Transition to renewable energy looks to stimulate German economy

Transition to renewable energy looks to stimulate German economy

Technology News |
By eeNews Europe

“Germany has the chance to take the global lead in the shift of a large-scale economy to renewable energy, with numerous advantages in the further development of these technologies and the corresponding creation of jobs. I cannot imagine a more effective, sustainable economic stimulus program than this process,” asserted Prof. Weber.

Fraunhofer President Prof. Hans-Jörg Bullinger commented: “We are perfectly positioned to develop concepts and solutions for a transition to renewable energy. Within the Fraunhofer Energy Alliance alone there are some 2000 scientists from 16 organizations whose work is focused in this sector. They develop system technologies such as power grids and energy storage systems and research new ways to increase energy efficiency. There are also additional teams of scientists from the Building Innovation and Traffic and Transport Alliances, who also devote a significant part of their work to the question of energy.”

“The transition to sustainable energy supplies is one of the greatest challenges of the 21st century,” asserts Prof. Eicke Weber, spokesperson for the Fraunhofer Energy Alliance and Director of the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg. “To keep electricity, heat and transportation prices affordable in the future, we have to use energy more efficiently and devote more research to the development of renewable sources.” Dr. Mario Ragwitz of the ISI, who coordinated the EU study, said: “We must sustain investment in renewable energy. And we must be patient.”

Another study entitled “Vision for a 100 percent renewable energy system,” illustrates how a reliable, affordable and robust energy supply based on renewable sources can be achieved in Germany by the year 2050. “The expansion of renewable energy creates additional costs initially; however, costs should peak in 2015 at a total of about 17 billion Euro. That is only about eight percent of total costs for energy in Germany, and costs will sink again after that. Between 2010 and 2050, overall savings of some 730 billion Euro can be achieved in the electricity and heating sectors alone,” reports Prof. Jürgen Schmid, Director of the Fraunhofer Institute for Wind Energy and Energy System Technology IWES in Kassel, summarizing the results of the study.

Prof. Weber said it is also clear that the costs of renewable energy will fall. He pointed out: “We predict, for example, that the price trend for photovoltaic modules (PV) will continue to follow a price-learning curve in the years ahead.” This trend assumes that the price of PV modules, currently between € 1.50 und € 2.00/Wp (net), could fall below € 1.00/Wp as early as 2016, which would put electricity generation costs in Germany in a range between 11 and 14 cents per kilowatt hour. The prerequisites for this reduction in costs are the further development of production, effective utilization of production capacities through corresponding growth in the global PV market, the continual implementation of technological innovations in production, and minimization of production processes and costs.

“These goals present a significant challenge to the PV industry, but they are attainable with advances in technology,” explained Prof. Weber. Optimizing the costs of supplying power will necessarily lead to a greater percentage of PV in the power mix, according the ISE.

“Photovoltaic energy will not only lower electricity production costs in Germany in the future, while offering the benefits of being both free of emissions and noise pollution, it also makes it possible to decentralize the generation of electricity and decrease grid load. Capacities can also be built up rapidly with minimal impact on nature,” said Prof. Weber.  The minimum percentage for a sensible PV share in the power mix is 14 percent, but in principle researchers at the ISE find a PV ratio of over 30 percent feasible in the medium term.

With a share of 6.4 percent, wind power in Germany holds first place in power production from renewable sources. “Wind power is already relatively inexpensive. Depending on the location, generating electricity with wind costs between 3 and 6 cents per kilowatt hour,” said Jürgen Schmid. In a new study by the German Wind Energy Association (BWE), experts from the IWES have shown that, according to geo-data, about 8 percent of the land area in Germany outside of forests and protected areas is available for use in wind energy generation. Using just 2 percent of the area per state would yield 198 gigawatts of installable output. In purely mathematical terms, then, onshore wind power could contribute about 390 terawatt hours to Germany’s annual energy consumption, which currently lies at about 600 terawatt hours.

The study makes clear that the potential of onshore wind power is by far not yet exhausted. “Currently, there are just 28 gigawatts of installed wind power,” confirmed Dr. Kurt Rohrig, who led the study and summarized the results.  In addition, massive wind farms are to be built offshore, which will generate some 20 to 25 gigawatts, or about 15 percent of Germany’s energy needs by the year 2030, according to targets set by BMU. The first German offshore wind farm, alpha ventus, was completed in 2010 and serves as both a demonstration and research platform. The related BMU research initiative is coordinated by the IWES.

Offshore wind farms present a particularly urgent need for innovation. They have to be designed and constructed to withstand wind, water, salt, UV radiation and waves over their entire life-span of some 20 years. A special offshore test chamber has been developed at the IWES in Bremerhaven that makes it possible for the first time to simultaneously simulate the changing mechanical and climatic stress factors to which the systems are exposed. Components are exposed to salt spray mist, waves, UV light and moisture, while at the same time being bent and stretched. The simulation allows researchers to draw conclusions about the reliability and durability of the systems being tested. In other test facilities for mechanical stress on large-scale rotor blades, static and dynamic tests are performed with millions of load alternations at various amplitudes. The facilities accommodate rotor blades up to 70 meters long. A new facility for blade lengths of up to 90 meters will go into operation on 9 June 2011. “The new site will give us the largest test facilities in Europe for rotor blades used in systems working at outputs of up to around 10 megawatts,” said Prof. Andreas Reuter, Director of the IWES in Bremerhaven.

A decentralized energy supply derived from renewable sources requires a different grid structure than those currently available, which are designed for a few central large-scale power plants. In the future, a large number of solar, wind, and biomass power plants will have to be coordinated so that predictions on their yield and load can be reasonably balanced. Gaps in supply arising from irregularities in the availability of sun and wind must be compensated for with quick intermediate energy supplies and control plants.

“We do not need nuclear power as a transitional technology,” agreed Institute Directors Eicke Weber und Jürgen Schmid. They believe the rapid build-up of renewable sources witnessed in the last years will more likely be impeded by the lack of flexibility of nuclear power plants. Gas-fired combined heat and power systems in combination with storage units and network expansion are more suitable transitional technologies.

Ultimately, it is about making networks more intelligent with a good deal of technical finesse. Experts refer to a smart grid through which the many power generating systems and consumers communicate and match their requirements between themselves in accordance with the availability of wind or sun power. A good deal of research still needs to be done here. Fraunhofer says it is working intensively on the development and implementation of new concepts.

Scientists at the IWES, for example, are participating in the new research project “Kombikraftwerk 2” together with nine other partners in industry and science. The project employs models and field tests to network wind, biogas and solar power systems using modern data and communications technologies, bringing them together to create a virtual unit which functions like a power plant. Researchers hope to demonstrate in detail that complete coverage of our energy needs with renewable energy sources is realistic and that the lights won’t go out even if the wind lies down and sunlight is scarce.

Redox flow batteries, for example, may be well-suited to providing the necessary temporary energy storage. These are large, robust, long-life vanadium flow batteries in which chemical vanadium compounds alternately absorb and discharge electrons across a membrane. Several Fraunhofer institutes are cooperating in the development of these flow batteries. The researchers’ long-term goal is to construct a battery facility with the size of a handball field. It would have a capacity of 20 megawatt hours, sufficient to meet the energy needs of about 2000 homes during a long winter night or a cloudy day. But, they are not quite that far yet. The largest laboratory facilities at the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT in Oberhausen currently produce several kilowatts of power. Researchers hope to reach megawatt levels in about five years.

There is a call, too, for innovative ideas that draw on as yet untapped potential. One possibility would be to use the heat storage capacity of buildings in an intelligent network as passive energy storage via electric heat pumps and intelligent energy meters. Researchers at the ISE are currently investigating the potential for remote storage employing tariff-controlled heat pumps. Yet another possibility involves using the batteries of tomorrow’s electric cars as energy storage devices when they are connected to the power grid.

A further unconventional idea is to use any surplus electricity for the electrolysis of water. The hydrogen derived would be used together with carbon dioxide to produce methane in massive volume that can be put to use to store energy in chemical form or be fed into existing natural gas grids. This would make use of today’s existing natural gas infrastructure and its immense capacity to store energy, while significantly reducing our dependence on imported gas.

All efforts towards sustainable energy must naturally be accompanied by reductions in consumption and improved efficiency. How this might look in practice has been demonstrated by the ISE through its participation in the refurbishment of energy systems in a 16-storey apartment building in Weingarten, a district of Freiburg. Primary energy needs for heating, warm water, ventilation, lighting and household electricity were reduced by 40 percent. In the next two years, ISE scientists will record and analyze the building’s energy consumption under real operating conditions. Results of the study will serve as a model and be taken into account in similar energy system renovation plans.

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