| dc.description.abstract | European Union is in search of identifying international sourcing countries to import biomass for bioenergy purposes, while ensuring sustainability constraints at present but also until 2030. Under the scope of addressing this challenge, Kenya is a case study selected to investigate its biomass potentials that stem from herbaceous, woody and lignocellulosic biomass and subsequently assess their suitability for export to the EU for the time being and by 2030. This goal was realized primarily through an internship conducted in Kenya, where the most promising feedstocks and the counties where these (feedstocks) were present in terms of residues availability were identified and selected for further scrutiny. In fact, the selected counties were used as case studies in order to determine domestic demand and other important parameters (e.g. farming practices, technological adoption) which were in turn applied to the remainder counties where the selected feedstocks were being produced. Thus, regarding the present situation in Kenya the technical, the sustainable and finally the sustainable feedstock surplus potential for each feedstock was estimated on a county level and subsequently summed up to reach conclusions regarding Kenya's total biomass potential. Accordingly, the costs and GHG emissions induced throughout the entire biomass supply chain were assessed and a discussion on the share of the national sustainable feedstock surplus potential meeting sustainability criteria was provided. With the view to estimating possible future ranges of the total sustainable feedstock surplus potential in Kenya two scenarios (BAU and Optimistic) were devised providing a sensitivity analysis with a moderate and a more optimistic situation under different assumptions for 2020 and 2030.
Timber sawdust and off-cuts & chips, coconut husk, sugarcane residues, sisal bogas & ball, rice husk & straw, coffee husk & pulp were the feedstocks identified for further analysis.
The analysis of the data of this research led to the conclusion that the total available biomass potential emanating from herbaceous and woody biomass, when considering domestic demand and sustainability constraints, ranges between:
• 30 to 60 PJ → In a short term;
• 33 to 93 PJ → In a medium term.
No biomass potential from energy crops cultivation was found to contribute to the final results. Subsequently, through a cost and a GHG emissions analysis the entire amount of biomass delivered to the main port for exportation at present was estimated at 9 €/GJ and 6 kg CO2/GJ, while for 2020 and 2030 the respective total amount under the two scenarios will deliver 7 €/GJ, and more than 90 per cent at 5 kg CO2/GJ.
With regard to land availability for energy crops cultivation, due to the woody biomass deficit (10.3 million m3), the high pressure on land use from the agriculture and the livestock sector, and the inaccessibility of the remote arid areas no potential was found. This situation was predicted to remain the same until 2030 due to unfavorable trends of key parameters related to land availability, such as food demand (75 per cent increase by 2030), maize yield (58 per cent decrease by 2030), woody biomass deficit (24 per cent increase by 2030) and livestock nutritional needs (150 per cent by 2030). The most determinant competing uses of the residues among the ones identified were found to be those for fertilizing applications and household domestic needs (fencing, firewood), where in the cases of sisal bogas and off-cuts & chips 100 per cent were used respectively. Subsequently, sugarcane stalks & leaves and bagasse were found to be the most significant sources of solid biomass in Kenya, seeing that they account for more than 70 per cent of the total technical biomass potential at present, implying a strong interdependence between the sugarcane sub sector and the national sustainable feedstock surplus. This is also indicated through the identification of the biomass supply costs and GHG emissions; currently, more than 90 per cent of sugarcane residues are not available due to the lack of access to a freight station in close proximity (<300 km). In fact, only 10 PJ of sustainable feedstock surplus are feasible to be presently delivered. However, in the short and medium term a number of parameters significantly affecting the present condition were taken into account. Namely, through the opening of the Kisumu freight station by 2020 the entire sugarcane residues volumes will become available. As a result, the final biomass supplied to the main port of Mombasa for exportation in 2020 and 2030 may rise from 10 PJ at present to 25 PJ and 27 PJ respectively, under a BAU scenario and delivered at 4 €/GJ and 5 kg CO2eq/GJ for about 80 per cent of the total sustainable feedstock surplus. Accordingly, in an optimal case through more positive vigorous changes on the same parameters (crop yields and timber supply) coupled with assumed annual harvested areas expansions, reduced logistic (train costs from 0.16 to 0.02 €/km) and fertilizer costs (30 per cent reduction), the total net biomass available at the main port may increase from the 10 PJ to 55 and 87 PJ in 2020 and 2030 correspondingly and 80 per cent of these amounts delivered at 5 and 4 €/GJ and 5 and 4 kg CO2eq/GJ for the same timelines in that order. In both scenarios additional parameters causing these changes are also the assumed pre-treatment facilities through which bulk and energy densities of the investigated feedstocks are increased. These result in lower logistic costs and GHGs emissions released throughout the biomass supply chain. The shares of sustainable feedstock surpluses holding these costs and GHG emissions are possibly available for exportation to the EU when compared with alternative competing fuels (biodiesel and petro-diesel) in terms of costs and emission reduction rates. | |
