Solar panels, what a difficult subject. When we bought our new house, we knew that the next step to make our house more sustainable would be placing solar panels on the roof. At that moment we hesitated. Why? One of the neighbours had a lot of trouble with leakage after the solar panels were placed on their house, which has the same situation as our house. How do you prevent this? How long does it take to earn the investment back? What kind of implications has it? What are the risks? How do you know if a company which places solar panels is trustworthy? Is it worth investing in solar panels on our Dutch house?

So, a lot of questions. This blog is not complete, but hopefully, it will guide you in your process.

Investigation

Our situation

The first step is checking how much electricity we use in a year. In our case, it is around 2600 kWh for a house holding with 2 adults and 2 kids. That is not so much. You can check your use of electricity at the yearly reckoning from the electricity company. It’s in our lifestyle to be economical in the use of electricity and when we replace a device we normally would buy the most energy-saving one.

Some more details about our situation are: we have a flat, well-insulated roof where solar panels can be laid on and already an extra wall outlet provided including an extra group in our meter cupboard. If your roof is not insulated, first sort this out before you are installing solar panels on your roof.

What are our wishes regarding solar panels on our Dutch house?

Of course, the quality must be good and it needs to generate enough energy for our consumption. Likely, it will increase a bit when the children are getting older. The installation has to be done by professionals, and we want to know who will be responsible in the case of leakage. The colour of the panels doesn’t make a difference, since they need to be installed on a flat roof. So nobody looks at them.

Reliable information

For this blog we used the following resources:

– The governmental organization that is giving an overview of information about making your house and live sustainable is called Milieucentraal. They claim that only scientifically proven information is on their website and that they are independent of commercial parties.

Consumentenbond – an independent consumer organization that tests a lot of consumer goods.

Vereniging Eigen Huis – a non-profit organization for house owners.

Quality marks

Always choose products with a long guarantee period. Because solar panels have an average lifespan of 25 – 30 years. Something you can investigate also is how long a company already produces solar panels.

For the installation: Zonnekeur is an organization that stands for the quality of the installer of solar panels. Maybe worth looking at.

Zongarant is an organization who guarantees the yield of the solar panels for the next ten years.

How do solar panels work?

For now, it is too much to go deep in this subject, so you find a brief summary here. In sunlight there is energy. A solar panel catches the sunlight and transforms this into usable energy. This energy will be transported through electricity cables where an inverter will take care of the needed voltage for the power grid of the house. So you can use the energy for your computer.

Things to know about solar panels in the Netherlands

The most energy will be generated in the summer months. Even in the winter solar panels will generate energy, but less. When the sun is not shining, the light still generates energy. Not every roof is on the right edge for solar panels.

Did you know that May is normally the sunniest month of the year in the Netherlands? With an average of 212 hours of sunshine.

When your roof is not suitable for solar panels, you can join other initiatives. Like solar park Welschap in Eindhoven.

In general, it takes 7 years for the solar panels to be recouped. Maintenance is not included in this calculation.

In the Netherlands, there is a “salderingsregeling”. This regulation says that when you generate more energy than you use at the moment, you can deliver that back to the power grid. In the end, you will be compensated for that by the electricity company which you use. It’s worth researching which electricity company will compensate you the most. In 2023 this regulation will be phased out.

Maybe you can even get a subsidy from the municipality for installing solar panels on your roof. That is not the case in Eindhoven.

And last but not least: You can ask the 21% VAT back on the purchase of the solar panels if placed on your Dutch house.

The solar panel system

1. Solar panels

There are a few types of solar panels, monocrystalline, polycrystalline and thin-film. All with their advantages.

Monocrystalline solar panels

These are the black coloured panels. You can recognize them because they have an aluminium frame. This type is used often because of their colour The efficiency of the solar panels is approximately the same as the polycrystalline blue panels, but they are slightly more expensive.

Polycrystalline solar panels

These are the blue panels. They are slightly cheaper than the monocrystalline ones. But they have generally the same efficiency as the crystalline ones. You can also choose red, purple or bronze but the efficiency is not as high as the blue ones.

Thin fill panels

This type of panels is increasingly used. The advantage of them is that you can bend them and that they are less harmful to the environment in the production phase. Their efficiency is not so good compared with crystalline panels, but they have a lot more possibilities. In some constructions, they are used as canopies, where the panels are used for shade also.

2. Mounting materials

It is obvious that there are materials needed to mount the solar panels. In our case, we have a flat roof. On a flat roof, the optimum is that the solar panels will be located in the south direction and are mounted with an angle of 15 degrees. Also, electrical wire electricity cable is involved and in most situations, there will be an addition to be made on the fuse box.  In your situation, this can be different, of course.

3. Inverter

This device will invert the generated electricity from DC to alternating current.

4. Optimizers

If your roof has some shadow on a certain time a day, it can be wise to install optimizers. They will take care that every panel are not limited in yield by other solar panels.

Calculate the yield of solar panels in the Netherlands

This is a more theoretical subject. A watt peak or Wp is used as an indicator for the efficiency of the solar panels. The efficiency is 0,9 kWh/Wp in a year in the Netherlands, in the optimum situation.

So in our case, we want to have 2700 kWh a year produced by the solar panels on our roof. So we need 2700 kWh / 0,9 kWh/Wp = 3000 Wp of solar panels. The Wp per panel is depending on the size and efficiency of around 300 Wp at the moment. So we need around 10 panels, depending on the kind of panels. Some years the sun will shine more than other years, so this is an estimate.

Installation of the solar panels

If you are an electrical engineer, you can do it yourself. In most cases, it is wise to ask a professional to install the solar panels. There are several reasons for it:

1. Guarantee period. Some companies only give you guarantee when the panels are installed by them.

2. Risk. There is always a risk that your roof will start leaking after installing, or that there is another damage. In most cases the company is responsible.

Maintenance

– Cleaning. The solar panels have a special coating, which is normally enough to clean them with just the normal rain. If the solar panels are getting dirtier, the window cleaner can wash the panels with osmosis water.

– The inverter needs replacement approximately every 10 years.

Offer

We got an offer for solar panels in 2019 and asked a new one in October 2020. Guess what? The difference between the two offers was 20%. But the other surprise was that there would be additional costs involved because our roof is too high to reach normal, due to safety reasons. We chose to accept this offer. Again a step further in the process to live more sustainable.

The costs for a solar system, generating around 2700 kWh a year costs us €4.000,00 including 21% V.A.T. Including installing the panels. The estimate is that we earn this investment back in less than 6  years. So worth the investment.

Conclusion

What a difficult blog to write. The ins- and outs of solar panels in the Netherlands are not that easy. Hopefully, this blog will guide you along the way. But I can imagine that is not enough. Do you need help with understanding the Dutch documents? Or are you searching for advice for making your house more sustainable? Contact us for a free online meeting!

Curious about the writer? Click here.

calculation house

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