frequently
asked questions
Do you have a question about our roof-top wind turbine ?
Find out all our answers to your most frequently asked questions here
topics
Who is your solution for ?
What are the installation criteria ?
Unfortunately, not today !
Installation difficulties : WindBoxe come in sets of 5, for better energy efficiency. This requires a roof of at least 12.5m in length, strong enough to support them: this is rarely the case on individual houses.
Low energy yields : Installation conditions are often not conducive to home installations. Located in dense urban areas, houses are often of the same height, not allowing the winds to accelerate and take off.
Industrialization to come : Today, we are at the beginning of the commercialisation of the WindBox. It is not yet available on the shelf.
Roofs must be flat and at least 12 m long. The roof can be made of concrete or steel. A structural survey is required prior to installation.
All flat-roofed buildings are in principle eligible. However, the output of a WindBox varies significantly depending on the building and the meteorological and urban data of the site.
There are four criteria for maximising output:
- Location in a windy area (refer to Global Wind Atlas to compare locations),
- A minimum height of 8m (the higher the building, the better the results),
- Moderate urban density (in the path of the prevailing winds),
- Good orientation with respect to the majority wind corridors.
Once a building is identified, we carry out studies of the production potential (solar and wind), in order to evaluate the relevance of an installation and its feasibility (in particular the selection of one of the facades).
No ! WindBoxe come in sets of 5 for energy efficiency reasons.
The WindBox is placed on the edge of the best exposed facades. The best orientation on the building is determined by the analysis of the majority wind corridors.
The WindBoxe are supplied “ready to use”. They arrive with their mounting brackets and inverters. They can be weighted down if the structure allows it, or attached directly to the structure and soon to be waterproofed.
The WindBox captures winds at 160°. If the majority axis changes, depending on the season for example, this is lost kWh.
In the majority of the studies conducted (200+), the winds that are lost by choosing the best exposed façade are between 0 and 5m/s. This represents less than 30kWh per year, a small amount of energy.
WIND my ROOF has chosen to do without this small energy gain, which is largely compensated for by a simpler design and installation than a model allowing the recovery of all the wind.
Some areas, with very disparate winds, will be less relevant for our turbines. This is the case of Bordeaux, France, for example. Again, targeting is key: the WindBox is not suitable for all buildings and regions.
This is the principle of decentralised renewable energies: to exploit the best sources locally with simple and efficient means.
The projects start with a series of studies, on the one hand on the production potential, and on the other hand on the building (structural study, electrical connection, etc.).
Once the relevance and technical feasibility have been validated, the design and assembly are launched. The installation involves lifting and electrical connection. A control office validates the installation.
Only a prior declaration before the work is required.
Learn more about WindBoxe
No, today there is only one version of the WindBox.
The WindBox is made of galvanised steel and aluminium.
I am worried about the nuisance...
There is no emergence (0 decibel) at 2 m from the module. Wind turbines rotate at a maximum of two revolutions per second, which is much slower than in the automotive sector, which uses the same type of parts. The wind will therefore be noisier than the WindBox.
Acoustic studies can be carried out on a case-by-case basis on projects.
No !
The WindBox has a visible and permanent shroud, allowing the birds to anticipate the obstacle. The blades rotate from 3 m/s (10.8 km/h), which is more than 60% of the time on average.
As a preventive measure, WindBoxes can be equipped with a safety net to prevent birds from entering the turbine.
Tests at the CSTB in Nantes in 2021 tested the WindBox in continuous winds of up to 180 km/h and down to -15°C. In mainland France, there will be no problems with the system being torn off during storms.
In the French overseas territories, further development is required, particularly with regard to the mounting brackets, before installations can be considered.
Tastes and colours…
A WindBox occupies 4sq.m and is 1m60 high for 350kg (87.5kg/sq.m). On an 8m high building, they will be very little visible, and can be confused with other traditional roof installations (air conditioning for example).
Architectural integration can be carried out on new projects, prior to their construction. On existing projects, work on the colours and the spacing between the WindBoxes can be carried out to better integrate the installation into the building.
Architects, we want to work with you !
What does your thing produce ?
The energy production depends on the wind and solar radiation of the area, the height of the buildings, the orientation of the facades and the urban density of the area. It can range from 0 kWh to 2500 kWh per year per unit. Multiply by the number of units installed.
The challenge is to find the most suitable buildings !
Yes, yes, yes!
Some regions are windier than others: Brittany, Normandy, the Hauts de France and the Rhône Valley are more suitable for our installations. On the other hand, Alsace and the Basque country are not suitable regions. To carry out projects there, you have to aim for very high buildings.
In Europe, the north of Germany, the United Kingdom, the Netherlands, Belgium, southern Italy and the Portuguese coast are all windy areas.
It should be noted that WIND my ROOF is not yet able to export outside Europe.
Coupling the two sources makes it possible to compensate for the seasonal nature of wind and solar power, and thus to smooth out the production curve throughout the year. Indeed, in most cases, wind power is more powerful in winter, solar power in summer.
There are a few exceptions: in the Bouches-du-Rhône region, wind power varies very little according to the season ! The addition of solar simply allows more to be produced in the same space.
In terms of occupied roof space, the WindBox generally produces more per square meter than solar alone:
In a case study in Le Havre, for example, the output of the WindBox is equivalent to 12.25sq.m of solar for 4sq.m occupied. In this windy and moderately sunny region, 4sq.m of wind is equivalent to 8.73sq.m of solar (30° tilt).
On another case study towards Marseille, the production of the WindBox is equivalent to 8.5m² of solar for 4sq.m occupied. Solar is stronger there, and 4sq.m of wind is equivalent to 5.2sq.m of solar (30° tilt).
In general, wind power will also be more suitable for certain regions that lack sunlight: the north of France and Europe in general have a low yield for solar, whereas these regions benefit from an exceptional wind field.
Other regions are neither windy nor sunny (“yes, but in Strasbourg we have a great Christmas market”)… We don’t have a solution yet, sorry !
It’s true that to make a nuclear reactor you need 500,000 WindBoxe in a tropical zone… But we never said that we were going to replace nuclear power plants.
The energy transition is a long and iterative process over several decades. WIND my ROOF aims to provide a complementary, local and renewable solution for buildings that need it.
It is by combining renewable and/or low-carbon sources that we can hope to achieve the objectives of the Paris agreements and the IPCC recommendations.
By the way, we all subscribe to JMJ and Bon pote in the team, and we recommend them to you !
Does it pollute?
The WindBox enables the local production of clean electricity, which is less carbon intensive than the European electricity mix.
For its photovoltaic solar panels, WIND my ROOF uses solar panels manufactured in France, whose carbon footprint is estimated at 25.2 g-CO2/kWh. For information, the carbon footprint of solar panels whose origin is outside the European Union is estimated at 43.9 g-CO2/kWh.
For its turbine, an in-house carbon assessment, based on data provided by ADEME, revealed an average carbon footprint of 25 g-CO2/kWh over 20 years, based on a wind turbine production of 1,000 kWh/year. The higher the production, the lower the carbon footprint.
WIND my ROOF is a French company that is committed to producing locally, as close as possible to its customers. Parts are sourced, when possible, from French or European producers. The WindBox is assembled in Saint-Nazaire, France. Since January 2022, WIND my ROOF has been producing its units there in the factories of SIMRA, a subsidiary of SEGULA Technologies.
In total, 75% of the WindBox’s value is produced in France, 9% in Italy. 11% is produced in Asia, as the parts do not exist elsewhere. The aim is to increase the European share.
And is it economically profitable ?
Today, we sell directly. Leasing and third-party investment models are being studied for implementation in the medium term.
For the time being, no. As the solution is new, we want to keep control of the projects that are set up. In the medium term, this will be possible.
The usual model on our projects is self-consumption with the resale of surplus. It is also possible to couple the WindBoxes to a storage system, to recharge appliances or electric vehicles. We are also working on collective self-consumption projects.
Today in France, total resale is not economically interesting: the feed-in tariffs for wind and solar (less than 6c€/kWh) are indeed lower than the cost of electricity for customers (from 8c€/kWh to 17c€/kWh depending on the sector).
The savings on the bill will depend on the production of the installation (hence the importance of good targeting) and the cost of kWh on the site (and its evolution over 20 years). For example, with a unit production of 2,000 kWh per year:
- For an industrial company paying 0.10€/kWh for electricity: 200€ savings per year and per unit;
- For a social landlord who pays €0.17/kWh for electricity: €340 in savings per year and per unit.
This will depend on the projects (production and cost per kWh of customers). The objective is to align with post-industrialisation rooftop solar panels, i.e. a return in 8 to 12 years in France.
Have you thought about...?
While on paper this sounds attractive, our brilliant engineers have looked into it and it is not effectively feasible. To work properly, the WindBox would have to be placed as close as possible to the exhaust, and the excess pressure created in the fan motors would consume as much or more energy than the turbine would produce at the outlet.
You can, but just to look pretty then.
“Nothing is lost, nothing is created: everything is transformed. Antoine Laurent de Lavoisier (1743-1794) anticipated this issue and knew that the aerodynamic drag of a WindBox on the roof of a truck would result in excessive fuel consumption and very poor efficiency.
This would not allow for optimal production.
The last WindBox will be the most efficient because the wind goes where it is easiest to go. The others would be useless. In addition, town planning regulations prevent installations that are too high on roofs, so it would not be possible.
I am not a climate sceptic but...
And you have every right to do so !
However, we are working hard (a lot) to try to find solutions for the transition of buildings, so we ask you to make constructive remarks and to be measured in your comments.