The sun...

...radiates more than 6,000 times the energy requirements of the entire world population, every day. Bosch exploits this energy, and is working on technologies that can guarantee both a secure supply of energy and economic viability, and this in every segment: silicon photovoltaics, organic photovoltaics, and solar thermal systems. 

State-of-the-art, highly sophisticated solar technology

With the acquisition of Ersol Solar Energy AG, Bosch hopes to strengthen its business in the area of renewable energies. Ersol develops, manufactures, and sells wafer-based silicon solar cells, and also manufactures thin-film modules. Worldwide, this photovoltaics company generated sales of 160 million euros in 2007. For 2008, ersol expects its sales to exceed 300 million euros. The company currently employs more than 1,000 associates at three locations.
Around two years ago, Ersol created a second area of specialization when it established Ersol Thin Film GmbH. This Ersol subsidiary produces thin-film modules. In these modules, silicon is vaporized as a gas onto a glass disk, and lasers are then used to cut fine lines into this film for the electric contacts. The advantage of this technology lies in the reduced raw material requirements: where the silicon used in wafers is approximately 200 micrometers thick, the thickness in thin-film technology is just 300 nanometers, or around 700 times less. The resulting film is only one-thirtieth the thickness of a bank note. Ersol is extremely proud of its thin-film unit, and operates one of the most modern production facilities of its kind in Europe. The first thin-film systems are already in use, for example in a 500-kilowatt project in Grevenbroich, near Düsseldorf, Germany.

Solar systems with a total power output of 2,300 megawatts were installed around the world in 2007. According to estimates from the European Photovoltaic Industry Association (EPIA), this figure will almost triple to 6,950 megawatts in 2010. In addition, solar energy will likely become less expensive thanks to more effective production methods and an increasing number of solar systems being manufactured. EPIA experts are confident that “from 2015 onwards, European consumers will find that electricity from a photovoltaic system costs exactly the same as conventionally generated electricity.”

Turning a window into a power plant

The transparent plastic film came with the morning mail, and has now been stuck to the window. People can still see perfectly well out of the window, but it has now become a miniature power plant. The unassuming film is made of a light-sensitive material that can convert solar radiation into electrical power. In the evening, the film becomes a light source, illuminating the interior of the house.
Science fiction? Not quite. The Bosch Group, the chemicals group BASF in Ludwigshafen, and Heliatek GmbH in Dresden have agreed to work together to make plastic solar cells ready for series production. In a few years’ time, the alliance hopes to be able to launch organic photovoltaics on the market at a price that can compete with conventional energy sources. While today’s conventional solar cells still cost around 350 euros per square meter, the aim is to bring the cost of organic photovoltaics down to less than 100 euros for the same output.

”With organic photovoltaics, we want to bring the company one step closer to our vision of a building that is self-sufficient in its energy needs,” says Siegfried Dais, deputy chairman of the board of management at Bosch. One major challenge still remains: how to make energy available at night that was generated with photovoltaics during the day. Suitable storage units are still not available. However, a first milestone has already been reached: a building that delivers the same amount of energy as it temporarily consumes from external sources. Some components of this system, such as solar thermal or wood pellet heating systems, are already part of the Bosch product range.

Cleaner heat with solar thermal systems

After wind power, solar thermal systems are the renewable energy source that make the greatest contribution to meeting worldwide energy needs. They emit no CO2 during operation. To meet the hot water requirements of a four-person household, all that is needed is two collectors, each with a surface area of around two square meters.
In 2006, Bosch Thermotechnology launched a new generation of efficient collectors that are particularly lightweight and easy to assemble and recycle. When combined with state-of-the-art condensing technology, these environmentally friendly solar thermal systems are also economical to run: for example, replacing an old system with one comprising a condensing boiler and solar collectors for water heating/heating support can cut energy costs for a household in Germany by up to 1,000 euros a year. Solar inside, a patented control unit for optimizing solar energy systems, also helps to reduce the energy needed to heat water by as much as 15 percent.

The market for solar collectors is expanding rapidly. In 2007, the global sales volume was 1.3 billion euros, and by 2014 this is expected to increase to 2.6 billion euros. Bosch is preparing to meet the increased demand by expanding its production: Bosch Thermotechnology is strengthening its Renewable Energies operating unit by expanding its manufacturing capacity in Wettringen, and by increasing total solar heating production to 350,000 collectors worldwide. Since each collector has an area of approximately 2.4 square meters, this is the equivalent of a total area of around 800,000 square meters per year. In 2007, Bosch Thermotechnology generated 12 percent of its sales with systems that use renewable energies. By 2015, this share is expected to grow to 30 percent.