Over the past 10 years, house with solar panels on the roofs gone from curiosity to a reality. This technology has been available for decades – cosmonauts used a solar-powered satellites since 1960, and during World War II, passive solar heating system (which converts solar energy into heat instead of electricity) have been used in US homes. The real implementation of active solar power systems as consumer goods was a problem. Active solar energy uses photovoltaic panels to convert sunlight into electricity, and it has traditionally been a very expensive technology.
The advantages of solar energy in residential houses are obvious:
- solar energy is infinite (or at least for the next 5 billion years)
- It provides clean energy
- no greenhouse gas emissions
- can help people save money on electricity bills
But there are factors that should be considered when deciding on using solar energy for your home, and the cost is just one of them.
In this article we will take a look at six most important issues which you need to decide on when considering investing your money in the installation of solar panels. The use of photovoltaic energy is a green solution and potentially very useful step, but it’s not quite as easy as getting your energy from conventional power.
Turning your home into a solar power requires more care than using the regular “old style” power supply, but not too much.
Solar panels have no moving parts. They are part of a complete stationary system. Therefore, as soon as they are installed, there is not much chance that something can go wrong. Practically, the only thing that the home owner has to do is to keep the panels clean. This is an important task, because if there is too much snow, dust and bird droppings on the panels, it can reduce the amount of the sunlight. The accumulation of the dust on the screen can reduce the amount of electricity produced by the system as much as by 7 – 10 percent.
However, it is not necessary to clean the panels once a week. It is absolutely enough just to clean it by watering the panels from a hose from one to four times a year. You don’t need to climb the roof in order to do that. A hose with a nozzle is working fine from the ground. If there is a construction in your area, then you need to clean the panels more frequently to avoid further accumulation of dust building residue.
In addition, from time to time, you will need to check that all parts are in working condition. Also, don’t forget to replace the batteries, but this is one time in a decade.
2. Surroundings and location
Location of your home has a big impact on the solar energy efficiency. This is an obvious problem: If your electric power depends on the sunlight, things like the shade of tall trees and shadows of the buildings would be a huge drawback.
This is a bigger problem than some people think it is. Different panel types work differently in the shadow. While polycrystalline panels can significantly reduce the production of electricity, mono-crystalline panel will stop the production of electricity completely.
Therefore, if you want to build a house with solar batteries, it is necessary to find out whether there is shade on the panels of the roof area during the sunny hours (usually from 10 am to 3 pm) and preferably during all sunny hours. The more hours panels are under the full sunlight, the more effective will be the production of electricity.
To achieve maximum efficiency it may require the complete removal or pruning trees in your backyard. If your house is surrounded by the tall buildings that block the sun from the roof, it would be much more of a serious problem.
Obviously, sunlight plays a key role when it comes to solar energy, and not all regions are equal in this respect. It is important to know how much sunlight reaches the ground in the area where your potential solar house would be located.
What we are talking about here is called insolation – a measure of how much solar radiation falls on the ground in a given area at a given time. It is usually measured in kWh / sq m / day, and it will show you how much sunlight will be available for your solar cells to transform it into electricity. The higher the value of insolation in your area, the more energy each of your panels can generate. The high value of insolation means that you can get more power out of smaller panels. The low value of insolation means that you could end up spending more money on panels to achieve the same power output. Does it mean that you have to build your house with the solar panels in the south-west, not north-west? Not at all. It simply means that you will probably need more panels to achieve the same power output.
Contrary to what most people think, the size of the solar power system has nothing to do with the size of the house. Instead, it is necessary to consider only two parameters:
- insolation, which we have just discussed
- the amount of energy you need
To get a very rough estimate of what kind of system you need in terms of productivity, take a look at your electricity bill and figure out how much kWh are you using per day. The average home uses about 900 kilowatt-hours per month, or about 30 kWh per day. Multiply it by 0.25 and we get 7.5, so we need 7.5 kW system.
A typical solar panel generates 120 watts, or 0.12 kW per day. To generate 7.5 kW, you’ll need about 62 panels. One panel is approximately 142 cm * 64 cm (55.9” * 25.2”), so 62 panels will occupy about 65 square meters or 213’3 ft.
You should also consider how much sun exposure and peak hours of sunlight you get in a day, so may be you’ll need to make some adjustments, if you are using use a rechargeable batteries with your panels. So it’s better to ask professionals for help.
In 1956, the solar panels cost was about $300 per watt, so 7.5 kW system was affordable only for people with very high income.
Today the prices have dropped significantly. In most areas, the electricity from solar panels cost about $3-5 per watt. You will pay closer to $3, if you install it yourself, and about $5, if you have a professionals do it. For panels of 7.5 kW or 7,500 watts, you will pay anywhere from $ 22,500 to $ 37,500 dollars.
If you need less power, the number becomes lower. If you only consume 600 kWh per month, or 20 kW / day, you get a system with capacity up to 5 kW., which will cost you close to $15,000.
Certainly, you can provide your home with electricity form solar energy just partially. If you want to invest in solar panels only $10,000, you can supplement the power you get from the network with a 1.5-kilowatt solar system.
Investing five digit numbers in solar panels is not affordable for everybody, so there is an option to rent solar panels. There are no advance payments, homeowners pay a monthly fee for rent of solar panels, and rental company owns them and provides the service.
The life spin of solar panels is 40-50 years, the inverter and controller about 15-20 years, and the batteries, depending on the type and area of usage – 4-10 years.
Although the issue of utilization of solar panels remains open, only 30% of manufacturers take them back for processing.
Nevertheless, demand on waste of solar panels is growing every year. Since the production of rare metals becomes more and more expensive, processing of panels will allow to re-use them.
In addition, there is a secondary market for photo and wind power systems, where the equipment can find further application. SecondSol can serve as an example – it’s an online platform, which is used as a marketplace for used solar modules.