What Are The Basic Steps to Plan My Residential Solar Energy System ?

If you are planning to install a Photovoltaic Solar Energy System, then figure out how much solar energy you can expect your panels to absorb, based on the average daily solar radiation for your area.

Step 1°: Calculate the Potential Solar Radiation Power

For most parts of the United States, an average of 4-5 kWh/m²/day can be achieved, though in some regions it is possible to achieve up to 8. To find the output for your area, please refer to this map put out by the National Renewable Energy Laboratory (NREL) Resource Assessment Program. In the delineation kWh/m²/day, the kWh stands for kilowatt hour, with “m” being the area of the absorber, or in this case, the photovoltaic cell, put into square meters. Solar panels, on average, work at about 7 to 17% efficiency.

Therefore, if you live in an area with an average solar radiation of 4.5 kWh/m²/day, and you have a total surface area of 1 m² (corresponding to 1.55 squared inches) of photovoltaic cells, you can expect to generate 0.315 kWh/day (315 Watt/day) estimating an average solar panel efficiency of 7%.

Step 2°: Determine Your Average Energy Usage

 

Once you know how much energy you can expect to get from the sun, you can determine about how much energy you will need based on your current monthly energy consumption. If you don’t have copies of your last 12 bills, you can view the state by state averages, as published by the Energy Information Administration here. According to the chart, a consumer who lives in New Jersey, for instance, will use an average of about 730 kWh/month in electricity, while one in Alabama may use as much as 1300 kWh of energy per month.

Step 3°: Calculate the Number of Panels Needed

 

Now that you know how much solar radiation is available and how much of it can actually be utilized by a solar panel, you can calculate how many photovoltaic solar panels you will need in order to replace your current source of electricity. You will need to find out the exact size of each cell in square meters, as well, which can probably be found on the website of, or in literature from, your manufacturer of choice.

If we assume an average energy usage of 1000 kWh per month, we will calculate: “Solar radiation” x “Surface area of the panels in m² ” x “0.07″ (7% Estimated solar panel efficiency) x “Average days per month” (365/12). We will then divide that number into 1000 (The average energy usage of 1000 kWh per month).

For example, in an area with solar radiation of 5 kWh/m²/day, with a solar panel of 2 m², the equation would be:
5 (Solar Radiation) x 2 (Surface Area of standard solar panels) x 0.07 (Solar Panel Efficiency) x 30.42 (Average n° of days per month) = 21.294 kWh produced per panel each month.

To cover at 100% the month Kw usage of 1000Kw divide 1,000/21.294 = 47, so you would need 47 m² of panels to completely eliminate your electricity bill. (Here a more detailed description of how many 80W solar panels are needed to power a home)

Step 4°: Calculate Upfront Cost vs. Long-term Savings

 

For nearly everyone, the upfront cost of a photovoltaic solar system will be a major factor. However, with the yearly utility savings and the government incentives, it can be well worth the initial investment. A lot will depend on the size of the system you install. Considering a single 2 m² of solar panel can generate 21.294 kWh/month and your electricity company charges an average of 20 cents per kWh, you would save about $51.2/year. 10 x 2 m² Solar panels could let you save 512 $ /year.

If that system costs $20,000 and solar Governmental rebates / Tax Credits may let you cover/cut the cost by 50%, you’ll have to payback 10,000 $. It would take you about 19.5 years for 10 x 2 m² solar panels to pay off the system and begin truly saving (if you consume 1,000 Kw /Month it will cover at 50% your energy bill).

In areas where the kWh cost is higher, the savings and pay-off period could be significantly reduced, allowing you to pay off the system in less years. Here you can read more about the cost of solar panels, find all solar energy incentives here and find more info about solar leasing.

How do I sell Solar Energy to a Utility Company?

 

This is available for grid tied solar systems. If you’ve taken or are thinking of taking the energy-efficient step of installing solar power at your home or business, know that this move can be cost-effective, too. The initial investment for a solar panel system can be quickly paid for by selling your surplus energy to a utility company.

The government requires 42 states and the District of Columbia to purchase surplus power from consumers. The way to take advantage of this process, and the subsequent rate you will receive for your surplus energy, varies by state. Here is a quick guide to getting the most out of your extra solar generated energy. Here more on how to sell solar energy to a utility company and how much to sell energy back to the grid.

Step 5°: Plan the Photovoltaic System Placement

 

Latitude Angle % of optimum
25° (Key West, Taipei) 51.5° 85%
30° (Houston, Cairo) 56° 86%
35° (Albuquerque, Tokyo) 60.5° 88%
40° (Denver, Madrid) 65° 89%
45° (Minneapolis, Milano) 69.5° 91%
50° (Winnipeg, Prague) 74° 93%

 

Above a nice table on solar panels orientation for winter months. A good rule of thumb to use when determining the correct tilt of solar panels is to find out the approximate latitude of your area and set the panels at an angle equal to that latitude. This should maximize the amount of solar radiation absorbed all year.

If the southward facing roof on which the panels will be installed is slanted beyond the angle of your area’s latitude, then the panels should be lifted at the bottom edges, in order to achieve the best radiation angle, whenever possible. For flat roofs, any of the four sides can be elevated to match the latitude angle. Here you can read more tips to find solar installers and photovoltaic system reviews.

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{ 8 comments… read them below or add one }

Nasser November 24, 2011 at 3:20 am

Hi,

We are bidding for big Government project to supply different size of Solar systems for both Domestic and Commercial use the scope still not clear, but from our resources/Network it is very big one.

I would like please to start making contact with you about your Solar products and also services you provide after sale.

Nasser
Oman , Muscat

Shareed Hosein December 16, 2011 at 3:20 pm

I will like to get a quotation for a solar system to provide 150 kWh per month (panels and energy storage unit).

I greatly appreciate your assistance and look forward to your response.

Best Regards,

Shareed.

richard Don Aki January 6, 2012 at 6:01 pm

Hi, ¶ ve A̶̲̥̅ cilent that say this is wat she wants in her house and ‎​A̶̲̥̅♏ not sure if all this will work pls ¶ need advise on what τ̲̅ȍ do because she wants the solar power of 1kva inverter,240watt solar panel 30ahm charge controller 12v 200amps battery τ̲̅ȍ back up one decoder,3 standing fans,7point of light,one LCD tv,and her music set and all this should back up for 12hours. I greatly appreciate your assistance and look forward to your response. Thank you. Richard

abdullateef abu hussein January 21, 2012 at 5:57 am

Dear Sir/madam,

can we have energy from solar panels in the indoor environments from lighting to move electromechanical system?

actually i have an idea in marketing communications and i need to have a mobile solution without electrical wires.

simply i need a power to move a robotic hand that it will move up and down or maybe many other movements.

Kind Regards

Abdullateef.

John E January 25, 2012 at 9:27 am

Hello,we need some Solar equipment to buy,i will like to know if you can supply us with any of this.example below:

Solar panel from 50 to 250watt.

Solar Charge Controller.

Sealed Lead Acid Battery 12v,80 to 200ah…for solar backup

Or any of this Solar pumps below:

Lorentz pump ps1800 c-sj5-12

Shurflo Pumps (Model# 9325-043-101) 9300 Series DC Submersible Pump

Grundfos SQFlex 11 SQF-2 submersible pumps

Please reply back soon,to let us know if you have any of it in stock,if yes,please advise unit cost for each.

And will like to know if you accept credit card payment.
stonecornwall@gmail.com

Regards

John.

arash February 26, 2012 at 5:20 am

hello.i am arash salehi mazdeh . i am irainian & i can”t speak english pleas your help me
i need for figur (current source power 0A-500A) THANKS

David Dante March 16, 2012 at 8:43 pm

I am interested in purchasing solar panels to offset my electricity costs… In my part of the country humidity & non-airflow is the worst! The air-conditioning is our largest electricity usage. I would like to store power during the sun hours to offset peak usage during afternoon hours. Suggestions?

David Dante

FORREST SCHOFIELD April 9, 2012 at 7:26 pm

Hi, my girlfiriend and I have some acerage picked out to buy, 40 acres of woodland near 4 corners, WY but there is a nice large elevated clearing in the woods ideal for a new modular home with a composition shingle roof which would catch the sun at almost all daylight hours of the day. We currently live in a singlewide trailer house in town. We use 2,600KW per month, but with our new place we will not have an electric furnace, we will have a wood broiler outside the home. Also we will not have an electric water heater, but we have one in our trailer in town. We would like a wind/solar mix that would give us 100% self sufficiency. We would like the main % of our power coming from the solar, and a smaller % of the power coming from the wind which would help charge the system at nite and during cloudy storms etc. But we are open to all suggestions, these are just our ideas. We will not be able to tie into an existing power grid, because there is no power to the site. We would like an approximate price quote for the entire system, so we can take these numbers to the bank and let them know how much our system will cost. Also, do you install or do we need to install? If you do offer installation, could I get the approximate total of installation seperately as well? Thanks for your help. We are planning on getting this ball rolling within 1 to 2 months :) thanx, Forrest.. other note: Its best to reach me at my email because I work night and day shifts at a coal mine- schofieldforrest@yahoo.com Cell 307-696-7021 please leave a msg if you call my cell, I don’t normally return calls from numbers that are foreign to me unless a msg is left, but e-mail is best :) thanks

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