before then). And that is ignoring the time value of money and whatnot (simply leaving your money in a savings account would be a better use of your money because you'd at least get some interest). So no, this isn't going to save you anything.

https://www.we-energies.com/re...

Up to 17 cents cheaper per KWH (22c day, 5c night).

Assuming you blow 10kWh per day, primarily between 6am and 11pm, that's upwards of $2.20/day.

If you move your entire 10kWh load to the battery system and charge it over night, it drops you down to $0.50/day.

$1.70 savings per day. That's 2058 days to recoup the $3500 expenditure, or just a bit over 5 1/2 years. Over the ten year warranty period you'll save ~$3000, assuming electricity prices remain constant.

-Rick

Most of the burned garbage is used to feed central heating systems. Same with a lot of other cities in Scandinavia. A few large central furnaces and a big network of hot water pipes.

Not so much to produce electricity. Most of the electricity in Scandinavia is water power or nuclear with a few coal/oil burners that are used for backup in case the current production is insufficient. Add to it a number of windmills but their contribution is small.

There is quite a lot of cogen too. If you are burning the fuel anyway, it makes a lot of sense to use the high-temperature combustion gasses to boil water at high temperature and then run a steam turbine. The steam needed for heating houses, running laundromats, heating businesses, etc is extracted at some point in the turbine.

Why? We can burn a fuel at several thousand degrees F. However, the best pipes we can make can only stand about 1100F (600C) and 3500psi, and these are very expensive and problematic. (For reliability, usually most power plants run at 1000F, 1050F and 2400psi, or sometimes slightly higher). Even at these lower conditions, pipes in the boiler still burst quite frequently (and pipes outside the boiler require wall thickness of several inches). Having high-pressure, high temperature, and high-cost steam pipes running all over town is both prohibitively costly and a safety hazard. So we run the steam turbine, and use cheap piping to houses at much lower pressure and temperature. WE Energies in Milwaukee, for example, tries to run their system between 1 and 200psi, with temperatures near the saturation point.

> WTF is a "feed-in tarif"?
In Europe that's a guaranteed purchase price by the utilities for home producers of "green" energy. You can also call that a subsidy. Now If you really believe that when WE Energy buy your PV electricity at $.25 per kWh they will be able to recoup these costs by selling it at a premium, this is were you enter the delusional category.

FYI WE Energy do have an offer at 100% renewable energy[1]: with a rate of $.14 (0.12611+0.01388 [2]) ! So basically all their customers are subsiding the purchase price of PVs, and the taxpayers subsidizing your installation. And you have the balls to tell me that I'm the one working from inaccurate or obsolete information ...

Also, if you did this installation recently, double-check your contract I am not sure that this scam will go for long, even in Germany the government is starting to see the stupidity of all this and is reducing the feed-in tariff.

[1] http://www.we-energies.com/business/wisconsin_service_rates/eft_smbus.htm
[2] http://www.we-energies.com/business/elec/std_rateplan.htm

> WTF is a "feed-in tarif"?
In Europe that's a guaranteed purchase price by the utilities for home producers of "green" energy. You can also call that a subsidy. Now If you really believe that when WE Energy buy your PV electricity at $.25 per kWh they will be able to recoup these costs by selling it at a premium, this is were you enter the delusional category.

FYI WE Energy do have an offer at 100% renewable energy[1]: with a rate of $.14 (0.12611+0.01388 [2]) ! So basically all their customers are subsiding the purchase price of PVs, and the taxpayers subsidizing your installation. And you have the balls to tell me that I'm the one working from inaccurate or obsolete information ...

Also, if you did this installation recently, double-check your contract I am not sure that this scam will go for long, even in Germany the government is starting to see the stupidity of all this and is reducing the feed-in tariff.

[1] http://www.we-energies.com/business/wisconsin_service_rates/eft_smbus.htm
[2] http://www.we-energies.com/business/elec/std_rateplan.htm

I have had them not work in the garage when it gets to around zero fahrenheit, aparently there are special ones for places that are cold. So there are a few places where they don't work or aren't as good, but for most places they are great. As for the price I have found them on sale and in Wisconsin and Iowa (at least) they have a rebate from the utilities companies. And if you have a farm you can get them free. http://www.we-energies.com/agricultureservices/ene rgyeff/ag_energyeff.htm
A way to calculate savings: http://www.alliantenergy.com/docs/groups/public/do cuments/pub/p010787.hcsp

US$0.15/kW-hour (my local power rates)

Ouch! I can Fold at night (7pm-7am) for only $0.03826kWh.

http://www.we-energies.com/pdfs/etariffs/wisconsin /ewi_sheet23-24.pdf

You should check with your utility to see if they offer a Time of Use plan.

As far as I know, utility companies don't offer residential customers variable pricing, the way they do businesses.

I get variable pricing on my residential electricity based on Time of Use:

http://www.we-energies.com/pdfs/etariffs/wisconsin /ewi_sheet23-24.pdf

coupla things to add to my post above:

If it wasn't clear in my first post, if I purchased one the units mentioned in this article, I would definitely set it to "charge itself" starting at 7:01pm each weeknight and then it should start providing power at 7:00am the following day. This would save me a lot of money since my electricity rate at night is roughly X/2 (where X is the normal rate). Using power during the day costs 2X. (Right now, X is around 10 cents, nightime is roughly 4 cents and daytime power costs about 20 cents).

Time of Use Plan:
http://www.we-energies.com/pdfs/etariffs/wisconsin /ewi_sheet23-24.pdf

Normal Rates:
http://www.we-energies.com/pdfs/etariffs/wisconsin /ewi_sheet21-22.pdf

In addition to the appliances listed above in my other post, I also make sure the dishwasher runs only during the "dark hours".

My HEPA filters in the living room and bedroom are on timers so they only run at night (using the cheap power).
My PVR (which runs MythTV) is set so that it automatically boots up at 6:55pm each night (this is a feature on the Abit motherboard). There is cron job that executes a "poweroff" around 2:00am or 3:00am so the PVR isn't running during the day, consuming the expensive electrons. There is nothing on daytime TV worth recording anyway. :^)

coupla things to add to my post above:

If it wasn't clear in my first post, if I purchased one the units mentioned in this article, I would definitely set it to "charge itself" starting at 7:01pm each weeknight and then it should start providing power at 7:00am the following day. This would save me a lot of money since my electricity rate at night is roughly X/2 (where X is the normal rate). Using power during the day costs 2X. (Right now, X is around 10 cents, nightime is roughly 4 cents and daytime power costs about 20 cents).

Time of Use Plan:
http://www.we-energies.com/pdfs/etariffs/wisconsin /ewi_sheet23-24.pdf

Normal Rates:
http://www.we-energies.com/pdfs/etariffs/wisconsin /ewi_sheet21-22.pdf

In addition to the appliances listed above in my other post, I also make sure the dishwasher runs only during the "dark hours".

My HEPA filters in the living room and bedroom are on timers so they only run at night (using the cheap power).
My PVR (which runs MythTV) is set so that it automatically boots up at 6:55pm each night (this is a feature on the Abit motherboard). There is cron job that executes a "poweroff" around 2:00am or 3:00am so the PVR isn't running during the day, consuming the expensive electrons. There is nothing on daytime TV worth recording anyway. :^)