convert to solar

What size solar install (grid tie) would I need to:

Heat the house

heat the shop

run the stove/oven

drive an electric car 13,000 miles per year

and cover existing usage.

Current yearly electric usage is 7,100KWh.

We use 1100 gal/yr of heating oil to heat the house. Boiler is 72% efficient.

Shop is heated with vent less propane system (95% efficient?) uses 425 gal/yr.

The kitchen stove/oven uses 47 gal/year of propane.

For heating, figure pure electric heat. Then again for 200% efficient heat pumps.

Electric stove.

Figure car goes 3 miles on a KWH.

A solar contractor (who got frustrated and hung up on me) said a nominal

1kw dc panel system would make  1,280KWh AC per year at my location with

south exposure and 6/12 roof pitch. This is about what I have been hearing they produce.

Don't worry for now if the electric company will allow me to have a grid tie system/inverter system that big.

Thanks.

1 KWH = 3400 BTU

so 425 gal = 38,675,000 BTU = 11, 375 KWH   ( or 1 gal prop = 27 KWH )

or about 62,500 KWH or electricity per year...... or  5200 KWH per month ..."roughly"

I guess my current 591 KWH per month is lower than average.

So with oil and gas burning efficiencies subtracted, and COP of 2 heat pumps, I need

36,000KWH per year less.

Add on an electric car and I need 30,833, add electric oven I need a 32086KWH/year solar system. Uhh, can I get that at Walmart?

WTB: grid tied solar carport to produce  32,086 KWH yearly. This should be 25KW nominal system at my location. Shed roof 60x25 approx dimensions.

So the big hitch is the local utility & local regulations will only let me install 115% of current usage, a 8.2KW system. About 1/3 of what I need to really go green.

I see go green urging from the governor, but look, right here, they force me to keep burning fossil.  Actually the last load of fuel oil was $5.90 per gallon, so I you assume it stays there and gas at 4.85 and propane at $4.00. I scared myself thinking all my electric propane and fuel oil was going to cost $16K per year. It will if prices don't come down.

And usually, the payoff period is about a year short of the PV panels' effective lifespan.  My friends' grid-tie 10KW system in Tennessee, for example... it was built to cost assuming that it would break even (meaning, paid for itself, and nothing more) over a 15 year operational span.  The energy sales TO his utility, plus the green subsidy, will have paid for the system at 15 years PROVIDED that it's generating full performance for the entire 15, but for two reasons, it won't.... first, one cannot guarantee that you'll have full terrestrial sunlight for every daylight hour of every day... even with panel directing (az/el), fresnel effect prevents full spectrum energy from hitting the panels (atmospher bends sunlight away as sun nears horizon) and weather (rainy, cloudy, snowy days)... and furthermore, the panels' performance naturally degrade as they age.

At current trajectory, the panels' output will be done at about the 13 year point, at which point, he'll be paying for the entirety of the system, and not recieving subsidies or energy sales payments.  The losses, at that point, will exceed all the gains.

As for output, his 10kw system averages about 30% of rated full output, and as others noted, it will NOT provide enough on-demand power for any 'surge' scenarios, you get what it gots.

In order to absorb the volume of energy noted above (5200kwh/mo) you'll need about a 70kw AVERAGE capture/production system...  that's roughly 280 250w panels, more than six inverters, and some way to STORE all that power (lots of batterie$?).

Neither environmentally friendly, or cost feasible...  especially considering that neither the PV cells, nor the inverters or storage medium will go for any extended period without constant maintenance.

be SURE to look at the REAL specs for 'heat pumps' ! 1st gen type are LOUSY when it gets kinda cold, miserable when it does get cold,so they have resistance heaters as 'backups'. 'Splits' are much better...'might' be what they are talking about, one outside unit does 1-6 'heads'( 1 per bedroom, 2 in larger rooms..) They'll come precharged, simple install, connect tubing, cross fingers and  you'll get both heat and air conditioning.

if (IF) you save $3700 per year, WHAT is the true initial cost (equipment and install fees), so you can figure out payback and 'is it worthwhile'.

The ONLY reason I replaced my 35 year old gas furnace was to get a better deal on insurance. The new unit is costing me MORE to run,only 93% eff, old one was 94.5% last winter.

You might get better savings with more insulation,adding mudrooms( dbl doors),sealing the heat ducts, etc.

Hydro up here is about 25c/kWh once you figure in all the 'lines of services', carbon tax and then 13% Hot potato Sales Tax.....

Really sad when you consider Niagara falls is 43 minutes from me....

We put geothermal in 2007 (I believe ) and it paid for it's self in 7 years going thur our REC we're all ele except the wife cooking stove our bill runs 200 to 230 every month, it was one of the smarts things we've done.

 I wouldn't do solar until they work out a lot more of the bugs it has which I think will be a long time from now.

  One thing I forgot to included was we had 5 acres to run geo lines.   

Thanks for all the responses.

I don't really want all that extra infrastructure, or to be a power plant operator.

There would be no problem if the price of electricity was such normal

working person could heat the house and charge the car. 4cents per KWH is what it should be. How to do that?

Could open a Jiffy lube. Heat the home with used motor oil. Run an old slow diesel with the oil to make electricity (and heat). But now I would be a co-gen power plant operator.