Gas Prices Cheaper than Electricity Prices?

The post I was commenting on the posting that said 80 kWh/month, that's less than I use for my PiP. Your 120 kWh/month is impressive and I complement you on your efforts to make it happen. However, it is definitely not my lifestyle.

 

Lensovet mentioned 80 kWh/month for one person. We consume ~ 120 kWh/month for two people.

I responded to you so that you would know that a sub 100 kWh/month lifestyle does not mean the family is living in a cave. In fact, I live very, very comfortably.

 

Basically everything was covered above but some common ways to cut down:

Always turn off lights and appliances. This was something I started doing in my teens when I became aware of the environmental impact of these things and my mother would always leave the light on in the bathroom. I do it to this day when I visit my parents.
All my computers are laptops with no external displays. Way more efficient than towers.
Never use the dishwasher (depending on how old yours is…this can be a massive draw)
Watch TV maybe once or twice a week (usually for a bluray movie on an overhead projector). Again depending on your TV's age and what technology it uses (plasma,etc), this can make a huge difference.
EDIT: Since this a rented apartment, I do not have a clothes washer or dryer. However, current "most-efficient" washers, which can be bought for under $500 when you combine sale pricing with rebates, will do a load for just 0.33 kWh.

My electricity usage is considered lower than "efficient" homes by PG&E during non-winter months. If I lived in my own home and could properly insulate it, this would probably be the case year-round.

Regarding PiP charging: I luckily charge my PiP for free from a shared outlet at the wall. If you get to charge the PiP for 100 kWh/month, that's great, and of course I'm not counting that in my total regardless. That still leaves you with a non-plug-in usage of 550, which is massive.

Now, since you have solar, you should probably keep doing this, as reducing your power consumption will end up stretching out your payback period to infinity.

 

Nope. If you are wasting it, you are wasting it, and payback doesn't enter into it. Efficiency is USEFUL work per energy consumed, not ALL work.

If you are net metering and might otherwise not be reimbursed for energy production, you might look into alternative ways of monetizing that excess solar (like a PIP, see back on topic). Wasting it helps no one, not even yourself.

 

Please enlighten me how someone in California whose electric bill never exceeds $50 can set up solar in a way that makes any financial sense. I'd love to hear it.

 

I'm not sure what you and Corwyn are disputing, but my personal answer to your question was one of two avenues:

1. Invest in PV
2. Join a solar farm

My locality did not have (2), so I went the investment route. My investment through mosaic recently ran afoul of regulatory rules in California, but in general it remains a viable, smart option.

 

Searching google for "solar farm torrance" gives me nothing. What do you mean by invest in PV? How is it an investment if you're still required to pay some minimum amount of monthly fees even if your net energy usage is negative?

(Or do you mean invest in a PV company through the stock market or something similar? Not that interested…)

 

Check out join mosaic.com
There are also other similar, competing enterprises.

 

thanks! cool idea, but doesn't really answer my original question, which was "Please enlighten me how someone in California whose electric bill never exceeds $50 can set up solar in a way that makes any financial sense". This implied "set up solar for my home", not "invest in growth in solar capacity in my community".

 

Your roof, or your neighbor's. Why does it matter ?

Your money, your environmental and financial return. That is what is important, right ?

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The other possibility is buying some shares in a solar garden. That might be more to your liking since it 'feels' more like your own panel. I'm not sure if solar gardens have gained legislative protection in California. This link is an advocacy site for SB 843.

 

Very nice. Your house probably use less electricity than Volt owners just with their cars.

I cannot do many things as you since we have a 6 months old baby.

 

FWIW here are some numbers from our PV system installed Sept 2012. (Smith Family Solar 5.520kW | Monthly)

We kept installed costs as low as possible by finding a contractor who would let us do much of the work ourselves. I ordered all the equipment from online wholesalers, did all the design and documentation for city and utility permitting, did most of the physical install, and had the contractor do the final hookup and hourly consulting along the way. The utility incentives were still decent then ($1/W up to $5k), but equipment prices have continued to fall and I had the added cost (~$2.5-3k) of having to build a shade structure as our roof was too shady. Balancing those out, a similar final installed cost per kWh should still be feasible.

Nameplate DC Rating: 5.52kW
Gross Out of Pocket: ~$17,000
Net After Tax Credit and Incentives: ~$7000 (including income tax on incentives)
Net $/W Installed: $1.36/W
Annual Production Estimate: 8167 kWh (PVWatts default 77% derating, corrected for shading)
Annual Production Est Efficiency: 1480 kWh/kW
2013 Actual Production: 9652.3 kWh
2013 Production Efficiency: 1749 kWh/kW
Min Expected Service Life: 20 yrs
Expected Total Production: 163.34 to 193.05 MWh
Expected Total Prod Efficiency: 29.59 to 34.97 MWh/kW
Expected Total Prod Value: $19,600 - $23,166 (flat $0.12/kW for 20 yrs, should be lower bound assumption)
Annualized ROI: 9.0 - 11.5%

If solar was sized and installed solely as fuel source for plugin vehicle:

Annual Production Efficiency: 1480-1749 kWh/kW (from above)
Net $/kW installed: $1360/kW (from above)
Net Annualized Production Cost: 0.039 - 0.046 $/kWh
Assumed Vehicle Efficiency: 4 mi/AC kWh (250 AC Wh/mi)
Production Cost Per Mile: 0.975 - 1.15c/mi
Equivalent Gasoline Cost @50MPG: $0.48 - $0.58 / gal
Annualized ROI: 16.8 - 20.7% (vs. flat $2.50/gal for 20 yrs, should be lower bound assumption)

Rob

As to lensovet's question of "how someone in California whose electric bill never exceeds $50 can set up solar in a way that makes any financial sense?"

Small systems can be challenging as with many things buying more is the way to reduce cost per unit. However, I think this is potentially where micro-inverter based systems really shine. These systems use one small inverter per each panel, and then each is wired together as 120V AC components rather than the traditional DC strings and large inverters. A big advantage to a micro-inverter system is they are very scalable, from a single panel to many panels at a relatively fixed $/W.

Here is an example (hypothetical, not designed/optimized):
Sharp 245W Panel: $172.80 (Sharp 245W Module)
Enphase M-215 Inverter: $131.00 (Enphase M215-60-2LL-S23 Microinverter)
Equipment Total: $303.80

This example comes out to $1.24/W for a system that is scalable from 245 DC W to kWs, and could be sized for smaller installations like you are talking about. Now there will be some additional costs, you have to mount it to something and wire it in, but the wiring is simpler than a traditional DC stringed system. In addition most people will be able to get a 30% federal tax credit on the total cost, which would likely more than make up for those overhead costs.

So making some (simplified) assumptions:
Assume $50/month = 122.5kWh per month average @20c/kWh plus taxes and fees
In SoCal a well placed system should make about 1470kWh/nameplate DC kW per year. (pvwatts)
1470kWh/yr = 122.5kWh per month
122.5kWh per month would require 1000 DC nameplate Watts.
4 panels / microinverters above would provide 980 DC W @ $1215.2
Assume total installed cost of $1500, -30% tax credit = $1050 net upfront cost (assuming no other rebates/incentives)
Annual Production should be about 1441kWh
Annual Production value should be $288 if prices stay at 20c/kWh for 20 years (unlikely, low bound)
Simple payback period is 3.7 years.
Total Production should about 28.8 MWh over 20 years.
Generating cost per kWh is about 3.64c/kWh
Total Production value would be $5764 if prices stay at 20c/kWh for 20 years (unlikely, low bound)
Profit on $1050 investment is at least $4714 over 20 years.
Annualized ROI on initial $1050 investment should be at least 22.4%

Now those numbers would have to be refined significantly, but I think they show that small systems can still be an excellent investment from a purely financial perspective. Let alone all of the additional benefits that go along with switching to solar.

Rob

 

How is it not? Investment: the action or process of investing money for profit or material result. If you pay a monthly fee to your stock broker does that mean that none of the stocks you buy are investments? If you buy a condominium, and have to pay a condo fee does that mean the condominium isn't an investment? You seem to be grasping at any possible straw to avoid considering solar, why not just relax, and run the numbers for yourself?

 

I think my kittens use more than 80kWh/mo. I swear they turn on lights and run the AC when I'm not home. :/

 

SCE does offer TOU rates. I'm in the process of switching this month.

 

Apologies for being dense, but what exactly is the return on the investment? A 20-year payback for a house in which my parents might not even stay for more than 10 years makes zero sense.

 

The ROI would in part depend on the resale value of the PV array.

It would be like the resale value of a Prius. Probably pretty good in Berkeley; maybe not so good in the Deep South.

 

The problem with TOU rates is the daytime rates are excessively punitive during summer months. It's not a realistic option for most households. However, with a PV array generating its peak output during those daytime peak rate hours, TOU can indeed be attractive. I'll be looking at this once my PV system goes live.

 

You may find that orienting the PV a bit more westward is in your favor if possible. Perhaps 200 degrees. You will not lose much (if any) total PV production, but you will have more late afternoon output in the summer for your AC consumption.

 

Similarly you may find that a flatter than ideal array angle will produce slightly less energy overall, but maximize production value by increasing summer production.

Rob

Time of Use plans with solar can be a bit complicated depending on how your utility company handles it. When we went solar I switched from TOU back to basic. The challenge was that as I understand on-peak solar production would only be applied against on-peak usage. If you made excess solar during peak time, which one could easily do if usage was shifted off peak, it would get rolled month to month and paid out at ~5c/kWh if there was excess at the end of the year. If you tried to keep some loads active during peak time, and ended up using too much you'd be paying peak rates (~21c/kWh) vs. off peak (7c/kWh) or basic (11c/kWh) even if you had off peak solar production that would have canceled it out. If they had allowed your peak production to cancel out off peak usage on a cost basis, TOU would have been a no brainer as each peak production kWh would have canceled about 3 off-peak kWhs. Even if they allowed it to cancel on a kWh basis, it would have at least been straight forward. But as it is, there is a very real risk of either having excess peak solar production devalued from 11c/kWh to 5c/kWh or excess peak usage go up from 11c/kWh to 21c/kWh. Either could easily end up negating the cost benefit of being on TOU.

The simplest thing was just to go basic and have all usage and production treated as net at the same rate. That said, I am thinking about trying to go back and try TOU, but it will take quite a bit of oversight to keep things balanced from a peak/off peak production/usage standpoint to maximize the benefit, or even just to keep from losing money.

Rob