While we may think that installing photovoltaic solar panels is expensive, they are actually quite affordable. The cost has come down considerably as the demand for alternative energy sources has increased. Today, they cost half as much as they did in 2008 and the solar market has increased substantially.
When solar panels are fitted onto the roof, they are positioned in such a way as to maximise the harvesting of solar energy. Throughout the day, this photovoltaic system will harvest as much solar power as is needed for the home. Anything over and above what is used will be stored in batteries. These batteries, if full, are able to supply the home’s power needs for approximately one whole day.
The sun will run your home’s power while it is shining. But any excess power will be stored. This allows your home to continue running off the grid at night or during thick cloud cover.
As a failover mechanism, the home isn’t physically taken off the grid, and instead the home’s photovoltaic off-the-grid system is tied into the utility electrical grid.
It’s the ultimate dream for every homeowner—being able to produce enough electricity to run your home without ever relying on the grid. The benefits to homeowners are twofold. First, it can significantly reduce your monthly electricity bill. Second, you’ll never be without power. Even if the grid goes down, your appliances and lights will carry on working.
Existing homes can also be retro-fitted with a photo-voltaic system, although this may incur some additional costs. We’ll look at what’s involved, how the system works and what costs and saving you can expect from using such solar power.
What is a photo-voltaic system?
Essentially, photo-voltaic means harnessing the power of the sun and converting it into electricity that can be used to power your home. The system can be independent or work in conjunction with your existing electricity supply. It consists of the following components:
- Solar panels
- An inverter (which converts direct current (DC) power from the solar panels into alternating current (AC) for powering appliances
- Batteries to store electricity which is not used immediately (these are for when the sun isn’t shining)
While there are currently no incentives offered to homeowners who install such a system, this may change in the future. And it may be possible that local councils will purchase electricity back from homeowners as more people install these systems in their homes. In other words, installing a photo-voltaic system in your home will not just save you money, but earn you money too.
What do you need and how does it work?
These are the main components of any photo-voltaic system:
The solar panels are made up of a series of cells that convert the power of the sun into electricity you can use in your home. They are often installed on the roof where they can capture the most sunlight during daylight hours. They are made from semi-conductor materials such as silicon. When light strikes the surface of the panel, the energy penetrates the cells and dislodges electrons from the material’s surface. Chemicals added to the surface of the panel help to create a path for the electrons to travel down. And this is what creates an electrical current.
- DC-AC inverter: This device converts the electrical current into one that can be used to power the appliances in your home.
- Solar storage batteries: Considering our sunny climate it is possible to generate more electricity than you need during the day. In this case, batteries can be used to store the excess electricity generated, ensuring that you have an uninterrupted and constant supply of power whenever you need it.
- Charge controller/regulator: These prevent excessive discharge or overcharging which may damage the storage battery.
The system is a simple but effective way on powering your home for free. But there are two different systems, each with its own advantages and disadvantages.
Types of Solar Power Systems
Either of these systems is suitable for the home or office. Which one you chose will depend on your needs. They are:
The stand-alone solar power system
This system only consists of two components: the solar panels and the DC/AC converter. It’s a popular choice for powering ventilation fans, water pumps and with small circulation pumps with solar water heating systems.
Because it doesn’t include batteries, there is no way to store the power generated for use when there is no direct sunlight. So it’s worth considering adding batteries to your solar panel that will allow you to store energy for use during periods of insufficient sunlight.
The grid-connected hybrid power system
This kind of system works hand-in-hand with your regular supply of grid power. Because the inverter changes the current of the photo-voltaic solar panels from DC to AC, the electricity is consistent with the voltage and power quality requirements of the grid. Therefore the self-generated electricity is automatically either supplied to the home, the batteries or the grid.
When it generates more electricity than the home needs, and the batteries are fully loaded, the system feeds power back into the grid. It also means that you will still have a supply of power, from the batteries to your home when your panels aren’t producing power due to lack of sunlight, or if it has been disabled to carry out repairs or is being serviced, in which case it either draws power from the batteries or the grid; based on the lower threshold of the batteries, or which part of the system is being repaired or serviced.
The automation ensures optimal use of the self-generated and grid electricity of the hybrid system.
Determining the size of the system you require
A photo-voltaic system can be pricey, but it doesn’t have to break your budget. The first step in determining whether the long term savings it offers are worth it, is to figure out how much energy you need to run your home comfortably. This is how you should go about it:
- Make a list of all the electrical appliances you use, how many watts they need to work and how many hours you use them every day.
- Now multiply the number of watts by hours of use to get the total needed for each appliance.
- Add these figures together and you’ll have the total number of watts your system needs to generate on a daily basis.
- Work out how many hours of daylight you get every day.
- Finally, divide the total watts you require by the number of daylight hours and you’ll have a figure that indicates how many watts your system needs to produce on a daily basis.
Let’s use your TV as an example. Say you watch about 2 hours of TV every evening, and it uses about 14 Watts, multiply that by 2 and you end up with 28 Watts to run your TV. You’ll need to do this calculation for every appliance in your home.
And let’s say that you work out your home needs an average of 3000 Watts a day to keep all these appliances working. If you get an average of 4.3 hours of daylight, then divide the 3000 Watts by 4.3 and you’ll need a solar panel system that can deliver at least 698 Watts to power your home without relying on the national grid.
Remember, if you use your solar panels in conjunction with the main grid, you can start small and add more panels as you can afford them. This way you can start reaping the benefits of solar power without spending a large amount of money.
And if you consider how much a photo-voltaic system will save on your monthly electricity bill, it won’t be long before you can afford to increase your system to cope with your demands.
Photo-voltaic Solar Panel Installation
If you don’t have the required technical skills, it is best to leave the installation of your solar panel system to the experts. A company that is properly accredited will be able to install the system correctly and safely.
You have three different options when it comes to installing the solar panels:
- Ground mounted solar panels
- Roof mounted solar panels
- Thin film solar panels
Each method has its advantages and disadvantages. Whether you are buying a green home with this feature or retro-fitting an existing home, you’ll need to consider the cost and practicality of each system before you make a decision. Here is some more information about each kind of installation to help you:
- Ground mounted solar panels
In this case the solar panels are fastened to the ground, and you have a few more options to choose from:
- Static Mounted System:This is the most cost-effective type of installation, provided you have the space for it. The panels are mounted in a position to capture the maximum amount of sunlight.
- Active Solar Tracker:These panels actively track the sun during the day to absorb the maximum amount of sunlight.
- Passive Solar Tracker:This system uses heat from the sun to move a liquid inside the tracker from side to side. So gravity does the work of moving the panels and it eliminates the need for motors, gears and controls. This makes it slightly cheaper than an active solar tracker.
Ground mounted solar panels are ideal if you have a large area of unused land. You can install more panels and enjoy higher savings. And you don’t have to make any changes to rooftop to accommodate the panels.
- Roof mounted solar panels
You can mount photo-voltaic solar panels on just about any kind of roof, although tiled roofs can present a bit of a challenge. The panels are mounted directly on the roof and will not interfere with the aesthetics of your home.
They don’t take up any space on land that you may want to use for other projects and they offer additional protection from the weather and general wear and tear. This increases the value of your property. They’re also faster and easier to install than ground mounted systems.
Although these aren’t more efficient at collecting sunlight than other solar panels, they have some attractive advantages. They are literally glued onto the roof which eliminates the risk of damage to your roof. They’re lighter than other panels too and in very hot climates they tend to work better than conventional panels.
The size of your property, the position of your roof, how much energy you need to generate and the installation costs all need to be taken into consideration. You should also work out how much you’ll save to determine your return on investment. You might be surprised to find that solar panels are not that expensive to install.
The benefits of a photovoltaic system
The energy generated from solar panels is a renewable resource. Unlike coal and gas it will never run out and you’ll enjoy free electricity for at least 25 – 30 years (this is the average lifespan of a solar panel).
Solar panels provide a safe, non-toxic and environmentally friendly form of power for your home. It doesn’t produce any harmful emissions and you’ll never have to suffer the inconvenience of a power blackout again. With the savings it generates, you’ll have more money to spend down the line as the cost of electricity continues to rise.
Light, heat and power have become a part of our modern lives. Without a steady supply of electricity we cannot work, cook, communicate or play. Unfortunately, increasing demand from businesses and individuals is placing a strain on our national grid. Not only can the national supplier not cope with this demand, but it is also forcing the price of electricity up all the time.
There has never been a better time to invest in this green technology. You will quickly recover your initial costs in the form of regular savings on your monthly running costs. And you can always start small and increase the number of panels as you can afford them.