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Re: Are you a net producer or consumer of electricity?

Posted: Mon Oct 01, 2012 3:31 am
by RegGuheert
kovalb wrote:The next time our hot water heater goes out I am going to strongly consider replacing it with a heat pump type - they are very efficient, especially when the garage they are in has an ambient temperature almost equal to the hot water.
Our water heater was due for replacement and I installed a heat-pump water heater on Saturday. As a result, I think we just changed from being net consumers of electricity to net producers. I'm thinking we reduced our electricity consumption by over 5 MWh/year with this change since our old heater was in bad shape and likely was leaking a lot of heat into the environment.

Assuming the compressor unit survives, this unit should pay for itself within two years given the tax credits and since we are running it in heat-pump-only mode. Unfortunately, that may be a big assumption. I see quite a few stories about failed compressors within the first year. But it's difficult to guess at a failure rate based on those types of anecdotes, particularly since some of those units may have been improperly installed or placed in inappropriate locations. It comes with a 10-year warranty on parts with one year including labor. We'll see how things go.

Re: Are you a net producer or consumer of electricity?

Posted: Mon Oct 01, 2012 11:33 am
by Phoenix
Can you share with us what heat pump you installed, its specifications and approximate price? Do you have solar thermal water heating in combination with the heat pump? Thanks.

Re: Are you a net producer or consumer of electricity?

Posted: Mon Oct 01, 2012 12:29 pm
by RegGuheert
Phoenix wrote:Can you share with us what heat pump you installed, its specifications and approximate price? Do you have solar thermal water heating in combination with the heat pump? Thanks.
Sure.

GE Model #GEH50DNSRSA (It's the discontinued version of their GeoSpring HPWHs. It holds 50 gallons of water.). Price for the floor model was $938 plus tax = $984.90. The new one retails for $1199.00, but I'm sure you can get a discount on that. I think there may still be a 30% federal tax credit on this, but I am not sure. Warranty is 10 years parts and 1 year labor.

I have looked carefully at solar water heating but it was coming in over $5000 if I installed it myself and twice that with an installer. Warranty was only 3 years for a self-install versus 10 with the installer. Solar water was more Rube Goldberg than a HPWH, although I imagine I would have additional maintenance on either one versus traditional.

In the past I had a Seisco 14 kW electric on-demand water heater. It suited us fine and saved about 60% over the tank we had previously. Unfortunately after about 18 months an O-ring cracked and the unit was destroyed when the water hit the control circuitry. There was a long lead time for a replacement, so I ended up with a tank again.

No natural gas here. We have propane, but it is expensive and I would be happy to get rid of it completely. My wife like to cook with it, so it survives...

Re: Are you a net producer or consumer of electricity?

Posted: Fri Oct 05, 2012 12:33 pm
by Goalnetpositive
After numerous changes, additions and subtractions, I should be a net producer even with the LEAF, I'll know for sure after the winter. I've found it's very important to watch both parts of the equation, use and production. The best solar installers tell you right up front the biggest bang for the buck is efficiency. Insulation, efficient appliances, lights. I've been doing all of the above. I have two sets of solar panels, both 4.73kw, for a total of 9.46. I added the second solar panel set as I was converting to solar hot water and geothermal HVAC from gas. I'm still careful to combine trips with the LEAF and to conserve whenever I can to try to stay on the positive side. I look at this as a safer investment than stocks for retirement, I know for sure I'm going to get a return on this investment.

I'm impressed with the number of LEAF owners who also have solar. It makes all the sense in the world, and it's good to have to wonder whether the LEAF makes the solar panels pay for themselves quicker or the solar panels help the LEAF pay off quicker.

Re: Are you a net producer or consumer of electricity?

Posted: Fri Oct 05, 2012 3:40 pm
by QueenBee
Goalnetpositive wrote:it's good to have to wonder whether the LEAF makes the solar panels pay for themselves quicker or the solar panels help the LEAF pay off quicker.
I'd strongly argue neither. The break even point on the LEAF is the same whether you have solar panels or not. The break even point on the solar panels is the same whether you have a LEAF or not. I say that with the caveat of tiered rate structures and if you are producing more power than your utility will buy back these would complicate the issue.

Re: Are you a net producer or consumer of electricity?

Posted: Wed Feb 03, 2016 12:48 pm
by RegGuheert
RegGuheert wrote:We are still net consumers. While we almost never run our air conditioner, we heat with a heat pump in the wintertime and that consumes more than the excess we produce during other months.
There have been several changes around here since 2012 when I wrote that, so I thought I would take a look at where we stand right now. While I have access to detailed data on the production of my PV array, I have very spotty data from the energy meter attached to the electrical grid. That is because the utility only reports our reading on the bill if it is above the high-water mark for the past 12-month period. Additionally, I don't make meter readings myself. As such, the only readings I have from 2015 were on February 3, March 3 and April 3. So I will try to calculate what portion of my annual consumption was provided by PV on those three dates this year.

February 3:

Feb 3, 2015 meter reading: 12,656 kWh
Feb 3, 2016 meter reading: 14,225 kWh
Grid consumption during past 12 months: 1569 kWh

PV production from Feb 2015 through Jan 2016: 18,361 kWh

Total electricity consumption: 19,930 kWh

Fraction provided by PV: 92%

I do expect this fraction to increase over the next six months since my heat-pump water heater lost its charge and was wasting massive amounts of electricity until June 15, 2015. For 1/3 year, I estimate that it could have used an extra 1.5 MWh over normal consumption. In other words, I am hopeful that I am converging on matching production and consumption. Time will tell.

Last year we consumed a total of 3118 kWh during February. Hopefully we will come in under that amount this month.

Re: Are you a net producer or consumer of electricity?

Posted: Wed Feb 03, 2016 3:11 pm
by kaikara
We produce about 500kWh more a year then we use. In Ontario so we get paid a lot for all the electricity we produce.

Re: Are you a net producer or consumer of electricity?

Posted: Wed Feb 03, 2016 3:14 pm
by dgpcolorado
My electricity production from my 2170 watt solar array was 120% of my use last year. Even counting charging away from home I would guess that I was a net producer.

For just my home system, I have a carryover credit of more than 900 kWh banked for use with my Model S, which I expect to use more electricity per mile, and be used for more miles, than my LEAF. Counting charging away from home, I would expect the Model S to tip me into being a net consumer. Those thousand mile trips will add a lot of miles over what the LEAF did; I burned gas in my ICEV for those miles in previous years.

I've already sold my ICEV, although I haven't delivered it yet. Once it is gone my last ICE device will be my little 16 inch chainsaw, which goes through about 0.6 gallons of gas each winter during tree thinning season.

Re: Are you a net producer or consumer of electricity?

Posted: Wed Feb 03, 2016 5:05 pm
by Zythryn
Cool thread, great to see a number of net producers!

We are currently a net consumer (PV panels cover about 30% of our home plus transportation.

In a few months we will have completed our new house.
Our new house is designed to produce, on an annual basis, all the electricity our house and cars use.

Metal roof just went up last week. Garage with two NEMA 14-50s and a backup/visitor 240V, 20Amp are all set in the garage.

Re: Are you a net producer or consumer of electricity?

Posted: Tue Mar 15, 2016 8:17 am
by RegGuheert
RegGuheert wrote:February 3:

Feb 3, 2015 meter reading: 12,656 kWh
Feb 3, 2016 meter reading: 14,225 kWh
Grid consumption during past 12 months: 1569 kWh

PV production from Feb 2015 through Jan 2016: 18,361 kWh

Total electricity consumption: 19,930 kWh

Fraction provided by PV: 92%
March 3:

Mar 3, 2015 meter reading: 14,413 kWh
Mar 3, 2016 meter reading: 14,763 kWh
Net grid consumption during past 12 months: 350 kWh

PV production from Mar 2015 through Feb 2016: 18,192 kWh

Total electricity consumption: 18,542 kWh

Fraction provided by PV: 98%

Good news! I'm approaching 100% PV coverage for all electricity usage (given almost-free storage through net metering). If we get some more sunny days this month, I may cross over on April 3.