This article discusses agricultural biomass for energy use in the Western Balkan countries (Bosnia and Herzegovina (B&H); Croatia; Montenegro; Serbia). It provides an overview of biomass production and conversion into energy, and discusses its benefits and limitations. Biomass is the most exploited renewable energy (RE) source in the world. Through photosynthesis plants convert solar energy into chemical energy which is contained in the biomass. Biomass is considered to be renewable and non-exhaustive. The agricultural sector in this respect is particularly interesting as it produces biomass comprising both crop (plant residues, energy and oil crops) and livestock (mainly manure) products. Unlike forestry, agricultural biomass has a short life-span in terms of production and its production can be planned, adjusted, and improved more quickly.
Elementary conversion of biomass to energy
There are essentially two main ways of obtaining energy from biomass. The first one is biochemical conversion: conversion to fuels, such as bioethanol, biodiesel or biogas. The second is thermochemical conversion such as combustion. The energy in biomass can be utilised as a liquid fuel (e.g. biodiesel), a solid fuel (e.g. burning corn husks), a gaseous fuel (e.g. bio-methane), or transformed into electricity through the burning of fuel to create heat which powers electricity producing turbines. Biomass can also be processed to biodiesel made from oil from agricultural crops (e.g. rapeseed oil), or from waste oil (e.g. waste streams from food processing). Furthermore, it can be processed into bioethanol where sugars are converted to ethanol or processed into biogas via decomposition – practically becoming methane. Biomass is most commonly used in households for heating, cooking, etc., or in industry as a heat source. It can also be combusted to produce electricity. In 2010 the global installed capacity of biomass power generation plants was 54–62 GW, representing 1.2% of total power generation capacity providing 1.4% to 1.5% of global electricity production.
Energy production from agricultural biomass in the Western Balkans
The ecological conditions of the Western Balkans, notably its diverse climate, relief, soils and vegetation cover, enable production of a range of livestock types and crops, many of which are suitable for biomass production. In spite of this, at present, energy production from biomass in the region is almost entirely based on forest products. The exception is emerging biogas production. Croatia has 26 operational plants, and Serbia has 5 , all having capacity of approximately 1 MWel. The potential for agricultural biomass production is especially good in the Pannonian region featuring deep, fertile soils. This region produces mainly cereals and oil crops, resulting in considerable post-harvest plant residues and food processing residues. It is also very suitable for production of energy crops and/or fast-growing forest species suitable for biomass production. The latter could be planted on marginal agricultural land, most of which is abandoned anyhow, to avoid competition for land with crops used for human consumption.
Western Balkans’ potential for production of energy from agricultural biomass
The region utilises eight million hectares (ha) of agricultural land, while nearly another million ha is unutilised (abandoned) , representing a massive theoreti cal potential for biomass production or other land uses , without putting pressure on food production areas. Serbia alone could annually produce a biomass of 1.7 Mtoe – which is almost equal to Croatia’s entire annual natural gas consumption , while B&H could produce 0.31 Mtoe. Wheat and corn are the two most produced crops in the region and thus have the most immediate potential for biomass production from residues. Croatia could produce 0.17 Mtoe just from the residues of wheat straw and 0.20 Mtoe from corn stovers . In addition to utilisation of agricultural residues, Perakis et al.(2010) have estimated that the region could potentially generate 157 MW from installed biogas power plants (operating at 8,000 hours per year this would result in 0.11 Mtoe of energy per year ).
The role of biomass in meeting EU obligations and GHG reductions
Implementation and utilisation of RE is one of the fundamental goals of the EU. It is crucial for reducing GHG emissions as well as ensuring energy independence of the Member States. As Contracting Parties to the Energy Community (or an EU member in Croatia’s case), all countries of the region have committed to implementing the EU’s acquis communautaire – including commitment to a certain percentage of energy consumed coming from RE sources. All Western Balkans countries consider biomass a strategic resource in meeting these commitments.
Environmental benefits of agricultural biomass
Biomass can be a GHG neutral source: emitting close to the amount of CO 2 that is absorbed from the atmosphere during photosynthesis. If the stock of CO 2 increase is the same as the amount emitted in the utilisation of biomass for energy, it can be considered approximately CO 2 neutral. Using biomass for energy can reduce fossil fuel use and therefore contribute to a reduction of net GHG emissions. The use of plant residues and livestock manure for energy can also decrease GHG emissions by limiting their decomposition and release of GHG to the atmosphere. Combustion of biomass or its products does not emit significant amounts of sulphur and thus does not contribute to air acidification. Additionally, usage of biofuels in agricultural machinery can reduce soil and air pollution because biodiesel and bioethanol do not contain harmful pollutants (notably heavy metals). It is also worth noting that agriculture in the Western Balkans, notably in the Pannonian region is highly dependent on mineral fertilisers. Fertiliser manufacturing is an energy intensive process requiring substantial quantities of natural gas. This process causes air pollution and contributes to climate change as does the use of fertilisers. In contrast, biogas production is rather environmentally friendly and its byproduct is high-quality environmentally friendly fertiliser and soil conditioner which can be returned to the land and used instead of mineral fertilisers.
Socio-economic benefits of agricultural biomass
The economics of biomass energy produc tion are critically dependent upon the availability of a secure, long-term supply of an appropriate feedstock at a competitive cost. The economic potential of biomass from agriculture depends most importantly on the price for the final energy pr duced versus the off-taker price. That price depends on availability of feedstock, heating values, moisture content, transport prices, cost of pre-treatment, etc. Biomass itself is generally very cheap. The price of livestock manure can even be zero or negative (i.e. if farmers are willing to pay for its disposal). However, availability and transport costs of agricultural biomass vary greatly. In the USA for instance, its price varies from $1.73 to $4.33 per GJ. Forest and wood production residues are currently more favoured over agricultural biomass in the region. Due to the number of variables involved, it is impossible to recommend a particular feedstock/technology for the entire region. Biomass production can assist in developing the local and regional economy by Potentials Southeastern Europe Potentials improving revenues and creating jobs.
Electricity production from biomass requires ~4 jobs per MW for operating a facility and an additional 10–20 jobs for agricultural production if energy crops are utilised. The UK projects that more than 40,000 jobs will be available in the biomass sector by 2020. These jobs comprise feedstock supply, operation and maintenance, construction and installation, and development. It is likely that the Western Balkans has similar potential.
Negative aspects of energy production from agricultural biomass
Burning biomass improperly in order to generate heat or electricity can emit carbon monoxide, nitrogen oxide, and fine particulate matter, resulting in air pollution. However, this can be greatly reduced using advanced technologies ensuring complete combustion and removal of pollutants. Biogas production can also result in explosions, diseases, and water pollution if operational safety mechanisms are not implemented effectively. Agricultural biomass production requires land. Thus it may potentially compete with food production (or forests), especially if the 1st generation biofuels or other energy crops occupying arable land are utilised. The 1st generation biofuels are produced from crops, which could otherwise be used for human consumption. This raises a range of ethical questions, notably those on the impact on food prices and overall food security. Using arable land for biomass can potentially result in increased prices of other crops and therefore increased food prices (See Figure 4).
Biofuels of 2nd and 3rd generation as a solution?
The 1st generation biofuels are currently the primary substitute for fossil fuels. The 2nd generation biofuels use more complex technologies and processes to produce biofuel – using crop residues or energy crops (e.g. from cellulose). Environmental balances for the 2nd generation biofuels are significantly better than for the 1st generation biofuels in terms of GHG emissions and other environmental impacts. However, their production costs are higher. To ensure successful deployment of second-generation biofuel technologies requires intensive research and development efforts in the coming years. Agricultural and forestry residues should be the feedstock of choice initially, since they are readily available and do not require additional land. The 3rd generation biofuels are produced from algae (mostly microalgae). Algae are the biggest producer of oils (biodiesel feedstock) on the planet, but this technology is not currently commercially exploited. The use of algae as a feedstock does not result in competition with agricultural land as they are produced in aquatic ecosystems. This type of fuel is considered by many as a future source of fuels, but it is still in an early stage of development.
Benefits for agriculture and the environment from biomass production
To conclude, in spite of certain obstacles preventing a wider uptake and utilisation of agricultural biomass for energy production (most of which relate to ensuring a sustainable CO2 flow and reducing competition for land resources), there are also numerous socio-economic and environmental advantages of employing agricultural biomass for energy production. As far as the Western Balkans region is concerned, it seems that the region has suffi cient areas to produce agricultural biomass on marginal/abandoned agricultural land without compromising or jeopardising food security. If crop residues are combined with livestock manure, the region can achieve robust agricultural biomass production, which would be a significant contributor to true sustainable development of the region.