Ademar Pereira Serra, Marlene Estevao Marchetti, Davi Jose Bungenstab, Maria Anita Gongalves da Silva, Rosilene Pereira Serra,

Franklyn Clawdy Nunes Guimaraes, Vanessa Do Amaral Conrad and Henrique Soares de Morais

Additional information is available at the end of the chapter http://dx. doi. org/10.5772/54576

1. Introduction

Approximately 80-90% of fresh biomass composition of plants consists of water, and 10-20% of fresh biomass comprises the dry biomass.

The elemental composition of dry biomass of plants consists above 90% of carbon, hydrogen and oxygen, the remains of nutrition composition is made of other essential nutrients to plants, such as: nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, boron, zinc, iron, manganese, nickel, silicon and other elements uptaken from the environment (Epstein & Bloom, 2006).

The nutritional state of plants influence the dry biomass production. The nutritional deficiency of some essential nutrient prevents the maximum potential productive of plants. According to Serra et al. (2011), the fresh and dry biomass production from medicinal plant Pfaffia glomerata Pedersen (Spreng.) was negatively influenced by nitrogen (N) and phosphorus (P) concentration into the plant, furthermore, the limitation of P in soil generated less growth on plant with less biomass yield and expressed visible N and P nutrition deficiency.

The nutritional diagnose of plants consists on determination of nutrients contents, this determination is made with the comparison of the nutrient content with standard values, and this procedure called by leave diagnose that uses information from chemical analyses of plant tissue. However, there is the visible diagnose that is made with visual observation of nutritional deficiency or excess symptoms.

The visual diagnose can be little practical, because, when the deficiency symptoms show in plants, the plant metabolism has been already damaged and the correction of deficiency can note be taken good benefits on increase of yield or better products quality, besides, the deficiency symptoms is shown in plant when the deficiency is acute (Marshner, 1995).

The tissue analyses has been considered the direct way to evaluation the nutritional state of plants, but, to do this evaluate it is necessary a well specific part from the plant to take this diagnose, this specific part is the leaf tissue that is the most used (Malavolta, 2006; Mourao Filho, 2003; Hallmark & Beverly, 1991; Beaufils, 1973).

The leaf tissue is considered the most important part of the plant where the physiologic activate happens and this tissue shows easily the nutritional disturb. To use the leaf tissue is necessary to have the chemical analyses. Furthermore, to assess the nutritional status there is the need to have leaf standard to sample, this leaf standard depend on the crop that intend to evaluate, but, nowadays there are many information about the most cultivated commercial crops.

The leave diagnose can be a useful tool to assess the nutritional status of plant, but, the procedure to analyse the data must be appropriate. Furthermore, because of natural dynamic of the leaf tissue composition that is strengly influenced by leaf age, maturation stage and interaction among nutrients on uptake and translocation into the plant, if all the damages criteria were not observed the leaf diagnose becomes very difficult to understand and used (Walworth & Sumner, 1987).

The interpretation of nutrients contents in leaf analyses can be made by several methods to assess plant nutritional status. To interpretate results of traditional chemical analyses of plant tissue for the assessment of the nutritional status of plants, the methods of critical level and sufficiency range are used more frequently (Beaufils, 1973; Walworth & Sumner, 1987; Mourao Filho, 2004; Serra et al., 2010a, b; Camacho et a., 2012; Serra et al., 2012).

There are other diagnose systems, such as: Compositional Nutrient Diagnosis (CND) (Parent & Dafir, 1992), plant analysis with standardized scores (PASS) (Baldock & Schulte, 1996), these two methods are less studied then critical level and sufficiency range, but there is CND standard published on Serra et al. (2010a, b) for the West region of Bahia, a state in Brazil and other authors (Parent, 2011; Wairegi and Asten, 2012).

The sufficiency range is the most used method of diagnose, and this method consists on optimum ranges of nutrients concentration to establish the nutritional state of crops, otherwise to use the sufficiency range it is necessary to develop regional calibration that is very expensive.

The Diagnosis and Recommendation Integrated System (DRIS) relate the nutrient contents in dual ratios (N/P, P/N, N/K, K/N…), because of the relation between two nutrients, the problem with the biomass accumulation and reduction of the nutrients concentration in plants with its age is solved (Beaufils, 1973; Walworth & Sumner, 1987; Singh et al., 2000). The use of DRIS on concept of nutritional balance of a plant is becoming an efficient method to assess the nutritional status of plants, this method puts the limitation of nutrients in order of plant demand, enabling the nutritional balance between the nutrient in leaf sample.

Because of several factors that can influence nutrient concentration in plants, Jones (1981) suggests that it is necessary to be critical in relation to reliability of DRIS standard, because in this way the use of leaf diagnose method can be well used.

Two large categories of field agricultural residues can be defined: field crop residues and arboricultural residues. Field crop residuals are the residues that remain in the field after the crops are harvested. Depending upon the crop, the harvesting method and other parameters, field agricultural residues may include various plant part such as stems, branches, leaves, chaff, pits, etc. varying in composition, moisture and energy potential. Arboricultural residues are the residues that remain in the field after farming activities performed during the cultivation of perennial crops (pruning vineyards and trees).

Total quantities of residues were estimated using recent statistical data for the production area for each crop as well as specific coefficients indicating the ratio of residues production to cultivated area.

For each crop i cultivated in region j, the annual energy theoretical potential Erescropi, j is calculated by SYNENERGY Project, based on the following formula [5]:

Erescropi, j,= n, Ai, j,Hi,

ri country specific residue production per cultivated area [t/ha]

Ar, j, cultivated area of crop i in region j [ha]

Hi country specific lower heating value of residue [GJ/t]

Data for crops production and harvested area in 2008 were obtained from the official statistical publications on the entity and state level. The coefficients used to estimate the quantities and the energy potential of agricultural field residues derived from local experts’ estimations and references.

The estimation of the quantities of agricultural residues available for energy production is based on the degree of availability which is different for each crop, varies from year to year and depends on several factors such as:

• the harvesting method,

• the moisture content,

• the demand of agricultural residues for non-energy purposes (cereal straw, for example, is used for animal feeding, animal bedding, etc.),

• the need for some residues to remain on the soil to maintain the level of nutrients (sustainability reasons).

The availability factor for arable crop residues is estimated to be 30%. The same factor for arboricultural residues is estimated to be 80%, mainly due to technical difficulties in collection. Based on these factors, it is estimated that 527.765 t of field crop and
arboricultural residues could be annually exploited for energy purposes (reference year of analysis 2008). This is equivalent to 7,47 PJ or 3,24 % of the total primary energy supply in 2008, which means that crop residues could contribute significantly to the energy supply of Bosnia and Herzegovina. Almost 90% of this potential comes from field crop residues, while arboricultural residues contribute the remainder.

Figures 1 and 2 present the technical potential of the most significant crop residues. Maize residues are the most abundant source of biomass contributing 75% to the field crop residues potential or 68% to the total crop residues potential. Wheat residues share in the field crop residues potential is also significant (17%), while barley, oilseeds, rye and oats residues contribute to a lesser extent. The major part of arboricultural residues comes from plum and apple tree prunings (73%). Other sources of arboricultural residues that should be taken into account are vineyards, pears, cherries, sour cherries and peaches prunings.

□ Maize

□ Wheat

□ Barley

□ Rye

□ Oats

□
Oilseeds

Plums Apples Vineyards Pears Cherries/ Peaches Other

Sourcherries

The crop residues potential in RS is more than twice that in FBiH and Brcko district and amounts to 5,20 PJ. In RS almost 90% of the potential comes from cereals, while this
percentage is somewhat lower in FBiH (83%), where the contribution of arboricultural residues is higher (16%). Oilseed field residues have a minor contribution (1-2%) in both entities.

In the Federation of Bosnia and Herzegovina, 53% of the crop residues potential is found in the cantons of Tuzla (FBiH-K3) and Una-Sana (FBiH-K1). Another 30% of the potential is found in the cantons of Posavina (FBiH-K2) and Zenica-Doboj (FBiH-K4) as well as in the Brcko District.

The changing plant density and availability of sources results, in cereals during the vegetation period and development, in changes of tillers number and size. Both the factors influence the organization of canopy structure. The tillering intensity affects the formation of adventitious roots, thus creating conditions for water and nutrients uptake.

Due to different fertilization scheme, these processes are different in winter wheat and spring barley. In winter wheat, the assessed production parameters were first influenced by different seed rate and later by different N fertilization in the regenerative doses at BBCH 23. In spring barley, N was applied prior to seeding or at the third leaf stage and the first assessment was only carried out at tillering (BBCH 22). At this time, all fertilized variants manifested higher values in all production parameters.

During tillering, the influence of plant density on the total amount of the above-ground biomass and dry matter per m2 decreased and the influence of tillers number increased in both crops. Increasing plant density resulted in increase in stand height and decrease of the average weight and number of tillers per plant.

Due to higher density of stand caused by higher seed rate or higher N dose, the competition in the stand increased, which influenced the variability in plant and tiller size. Higher inter­plant competition was expressed by lower values of the CV for plant weight and number of tiller per plant. On the other hand, intra-plant competition increased the values of CV for tiller weight. These effects were most expressed at BBCH 31 in variants with higher seed rate and N fertilization in both crops.

Canopy management during the vegetative growth should predominantly be focused on the following parameters:

— density of emerged plants,

— intensity of tillering, variability in plant weight (size) and stand height during tillering,

— strong tillers and their uniformity at the beginning of stem elongation.

When considering further developments in Bosnia and Herzegovina’s energy sector, conventional energy wisdom has to be adapted to fit the specific context. Although hydropower will remain the mainstay of the renewable energy sector in the near future, biomass as an energy carrier does have potential on the Bosnia and Herzegovina market.

While the size of the Bosnia and Herzegovina’s market place allows for some economies of scale, its capitalization, the purchasing power and even the monetization of Bosnia and Herzegovina remains low. In the rural areas, the private sector is still underdeveloped, but the human resource base is not limited, and the electricity grid is developed at a sufficient level.

Key barriers that were identified can be summarized (: the development of large-scale bioenergy plantations that can supply sustainable amounts of low-cost biomass feedstocks; the risks involved in designing, building and operating large integrated biomass conversion systems capable of producing bioenergy and biofuels at competitive prices with fossil fuels; and the development of nationwide biomass-to-bioenergy distribution systems that readily allow for consumer access and ease of use [19].

Decentralized renewable energy technologies and markets offer opportunities; but they need support, including targeted policies, capacity building, adequate financial resources to meet high up-front costs, and special effort to link-up with income generation activities. Specific barriers include [20]

1.1. Samples

The seaweed biomass

Many kinds of seaweeds samples (10 species of green algae, 21 species of brown algae and 21 species of red algae) were taken along several coasts in Niigata Prefecture (referred to the figure in our previous paper [32]) since April, 2004. Among seaweed species, the seaweeds for biosorbent used in this work were Sargassum hemiphyllum (brown algae), Ulva pertusa (green algae) and Schizymenia dubyi (red algae). Each seaweed sample was washed in the surrounding seawater to remove attachment at sampling place. After transport back to the laboratory, the seaweed was first washed with tap water and ultrapure water thoroughly and then air-dried for 2-3 days. Afterwards, it was dried overnight in an electric drying oven (Advantec DRA 430DA) at maximum temperature of 55 °C to avoid degradation of the binding sites, the biomass was ground. Sizes of biomass ranging from 0.5 mm to 1 mm were obtained by passing through sieves (SANPO Test Sieves).

Based on Diniz and Volesky’s study [31], each sieved biomass sample was loaded with Ca2+ in a solution of 50 mmol • dm-3 Ca(NO3)2 (biomass concentration of 10 g • dm-3) for 24 h under gentle agitation in order to remove the original cations on seaweed. Later, the biomass was washed with ultrapure water to remove excess Ca2+ until the mixture was reached approximately pH 5. Finally, the washed biomass was dried again overnight at 50°C in an electric drying oven, and stored in desiccators (containing silica gel as a desiccant) before use.

The shell biomass

Buccinum tenuissimum shellfish used for shell biomass were collected at fishermen’s cooperative association. After being separated from the meat by boiling, organism shells were washed thoroughly with ultra-pure water after washed with tap water repeatedly. After drying, the shells were ground and sieved through a sieve (SANPO Test Sieves) to remove particles having size more than 500 pm. Sieved material was used for adsorption experiments. Afterwards, a part of this sieved materials was heated for 6 h at 480°C or 950°C in an electric furnace (ISUZU Muffle Furnace STR-14K, Japan). Moreover, adequate ultrapure water was added to a part of heat-treatment (950°C, 6h) samples, and heated at 100 °C on a hotplate for evaporation to near dryness (removing water), and finally dried in an electric drying oven at 60 °C.

The stand structure depends on initial plant number, available sources and their change during the growing season. The value of obtained information should be adequate to consumed labour. In this respect, a sample size is of great importance. In general, it governs that with the increasing size and number of samples the exactness of results increases, however, labour intensity is also higher. The two problems (labour intensity as well as the value of obtained information) are to be solved, i. e. what information is provided by plant and stem analysis and how to use it.

Classical methods for the assessment of stand structure based on counting plants and stems (spikes) per unit area of the stand are labour consuming and interpretation of results is often difficult. They provide information on plant and stem numbers and/or their size (weight), however, they do not allow assessing the relationships in the stand (inter — and intra-plant competition).

Using a current level of knowledge and novel technologies could enable to make diagnostics of stand state and structure (to assess the amount of produced biomass and its structure) more effective. Based on data published over the last years [20-23], it can be assumed that spectral characteristics and area sensing of stands can be used for this purposes.

Based on the character of processes influencing the stand structure, the growing season of cereals was divided into the three parts:

1. vegetative, including the period from emergence till the end of tillering (BBCH 10-29),

2. generative, including the period of stem elongation and heading (BBCH 30-59),

3. reproductive, including anthesis, grain formation and maturation (BBCH 60-99).

The Diagnosis and Recommendation Integrated System (DRIS) was developed by Beaufils in 1973, this method consist in dual relation between a pair of nutrients (N/P, P/N, N/K, K/N…) instead of the use of sufficiency range or critical level that are called univariate methods, because only the individual concentration of the nutrients in leaf tissue is taken into consideration while no information about the nutritional balance is provided. DRIS enables the evaluation of the nutritional balance of a plant, ranking nutrient levels in relative order, from the most deficient to the most excessive.

With the use of dual relation on DRIS, the problem with the effect of concentration or dilution on the nutrients in plants is solved, because, according to Beaufils (1973); Walworth & Sumner (1987) with the growth of leaf tissue, on one hand the concentration of nitrogen, phosphorus, potassium and sulphur decrease in older plants and the concentration of calcium and magnesium increase in older plants on the other hand. When it is used the DRIS method, where the dual ratio is used, the values remain constant, minimizing the effect of biomass accumulation, that is one of the major problem with sufficiency range and critical level method.

It is feasible to find on literature some crops on which DRIS had already been used to assess the nutritional status of plants, such as; pineapple (Sema et al., 2010), cotton (Silva et al., 2009; Serra et al., 2010a, b; Serra et al., 2012), rice (Guindani et al., 2009), potato (Bailey et al., 2009; Ramakrishna et al., 2009), coffee (Nick, 1998), sugarcane (Elwali & Gascho, 1984; Reis Jr & Monnerat, 2002; Maccray et al., 2010), orange (Mourao Filho et al., 2004), apple (Natchigall et al., 2007a, b), mango (Hundal et al., 2005), corn (Reis Jr, 2002; Urricariet et al., 2004), soybean (Urano et al., 2006, 2007), Eucalyptus (Wadt et al., 1998), among other crops.

According to Baldock & Schulte (1996), there are four advantages of DRIS; (1) the scale of interpretation is continuous numeric scale, and easy to use, (2) put the nutrients in order of the most deficiency to the most excessive, (3) identify cases where the yield of plant is been limited by into factor as nutritional status and (4) the Nutritional Balance Index (NBI) give a result of combined effects of nutrients. Nevertheless, the disadvantage of this methodology is that the DRIS index is not independent, because one nutrient concentration can have hard influence on the other DRIS index for one nutrient but this problem can be corrected in parts with a hard selection of the nutrient that will compound the DRIS norms.

Energy can be derived from livestock manure as long as they are collected in lagoons or large tanks and can be considered feasible only in in-stall livestock systems, excluding therefore sheep and goats from such practices since their breeding is extensive making collection of manure impossible.

Since animal manure is of a high water content, it can be digested anaerobically for the production of biogas, which can be burnt for heat or/and electricity production.

Intensive livestock in Bosnia & Herzegovina consists of cattle, brood sows and poultry farming. According to official statistics there were 378.000 cattle (heads), 276.000 pigs and 11,26m poultry in 2008 [1,2]. The energy potential Eresanimi, j for animal species i in region j was evaluated based on the formula [5]:

Eresanimr,) = prCi. jYiHi

Ci, j number of animal species i nurtured in region j [heads] pi country specific manure generation factor for species i [t/head/yr]

Yi country specific biogas yield [Nm3/t manure]

Hi country specific lower heating value of biogas [GJ/Nm3]

The manure generation factor, the biogas yield and the energy content of the produced biogas of the examined animal species depend on factors such as body size, kind of feed, physiological state (lactating, growing, etc.), and level of nutrition and coefficients regarding the residues produced on average per animal and the biogas yield per ton of produced residues were assumed according to the experts analysis in whole this region [5]. The amount of biogas that could be theoretically produced amounts to 292 million Nm3, which is equivalent to 6,50 PJ In order to estimate the technically available livestock manure and since no further data regarding the regional distribution of animal farms that are of adequate size for biogas production were available, it was assumed that the technical potential of livestock manure would be 20% of its theoretical value, which is now the case for Croatia [5]. The available livestock manure for energy production amount to 1,30 PJ, or 0,56% of the total primary energy supply in the country in 2008 [5].

Residues from cows contribute the largest share to the total potential (50% in total), while poultry has a sizeable share (38%) and pig residues have the lowest share (12%).

Furthermore, in the same Figure it is shown that the potential is higher in the Federation of Bosnia and Herzegovina and Brcko District than in RS.

In FBiH the highest potential is found in the canton of Tuzla (FBiH-K3), which makes 40% of the total potential in FBiH and Brcko District. Furthermore, this canton exhibits the highest poultry residues potential, since 35% of the country’s poultry is farmed there. Another 18% of the FBiH potential is found in the Zenica-Doboj canton (FBiH-K4) and therefore, 58% of the FBiH potential is concentrated in the north-east.

Exploitation of livestock manure for energy production via anaerobic digestion (AD) is considered to be feasible only for medium to large scale livestock units. A feasibility study called ANIWASTE financed by the EC in 2005 has sampled more than 300 farms in the wider region of Banja Luka and Lijevce polje, which is the region with the most intensive cattle raising activities. The average farm in this region has 100 pigs, 10-20 cows and 5.000­10.000 poultry. In general, the sector has passed through a post-war transition period in Bosnia and Herzegovina, which has resulted in small family farms [8].

N. Abdullah and F. Sulaiman

Additional information is available at the end of the chapter http://dx. doi. org/10.5772/55302

1. Introduction

Oil palm is the most important product from Malaysia that has helped to change the scenario of it’s agriculture and economy. Lignocellulosic biomass which is produced from the oil palm industries include oil palm trunks (OPT), oil palm fronds (OPF), empty fruit bunches (EFB) and palm pressed fibres (PPF), palm shells and palm oil mill effluent palm (POME). However, the presence of these oil palm wastes has created a major disposal problem. The fundamental principles of waste management are to minimise and recycle the waste, recover the energy and finally dispose the waste. These principals apply to agro­industrial wastes such as palm oil residues as they do to municipal waste. We can simply no longer afford to dispose the residues when there is an economically useful alternative. We must first consider the current uses and disposal of mill residues in order to address the potential for recovery of energy in the palm oil industry. One of the unique aspects of Malaysian renewable energy sources is that the palm oil mill is self-sufficient in energy, using PPF, EFB and shell as fuel to generate steam in waste-fuel boilers for processing, and power-generation with steam turbines as described in Section 2.2.

World palm oil production in 1990 doubled to 11.0 million tonnes from 5.0 million tonnes in 1980, and by the year 2000, the production doubled to 21.8 million tonnes. Malaysia produced about half of the world palm oil production (10.8 million tonnes), thus, making Malaysia as world’s largest producer and exporter of palm oil during this period [1]. In 2008, even though Malaysia had produced 17.7 million tonnes of palm oil based on 4,500,000 hectares of land used for its plantation, Indonesia became the world’s largest producer and exporter of palm oil, replacing Malaysia as a chief producer [2,3] Palm oil has made impressive and sustained growth in the global market over the past four decades, and it is projected in the period 2016 — 2020, the average annual production of palm oil in Malaysia will reach 15.4 million tonnes [4]. In 1999, the land area under oil palm plantation is about 3.31 million hectares, and it has been projected that Sarawak will have about one million tonnes hectares of oil palm by the year 2010 [5].

© 2013 Abdullah and Sulaiman, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons. org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The oil palm industry has always been linked to the environment because it is a land intensive industry. Any unplanned development will lead to the degradation of the forest systems, loss of habitats including plants and animals, extreme land degradation and pollution (water and airborne) due to the use of large quantities of pesticides and herbicides required to maintain the plantation. The Roundtable for Sustainable Palm Oil (RSPO) was established in recent years with the support from the government and Malaysia Palm Oil Council (MPOC). RSPO consists of palm oil producers, processors, traders, consumer goods manufacturers, retailers and non-governmental organizations (NGOs), and they will develop the principles and criteria of a sustainable palm oil industry, and facilitate the development of sustainable palm oil production. The proposed guidelines include commitment to transparency, compliance with all applicable local, national and ratified international regulations, adoption of sustainable cultivation practices (including water management, pesticide control and soil erosion), conservation of resources and biodiversity and community development [6]. The oil palm industry has long avoided the openings of virgin forest land, which thus minimize environment degradation and enhance the sustainability of oil palm growing. As initiatives, the Ministry of Plantation Industries and Commodities (MPIC) had announced in 2006, the RM20 million Malaysian Palm Oil Conservation Fund (MPOCF) with aims to help protect affected wildlife (including orang utan and other protected species) and to sustain biodiversity conservation programmes that are expected to be beneficial to both the industry and society.

Oil palm is the most important product of Malaysia that has helped to change the scenario of its agriculture and economy. Despite the obvious benefits, oil palm mill also significantly contributes to environmental degradation, both at the input and the output sides of its activities. On the input side, crude palm oil mills use large quantities of water and energy in the production processes, and on the output side, manufacturing processes generate large quantities of solid waste, wastewater and air pollution. The solid wastes may consist of empty fruit bunches (EFB), mesocarp fruit fibers (MF) and palm kernel shells (PKS). The liquid waste is generated from an extraction of palm oil of a wet process in a decanter. This liquid waste combined with the wastes from cooling water and sterilizer is called palm oil mill effluent (POME). During POME digestion, odor released into surrounding air, thus, reduces air quality in the surrounding lagoons area. Disposal of EFB into oil palm plantation without recovering remnant oil in the EFB contributes to oil spills. Incineration of EFB means wasting renewable energy source and heat which actually could be provided for boiler in palm oil mill. At present, PKS and MF wastes are used extensively as fuel for steam production in palm-oil mills. EFB is a resource which has huge potential to be used for power generation, currently not being utilized. The application of shells for road hardening has no impact to the environment, however, current practice is actually wasting potential renewable energy source. Methane gas is one among other green house gases which can cause ozone depletion. However, at present, methane in biogas generates during POME digestion is not being utilized or captured and it just escapes into the atmosphere. Palm oil mill residues are currently underutilised; therefore, maximizing energy recovery from the wastes is desirable for both economic and environmental reasons.

All economic activity begins with physical materials and energy carriers such as fuels and electric power. Without materials, there might be no food and shelter technology; without energy, there might be no work, thus, no economic activity. The reliable sustainable resource is important to fulfill the need of energy. Oil palm waste is a reliable resource because of its availability, continuity and capacity for renewable energy solution. Furthermore, in current situation the presence of oil palm wastes has created a major disposal problem, thus, affect the environmental. The technological, economic, energy balance, and environmental considerations must be kept at a balance to meet the best solution of utilization oil palm wastes. There is abundance of raw materials available of the palm tree consisting of around 90% of biomass wastes and only around 10% of oil. About 90 million tonnes of oil palm fruit production was recorded in 1998; however, 43-45% of this was mill residues in the form of EFB, shell and fibre. Palm fronds and stems are currently underutilised, and the presence of these oil palm wastes has created a major disposal problem. Therefore, maximising energy recovery from the wastes is desirable for both the environmental and economic reasons. Direct combustion, gasification, pyrolysis, liquefaction, fermentation and anaerobic digestion are alternate conversion technologies available to maximise energy recovery. Therefore, sustainable development can be promoted by encouraging energy projects for the long term, utilising local skills and creating employment.

• The high capital cost of biomass energy systems is a major barrier to the increased use of these systems, despite such technologies being among the cheapest renewable energy technologies;

• The capacity to assess biomass energy proposals/loan applications is limited or non­existent;

• There are significant other priorities for public and private funds for reconstruction, food security, poverty alleviation, following the war, and local financial resources are consequently scarce;

• Since there are virtually no biomass energy projects there are no economies of scale;

• A large fraction of the energy economy (fuel wood) operates outside the formal economy;

In order to avoid financial barriers, some promotional mechanisms are usually used in realization of bioenergy projects [21]:

• Feed-in tariffs and fixed premium;. These systems exist in various European countries (including Bosnia and Herzegovina) and are characterized by a specific premium or total price, normally set for a period of several years, that domestic producers of green electricity receive. The additional costs of these schemes are either paid by suppliers in proportion to their total sales volume and are passed through to the power consumers, charged directly to buyers of green electricity or paid by national governments using environmental taxes on conventional electricity. Fixed feed-in systems are used, for example, in Austria and Germany. Fixed-premium systems are used in Denmark, the Netherlands and Spain.

• Green Certificate Systems; A system of green certificate systems currently exists in five EU Member States, as well as Australia. In this case, renewable electricity is sold at conventional power-market prices, but with the right to sell government-issued certificates that guarantee the renewable character of electricity to consumers or producers that are obliged to purchase a certain number of green certificates from renewable electricity producers according to a fixed percentage, or quota, of their total electricity consumption/production. Since producers/consumers wish to buy these certificates as cheaply as possible, a secondary market of certificates develops where renewable electricity producers compete with one another to sell green certificates.

• Tendering; Under a tendering procedure, the state places a series of tenders for the supply of renewable electricity, which is then supplied on a contract basis at the price resulting from the tender. The additional costs generated by the purchase of renewable electricity are passed on to the end-consumer of electricity through a specific energy tax. Pure tendering procedures existed until recently in Ireland and France.

• Investment subsidies; In some countries, direct investment subsidies apply for biomass combustion systems. This is the case, for example, in Germany for domestic wood pellet stoves.

• Tax deduction; Support systems based only on tax deduction are often applied as an additional policy tool to support renewable energy. In the Netherlands for example, a company investing in a biomass combustion system may deduct an additional 44 per cent of the investment cost from their taxable income.