Estimate Your Roof's Solar Potential with RoofRay

Speaking of useful online tools, I should mention also a solar array modelling service, provided by RoofRay on their homepage. They use Google Maps and various other information to help you estimate the solar potential of your home or business before taking the financial plunge to invest in solar energy.

Using the site's modelling tools, you can evaluate how much solar energy your home could capture and how that would affect your monthly bills based on past weather conditions, current electricity bills, the slope of your house, as well as how many panels your roof can hold.

With Google Maps you can calculate the square footage of your roof and build virtual panels. Then RoofRay estimates the output potential of the roof, costs of installation, and ROI. Another section shows existing installations that have already been completed by other people, including specifics of the roof used and total peak power.

Of course, RoofRay does not replace solar experts, but undoubtedly could answer some of your basic questions, and generally it is a quite interesting online service that deserves our attention.

Website: www.roofray.com

Updated 2021: Seems like this site is not working anymore, so you can try:      Solar Calculator (solarreviews.com),  SUNSEI Solar Design Tool & Google Project Sunroof

Solar Power Calculating Tools Online

There are a lot of online solar power calculating tools that can help you size your solar power installation. These tools are great in order to determinate how much solar power you'll need to run your home appliances.

NREL's PVWatts® Calculator - Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations.

Off-Grid Solar System Calculator - Wholesale Solar custom designs Off-Grid Solar Home Power Systems. Calculate your appliance needs, get an approximate system size, learn what Off-Grid system is best for you!

CalculationSolar.com - free online platform, which perform calculation of photovoltaic solar installations anywhere in the world.

Solar Calculator (EnergySage) - Use this solar panel calculator to quickly estimate your solar potential and savings by address. Estimates are based on your roof, electricity bill, and actual offers in your area.

Solar Calculators (altE) - a number of useful tools to help estimate your electricity usage, sizing for your grid-tie or off-grid solar power system and more.

Solar Panel (Power) Calculator - online tool used in electrical engineering to estimate the total power output, solar system output voltage and current when the number of solar panel units connected in series or parallel, panel efficiency, total area and total width.

Photovoltaic power calculator - quick online calculation of solar photovoltaic power and energy (PV panels or systems).

Solar Power Calculator - this tool will help you determine the yearly savings you will earn when installing  a PV solar system for your home.

PV Calculator | PVshop.eu - PhotoVoltaic calculator for grid connected and PV off-grid systems in PVshop.eu. (EU)

Solar Energy Calculator | Energy Saving Trust - use the Solar Energy Calculator for an idea as to the benefits you may see from installing a solar PV system. This tool gives estimates based on information you provide, and a number of assumptions to indicate potential benefits. This is to help you decide whether a PV system is for you. (UK)

Solar Power Calculator   - an independent resource for calculating your solar power requirements and potential monetary savings. Find out if solar is right for you. (AU)

Amp & Watt Hour Calculator & Solar System design Tool - This Amp &Watt Hour Calculator is provided to help you make some basic electrical calculations and design your own solar power system. (AU)

Keep in mind that the above calculators are useful as a general guide for sizing your solar electricity system and you probably will also need advices and help from professionals.

Calculating Your Solar Power Requirements

One of the most important thing you have to figure out when planning a solar power installation is the size of the solar system you’ll need.

First of all you need to calculate how much power you use on a daily basis. Your electric bill will be of help for this or you can make your own calculation. The power consumption of appliances is given in Watts (eg 21" fluorescent light, 13W). To calculate the energy you will use over time, you have to multiply the power consumption by the hours of use.

The 13W light fitting, on for 2 hours, will take 13 x 2 = 26WH.

Repeat this for all the appliances you wish to use, then add the results to obtain your daily power consumption.

You have to determinate also how much energy your battery can store. Battery capacity is measured in Ampere Hours (Ah). Convert this to Watt Hours by multiplying the Ah figure by the battery voltage: for a 20Ah, 12V battery the Watt Hours figure is 20 x 12 = 240WH.

The more energy you take, the faster the battery discharges. Keep in mind, however, that deep cycle batteries which are usually used in solar power systems, should not be discharged beyond 50% of their capacity. i.e. 50 % capacity remaining. Discharging beyond this level will significantly reduce the life of the batteries.

To calculate the energy your solar panel can supply to the battery, multiply Watts by the hours exposed to sunshine, then multiply the result by 0.85 (factor to allow for normal system losses).

For example, the Solar 40W panel in 4 hours of sunshine, 40 x 4 x 0.85= 136WH. This is the amount of energy the Solar panel can supply to the battery.

On the basis of all these calculations you'll determinate the size and number of solar panels you'll need, the number of batteries, power inverter size, etc.

Basic Things to Consider Before Buying a Solar Electric System

Installing a solar power system requires very careful initial planning. First of all, you need to know exactly how much electricity your home uses each month. You may look up in your old electricity bills but also you should think about how your electricity needs will change over the next 10 years.

Solar photovoltaic panels can be installed on the roof, along a wall of the property or as standalone systems. If you are planning to install them on your roof, you need to make sure that the roof is strong enough to hold a solar panel because some of these panels can be quite heavy. A roof inspection (and any necessary repair) is recommended prior to a PV installation. Another thing you need to know is that the more sunlight modules collect, the more electricity they produce, thus the more energy your home will receive. Make sure that the roof (or wherever you intend to install your solar panels) is clear of any obstacles, such as trees or buildings, especially during peak production hours between 10am and 2pm.

Ideally, a solar system will go on a south/southwest-facing roof, although east and west facing roofs are good candidates, as well.

You should decide whether your system will be grid-connected, off-grid or hybrid. With a solar PV system connected to an electric distribution system (grid-connected) you can receive back-up power from it when your system doesn’t produce enough energy for your needs. When your solar PV system produces excess power, that electricity can be send back into the grid, and your local utility is required to buy it from you.

Picture: apps1.eere.energy.gov

A grid-connected solar power system is easily integrated into the existing electrical infrastructure of a house and the system can provide decades of reliable and environmental friendly electricity production.

A stand-alone (off-grid) solar PV system is independent of an electricity distribution grid operated by a utility. The electricity is provided by solar power alone and stored in a battery for later use. Such systems typically make sense in remote locations.

The average solar PV panel last approximately 30 years and many manufacturer warranties last for up to 20-25 years. Solar PV panels are designed and installed to be low-maintenance. However, it is very important to have your solar panels cleaned regularly because they benefit from being hosed off with water twice a year, especially after long periods without rain. Dust or dirt may cause a 10-15% reduction in their efficiency.

Before buying and installing the panels it is also essential to make sure that you understand the installation regulations in your local area. In most cases it is wise to check with the local authority before installing your solar electric system.

Lemonade Award

I was nominated with an award - the Lemonade Award and this is my first award as a blogger (well, this is also my first blog). So, I would like to thank Eco Mama, Its all about our home, the Earth! and Goal For The Green for awarding me with it, and assure you that I really appreciate this acknowledgement! I think that making lemonade out of lemons can be an interesting endeavor, and besides, I like both lemons and lemonade :)

The Lemonade Award is passed to bloggers for showing great Attitude and/or Gratitude and now it's my turn to pass it to ten other blogs.

And here are my nominations :

SolReka
Environmental Chaos
Passionate Green
Chasing The Wind
Green not Mean
Eco-Blogical
Bulgarian Slivatree
Newton's Ocean
Life on a Southern Farm
Teddy Tour

The rules of this award for recipients:

1. Put the logo on your blog or post.

2. Nominate at least 10 blogs which show great Attitude and/or Gratitude!

3. Be sure to link to your nominees within your post

4. Let them know that they have received this award by commenting on their blog.

5. Share the love and link to this post and to the person from whom you received your award.