Vízügyi Közlemények, 2003 (85. évfolyam)

1. füzet - Rövidebb tanulmányok, közlemények, beszámolók

Hullámtéri energiaerdők létesítése 171 The inner floodplain serves for the conveyance of flood flows and ice, when the river overflows the banks, thus it is part of the flood channel. Consequently in this area the first priority is to be given to the safe passage of flood flows. From this the following requirements are specified: — In areas near to the river bank only grasslands (meadows) are allowed. It is forbidden to plant vegetation (such as trees), which would hinder the flood control operations: — In these near-bank areas the some other land uses, such as plough-land cultivation, can also be allowed subject to some restrictions; — In the middle part of the inner floodplain, which are unsuitable for plough-land cultivation due to frequent inundation, extensive meadow and forest cultivation can also be allowed, in harmony with the objectives of nature conservation; — In order to protect the flood-levee against wave action a protective forest belt should be planted. It is to be noted that the protective forest belt is not the same as the other forests and forest plantations of the floodplain. In selecting the trees to be planted in the floodplain an important requirement is that the specie should be resistant to inundation (this does not mean permanent inundation but means that there are some rivers where temporal inundation of the floodplain should be taken into account in nearly every year). In this situation poplar is the tree which should be considered. The lifespan of the plantation is 20 years and the size of the plantation, depending on the machinery, is 0.2-0.21 km

2. It is important to analyse the possible income: — Selling of tree is a difficult task due to the non-established market. The price varies, according to a study of the Centre of Environmental Sciences in the range of 460-800 HUF/GJ. In the calculation of economical options the author used the following Figures: alternative interest rates, -12-16%; depreciation; annual 5%; in terms of tree-falling 3., 4. and 5 years were considered; price alternatives were; 600, 800 and 1000 HUF/GJ (Table II). On the basis of these data the index of the net present value of the plantation was calculated as shown in Table II. Summarising it can be stated that although alternative sources of energy are needed not all technologies are suitable for an economically beneficial investment There are several ways and means of obtaining financial support for the investors. These would facilitate the situation of the investors, but the recovery of invested resources is a requirement from the point of view of the national economy. In the area investigated the planting of vegetation for power generation purposes is theoretically possible. The most suitable tree specie for plantations on the inner-floodplain is the poplar-tree, on the basis of its sprouting efficiency, rapid growth, fuel value and soil requirement. The machinery for making the plantations and harvesting the timber is technically available, although economic operations need areas of several hundreds of hectares The presently non-solved problem, for all renewable energy resources and within this for the biomass production, is the non-existence of the respective market and the non-interestedness of the consumers. The prices shown in Table III indicate that the price of 1000 HUF/GJ, which would assure cost recovery, cannot be achieved in the light of the present prices of fossil fuels. Until there is no need for energy generated by using non-traditional energy resources and until the prices of the latter are not competitive, there will be no chance for making such plantations in an economic way. # * #