Homemade Solar Cell

With our current economic melt down and energy prices fluctuating daily, many of us are thinking of installing solar panel power to contribute to our homes’ energy needs, and reduce our power bills.

But when you install solar power, how much do you actually have to generate to say cut your bills by 50%? And what kind of costs will you be looking at?

Here is a simple 4-step formula to help you calculate your home’s solar panel watt requirements and costs:

1 – How Much Power Do You Use Per Day?:

Your first step is to work out the average daily kilowatt hours (kWh) used. This can be done by looking back at your last twelve months power bills, and see how much power used per month, and get the monthly average. This will give you a better estimate of your average power needs by eliminating the effect of the seasons. It is calculated by adding up all 12 bills and dividing the total power used by 12. If you do not have the the past year’s bills, then look at your most recent one.

Then divide your monthly usage by 30 (the average number of days in a month, to get your daily power used.

- Here is an example: Lets say the power used last month was 800 kWh. Your average daily usage would be 800/30 = 26.7 kWh per day.

- Now if you want to only halve your power bill then you need to produce 26.7 / 2 = 13.4 kWh of solar panel watt power per day.

2 – Calculate Total Solar Panel Watt Needs:

Before you can work this out, you need to find out how many usable hours of sunlight your region gets per day. A simple way to find that out is to have a look at an insolation map – there is one available on our website, where the original article was posted.

Once you know your daily sunlight hours, go back to your daily kilowatt hours needed and divide it by the daily sunlight hours, then multiply it by a factor of 1.25 (takes into account energy losses from the solar panel watt wiring, battery , and inverter)

- From the previous example, if you live near California where the average daily usable hours of sunlight is 5.5 hrs, the solar wattage needed is:

13.4 kWh / 5.5hrs x 1.25 = 3.045 kW or 3045 Watts per day.

This means we need solar panels with the capacity to produce at least 3045 Watts of power.

3 – The Cost Of The Panels:

Next you need to work out how much it will cost to buy solar panels that produce at least 3045 Watts. Currently the highest average cost for solar panels in North America is $4.85 a Watt.

- In our example: It will cost us at the most 3045 x 4.85 = $14,768 to install solar panels to halve our power bill. And that’s before wiring, charge controllers, batteries, inverters, and electrician costs.

4 – Offset Tax Credits And Rebates:

Before you think you are going to have to fork out at least $14,768 for only 3045 Watt of solar panel power, you need to consider the effect of government subsidies and incentives.

With the new renewable energy tax credits going into effect from January 1, 2009, and state-side rebates from states such as New York, Connecticut, New Jersey or California, our solar installation costs will be much lower than expected.

- Continuing on from our example: If we lived in California, our state tax incentives would be about 20 % of the investment, and the federal rebates 40% of the remaining cost. So, our solar panels would only end up costing us:

$14,768 – $14,768 x (20%) – $14,768 x (1 – 20%) x 40% = $7,089.

Just remember that this formula is basic way for you to get an idea of what home solar power will cost you. Some things could not be factored in – such as the state or country you live in, the special offers of local solar companies and the cost of the other parts (inverters, charge controllers, batteries, installation fees).

However, from the example, you can see that for Californian to reduce their power bill by half, they would have to buy $14,768 worth of solar panels, costing them $7089 after rebates. A cheaper option would be to learn to source affordable and even free solar cells, and build your own solar panels. This can be done by following a relatively inexpensive step-by-step solar power manual, such as Earth4Energy.