The transition to production solar energy in France should accelerate for businesses and public buildings thanks to the solar plane in 2022. This energy production involves the installation of photovoltaic panels allowing the production of carbon-free solar electric energy.
But what about individuals? With the collapse of solar photovoltaic prices, divided by almost 10 in 10 years, photovoltaics really constitute in 2021 an economical and ecological solution to produce electricity.
The end or the sharp decrease in solar aid has purified the market for companies and craftsmen with long teeth who did not hesitate to overcharge to put premiums and various aids in the pocket to the detriment of the customer and with political complicity. It was not to the benefit of the customer. It is moreover with the end of premiums and reduction in solar aid that market prices have fallen and have become "profitable" naturally. As if by chance ...
Thus in 2021, we can find an installation at an honest price, turnkey between 1 and 1.5 € / Wp. That is to say that a 3 kWp installation should not cost more than 4500 € all inclusive but its real price should rather be around 3000 €. Let's see this in more detail!
What are the elements that make up a photovoltaic solar installation?
To achieve a installation producing solar electricity, you will need at least one solar panel and an inverter or load converter. A photovoltaic production installation will therefore of course include photovoltaic solar panels and needs a suitable inverter at the maximum power of the panels to connect to the network. More rarely, there are hybrid inverters which on the one hand recharge batteries for stand-alone sites and on the other hand convert the energy stored in the batteries into usable electric current.
There are two main types of panels currently on sale: solar panels monocrystalline and polycrystalline. Indeed; the amorphous panels offered for a few years, required much more surface area have almost disappeared from the market. They have a much lower efficiency than monocrystallines since they produce 2 times less energy for the same occupied surface.
Each type of panel has its Strengths and weaknesses which we will discuss a little later in this article. These two types of panels are composed of an aluminum frame, a glass or polymer surface which “encapsulates” silicon photovoltaic solar cells. These are interconnected to produce electricity at a higher voltage. Indeed; a solar cell produces a peak voltage of a few volts, generally around 3V. About ten cells are put in series to reach a nominal voltage in photovoltaic panel output between 35 and 45V. This voltage changes depending on the panel configuration and the type of cell used. A panel generally contains at least 4 rows of cells in series and these 4 rows are mounted in parallel.
When several solar panels are connected in series we speak of a solar thong.
Once the electricity is produced at the level of the solar panels, it must then be routed to the interior of your house. Cables, generally 6mm² in section, will therefore be necessary for your installation to connect the solar string (s) to the inverter . The cables are connected with MC4 type standard connectors which provide ease of installation and guarantee compatibility (if you want, for example, to expand your installation in the future), Security (they are completely waterproof) and longevity, life expectancy. There is 4mm² but generally the use of 6mm² is the norm for small and medium installations. Using 6 mm² allows a good safety margin for heating for most installations in private homes which rarely exceed 5000 W. Indeed; by taking 5 A per mm² and with a nominal voltage of 300 V, they make it possible to produce 9000 W in complete safety. For more powerful installations, it will be necessary to mount strings in parallel or use more inverters.
Electrical incidents remain very rare on the following installations safety standards at the installation.
To be able to use the electricity which is produced in direct current by your panels, it will be necessary to convert to alternating current usable by your electrical devices and the electrical network. This is the role ofphotovoltaic inverter. The role of the inverter is not only to transform direct current into alternating current. To inject into the network, it must also adjust to the frequency of the network and monitor the voltage of the network. It also has various safety functions, for example the installation is grounded via the inverter. Also in case of under or over voltage or network frequency, it goes into safety to protect the network and your installation. Some inverters even have a Wifi function to monitor production from a distance. Obviously its power must be adapted to the power of the solar panels. For large installations, over 10 kWp, several inverters are used, generally one inverter per string.
There are also micro-inverters, that is to say one inverter per panel but we do not recommend this solution because, if it allows to better manage the problem of solar masks, it can present reliability problems because these microinverters are exposed to bad weather and strong temperature variations between summer and winter. It is especially the high temperatures in summer that can be harmful to the electronics, for example, in the event of a heat wave.
Integrated solar installation or installed on the roof?
Whether your installation is carried out on your roof or more rarely on the ground, you will need to provide supports on which your panels are securely fixed. The quality and choice of these supports is important, your panels should not take off at the first storm!
In France in private homes, the panels are generally integrated into the roof for pricing reasons and only policies. That is to say that they replace the roof covering which is therefore removed during the work.
Ceci complicates installation, increases cost and inconvenience. These disadvantages are numerous, let us quote a few: heavier installation work therefore more expensive, risk of leaks because we touch the existing roofing (often in good condition), less production because the panels heat up more, roof to be redone when the panels will be at the end of their life (remember to keep your tiles or other roofing elements somewhere!) ...
The only, small, advantage of an integrated installation is aesthetics and almost zero wind resistance. An integrated installation is only really interesting economically when it is necessary redoing a roof during a major renovation.
Most other European countries do not require integration Unlike France.
Off-grid and on-grid solar installation: how to choose between autonomy and self-consumption? What profitability in 2022 for a photovoltaic installation?
First of all, it is important to remember the characteristics of these two types of installations.
Installation en self-consumption or "on-grid" (on-the-grid = on the network), the home's electrical network remains connected to the electrical network (from Enedis for example in France) and the inverter injects solar production into it. It is possible to consume its solar production directly or to inject it at 100%. In France, there is generally a double meter for tariff and political reasons and solar production is “bought back” by the supplier according to actual solar production. In other countries we have a meter which "turns upside down" and the profitability of the solar installation is made by erasure of the invoice.
In other words, the surplus solar production is injected into the electricity network and when the panels do not or do not produce enough, the network supplies the home. This practice poses "moral" problems for some providers or policies that may decide to tax solar installations at a flat rate as is the case in Belgium with the Prosumer tax, falsely called Tariff Prosumer.
In the case of a real metering of the injected solar electricity, the electricity can be bought back at a contractual rate more or less interesting compared to the real market price. These contracts have changed significantly in recent years and depend on the electricity supplier and the country, inquire precisely before you start.
Also the placement of a solar production meter represents additional costs and administrative procedures for signing the buyback contract.
Installation en autonomy or " off grayd " (off-the-grid or OTG = not on the grid), the solar installation is not connected to the grid and the solar energy can be used directly or stored in batteries. The storage is useful for homes isolated from the network or for example light homes such as a mobile home or a motorhome (all have solar charging today).
But an off-grid installation can very well be installed in a house connected to the network. For example to power a solar pumping system (with or without battery) or lighting at the bottom of the garden. Indeed ; a solar installation can cost less than pulling a cable under the lawn!
The profitability of the off-grid installation will only be electricity savings achieved.
In the case of isolated dwellings, energy will then be stored using a battery system so that it can then be used as needed. This solution will not require any connection to the Enedis network but the energy source is limited to the storage capacity and the power of solar production.
However, each of these solutions has advantages but also drawbacks. The choice will therefore have to be made according to your needs and your projects personal. Thus an isolated house, located far from the Enedis network will be better candidate for an autonomous installation because the connection to the network is the responsibility of the individual ... and this site can cost tens of thousands of euros !
Likewise, if your objective is to have a long-lasting and resistant solution in the event of a cut in the national network, only an autonomous installation will allow you the continuity of energy production, since in self-consumption the production of energy by the panels is stopped in the event of an incident on the network. Fortunately, network cuts are rather rare.
The disadvantages of photovoltaic autonomy are the limited power and stored energy capacity, the limited battery life (count a good ten years in the best case) and the additional cost of the batteries which can double the cost of the installation. Installation which can nevertheless remain interesting when we know the price of a connection of a non-serviced area!
But if you are connected to the network and you have significant power consumption, theself-consumption is the preferred solution. She is more reliable and ensures stable and uninterrupted energy use due to the depletion of the resources produced.
This solution is also the one that allows part of the energy produced to be resold if production exceeds consumption. As said above, bya financial point of view, calculations are to be made on a case-by-case basis. If you are not logged in, a self-consumption installation will result in grid connection costs which may be important depending on your geographic location. There will also be a monthly subscription to plan, see a tax to pay in the event that you resell your surplus energy. In the case of a stand-alone installation, the number of panels necessary for your needs may be larger and energy storage will be expensive and will require regular maintenance with a risk of possible “black-out” during winter periods. In this case, only the backup generator can still have current.
Choose the type of your panels: polycrystalline or monocrystalline?
The photovoltaic panels on the market are currently divided into two main categories.
The first is that of panels polycrystalline. Their solar cells are made up of several silicon crystals, which gives them a "fragmented" appearance and generally bluish color. They are the most affordable but not necessarily the most efficient: their efficiency is between 15 and 17%, so they will take up more space for the same electrical power or provide less power for the same occupied surface.
The second is that of panels monocrystalline The solar cells of these panels are made of a single crystal of silicon, which gives them a darker color which is also More aesthetic for some people. These panels are currently the most produced and it is likely that polycrystalline panels will eventually disappear over time to their advantage. They are more efficient than polycrystalline panels since their efficiency is currently between 20 and 25% for consumer panels. It is between +15 and +65% better than polycrystalline panels. This is significant, for example between 10 polycrystalline panels which occupy 16 m² and 10 monocrystalline panels which occupy the same surface area, it is possible to go from a production of 2,9 kWp to 4,2 kWp.
The available surface being one of the important factor of your solar installation, it will condition the choice of the type of panels. Polycrystalline panels, less expensive in energy produced, are therefore wise if you have a large area. Conversely, if your available surface is small, choose monocrystalline panels.
The choice must also be made according to your budget, your electricity consumption and the orientation of the solar installation. For example, less well oriented panels will have to be monocrystalline in order to compensate for the reduction in brightness.
Each manufacturer or seller of solar panels must be able to provide you with the exact performance of your future panels, as Alma-Solar does on each product sheet. Do not hesitate to make comparisons, as in the table below (in green the best offers, for the site in question according to the criteria of surface area, performance and price):
However, it is important to remember that in practice, the performance of the different panels will not always necessarily be the maximum indicated by the manufacturer. The inclination and orientation of the panel according to the sun and especially the solar masks (shadows) are important criteria to take into account.
Thus the installation of polycrystalline panels on a solar tracker, that is to say a mobile support allowing to vary orientation and inclination according to the brightness, can sometimes be a relevant technical choice provided you know how to support the financial overload and the footprint and aesthetics in your garden of a tracker.
Its power, also limited by the surface area and the trackers require more maintenance, the possible production gain over the year with a tracker is 30%.
Photovoltaic panels and ecology, what about recycling?
When your solar panel reaches the end of its life, two solutions emerge for its recycling. If you do not want to replace your panels, the state requires you to take them directly to a recycling company. However, if you want to install new solar panels after removing the used panels, it is often the installer of the new panels who will then take care of recycling the old ones.
Contrary to popular belief, the photovoltaic solar panel is in largely recyclable and is not very dangerous for the environment. Only a small part of its structure (around 5%) cannot be recycled. In France, it is the organization PV Cycle which is responsible for collecting and organizing the recycling of used solar panels. This recycling is carried out in Veolia factories, directly in France.
The following two videos provide an overview of the existing recycling facilities for photovoltaic panels in France:
It is obvious that these recycling possibilities will have to evolve according to the increase in the number of panels to be recycled, but the sector in France is launched, and gives hope for a positive evolution in this field. On the other hand, the real lifespan of solar panels would most often tend to exceed that announced by the manufacturers, allowing a less regular replacement. A lifespan close to the 40th years would be more likely than that of 20 to 25 years initially announced. Some manufacturers, like I'm Solar, even certify their panels for a 50 year lifespan, while the energy will only increase in the future!
It is today that the solar photovoltaic market has become healthier that it is necessary to invest massively as long as you still have the means ... the coming years, post-Covid, will be the subject of many changes, particularly at the level of energy prices.
Now is the right time to produce green electricity! Why wait ? In a future article, a solar self-installation based on Alma Solar panels will be presented to you.