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  PHYSICS 

  Solar Panels over the Roof       Installed February, 21, 2006. 

  [The front of the house faces north, and there are no panels on that side.  To see the panels, turn the corner and drive up Straton Rd.]         09/27/13 

  PV panels that cover an entire roof section produce more power, and they look good too!  They also shade the attic, keeping it cooler which reduces need for air conditioning.

PERFORMANCE  DATA

Calculate your family's carbon emissions at www.carbonfund.org
Climate Physics Explained
Green Energy Ohio
American Solar Energy Society
 National Renewable Energy Laboratory
Third Sun Solar and Wind Power

           Fronius         Evergreen Solar           

Calculate the performance of a photovoltaic array with PV Watts

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The installer: Third Sun Solar and Wind Power of Athens, OH. 

The system uses 42 Evergreen Solar EC-115 panels and a Fronius IG 5100 inverter. 

I applied for and received a grant from the Office of Energy Efficiency of the Ohio Department of Development.  This grant paid for a major part of my installation costs. 

Want to know how you can get one of these grants?  Find out more through Green Energy Ohio, or from the Ohio Department of Development.  These grants are no longer available. 

 

In February, 2006, I installed a 4.83 kW grid-connected photovoltaic system that  powers my home.  As of March 2012, it has produced 36 MWh of electricity, reducing CO2 production by 19 metric tons.  The system produces more electricity than we use!

 

 Benefits:

  • Reduce CO2 emissions by over 3 tons/year.

  • Reduce electricity net consumption by over 5900 kWh/year.

  • Reduce electricity cost by about $700/y.

  • Reduce coal resource consumption at the power plant by about 1.3 ton/y.

  • Added (non-taxable) resale value of home: >$12,000 ? 
  • Roof-shading by panels keeps attic cooler, reducing air conditioning load.
  • Sale of SRECs (solar renewable energy credits) to public utilities provides INCOME of about $1700/y (this amount scales with system size).
  • Total personal investment recovery in less than 10 years (depending on utility prices).  After that, electricity produced is free [...as in cold, hard cash free...as well as pollution free.]

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Residential Solar Power in Ohio

Is there enough sunlight in Ohio to power your home?  ēYes, 41 m2 of panels powers my home.

Is it affordable? ē Yes, with state and federal incentives, it costs less than a new car and pays for itself within the warranty period.ē

 How do you get started? ē Contact Green Energy Ohio at  www.greenenergyohio.org

Green Energy Ohio is a nonprofit organization dedicated to promoting economically and environmentally sustainable energy policies and practices in Ohio.  GEO is also the Ohio Chapter of the American Solar Energy Society.

 

Costs:

Please note: This system was installed more than six years ago, now it would be  cheaper!  The current 30% federal tax credit has no upper limit (the state incentives have lapsed however) and the price for PV panels and installation has decreased.  For the past 3 years, payoff of this system has been greatly accelerated by the sale of SRECs.  People and businesses installing solar today are using these SREC sales to make installing solar not only affordable, but potentially profitable. 

  • Net 2006 cost ~$19,000 [About the same as the new car I did not buy.], and neglecting added resale value, and SREC sales.

  • Total cost was about $44,000, of which $23,000 was paid for with the ODOD grant.  Another $2000 was paid by the alternative energy  Federal Tax credit.

  • Premature roof replacement: ~$500.  To be sure I would not have to remove my panels at some time in the future, I put new 40-year shingles on the roof before installing the PV panels.  [My previous shingles were aging and would have needed to be replaced within about 3 years anyway.]
     

This is a grid-tied system.  If I use more electricity than I produce in a given month, I will pay American Electric Power for the difference at retail prices.  If I produce more electricity than I use, AEP will pay me at wholesale prices.  There are no storage batteries [I won't have to buy them or dispose of them].  I send the surplus power that I produce during the daytime to the utility grid, and get it back at night.

Frequently Asked Questions:

How much does a system like this cost?     About the same as a new car.  If you can afford a new car, but donít have to buy a new car, you can choose to put a grid-connected photovoltaic (PV) system on your house.

 

How many people around here have solar electric homes?     This is a very difficult question to answer, because itís hard to know how many people have ordered solar panels over the internet and installed them on their own.  I would guess that the half-dozen or so certified installers in Ohio have collectively installed a few hundred grid-connected photovoltaic systems.  These vary in size.  I also suspect that my 4.8 kW system is one of the larger residential systems.  Some idea of the total can also be obtained from the Green Energy Ohio Solar Tour book.  There is now at least one other solar home in the city of Delaware.

Another way to answer the question is by looking at the national statistics.  This is complicated by the rapid growth in the industry, which leaves information that is only a year old extremely out of date.   51 megawatts (grid-connected PV) were installed in the US in 2004  [with the amount installed increasing at about 35% per year].  Of this amount, 96% was installed in California, New Jersey, Arizona, New York and Massachusetts.  Ohio had a tiny piece of the remaining 4%.  The United Statesí share represented only 9% of the world total; Germany and Japan together installed 69%.   Source:  Solarbuzz.com

How long will it take to pay for itself?     From an environmental standpoint, right away.  It will reduce the amount of CO2 released into the atmosphere by over 3 tons per year, mitigating my familyís contribution to global warming.  From an economic point of view, itís a long term investment closer to the 20-year warranty on the panels (SREC sales have since cut this estimate to less than half of this), but it is much less than this if you subtract the resulting increase in the value of the home.  The "Solar Estimator" at FindSolar.com, can be used to calculate the price of a system including this change in home value. 

 

How do you store the power?  How big are the batteries?     I donít store the power.  There are no batteries.  When I produce extra power it goes out to the distribution grid and my electric meter runs backwards.  When I use more power than I produce, my meter runs forward.  Iím still connected to American Electric Powerís distribution grid.  

Some systems do have batteries.  In fact, an energy storage system is necessary if you are not connected to the distribution grid.  But if you do use batteries, first you have to buy them, then you have to replace them, and then you have to discard them.  If you are off-grid, you also have to budget your power use so that you donít max out your system. 

With my grid-connected system, I donít need to budget power on a minute-by-minute basis.  I only need to break even at the end of the billing period.

On the other hand, without batteries there is no back-up power.  When the grid goes down my lights still go out.

Where does the power go when your meter runs backwards?     It goes to the grid to help the other power producers provide electricity to all users. 

The electric distribution grid works sort of like a bathtub with a dozen or so faucets and thousands of tiny drains.  Each faucet represents a power plant and each drain represents a user (a home or a business).  If the amount of the water flowing in is equal to all of the water flowing out, then the water level stays the same in the tub, neither rising nor falling.  All of the drains get their apportioned amount of water (users get the electrical power they need).  The user doesnít get his electrical power from a particular power plant any more than the water coming out of one of the drains would come from any particular faucet. 

My house uses electricity (like a drain) and it produces electricity with the solar panels (like a faucet adds water to the bathtub).  This doesnít have to occur simultaneously as long as other sources and users are able to adjust to the difference.  Sometimes I add more than I use; sometimes I use more than I make (especially at night).

Do you use this to heat your house?     No, it provides my electricity.  Solar space-heating systems and solar water-heating systems exist, but these are different technologies that capture and use the heat from sunlight directly.  My panels generate electricity.

 

What percentage of your electricity does your system produce?     It produces slightly more power than we use.

 

How long did it take to install?     It took two days for a trained crew of three people to install.

 

How did you get your grant?     The installer (Third Sun, Athens, OH) helped me with the application.  One of the conditions of the grant was that the system has to be installed by a certified installer.  So one way to get started was to simply contact a certified Ohio installer.  A list of these is available at the GEO website.    The other way was to contact the Office of Energy Efficiency at the Ohio Department of Development.

Was it hard to apply for the grant?  Not at all, the installer took care of all the details.  The installer wanted you to get the grant.  The grant made it easier for the installer to get you to buy their products and services.  I just had to sign the forms that Third Sun prepared. 

Why did you want to install a photovoltaic system?     I want to help the environment and I want to be able to do things that require electrical power.  With a PV system I donít have to choose between these. 

I also wanted to demonstrate to others that alternative energy is not a future technology.  Itís a present day technology.  All we need to do to reduce our dependence on fossil fuels is to grow the alternative energy industries.  

Right now photovoltaic manufacturers canít keep up with the demand.  But they need to sell more photovoltaic panels before they can afford to invest in more manufacturing capacity.  If they do build capacity, prices will fall, making systems more affordable to more people.  This in turn will increase the demand for even more panels, continuing the spiral. 

Government incentive programs, such as the Ohio Department of Development grants, help to front-load the growth spiral.  They make systems such as mine more affordable until increased manufacturing capacity brings prices down.

Why did you choose a photovoltaic system instead of a solar heating system or a wind generator?    The PV system's high capital investment and slow payoff compared to solar water heating and solar space heating is offset by maximum benefit to the environment.   The PV system also has high reliability and no maintenance. I'm also a technology guy; I like things that use electricity.  I can keep running computers, machines and toy trains without sacrificing my children's future. 

Wind power may not be practical on many small suburban residential lots at central Ohio wind speeds.  Wind generators need to be well above all obstructions to work efficiently, and there may not be enough room for a tall tower on a suburban lot.   If utility rates continue to increase or alternative energy equipment prices continue to fall, wind turbines mounted near roof-level may become practical in Ohio (as they already are in some parts of the country).  New technology may also be more efficient to operate and to install.  See the new SkyStream 3.7 for an example of new wind technology.

This contrasts highly with utility wind power. New wind-powered electricity production has become cheaper than new coal-powered electricity production capacity, and closely rivals the cost of electricity produced by natural gas, without the greenhouse gas emissions of either. 

Never-the-less, I have recently (Dec. 2011) purchased a 400 W wind micro-turbine at a local hardware store as a demonstrator (justifiable more by my role as a teacher than by cost of the turbine!).  Be aware if you try to do this, the cost of the micro-turbine itself is only about a quarter of the cost to get it operational.

 

 

    

This Fronius IG 5100 inverter in my basement converts DC power from the panels to AC synchronized with the distribution grid.

 

The prototype system:

solar power

The solar panel shown providing a small amount of extra power to my residence [Delaware, OH] is an Evergreen Solar 100 watt solar module.  It has a Trace Engineering inverter attached to the back of the panel which allows the module to be connected to my circuit breaker box.  This provides the grid interface, on my side of the power meter.  No batteries are required. 

About $250-300 worth of equipment and supplies were required to mount and wire the module.  The module itself retailed for just under $1000 in 1999.  Rebates reduced this to about $700.   This type of module allowed me to start receiving the benefits of solar power without investing thousands of dollars first.  It also helped me to learn what would be required to install a larger system. 

This module was placed into service in 2000.  Although it provides power to the house, it is mounted on the tool shed.   Wiring was done by  SafeCircuits Electrical Services  [Lewis Center, OH].     Grid interface is with American Electric Power.

Energy produced per day during April 2006 as displayed by the Fronius software and data logger that came with the inverter.

 

 

AC Power for the best day of the first week of operation.  The power slowly increased from sunrise to solar noon (about 12:45 pm EST) as the sun angle to the panel improved, then declined toward sunset as the sun angle to the panel decreased.

Solar Homes: Runnin' On Sunshine
Follow this link to the GEO website to listen to this podcast.