Saving money with Photovoltaics

[henjulfox]

Folks,

It's getting to be a regular post - folks asking how much money they can save by buying some photovoltaic panels. I can't blame them too much. It's what they've been told. At least they are smart enough to come here and ask the question.

I put together a spreadsheet a while back to keep track of how close (or far) I am from breaking even. Helps to keep things in perspective. I've gone through and changed it a bit so that it's a bit more universal and flexible. You should be able to plug in the size and cost of your system and it calculates how much you can save over the 25 year life of the photovoltaic panels.

It is not perfect. It's not meant to be. I'm up for any sugestions anyone has for improvements (without complicating it too much)

http://www.otherpower.com/images/scimages/3613/pv_calculator.xls

-Henry

[Titantornado]

The Department of Energy has a calculator for figuring savings for grid tied systems.  It can be found at http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/

[henjulfox]

Rod,

Excellent. Thank-you. Assuming their math is correct it showed me that the factors I was using for my area are about right.

-Henry

[drone]

Brilliant site... I can use the northern NY calculations to approximate values in Canada, a couple of hours north of the border. Cheers!

[SpirckleM]

Interesting comparison of UpperState NY vs Tampa Florida shows you can save more money installing PV in upper state NY than in sun-drenched Florida due to higher electricity costs despite the greater average hours of sunlight you get in Tampa.

[Gresford]

Do you know where to find a similar calculator for off-grid applications?

[ghurd]

Sort of.  

Figure 99% of the time the answer is 'No Savings if grid is available'. Rebates, power company policy, and region will have a large effect.

Figure 90% of the time the answer is 'Big Savings compared to gas genset costs'. Depending on the load.

G-