Comparison of two perennial energy crops for biomass production at the end of their life cycle

K.D. Giannoulis*, D. Bartzialis, E. Skoufogianni, G. Charvalas and N.G. Danalatos

University of Thessaly, Dept. of Agriculture, Crop Production & Rural Environment, Fytokoy street, GR38446 Volos, Greece
*Correspondence: kyriakos.giannoulis@gmail.com; kgiannoulis@uth.gr

Abstract:

Nowadays fossil fuels are decreasing, causing the world’s interest in renewable energy sources to rapidly grow. One of the most interesting renewable and ecologically pure fuels is biomass, which is considered to be carbon neutral. Biomass is a promising source of energy, as it can be used directly as an energy resource. Its quality characteristics such as gross calorific value and ash content are of paramount importance so as to improve the combustion process. Furthermore, during the last three decades, there has been an increasing interest in the production of biomass pellets for domestic and industrial use. Alternative feed stocks will need to be sourced to meet the demand for biomass pellets. Investigation for new energy crops that produce high amounts of biomass under low inputs and of high energy efficiency are the main tasks of this field. Therefore, the aim of this study is to assess the biomass yield and the quality characteristics (gross calorific value and ash content) of two perennial energy crops (Cynara cardunculus L. and Panicum virgatum L.) growing in a typical soil (Fluventic Xerochrept) of the main agricultural land of central Greece. The comparison for both cultivated crops was made in order to show the results during their 8^th growing year. The examined factors were the irrigation (two levels: irrigated and rainfed) and the nitrogen fertilization (two levels: 0 and 80 kg N ha^-1) as well as their effect on the dry biomass yield and the gross calorific value. It was found that higher dry biomass yield was produced from cardoon (21.3 vs. 14.23 t ha^-1), while the higher average gross calorific value was observed for switchgrass biomass (17.31 vs. 15.65 Mj kg^-1). Finally, multiplying the dry biomass yield (t ha^-1) with the gross calorific value (Mj kg^-1) it was found that 334 and 245 Gj ha^-1 from a cardoon and a switchgrass cultivation could be produced, respectively. Cardoon has better results than switchgrass probably due to the fact that switchgrass is growing from March till October; while cardoon’s growing period is from October to June and in such areas precipitation is in shortage during summer months. Both crops could achieve high amounts of energy per hectare and thus their introduction in future land use systems, for an environmentally friendly energy production should be seriously taken into consideration.

Key words:

biomass, cardoon, gross calorific value, switchgrass, yield

Energy crops utilization as an alternative agricultural production

T. Ivanova¹, А. Muntean², V. Titei³, B. Havrland¹ and M. Kolarikova¹,*

¹Czech University of Life Sciences Prague, Kamycka 129, CZ16521 Prague 6, Czech Republic; *Correspondence: kolarikova@ftz.czu.cz
²The State Agrarian University of Moldova, Mirceşti 42, Chișinău 2049, Republic of Moldova 3Botanical Garden of the Academy of Sciences of Moldova, Padurii 18, Chisinau 2002, Republic of Moldova

Abstract:

Nowadays an increasing attention is given to the production and use of solid biofuels as an alternative to traditional fossil fuels. The common raw material for the production of solid biofuels is a biomass of vegetal origin, which is mainly represented by waste and secondary agricultural products as well as forest or wood residues. Unfortunately, these types of materials do not always meet the quality requirements for the production of biofuels in the form of pellets and briquettes. This is primarily due to the fact that much of the agricultural wastes have low calorific value, high ash content, low density, etc. and at the end all these facts also negatively affects the price of biofuels. In addition, an intensive use of agricultural waste as a raw material for the purpose of biofuels’ production could have a negative impact on soil fertility. Based on abovementioned disadvantages of agricultural biomass, there is a big potential in utilization of alternative biomass such as energy crops. Several energy crops from the same biological family Asteraceae were selected for the research purposes. The main focus of this article is evaluation and comparison of the main solid biofuels’ properties, which were measured according to European and International standards. Assessment of an energy potential of selected crops for the Republic of Moldova is presented here as well.

Key words: