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Thanks for visiting the Mike's Make blog. It is a compilation of many of my interests. I hope you find the articles in this blog helpful and entertaining. Leave a comment and let me know what you think.

Tuesday, May 15, 2012

Design of a Utility Interactive Photovoltaic (UIPV) System

Part 1 - Power Requirements
Why not power the whole house? This can be done, but it will be expensive and a lot of people don’t have those kinds of resources. But you should figure out how much electrical power you do use. This will vary from day to day and month to month but you can determine your electrical usage by looking at your past electrical bills. This may enlighten you to how much electricity you use and how it is sometimes taken for granted.  A lot of this information is now easily accessible online. For instance, Florida Power and Light provides billing graph histories that keep track of your electrical usage in both dollar amounts and electrical usage. This makes it even easier to analyze the size requirements of the PV system. In determining the requirements of a PV system to be used in my house, I accessed my electrical usage from the FP&L website.  I determined that the best use of a PV system would be to try to minimize the effects of the peak usage rates when electricity demand exceeds 1000KWh in a month. I found that on average I exceed this value by 338kwh. About 4 months of the year I have high demand where I expect not to make this goal, but the rest of the months I should.      


 
So how much do you spend on a PV system and why? Try to determine the best return on your investment and what you can afford. Sometimes the system will pay for itself faster if you balance the initial investment with the potential payback. And yes, unlike other investments, this system will eventually pay for itself if quality materials and workmanship are used during the installation and the system has the proper maintenance during it’s lifetime. One way to balance your initial investment with the potential payback is by avoiding increased rates for excessive electricity use. For instance, FP&L charges higher rates for monthly electricity usage that exceeds 1000KWH. (See graph 1). Not only that, but FP&L additional chargers include a 1% storm charge, a 6.23% franchise charge, a 2.5% gross tax and a 5.84% utility tax. That’s a 15.57% tax based on the amount of power usage. This is not going away anytime soon.  If you can avoid having to pay for electricity at these increased rates, your return on investment will be greater and payback will be quicker.  Another thing to consider is the point at which rebates and incentives kick in. 
So how much do you spend and why? Try to determine the best return on the investment you will make and what you can afford. Sometimes the system will pay for itself by avoiding increased rates of excessive electricity use.  For instance, FP&L charges higher rates for electricity usage that exceeds 1000KWH (See graph below).
This higher rates is around 17% higher than the rates for electricity usage under 1000KWh. If you can avoid having to pay for electricity at these increased rates, which  then your return on investment will be greater. 



The PV Calculator located on the Kyocera website at http://www.kyocerasolar.com/products/pv_calculator.html is a way to determine the approximate cost of a PV system. This site uses cost per watt, local utility rates, annual utility cost and PV system size to calculate how much a PV system will cost, how much of the cost will be covered by energy initiatives, and how much you can save on your monthly bill. 
 


Protect yourself against higher Electricity costs in the future. In February 2000 electricity costs were .04217 for first 750KWh and .05217 after that. The fuel charge was constant at a .0187. FP&L changed the way they calculated electricity costs and now charge .04134 for the first 1000KWh and .05166 for electricity after that. The fuel charge is also a variable rate based on consumption and ranges from .06021 for the first 1000KWh and .07021 for electricity after that. I guess you could say FP&L lowered their rates but in real terms electricity costs have gone up over 67%.


Part 2- system design

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