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ABOUT WOOD BIOMASS PLANTATIONSWhy wood ? (burning technology, price/cost, energy-balance, weather resistance)Why wood ?
Coal-operated power plant furnaces have long history in past, its technology is reliable and safe. Its character is the high temperature in boiler, because that is the way to create high pressure and temperature steam , which is the basis of the good procedure efficiency. Luckily, the melting-point of wood-cinder is hardly lower than coal’s, so most of the boilers can be easily converted into a mixed or fully wooden heated one. Furnace producers have wide range of goods in different size and performances with BFB or CFB technology. There is a same situation with smaller heaters, boilers, more producer provide and offer different, converted or new boilers for wood burning. Even a family-hause size sortiment is available, boilers, fireplaces can be run by wooden logs, chips, pellets. To sum up: there can be found good and proved boilers to burn wood.
There is an other story about herbaceous plants, mostly side products of agriculture. Their cinder starts melting on 7-800 degrees C, gets sticky and liquid-like, because of high alkali-metal content. This way the temperature of boiler should be kept lower during burning them to avoid cinder sticking. So burning will not be perfect, efficient. There is an other interesting consequence of this fact, which is even more awkward: alkali-metal is to attack and corrode heat-changers in boilers, so those should be produced with a special covering material. It is not a miracle to realize that there is no available assortment from these boilers. Only one producer can be found on market, but the price of a boiler like that is as high as a full wood operated furnace-plant. On the other hand there is a misbelief to have problems only with inefficient feeding boilers with herbaceous plants, and to make pellets out of stocks would solve this problem. It would solve feeding problems, but still not solve cinder sticking. To sum up: burning herbaceous plants has still problems, needs developing, very expensive, the system is actually not reliable yet. <top>
Bigger users actually pay at least 20 500 HUF+VAT price for an atroton (calculated total dry mass content in wooden stock – ’absolute trocken’) wooden chips coming from biomass plantations. Fuel value of a completely dry wood stock is about 18 Gjoule/at, in essence undependently from tree species and kind, so calculated price of fuel from plantations is about 1 150HUF/GJ +VAT. To compare it would worth noticing the actual price of natural gas is about 3 500 HUF/GJ +VAT on market, which is still going to grow multiplically with higher public demands and decreasing stocks in the next decades.
There is a determining role of an actual estabilishing cost and first year nursing cost in productional efficiency of a new biomass plantation. These plantations can be harvested practically in every other year, so their lifetime lasts for 5-6 harvesting period. Considering the actual prices, 6 atroton/ha/year yield provides profit from plantations. With utilisation of specially breeded clones even 10 atroton/ha/year/ yield can be reached. <top>
There can only be sense in prodution of any kind of energy plant, if energy balance of the complete procedure till end using is reasonable, meaning utilisation of 1 unit energy (incl. machinery cost, used chemical fertilizer, heat and electricity needs during processing, etc.) creates as much as possible unit of an energy at the end.
As a comparison, bioethanol has about 1:1,3 energy balance only, biofuel has about 1:1,6 ratio. It is questionable if there is any reason to use fields with a low efficiency like this, using governmental subsidiaries and tax allowances. In the same time, material from wooden biomass plantations have 1:10-1:16 energy balance ratio according to experiments. One of the consequences of a good energy balance is an independent productional cost from changing prices of convenient energy sources. <top>
Wooden biomass plantations estabilished from well-chosen clones are tolerating weather extremities very well. There could be experienced both extremely dry and very humid or freezing weather in the last decade. As a result of these extremities, agricultural yields decreased dramatically or even perished. Plantations from Alasia New Clones hibryd poplars and GYK Black locust were still growing well under those harsher circumstances. <top>
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