“Our organic solar sail is a world first”

When Rum Route 2022 which will set off from Saint-Malo next October, skipper Marc Guillemot will be at the helm of a boat equipped with a solar sail unprecedented. It incorporates photovoltaic cells soft organics that produce enoughenergy to provide for the daily electrical needs of the racing yacht. This is a world first developed by the French company Heole. This very young shoot founded in 2021, based in Vannes (Basse-Bretagne), develops flexible, light and even translucent if necessary. In addition to the yachting market, Heole also works on fabrics store and tents as well as lighting balloons. Jean-Marc Kubler, associate general manager of Heole, explained to Futura the ins and outs of this innovation, its advantages, and the prospects it opens up.

Futura: What are the flexible organic photovoltaic membranes and fabrics that you manufacture?

Jean-Marc Kubler: Heole defines itself as a builder of energy autonomy for objects in movement or isolated. Our innovation combines three key building blocks: the technology of organic photovoltaic cells (OPV for Organic PhotoVoltaic), their encapsulation in different supports while preserving their properties (flexibility, lightness, translucency), the extraction of the current produced to supply the electric circuit of the object.

Futura: What is the difference between a membrane and a solar blanket?

Jean-Marc Kubler: A membrane refers to the technology sailboats use to make translucent sails. We are developing the same type of materials for tent fabrics and airships using different characteristics.

Futura: You talk about an organic technology. What is it about ?

Jean-Marc Kubler: OPVs consist of a layer of polymer of 150 microns which converts light energy into electrical energy. It is caught between two flexible films of PET. Compared to photovoltaic panels in siliconthe characteristics are remarkable from the point of view of lightness, flexibility and transparency. For example, the translucency makes it possible to install devices vertically, in the sail of the boat, and to capture the light on both sides. We are then much less dependent on the orientation of the solar panels for navigation.

Futura: You explain that OPVs have a much better life cycle analysis than silicon. Can you clarify that for us?

Jean-Marc Kubler: The life cycle analysis is expressed in grams of carbon per kilowatt-hour produced. A hydroelectric plant releases 5 g of carbon per kWh, OPV cells between 5 and 15 g, nuclear 55 g and silicon 65 g. OPVs are therefore between 5 and 10 times less polluting than silicon.

Futura: In this case, why does silicon still hold the rope in the development of photovoltaics?

Jean-Marc Kubler: The production power of silicon is of the order of 200 watts peak per square meter whereas OPV is marketed at around 40 watts/m². But the peak watt is measured under optimal sunshine conditions of 1,000 watts/m², with panels placed orthogonally to the rays of the Sun. In the ideal scenario, we have a production of 200 watts/m². The OPV has the advantage of working with diffused light, and even when there is not much light. It makes a huge difference.

Futura: What are the advantages of your technology compared to conventional photovoltaic panels?

Jean-Marc Kubler: We compared the production of electricity between silicon and OPV over a day of navigation, with the cells oriented in the same position. As a result, OPV produces two to three more watt hours per day than silicon.

Even when the silicon panels are installed horizontally on the deck of the boat, we have found that the shadows generated on the surfaces significantly impede energy production. On a ship like Energy Observer, which is covered with silicon photovoltaic panels, the rigid Oceanwings wings cast shadows that lead to less than optimal operation. OPVs make it possible to optimize energy production much more efficiently.

Futura: Your first concrete application is a solar sail intended for Marc Guillemot’s racing yacht for the next Rum Route. What energy autonomy does this sail bring to the boat?

Jean-Marc Kubler: The mainsail that we designed for Marc Guillemot’s boat incorporates 12 m² of photovoltaic cells which make it possible to produce the kilowatt of electricity needed daily to supply the pilot, the lighting, the fridge and computers. We have not changed anything in the equipment of the boat in matter of battery. We use the original installation.

Futura: How fast is the yield of OPV cells progressing?

Jean-Marc Kubler: OPV technology follows a growth law similar to that of semiconductors or some LEDs. This year, we should see the first commercial products at 80 watts/m², or 8% efficiency, arrive on the market. With our current sail, we will no longer be able to produce one, but two kilowatts. This law of growth operates a doubling of the yield every three years. It is accompanied by a division by ten of manufacturing costs over ten years. You understand that the prospects of this process are absolutely fantastic.

Futura: Why did you choose boating to start developing your technology?

Jean-Marc Kubler: Sailing racing is similar to Formula One, in that it represents a formidable test bed. We experience the resistance to the corrosionrain, sea water… So we know that if our sail holds up during the Rum Routeour OPV technology will be very reliable for other applications.

Futura: What capacity and lifespan are you aiming for for your products?

Jean-Marc Kubler: We are aiming for a duration five years of use on a boat. With the results we are currently obtaining on our sail tests, we are confident of achieving this. She has already done Transat Jacques Vabre 2021 then the whole season racing and it still works. If we talk about the yachting market and take a sailboat of 10 to 12 meters with a mainsail of 60 m² with 40 m² of OPV cells, we can aim for 6 kilowatt hours of energy production . This largely covers the needs on board. We can even consider recharging the batteries for the auxiliary electric motors. Our dream is to see ships leave one day without windhigh sail, to power their engine.

Futura: You say that the Heole photovoltaic cells have no significant impact on the weight of the sail. Can you specify specifically?

Jean-Marc Kubler: We are on a overweight 750gsm. But this gain is compensated by the progress made on the materials of the sails which are constantly progressing to be always lighter. I would also point out that our commercial target is recreational sailing where the weight criterion is of much less importance than in competition.

Futura: What are the other potential applications for the general public?

Jean-Marc Kubler: The demonstrators that we are developing this year are fabrics for building awnings, tent fabrics and lighting balloons. With 1 m² of Heole membrane integrated into a blind, we currently manage to supply theLED lighting a 10 m² office for six hours. Today, we are on a yield of 4%. At the end of the year we will be at 8%, in ten years we will be at 20%. With the prospects for yield growth, we will be able to feed a lot more.

Regarding the illuminating balloon, it is an object that captures light and restores it in the form of LED lighting at night. It is installed on pillars to make public lighting, for example in a craft area. We are also targeting the sailing shipping market.

Futura: What is the additional cost of a sail fitted with a Heole membrane?

Jean-Marc Kubler: We are aiming for a price about twice as expensive as a non-solar sail of the same capacity. This delta should be reduced by half or three quarters in the years to come.

Futura: What about OPV recycling?

Jean-Marc Kubler: OPVs are 100% recyclable. The sailmaker with whom we have a partnership for the production of solar sails uses a totally recyclable process.

Futura: How does the boating world react to your innovation?

Jean-Marc Kubler: Very enthusiastic. No noise, no pollution. Yachtsmen are enthusiastic about this technology and the prospects it opens up.

Futura: What deadline are you aiming for for your commercial start-up?

Jean-Marc Kubler: We hope to market pleasure sails from 2023. For the other product families, we expect to have two or three demonstrators by the end of the year.