Is 100% Solar Power Economical?

SanDiegoDave100 writing in The Motley Fool ran some numbers on using Solar PV to provide 100% of his homes electricity and electricity to a Tesla electric car.

His current cost for 600 kWh per month costs $101 and gas for his car $180 for a total of $281.

At $0.25 kWh/mile and 1500 miles per month he would require 375 kWh of electricity, combined with 600 kWh for the house would require 975 kWh of solar power. He determined that he would require an 8 kW solar system, for a San Diego location, at an installed cost of $55,000 before rebates of $17,600 for a net of $37,820.

A home equity loan of $37,800 at the current 6.5% rate would be only $239/month, a saving of $40/month.

He neglected to state how he would store the electricity so he could operate his house and charge his car at night, but it still is an interesting calculation. Perhaps he could be tied to the grid and sell his surplus during the day and buy electricity at night, but he did not make that calculation. The rates might even be in his favor if he was selling at peak rates and buying at off peak rates.

Thanks to AutoblogGreen for the tip.

Comments

[marcus]

He also neglected to include the small cost of the Tesla. But hey, if I had the money, I’d do it!

[Buddy Ebsen]

Its 0.25 Kwh/mile, not $0.25.

What a strange pricing scheme, why do they offer cheaper rates between 300-400 Kwh/month?

Also he says 600 Kwh/month, then says 300+100+300... isn't that 700?

I wonder how this calculation would work in Ontario, Canada where they pay $0.42/Kwh for solar to the grid? Feed the grid all day at 0.42/Kwh, charge your car at night for $0.10/Kwh... much less sunshine here than in San Diego, though.

To the previous poster: Tesla claims they will eventually produce a sedan at a comparable cost to conventional, so assume a net zero cost replacement.

[Chad K]

If you have $100,000 for a Tesla, worrying about cost savings of $40 seems insignificant. If you're buying the car anyway, if it costs you $200/mo more, it seems like it's worth it for someone who spends 100k to support the environment.

[David Allen]

He says he needs 600kWh per month! Where is all that power going? I use around 150kWh per month with a family of four. He should first do the sums on adding efficiency to his home before adding photovoltaics.

[Chad K]

150kWh/mo? Holy crap. I average close to 1100kWh/mo at my house, and that's considered below average in my neck of the woods. I think my dishwasher or clothes washer alone probably uses 150kWh per month, and they're the super-high-efficiency ones.

[amazingdrx]

The average is around 600kwh per month. I suspect it could be cut in half with solar assisted geothermal heat pump heating/cooling and very efficient appliances. A lot of that power goes to very inefficient conventional electric air conditioning and even electric heat.

Cut it in half and use that half to power the electric car (maybe an economy electric car conversion instead of the Tesla?). It would take a cogenerating solar system that collects the waste heat from the PV cells.

A reasonably priced electric conversion around 25k might replace a gas car. The Tesla is an extra expensive status symbol obviously.

If the homeowner could sell the clean energy credits like the homeowner in New Jersey did, it would help the economics quite a bit. That is a state law change that would really help solar.

How about a 3k tax rebate for the car, a 2k rebate for the geothermal heating/cooling system, and a 3k tax rebate for the solar system, from the feds. Siphon off some corporate welfare from big oil to pay for it.

Even if the oil boys only gave up 1 billion it would be a good start. After all they are making record windfall profits off of oil price rises due to the war and global climate change related storms.

[Ben]

In San Diego you pay your bill once per year and your meter runs backwards when you are generating more electricity than you use. In the evening when you charge your car, wash your cloths etc the meter is now runing forward. The hope is you will have a o balance at the end of the year.

[Jerry Henley]

You guys are driving me crazy...lol the numbers don't get near adding up. I calculate them all the time. Let me share this with you so you will know.

I live in the South, it was over 100 degress several times this last week. I get a ton of solar exposure sometime 10 hrs or more a day. I have 3 acres and a enough roof space to power a spacecraft. However here is the problem.

My bills are as follows;

month 1 = 1086 KWH $176.00
month 2 = 1413 KWH $176.00
month 3 = 1602 KWH $179.00
MONTH 4 = 1924 KWH $175.00

Imagine how much a solar power system would cost me to produce this amount of power required? $80 - $100 thousand dollars?
What would a loan at just 6 percent cost me over the next 20 years, hell I have no incentive to produce solar, I want to! am I not getting something here? The problem is when I look at a 125 watt solar panel that cost $900 damned dollars, couple that with $1095 dollar batteries and I need a bomb box to store them in with the inverter(s) etc. (H E L P!) :)

It would cost me a 1000 a month to make my own??

[Jeff]

Only a ignorant fool would think that he or she is saving the planet by buying solar panels to power their house.
The math never adds up because it can't. YOU CAN'T GET SOMETHING FOR NOTHING IN A MARKET ECONOMY. Power delivery in the US is one of the most efficient infrastructures ever built by man. To think that you really could buy the entire package (panels, inverters, controllers, batteries and installation) for less per kwH than it costs to produce hundreds of gigawatts is simply a enviro fantasy.
Of course all of this is based on the unscientific assumption that we are destroying the planet by using grid electricity. It is not the skeptics that are the anti-science crowd in this debate, its the Global Warmers who twist science and economics to attempt con the US into hamstringing capitalism.

[Bob Wallace]

One might be lead to assume that it would take an "ignorant fool" to jump from a "thought piece" about how much solar cost back a couple of years ago (a bit less than buying the same power from the grid and pump) all the way to running ones own utility company. SDDave100 did not advocate unhooking.

Of course, reading your second paragraph could easily assure one that the assumption is likely correct.

As for "capitalism", it's alive and kicking. You might want to take a look at how much private capital is flowing into wind and solar. The smart money recognized long ago that global climate change was real and started making adjustments.

In fact, the first industry to acknowledge GCC was the insurance business. They could see the problems they were going to have from more intense storms, flooding....

[Common Sense]

It's not how much money one sees being invested into a given technology or sector of the economy that's important to me... it's only the ACTUAL monies that are able to be generated FROM the technology or market sector. Hell, I can throw money into the wind, but if I don't get AT LEAST the amount I throw up into the wind back I'm just spinning my gears or - even worse - I'm just wasting my time, energy, and money.

Er go, at least for now, wind and solar energy - regardless of ANY government incentives to the contrary - are a waste of time, money, and energy. (Ironically!)

[Frank]

I figured out that when a 205 watt solar panel can be purchased for $100 or about 50 cents per watt, I could pay off that panel in 3-1/2 years. So, I predict that the 50 cents per watt figure might be reached within 5 years based on the rapid decline in prices due to more efficient approaches.

[GTech]

Visit http://www.gtech-canada.com One of the great pros of solar energy is the ability to harness electricity in remote locations that are not linked to a national grid. A prime example of this is in space, where satellites are powered by high efficiency solar cells.