Dr. Karl Tragl: Energy-efficient production as a competitive factor

Without energy available any time for our modern necessities of life, the world would not stand still, but it would be unrecog­nis­­able. We need it for travel, warmth, light, to prepare meals and drinks, to commu­nicate worldwide, to produce and transport products and services. How much energy that consumes depends on the efficiency of its use.


The supply of energy is not unlimited, it generates costs, and its production has an impact on our environment. As a re­­sult, energy efficiency has become a strong competitive factor round the globe, and its significance will further increase in the future. Besides performance, price, quality and design, the carbon footprint – the amount of carbon dioxide (CO2) that is generated during the manufacture and distribution of products – is gaining in importance in the buying decision. Above all, however, energy has become one of the key cost factors in a modern industrial environment. Energy manage­ment and decreased energy consumption are, thus, gaining in importance for companies. In order to survive the com­­petition, they must significantly reduce their CO2 emissions. This presupposes increased energy efficiency all along the entire added-value chain.

Bosch Rexroth AG – a worldwide leading supplier for mobile work machines, industrial applications and renewable energies – addresses the topic in two ways. For one, the company has committed to reduce carbon dioxide emissions in all factories worldwide by 20 per cent by 2020. For a very broad product line, the global player utilises a large range of production processes in over 30 production sites: from foundry engi­neering to cutting technology, from circuit board assembly to installation. Simul­ta­­neously, the group devel­­ops inno­­vative automation solutions and products that support machine manufacturers and in­­dustrial users on the path to increased energy efficiency. Those developments are based on the universal Rexroth 4EE system – Rexroth for Energy Efficiency.


The emissions of mobile work machines and utility vehicles can also be reduced.

Four levers for energy efficiency. In Ger­­many, over 100 million machines that are not yet consumption-optimised are in use. There are whole series of energy-efficient automation solutions that are suitable to be applied to ma­­chines already installed. Retrofittable variable-speed pump drives for hydrau­­lic power units, for instance, control the energy supply in accordance with the demand, creating savings po­­ten­­tials of between 30 and 80 per cent in the field and often even improving productivity. Investments are frequently re­­­couped in the first year of operation thanks to high energy savings.

Only an integrated approach enables ma­­chine manufacturers and industrial users to save energy while maintaining produc­tivity without replacing the entire machin­­ery. The energy efficiency specialists at Bosch Rexroth have identified four levers for increased energy efficiency (Rexroth 4EE – for Energy Efficiency) in all ma­­chine types: Efficient Components, Energy on Demand, Energy Recovery, and Energy System Design. They help recognise and utilise all significant savings potentials – from design to operation to modernisation. Efficient Components (with opti­­mised energy conversion efficiency) form the basis. Optimised hydraulic pumps, for example, not only considerably reduce fuel consumption but can also lower the emissions of mobile work machines and utility vehicles. In addition, the energy conversion efficiency can be raised signif­­icantly. Energy on Demand (energy sup­­ply in accordance with demand) reduces unnecessary consumption for all functions through controlled drives.


Examples include situational pressure controls, fre­­quency converters for eco­­nomical speed control, variable-speed pump drives for reduced idle power, and switch­­ing valves for energy shutdown during pauses. Ener­­gy Recovery (rege­ne­ration of braking energy) keeps ener­­­­gy in the system or feeds it back to the power grid. Servo drive con­­trollers, for in­­stance, achieve that by buff­­ering ener­gy, supplying it to other shafts or feed­­­­ing it back into the grid. Energy System Design (software solutions and programmes) provides customers with technology-independent application sup­­port across the entire production process.

Combining its 4EE system with the energy-saving experience gained in its own plants enables Rexroth to offer a well-founded consulting service. Within the scope of optimising an existing installation, Rexroth energy efficiency advisers analyse the ini­­tial situation and identify savings potentials across the entire added-value chain and all machine types. The specialists then extrapolate consumption reduction meas­­ures and support them with profit­abil­ity calculations.


Energy has become one of the key cost factors in the modern industrial environment.

A practical example: at about 300 days of operation per year and a daily operating time of twelve hours, an optimised parcel sorting facility consumes about 23,400 kilowatt hours per year less than before. As a result, the CO2 emissions are re­­duced by over 14 tonnes per year. In order to achieve that, up to 20 drives were com­­bined into one load circuit. A state-of-the art supply unit returns the braking ener­­gy into the supply grid. In doing so, the braking energy is not lost through conver­­sion into heat. Moreover, the electronic control and servo motor being integrated into one compact unit reduces the wiring needs by up to 85 per cent.

Energy efficiency and climate protection are key challenges for the entire ma­­chine and plant construction sector. Quick re­­­sults require an integrated, systematic approach to all of the technologies in the entire added-value chain. Experience shows that it is very well possible to com­­bine climate protection and efficiency. Whether manufacturer or end user – solu­­tions for an increased energy efficiency give innovative companies an obvious head start in the international competition.


dr_karl_tragl_downloadDer Autor studierte Physik und promovierte im Bereich Elektrotechnik. Er war mehrere Jahre für die Siemens AG in München und Congleton (England) tätig. Ab 2001 übernahm er leitende Funk­tionen bei der Bosch Rexroth AG unter anderem als Geschäftsleiter Technik. Seit 2010 ist Dr. Karl Tragl Vorstands­vorsitzender der Bosch Rexroth AG.