Global Ecological Problems and Issues

However, hydrogen has to be manufactured from fossil fuels, biomas or methane (fossil natural gas or biogas) or produced by breaking water to hydrogen and oxygen with the help of electricity, in a process known as electrolysis. The electricity for electrolysis has to be produced somehow, for instance by burning some of the produced hydrogen in order to produce electricity. A further problem is that the storing of hydrogen also consumes a lot of energy.

For these reasons it is likely that the production and storing of methane will always be cheaper than the production and storing of hydrogen, which the transnational oil companies and car manufacturers are so interested in. Thus it is very likely that methane will be the main fuel of tomorrow's cars, lorries, buses, ships and aeroplanes. It is likely that methane will also play a role in the production of electricity and in the co-production of heat and electricity.

In many industrialized countries most of the production of heat and power is currently based on methane because it is very convenient to use. Unlike the burning of coal, oil or wood the burning of methane does not produce health-threatening small particle emissions.

It has sometimes been claimed that methane has no future as a source of energy because the natural gas deposits are going to be exhausted relatively soon. However, most of the existing fossil fuel reserves can only be utilized in a commercially viable way in the form of methane.

It is currently estimated that the world's oil reserves might amount to 200 billion tons. This, alone, is probably not enough to cause serious climatic destabilization. Unfortunately there is at least 1 000 billion tons of coal that could be utilized by conventional methods (by excavating the coal and brining it to surface as coal). This is five times more than the known oil deposits. However, through a method called underground coal gasification (UCG) even the coal deposits laying very deep under ground can be utilized in an economically feasible way. UCG techniques multiply the commercially available coal deposits to at least 7 000 billion tons. This is the most important threat to climatic stability and the glaciers.

UCG was originally developed in the Soviet Union, in Uzbekistan, in the 1930's. In the 1950's the USA tried to develop a method of UCG that would have used atomic bombs to gasify the coal deposits. It turned out that the gas produced this way would be too radioactive to be used, and the whole programme - known as the Ploughshare programme - was cancelled. However, at least the US, the British and the Australian governments are planning to start major UCG programmes with somewhat more rational technologies. In Australia there already is one company which is selling methane produced by UCG with an economically competitive price.

However, methane can also be produced with the help of bacteria from all kinds of organic waste matter. China and India already have millions of biogas reactors producing cooking energy and gas for lighting for individual households or whole villages. This kind of programmes should be expanded so that all cow dung, human waste, organic household waste, paper waste and crop residues would be used to produce biogas. It is much better to convert for instance the cow dung to biogas instead of burning the dung in the form of a dried cake, because the burning of biogas does not produce harmful particle emissions. Also, composting or burning of cowdung wastes valuable fertilizer by vaporizing the nitrogen into the atmosphere. In the production of biogas all the nutrients remain in the matter that is left at the bottom of the biogas reactor after the gas has been extracted for burning. In other words, biogas reactors should also be seen as small factories of organic fertilizers.

Among the northern countries Sweden has the most ambitious biogas programme. Sweden is producing biogas from municipal waste to fuel cars and municipal heat and power production plants. The final aim is to produce enough biogas to fuel 700 000 cars. Sweden has about eight and a half million people, larger countries could produce much more biogas from their municipal waste.

Besides this biogas can be produced from almost any plant matter, including sea weed, water hyacinths and single-celled algae. Plants growing on water tend to grow with a much faster speed than plants growing on land. For example macrocystis seaweed can grow with the speed of 130 centimeters per day if they are harvested regularly. This means that they can produce enormous amounts of organic biomass per hectare. Some freshwater plants also grow very quickly. Tropical stands of water hyacinths can increase their weight by 25 wet tons or by 800 kilograms of dry matter per day per hectare. Water hyacinths are an excellent raw material for biogas production: each kilogram of dry weight produces about 370 litres of biogas, with an average methane content of 69 per cent and an energy value of 22 000 kJ per cubic metre.

In Jamaica experimental trials growing single-celled algae like chlorella have produced 2.5 megawatts of electricity on 7.5-10 hectares of water tanks. The biomas production of the single-celled algae (many of which can be grown in salty sea water) is 150-200 times more than what willow coppices can produce.

In Brazil fuel alcohol became 25-50 per cent cheaper than benzin after all subsidies for energy production had been removed. The production of fuel alcohol requires better raw materials, more expensive equipment, a more laborious production process and more external energy than the production of biogas. Therefore it should be possible to produce large amounts of biogas with economically competitive prices.

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