Every year around 1.2 million people visit Mainau, the Flower Island, on Lake Constance. What few of them know: nature reigns behind closed doors here as well. The island produces its own environmentally friendly heating by using wood chips instead of oil.
As oil prices rise and rise, Mainau forester Theo Straub feels more and more vindicated - Straub is in charge of wood-produced energy on the island. Ten years ago, there were 19 oil-fired boilers at 16 locations on Mainau. Tankers brought oil over the bridge, crossing Lake Constance and driving through a conservation area.
At the beginning the oil dealers laughed
"We were laughed at by the oil suppliers when we were considering converting to wood", recalls Mainau forester Theo Straub. (Photo: van Bebber)
The aristocratic family and Mainau GmbH decided at that time not to replace the boilers and to bring their energy concept in line with environmental protection. In 1961, Mainau adopted the "Green Charter" – the first and still current environmental manifesto in Germany. The tourist island, ever mindful of its financial costs, thus announced its intention to try and become self-sufficient in terms of energy supply.
The launch was controversial, particularly on the mainland. "We were laughed at by the oil suppliers in the beginning ", says Straub. This mockery was particularly directed at the higher expenditures that would be necessary for the planned mix of combined heat and power stations, fed with natural gas, and a wood-chip heating system. Replacement oil-fired boilers would have cost 2.5 million Deutschmarks, instead of which Mainau invested a whopping five million Deutschmarks. And at that time fuel oil was still clearly cheaper than wood.
The money remains in the regional economy
From autumn to spring 40 percent of the necessary warmth comes from wood chips. (Photo: van Bebber)
But Straub just laughs. Today everyone is talking about exploding oil prices. Instead of counting in litres, today Straub counts in cubic meters: the quantity of the small pellets of chopped wood. A cubic meter costs approximately twelve euros and is stored in the silo on Mainau. It replaces 80 to 85 litres of fuel oil. Further advantages are that the money stays in the region instead of flowing out to the international oil companies, there are no tankers crossing the bridge over the freshwater reservoir Lake Constance, and the environmental balance of the island has been greatly improved.
In the beginning, however, success was not guaranteed, even though the region and the German Environment Foundation worked to promote the project. There were hardly any wood-chip plants on a similar scale. "It was pioneering work", says Straub. When the plant started up in 1997, Straub had to operate it manually throughout the day and night. Today it is fully automatic. The wood power station runs from October through to April when the heating needs on the island are greatest. The palm tree and butterfly houses are major users. Local power stations working on natural gas deliver the main supply of electricity. But from autumn to spring, 40 percent of the heat needed comes from wood chips. Forester Straub burns 1,400 cubic meters of wood during this period.
A cubic meter replaces 80 to 85 litres of fuel oil. (Photo: van Bebber)
The wood originates from the Mainau forests on the mainland, from the greenery cut on the island, or from other suppliers. Straub can use wood for this purpose that could not be sold on the wood market. One positive side effect: Straub has fewer problems than before with the bark beetle since there isn’t as much wood in the forest these days. When trees had to be cut down in Constance to make way for a by-pass, the construction companies were delighted to find a customer for the wood. "In some cases we are even paid to go and collect the wood,” says Straub.
The wood arrives on Mainau from a machine that has chopped it into tiny pieces. It burns at 850 degrees and heats water. The heat is transported over the island through a 2.3-km-long pipe. At the moment, the leftover ash still goes to the dump, but Straub plans to upgrade the plant so that the system will be able to separate the combustion chamber ash from the smoke filter ash. The filter residue contains large amounts of heavy metal because trees store environmental pollutants. However, the remaining ash is an outstanding fertilizer – and it returns to where the energy came from: the forests, meadows and gardens of Mainau, the Flower Island.
fvb – May 2006
© BIOPRO Baden-Württemberg GmbH
Information about wood energy
Mainau’s experiences have become part of wood energy project quality management. Several states in the Federal Republic of Germany, Switzerland and Austria have information about wood power stations (Internet: www.qmholzheizwerke.de). For the past few years now, the wood energy forum has regularly taken place on Mainau where wood power station suppliers are able to present their products and give advice to those who are interested. The next event will take place October 20-22, 2006.
یک شرکت آمریکایی به معرفی اولین دستگاه تأمین سوخت ماشین در خانه پرداخت! این دستگاه شکر و مواد مشابه را به اتانول برای سوخت اتومبیل تبدیل می کند.
