Calculate how many solar panels are needed for a house
The sun has been shining on Spain’s self-produced energy sector ever since new regulations were approved last April by the Socialist (PSOE) government. Since then, demand for photovoltaic solar panels for homes and businesses has soared.
While a few years ago I had to persuade my clients to install solar panels, now that the news has propagated, they are the ones who demand that their new houses should have a solar system installed.
Local companies say that they are being overwhelmed with demand after a government decree eliminated bureaucratic hurdles and installation prices dropped dramatically.
Last year, 235 megawatts (MW) of new photovoltaic power were added in Spain, and this year the industry expects to see an installed capacity of 400 MW.
Although it is true that most of this extra power is being demanded by small and medium businesses and by the industrial sector, which stand to benefit the most because they can produce and consume energy simultaneously.
For now, households, which typically have 3kW solar power systems, represent around 10% of self-generation from the sun, but it is expected that this figure will rise throughout the year.
The cost of solar systems has dropped by nearly 80%
Now that self-generation is legal and makes economic sense, companies are working round the clock to meet the demand. Gone are the administrative hurdles kept in place for years by right-wing Partido Popular (PP) administrations. And the price of installing solar systems has dropped by nearly 80% in just one decade. Even some local authorities are incentivising self-production with lower property taxes for homes with solar systems.
Companies expect to have installed 1,500 systems by the end of the year, and 5,000 by 2021. These are mostly home systems for stand-alone houses and other installations that do not send excess production back into the grid.
All this encourages people to install a solar energy system, although it can be somewhat complicated to know how to calculate the solar panels needed for your house.
How to do it… simply
In this article we will reveal how to calculate the approximate number of solar panels we need for our home.
It is important to know that if there are any shadows on the panels this may invalidate the exercise. A 10% shadow may turn off the whole system, so please take into account chimneys, aerials etc.
On the one hand, we must know that the PV power that we can install on a roof that is well oriented i.e. South-facing, could provide us with 150Wp/m2. Thus, the two standard panel formats that are found in most systems are those of 72 cells: measuring 2x1m, providing about 320Wp, and the one with 60 cells: measuring 1.6x1m, providing about 280Wp. The truth is that the smaller modules make the best use of the available space.
So let’s say that you require about 5.5KW in your home, you will therefore require about 17 panels of 320Wp or about 20 panels of 280Wp, or about 34m2 of roof space for the first example and 32m2 for the second. Taking into consideration circulation spacers around the panels etc. you would require about 40m2 of roof or terrace for the installation of the panels.
A good reason to install solar panels
Solar panels will reduce the energy you consume and thereby your electricity or gas bills would be less. All this counteracts the different price rises that we have faced in recent years. Due to what we mentioned earlier - being more respectful towards the environment - we are increasingly receiving greater financial support for installing solar panels..
Another advantage to take into account once we have learned how to calculate the necessary amount of photovoltaic solar panels is based on the fact that we will be increasing the value of our house considerably. The truth is that the sun has the advantage of reaching everywhere and therefore, it is very useful for rural areas or farmhouses that do not have access to electricity.
Now that we know how to calculate the number of solar panels required and what advantages of acquiring solar energy, it is time to install them in our house to enjoy a cleaner world and considerable energy savings.