MÜMLING - KRAFTWERK
~ A RECENT HISTORY ~
Bernhard O. Voelkelt
Over 400 years ago man first started to use the renewable energy water at the present day location of the Mümling Kraftwerk (the Mümling Power Plant). Originally a small single story building served as a flourmill. As times and technology changed, man adapted the use of the water to better serve his needs.
The value of this historic power plant for the region can perhaps be recognized in the fairy tail “The Silver Mill near Hainstadt”. In this fairy tail, the righteous millers of the Spatmühle saved the life of Count Ludwig Wertheim of Breuberg, who was held hostage by warlords. The ransom was to be a huge sum of silver coins. But, the treasury of the Wertheimers was empty and only a miracle could save the life of the count. This miracle occurred when the Spatmühle produced silver coins instead of the usual ground stone the morning after witches’ night. The count was saved and in gratitude, he lifted the rule of servitude imposed on the millers making them free men.
The run-off area of the river Mümling at this location encompasses 324 square kilometers (about 126 square miles). This surface area provides an annual water run-off averaging 3,3 cubic meters (about 116.6 cubic feet) per second(2). Today, the Mümling Kraftwerk is the largest hydropower plant in the Starkenburg region, a region that includes four counties or the entire Southern part of the state of Hessen. The power plant rests on and supports a precious ten-acre estate rich in biological diversity and home to many rare plant and animal species - some of which are “red listed” like the water bat, the fire salamander, or the king fisher bird. Some of the estate’s majestic trees are over 200 years old and 90 feet tall. They have developed their own eco-systems, offering habitats to woodpeckers, bats and rare ants.
The name Spatmühle (spar mill), which is still used today on maps and as postal address, was given to the mill by Friedrich Kurtz(3), who was involved in the business of mining “Schwerspat” (Barite, BaSO4, heavy spar) near the village of Klein-Umstadt. In 1839 he asked for permission to change the existing mill into a spar mill. His request was granted on February 17th, 1840 and in 1841, he opened the Spatmühle at this location. Even though his horse and oxen drawn wagons needed a half a day to transport the heavy spar to the Spatmühle, the effort was justified because only the river Mümling, in its lower section, harbored enough energy to break and grind the rock.
A rock-grinding mill requires twice the energy of a flower mill. This spar mill had one hammer and seven grinding wheels, which were operated by three undershot driven water wheels. In 1845 the first expansion occurred. Four additional grinding wheels were added. The water wheels were replaced by a coarse cast iron turbine, which still transmitted the power to the machines by means of belts. This type of turbine is generally regarded as the predecessor of today’s modern turbines used in the production of electricity. There were five spar mills between the city of Höchst and the Bavarian border. This one was the largest of them; it even had its own railroad-loading track.
After the era Friedrich Kurtz, ownership of the Spatmühle changed several times until Wilhelm Kurz purchased it in April of 1917. Wilhelm Kurz was a mining engineer from Germany’s coal and steel town Essen. He visited the Odenwald forest frequently to inspect and purchase beech wood shoring timber, which was used in the mines. Not only did he fall in love with the natural beauty of the rolling hills and the pristine environment, he also married a young woman whose family owned the region’s first hydroelectric power plant in the nearby city of Höchst(4). This power plant began operating in 1894, making the city the first in the county to have the amenity of electricity. Unfortunately, this power plant no longer exists today.
The conversion of the Spatmühle to a hydroelectric power plant was the result of a catastrophic flood in the fall of 1918. The wooden spill gate and weir, which directed parts of the river to the mill, was destroyed by the water masses. A young man from the village, who tried in vein to keep the spill gate clear of driftwood, lost his life when he was torn away by the water as the spill gate collapsed under him(5).
Wilhelm Kurz rebuilt the spill gate with massive sandstone quarters. He also decided on a fundamental modernization of the entire facility. He planned to build a modern hydropower plant. He envisioned the hammer and the grinding wheels of his spar mill to be powered by electric motors. This would increase production capacity and the surplus energy could be sold to the surrounding villages, which were still without electricity at that time.
Despite the difficult economic times right after World War I, construction of the power plant progressed well. In the summer of 1919, two horizontally mounted Francis turbines were installed. The renowned manufacturer J.M. Voith of Heidenheim, today it is the multi-national corporation Siemens-Voith Hydro, delivered one turbine with the capacity of 3,3 m3 (116.6 cubic feet) water per second. The second turbine, typically used in single operation during the summer months, had a maximum capacity of 2,2 m3 (77.7 cubic feet) per second. In the early part of 1920, two direct current generators operating at 110 Volts were added on the generator level of the power plant building.
In the Fall of 1920, construction of the power plant was completed. During the day, the generated electricity was used in the spar mill to power the electric motors of the hammer and grinding wheels. In the evening, when the mill’s workday was done, the electricity was routed into the village Hainstadt via cables along the railroad track. In Hainstadt the “Age of Electricity” began on October 15th, 1920 with a big celebration and festivities that lasted all night long – now, that electric light was used to illuminate the streets(6).
The original spar mill existed only four more years. In 1924 a fire destroyed the production hall with all the equipment and parts of the main building. Wilhelm Kurz, who was struck by ill fortune for the second time in only a six-year period, decided not to rebuild the spar mill. For one, he had not recovered financially from building the hydropower plant. Second, the heavy spar, which was primarily used in the production of water-based paints and shipped as far away as Holland, was slowly being replaced by the advancement of oil-based paints. Since Wilhelm Kurz had already recognized the value of electric power, he decided to concentrate his efforts on electrifying the villages of the lower Mümling valley. The four-year-old power plant became the second plant in the county that solely generated electricity, eventually supplying seven villages with electric power. From this time on, the facility only generated electricity for the public grid and for personal use within the estate.
Against the payment of 50 billion Marks, Wilhelm Kurz received a concession on March 9th, 1925 to operate the “Mümling-Electricity-Plant”. This right constitutes a revised edition of the Riparian Right of 1857 and contains all pertinent calculations and documentations about run-off and flood behavior of the river Mümling. This concession is still valid today as an “Old Riparian Right” and cannot be revoked under Germany’s modern laws promoting the production and use of renewable energy. This document is in the possession of the present owner of the power plant. Today, the plants legitimacy also rests on its privileged status under German laws, e.g. the Federal Building Code, the Law for Renewable Energy, and the Federal Environmental Protection Laws.
Wilhelm Kurz’s marriage did not produce any heirs. His maid, Hedwig Graumann, who he adopted as his daughter, inherited the entire estate upon his death. Mrs. Graumann operated the power plant with the help of one of her three sons until 1975. At that time, pending repair work of the canal and the strenuous manual operation of the power plant forced her to shutdown the plant.
In 1981, Dr. Otto Voelkelt of Frankfurt purchased the entire Spatmühle estate. A dentist by profession, Dr. Voelkelt very early realized the value of renewable energy for a sustainable future. With considerable financial effort, he modernized the power plant’s ageing equipment. The 110 Volt direct current generators were replaced with high efficiency 400 Volt alternating current generators; a modern control station was installed - which permits an automatic operation of the power plant; an automatically operated rake was added - which cleans the water of coarse substances on demand; and, the canal received required repairs.
On November 25th, 1981 the revision of the power plant was completed. With the new generators, the plant’s peak electricity production jumped to 142 kW. With an average daily production of 1600 kWh of clean electricity, the plant is capable of producing up to 600.000 kWh of electricity annually. That’s enough electric power to supply 150 households of four people, each using an average of 4000 kWh electricity per year(7). At the present guaranteed rate of reimbursement, regulated by the Renewable Energy Law, of Euro (€) 0.0767 per kWh, the plant generates an annual gross revenue of approximately € 46,000.00.
However, at today’s level of environmental awareness and recognition, the power plant’s principal contributions rest in the public realm.
If a conventional coal or oil operated power plant would be cut back by the Mümling Kraftwerk’s energy production, the earth atmosphere would be spared the emissions of 600,000 kg CO2, about 54,000 kg Sulfur, and about 6,000 kg NOX. According to the World Bank and the International Monetary Fund, this constitutes an annual economic gain for society of $ 600,000.00. This compares with the German study “Comparison of External Costs in the Production of Energy in Relation the Law for Renewable Energy” by Prof. Dr. Hohmeyer of the Flensburg University(8), who concludes the value at about $ 0.50 per kWh.
The value of this hydropower plant to society is even more apparent in it’s immediately recognizable environmental contributions. Before the water reaches the turbines, it must be cleaned from a variety of natural and man-made waste products. Leaves and branches, but foremost urban garbage – car tires, glass bottles, metal containers (some filled with dangerous substances), motor oil canisters, plastics in all forms and shapes, medical refuse like used insulin injectors, and sometimes a carcass of a deceased animal, all have to be removed from the water to avoid damages to the turbines.
The natural waste, like the leaves and small branches can go back into the river. In fact, they are valuable components to the water’s biological qualities. But, what is one to do with the colorful array of man-made garbage? The law has not carefully analyzed this specific situation. The law is very simplistic in asserting that the individual that “holds” the trash is responsible for its disposal in accordance with applicable disposal regulations. Thus leaving this duty entirely in the hands of the power plant operator. Yet, this garbage is not produced by the power plant operator, it is given to him by unknown perpetrators, and he certainly does not want it. Since proper trash disposal is very expensive – especially for sensitive or critical waste, and since the garbage culprit can rarely be determined, there should be a joined effort by the public and the power plant operator to keep the rivers clean.
Clean rivers are a major aspect in the concepts of sustainable development and an important part of the Agenda 21 development goals, agreed to at the Rio de Janeiro Environmental Summit in 1992. Yet, only a few counties and cities recognize this valuable environmental service performed by hydropower plants and offer free pick-up and disposal of the collected waste. It took over ten years, many public appeals, and a permanent exhibit of collected garbage to finally reach such an arrangement for the Mümling Kraftwerk in January of 2002.
When the surplus water runs cascading across the retaining wall of the weir next to the spill gate and when the water runs through the spinning turbines, it is enriched with oxygen. This added oxygen increases the self-cleaning properties of the water. In the summer months, when the water run-off is low and the water temperature increases, this additional oxygen greatly benefits aquatic life(9). It is not without reason that fish seek out the exits of power plants in the summer.
Maintaining a steady water level in the upper portion of the river creates hydraulic pressure against the embankments of the river, thus stabilizing these valuable river zones. Embankments experience less erosion. Therefore, they can develop a lush flora, providing excellent habitats and retreats for a multitude of animals like ducks, the king fisher, cranes, frogs and toads to name only a few. Additionally, the hydraulic pressure also stabilizes the groundwater table in the surrounding meadows in that it reduces the speed by which groundwater enters the riverbed. This protects meadows and agricultural plots from lack of water during the summer.
The power plant is even capable of offering some protection from floods. It safely regulates floods up to a run-off of 42,35 m3 (1495.80 cubic feet) water per second. Lager floods, up to 120 m3 and more (about 4,238 cubic feet) water per second, are designated to exit the river bed about 100 meters above the power plant’s spill gate to enter one of the largest natural flood retention areas in the Mümling valley. This aspect was already desired when the power plant received it’s Riparian Right in order to protect the valuable buildings of the Spatmühle estate, the former railroad line, communities further downstream and the county road – which today is a very important federal highway and major link in and out of the Odenwald forest.
One should think that a facility like the Mümling Kraftwerk, with all its benefits to society, would receive special protection and consideration from the society it serves. Unfortunately, this is not the case.
In 1988 the local branch of the Federal Tax Agency audited the power plant to determine if it was in a position to produce profits within the first five years of operation under the new ownership of Dr. Voelkelt. Because of the local chief auditor’s political affiliation and numerous political posts in the county, in this writer’s opinion, it was probably deliberately overlooked that a power plant of this size needs 10 – 20 years before producing profits. This is what the official tables from the Ministry for Economic Development indicated at a time before more favorable laws were passed that now regulate the reimbursement for grid delivered renewable energy.
Naturally, the Mümling Kraftwerk could not produce a profit during the first five years of operation. The tax agency, however, concluded and declared that Dr. Voelkelt operated this power plant as a hobby and without any intentions to produce a profit. The agency revoked the power plants status as a recognized business and demanded back payment for previously taken deductions.
This decision had severe consequences for the power plant and its owner. Maintenance, small repairs, an already planned modernization of the spill gate, not even the proper disposal of the drift-garbage could be deducted as business expenses. The owner had to pay back all business deductions taken until 1988, an amount equal to approximately $ 450,000.00, thus effectively jeopardizing the power plant’s survival.
When the century flood of Christmas 1993 hit the Spatmühle estate on December 25th, causing a hydraulic ground breakage near the turbine chambers and destroying 120 feet of canal, the owner was in no financial position to pay for an immediate reconstruction. He had not recovered from the unreasonable financial loss sustained through the regional tax agency.
It took six years and a considerable effort and sacrifices by Dr. Voelkelt and his son Bernhard, who joined the effort to save the power plant in October of 1995, before reconstruction of the damaged sections could begin in the spring of 1999. The principal hurdle was the fact that this power plant was not recognized as a business. Most banks refused any loans when they learned about this situation. Finally, a bank that specializes in the financing of environmental projects offered financing at reasonable conditions. In addition the son was able to secure federal subsidies and found a sponsor in the region’s green energy utility company. All together, investments of over $ 700,000 were required to rebuild, overhaul, and modernize the power plant.
On the 30th November 1999 work was completed and the power plant went online again. Since then, the power plant generated over 1400 Megawatt hours, that translates into 1,400,000 kWh, of clean electricity (as of May 2002). This is a significant contribution to the regions efforts to meet the voluntary CO2 reduction goals under the Kyoto Accord and a noticeable contribution towards a sustainable future.
If the tax agency will reverse its political decision and recognize the power station as a valuable and viable business is not yet determined. However, thanks to the son’s political efforts, this power plant now has many sympathizers and supporters. Over 20 newspaper articles were published about the power plant in recent years, assuring that the spotlight remains focused on the largest hydropower plant of the region. In addition, Bernhard Voelkelt is prepared to challenge all adversaries – especially the tax agency – in a European court of law.
Not only the tax agency provides unreasonable and surreal operating parameters for this power plant, but also the county’s own Water Management Association. This association is a semi official body headed by the county supervisor (Landrat) and the mayors of cities along the river with purpose of maintaining the river in accordance with the state and federal water laws.
To protect an illegal cornfield located inside a designated flood area, which is forbidden by state and federal riparian laws, but “officially” tolerated because of the farmer’s political affiliation and his friendship with the mayor, this association built a dam in a critical left turn of the river during the summer of 1996. This turn is located 100 meters above the power plant’s spill gate and constitutes the principal entrance to one of the largest flood retention areas in the entire river valley, as previously mentioned. During floods this dam deflects the approaching waters to the left, directly onto the Spatmühle estate – thus increasing the danger of flood damages to the estate and placing lives in harms way.
This dam is not only in severe conflict with accepted hydrological scientific knowledge10; it also contradicts several paragraphs of state and federal water laws and the fundamentals of the power plants “Old Riparian Right”.
Despite the fact that the riparian right was legally confirmed in 1984 and in 2000, the county supervisor’s institutions, the Water Management Association and the Water Agency, misrepresent this dam as legitimate maintenance work. By doing so, they declare 3000 square meters (3600 square yards) of cornfield as more valuable than the power plant, the buildings of the Spatmühle estate, the safety of a federal highway, a protected wooded wetland area, and the lives of the people living on the estate. Bernhard Voelkelt produced nearly 100-pages of analysis and documentation on this subject, which clearly demonstrates this to be a case of political power abuse.
In comparison with other hydropower plants in the county, the operational parameters for the Mümling Kraftwerk are deplorable. Why? Is it that the laws are not in favor of hydropower? No, is the simple answer. Germany has perhaps the best laws in the world to promote the use of renewable energy. Is it that the people in the region prefer their electricity to be produced in coal, oil, or nuclear power plants? Again, the answer is a simple no. In 1998, Bernhard Voelkelt staged an event at the power plant to gather support for the Mümling Kraftwerk. Out of approximately 450 visitors, 388 individuals indicated their support for this power plant by signing a petition for fair operating parameters.
The reason why this power plant has to struggle for survival under scandalous operating parameters is based solely on regional political interests.
But, the politicians responsible for the conditions, for example the county supervisor and the mayor of Breuberg, should take pride in having three functional hydropower plants within the city’s boundaries - a rare and precious fact. They overlook that combined these three plants produce up to 1.2 million kWh of clean electric power annually. This amounts to about 50% of the entire production of renewable energy in the county! Thus reducing the city’s negative environmental impact balance by 1200 metric tons of CO2, an amount equal to the capacity of 48 fully loaded 18-wheeler trucks.
As long as courageous and spirited individuals are willing to dedicate their energy to keep these hydroelectric power plants operational, the centuries old tradition of using this form of renewable energy will always contribute towards a sustainable future of this region.
The names of the owners might change; the value these power plants represent to society will never change.
Addendum - 2005
Since the beginning of 2005 the Mümling Kraftwerk has once again full status as a recognized business. The wrongfully created dam was removed in 2002. All this is the result of exceptional public education and relations work by Bernhard Voelkelt and the support of major political friends and partners on the regional and federal levels. The power plant enjoys the support of the county and state Green Party. Secretary of State in the Federal Ministry for the Environment and Nuclear Safety, Mr. Rainer Baake, visited the power plant to voice his support in September of 2002. Renewable energy legend Dr. Hermann Scheer, Nobel laureate and principal architect of Germany’s renowned Renewable Energy Act and recognized global leader in renewable energy, became a personal friend of Bernhard Voelkelt and a firm supporter of the power plant.
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