Harvesting technologies and value-adding to biofuels of herbaceous biomasses

48
biomasses is their tight bond with the territory, the biomass energetic potentialities 
esteem must start from the quantification of biomass amount available in a given 
territorial context).
3. Analysis of technologies and machines suitable for harvesting Estonian 
spontaneous herbaceous biomass: the development and optimization of harvesting 
systems is of fundamental importance for the containment of production costs and 
the improvement of the energy balance for these type of energy source.  
4. Description of the current conversion technologies, able to transform harvested 
biomass into biofuels suitable for commercialization. Mechanical, thermochemical 
and biochemical processes are presented.  
5. Appraisal of the production cost of the various biofuels from wetland herbaceous 
biomass. Emphasis is put on the analysis and costs quantification of the harvesting 
process.
49
Section 1 
Energy requirements and renewable 
resources
The goal of this introductive section is to give a general survey of global, European 
and Estonian national consumption of energy, in order to highlight the strategic role 
played by renewable resources. Energies alternative to fossil fuels propose 
themselves like a concrete and efficient solution able to satisfy a large part of 
energetic requirements: it has been established that, within 2010, at least 12% of 
European Union energy consumptions will need to originate from renewable energy 
sources; despite the growing interest on these technologies, we notice a certain delay 
in their diffusion.
1.1 Energy requirements 
“Anthropologists say that the per capita energy consumption is a good index of the 
state of development of a society. Well, in the last 200 years occidental societies 
have used more energy than all other civilizations that have followed one another on 
our planet. We have reached a standard of living without precedent and this fortune 
is due to deposits of fossil fuels originated millions of years ago. A manna, of course. 
That yet did not come from the sky, but from the bowels of the earth” [2]. These 
words of the discussed economist Jeremy Rifkin – taken from his widely known 
work “The hydrogen economy” – effectively express a well known concept: quality 
50
of living and environmental impacts are tightly tied to energy consumptions. Energy 
facilitates all human activities and endeavours. Energy is used for heating and 
cooling, industrial production and cooking, illumination and education, 
transportation and amusement, etcetera. Energy is essential for life and the human 
development have been accompanied and stamped by energy.  
The original source of energy for all activities was human energy given by muscles. 
This energy provided the mechanical power necessary in the dawn of our history. 
This era was followed by a time characterized by the use and control of fire from the 
combustion of wood. Our ancestors have used firestones, tinder and dry grass or 
straw to light a fire. They have got the possibility to cook food, heat dwellings and 
extract metals such as bronze and iron. That was the beginning of the use of biomass 
as an energy source and, because of the low population, it represented a very 
sustainable use of energy without any relevant impact to nature. Until the latter part 
of the 17
th
 century man relied almost entirely upon the combustion of wood and 
charcoal for his energy needs, as he had done for millennia. This situation applied in 
Estonia just as much as it did in the rain forests of Africa, jungles of Asia or outback 
of Australia. It was the discovery of easily winnable coal that created the Industrial 
Revolution in England and, soon afterwards, Germany, that marked the beginning of 
the decline of biomass energy in what was to become the industrialized or developed 
world. After coal, man acquired the control, in rapid succession, over oil, natural gas 
and, finally, nuclear energy. Thus, from one point of view, history is the story of the 
control over energy sources for the benefit of society, at least in some parts of the 
world. Since the last century, epoch characterized by a remarkable technological 
development, it is evident a strong correlation between economic growth and 
energetic consumptions: energy is the most important production factor of the world 
economy. Our technological civilization demands for a high availability and quality 
of energy: from the daily 2000-3000 kcal consumed by the Neanderthal man like 
food ingested, we passed to the daily 250000 kcal per capita of nowadays tecno-
industrialized societies, utilized mainly in the industrial sector and in transport.  
1.1.1 Global energetic consumptions  
The demand of energy is constantly increasing since 1900: world energy 
consumption is passed from 1.8 billions of toe (tons of oil equivalent) in the year 
51
1900 to 10 billions of toe in the year 2000. The present rate of growth of energetic 
requirements is rather constant since some decades, as shown in figure 1.1.  
Figure 1.1: Evolution from 1971 to 2004 of world total primary energy supply by       
fuel [3].  
Today the world annual energy consumption is more than 11 Gtoe, equal to a per 
capita consumption of about 1.7 toe/year (1 toe = 41.868 GJ). The figure 1.2 
illustrates the distribution of different kinds of energy consummated, according to 
data furnished by the International Energy Agency (IEA, 2004): it is evident the 
predominance of fossil combustibles, in particular of petroleum, that holds the 
biggest share.
Figure 1.2: 2004 fuel shares of world total primary energy supply [4].  
52
As already said, economic growth is by far the most important driver of energy 
demand. In past decades, energy demand has risen in a broadly linear fashion along 
with Gross Domestic Product: since 1971, each 1% increase in global GDP has been 
accompanied by a 0.6% increase in primary energy consumption (figure 1.3).  
Figure 1.3: World primary energy demand and GDP, 1971-2002 [5].  
Because of the tight link between total energy demand and economic output, the 
appetite of industrialized societies for energy often exceed the capacity of local 
sources and therefore the energy supplies of many countries must be imported from 
distant suppliers. Efforts to establish influence and control over oil wells and 
shipping routes or gas fields have often generated political problems, sometimes 
dramatic conflicts (e.g. Gulf War II).  
Considering also the constant demographic increase, because of which the world 
population will reach 9 billions in 2050, and the vertiginous economic growth of 
giants like China and India, the world energy consumption is projected to increase by 
some 70% over the 2000-2030 period (figure 1.4); this translates into an average 
increase of 1.8% year
-1
 to be compared with 1.4% year
-1
 over the 1990-2000 period.
53
Figure 1.4: World final energy consumption [6].  
The present consumption of fossil fuels is not sustainable: keeping the development 
trend of today, fossil reserves – in primis petroleum – are destined to exhaust itself 
within about one hundred years. Keeping this in mind, renewable resources prove to 
be of strategic importance to achieve a sustainable energetic supplying.  
1.1.2 The European energetic situation  
The European Union is consuming more and more energy and importing more and 
more energy products. The evolution of final energy demand shows contrasted 
patterns from one world region to the other in relation to their level of industrial 
development. In the EU, the final energy demand is projected to increase by 0.5 % 
year
-1
.
Figure 1.5: EU final energy consumption [6].  
54
Community production is insufficient for the Union’s energy requirements. As a 
result, external dependence for energy is constantly increasing. The present dramatic 
rise in oil prices once again reveals the European Union’s structural weaknesses 
regarding energy supply, namely Europe’s growing dependence on energy, the role 
of oil as the governing factor in the price of energy and the disappointing results of 
policies to control consumption.  
If no measures are taken, in the 
next 20 to 30 years 70 % of the 
Union’s energy requirements, as 
opposed to the current 50 %, will 
be covered by imported products 
(considering also the decline of 
EU oil, gas and coal 
productions).
Figure 1.6: EU-25 total energy 
(in million toe) [8].  
This dependence can be witnessed in all sectors of the economy. For example 
transport, the domestic sector and the electricity industry depend largely on oil and 
gas and are at the mercy of erratic variations in international prices. In economic 
terms, the consequences of this dependence are heavy: it cost the Union some € 240 
billion in 1999, or 6 % of total imports. In geopolitical terms, 45 % of oil imports 
come from the Middle East and 40 % of natural gas from Russia. Renewable 
energies, as indigenous sources of energy, will have an important role to play in 
reducing the level of energy imports with positive implications for balance of trade 
and security of supply. In particular, biomasses could substitute natural gas in the 
production of heat and electric energy. The strong dependence of EU on the energy 
import had already been underlined in November 2000 by the Green Paper “Towards 
a European Strategy for the Security of Energetic Supply” [7]. The EU now has to 
face new challenges characteristic of a period of profound transition for the European 
economy. In the decade to come, investments in energy, both to replace existing 
resources and to meet increasing energy requirements, will oblige European 
economies to arbitrate among energy products which, given the inertia of energy 
55
systems, will condition the next 30 years. The energy options exercised by the 
European Union are conditioned by the world context, by the enlargement to perhaps 
30 Member States with different energy structures, but above all by the new 
reference framework for the energy market, namely the liberalisation of the sector 
and environmental concerns. Much progress has been achieved towards completion 
of the Internal Energy Market. Agreement has been reached on the first phase of 
liberalisation of the electricity sector and negotiations in the gas sector are well under 
way. Opening the markets for the network-bound energies will bring market forces 
into play in sectors which until recently were for the most part dominated by 
monopolies. This will provide a challenging new environment for renewable 
energies, providing more opportunities but also posing the challenge of a very cost-
competitive environment. Suitable accompanying measures are needed in order to 
foster the development of renewables.  
1.1.3 The Estonian national energetic scenario   
Estonia, officially the Republic of 
Estonia (Eesti or Eesti Vabariik), is a 
country in Northern Europe. Estonia 
has land borders with Latvia 
(339 km) to the south and Russia 
(229 km) to the east. It is separated 
from Finland in the north by the 
narrow Gulf of Finland and from 
Sweden in the west by the Baltic 
Sea.
Figure 1.7: Map of Estonia [57].
Estonia has been a member of the European Union since the 1
st
 May 2004. Its 
coastline is 3794 km. Estonia's capital city, Tallinn, is located in the northern part of 
the coast. Indigenous Estonian-speaking ethnic Estonians constitute nearly 70 
percent of the total population of about 1.3 million people. First and second 
generation immigrants from various parts of the former Soviet Union (mainly