How many solar PV panels do you need?
So you are interested in going green and choosing solar energy, good! But, how many solar panels do you need to meet your energy demand? Is 1 OK? or do you need more? Let us walk together to understand how many and what type of panels you will need in just 3 simple steps. Alternatively, you can also use our solar panel calculator.
STEP 1: Find your current energy consumption
Start by finding the annual electricity consumption of your house. You can get this from your annual electricity bill that is sent by your energy service provider. Look for ‘Stroomverbruik normaal / dal’ in the bill (refer to the picture below). For a 2-tier consumption system, you must take the sum of normal and dal consumption. To make more accurate estimation of energy consumption it is preferred to take an average of the last 2-3 years.
If you are unable to find the estimate you can take assume it to be 2900 kWh, which is the average energy consumption of a Dutch household.
STEP 2: Calculate the total power of Solar PV system required
The power demand from solar panel installation is calculated from the annual energy consumption of the house (from STEP 1) and the sunshine availability (also known as equivalent sun hours) in the Netherlands. One equivalent sun hour is achieved when a solar PV panel receives solar energy intensity input equivalent to an irradiance of 1000 W/m2 for 1 hour. In the Netherlands, the equivalent sun hours vary from 900 to 1200 hrs per year based on the location and time of the year. So, to take an average, 1000 equivalent sun hours per year is a good approximation for the Netherlands.
Now, using the annual energy consumption and equivalent sun hours we calculate the power supply required from solar PV system.
Power supply required from solar PV system = Annual energy consumption / Equivalent sun hours.
To incorporate the deviations from the optimum angle of panel placement, a multiplicative factor of 1,2 is used to determine the total power of solar PV required.
Total power supply required from solar PV system = 1,2 x Power supply required from solar PV system
This is done as the power production of the panels depends a lot on the optimal positioning of panels. For the Netherlands, the panels placed facing south and tilted at 34°, receive maximum direct sunlight during the year. The optimum placement of panels depends on the orientation, type of the roof and the angle of the roof.
STEP 3: Calculate the number of panels required
Finally, the number of panels can be determined based on the total power of solar PV required (STEP 2) and the peak wattage of the solar PV panels. The peak wattage of different solar PV panels can be seen from the products page. We provide various panels with peak wattage ranging from 335, to 495 wP of brands such as Trina, Hyundai and JA Solar.
Number to solar panels required = Total power supply required from solar PV system / peak wattage of the solar panel
This is a simple way to make a first estimate of the number of panels that you will need. However, it is important to measure the roof area and tilt accurately to position the panels optimally on the roof for optimum energy production. Also, your stoppenkast (fusebox) sets a limit to the size of PV plant that can be installed.
To know more accurately about the panels contact us for a FREE consultation now. Our solar specialised engineers propose the best design for panel placement and our monteurs come to your location to check its feasibility before the installation.