What do we burn?
The power plant of Pécs generates energy mostly by burning wood and straw. 35% of the biomass of the wood-fired unit is firewood coming from state forestries in Baranya and Somogy Counties, while a smaller portion is from smaller private forests. Woodchip made of forest waste and woodworking by-products delivered in different forms provide 31 and 23% each. 11% of the fuel originates from the agriculture.
100% of the biomass, burned by the straw-fired unit comes from the agriculture.
From the forestries only wood material not suitable for any other type of utilization – for example in the furniture sector is used to produce energy. A determining factor of wood utilization is the quality of the wood, i.e. what wood faults can be detected on it. Wood fault is any deviation from the shape, structure or colour typical to the given wood species.
There are several misconceptions about the utilization of forest-based raw materials in the energy sector. It is often quoted that because of the agreements between the forestries and Pannonpower, the forestries “cut down the woods of Mecsek Hills”. The obviously exaggerated opinion that the woods of Baranya County will be burnt in the boilers of the power plant is also widespread. The truth is however that there are extremely strict requirements concerning loggable volumes for forestry companies holding certificates from the Forest Stewardship Council (i.e. companies who can prove that they practice sustainable forest management). Moreover, it is the essential interest of the owners of forests to sell to the power plant wood material which is not suitable to be sold at a higher price for some other type of utilization, e.g. in the furniture or construction sector. So the power plant receives only types of wood which would be sold as firewood anyhow.
Pannonpower was one of the first to start its own biomass plantation in Hungary. Our company decided in 2004 to establish a mainly poplar-based energy plantation: this pilot project was launched in a 45 hectare area. The surface of energy plantations has since increased ten times and their expansion continues. The energy plantations provide yield already in the second year after planting which suits the fuel demand of the power plant.
Energy crops can easily be harvested with the machinery already used in the agriculture (or with their minimal alteration), thus their cultivation can be launched without special equipment or significant investments. Due to the maximum two-year rotation period the investment is returned relatively rapidly. The 20-30 t/ha/year yield is considered rather good. The experience gained in the pilot plantation shows that the energy crop is resistant to diseases and its germination rate is over 95%.
Our results prove that energy crop production is expressly easy, apart from their planting they do not require much care or special harvesting equipment which cannot be used elsewhere. Therefore energy crops may provide a take-off point for the agriculture of the region – since Pannonpower committed itself to biomass-based energy production, they have a reliable purchaser in the region.
The biomass volume producible at present cannot meet the heat demand of a city of 150,000 residents. Pannonpower assuming responsibility for the environment does not count solely on forest raw materials and plantations for energy production therefore in 2008 a decision was made to establish a new 35MW straw-fuelled unit. The erection-construction works of the new unit have already started, and from 2013 the 100% green district heating supply of Pécs will be realized.
Among the biomass raw materials used by the power plant at present the calorific value of straw is the highest. In addition, we were looking for a biomass combustion technology the fuel composition of which was flexible enough to ensure the security of district heat supply. The selected fuel is available within a fairly short distance of the power plant and will, at the same time, provide farmers with a predictable, stable and completely new source of income.
With straw combustion, Pannonpower is opening a market for a “product” for which there has not been any demand until now. Thus it can be a take-off point for local agriculture. The average transportation distance of the fuel to be delivered to the power plant will be 70 km. 80% of the straw fuel will arrive from Somogy, Tolna and Baranya Counties, but there will be deliveries from Bács-Kiskun and Csongrád Counties as well as Croatia, too. The boiler capacity can be covered by less than 3,5% of all the by-products generated in the region.