EUBIONET
Biomass survey in Europe
Country report of Greece
Greece 2003
Contents
1. Introduction..................................................................................................................3
1.1 An overview of the Greek energy market ..........................................................3
2. National RES policy and role of bioenergy .................................................................5
3. Energy market and the role of biomass fuels...............................................................8
3.1 Agricultural residues ..........................................................................................8
3.2 Agro-industrial residues ...................................................................................13
3.3 Forest biomass potential ...................................................................................15
3.4 Energy Crops ....................................................................................................21
3.5 Achieved results ...............................................................................................23
3.6 Animal wastes ..................................................................................................26
3.7 Biogas Production ............................................................................................30
3.8 Bioenergy in heat market..................................................................................32
3.9 Bioenergy in the electricity market ..................................................................34
4. References..................................................................................................................37
2
1.
1.1
Introduction
An overview of the Greek energy market
Low-quality lignite accounts for 82% of Greece’s indigenous energy production and
64% of its electricity supply (IEA, 2002).
Even though the government favours the use of gas in power generation, new lignitefired power plants are licensed, provided they use only state-of-the-art technologies and
will not make it more difficult to Greece to meet its greenhouse gas emissions target.
The Greek State owns all lignite deposits, and the Public Power Corporation (PPC) had
exclusive rights to mine lignite until the electricity market was liberalised and a bidding
process was established to lease them. But, as the bidding process was introduced only
very recently, there have not yet been any bidders. Today, PPC mines 95% of all lignite
in Greece, and uses it in its own lignite-fired power plants.
Greece successfully introduced natural gas into its energy mix in 1996. In 2000, natural
gas accounted for 6.1% of primary energy supply, and gas consumption is growing fast.
It has already a good footing in power production and has replaced some oil use in the
industrial sector. In the future, most growth in gas demand is expected to come in power
generation and in the residential and services sectors. The current gas infrastructure is
sufficient to meet demand for several years.
Concerning renewable energy sources, the actual share was 5.2% in 2000. A new
indicative target has been set to generate 20.1% of electricity by renewables in 2010.
The government recognises that the licensing procedures for renewables are still too
complex, and it now plans to establish a “one-stop shop” for permits and licences. There
is also an effort to identify the potential of new energy sources. The Centre for
Renewable Energy Sources ( CRES) investigates their technical and economic aspects.
Because of Greece’s windy and sunny climate, this potential is significant. Today,
renewables are mainly promoted through financial incentives, such as tax breaks, direct
subsidies and an attractive feed-in tariff system. The government should explore
possibilities of introducing a green certificate system to reduce the cost of promoting
renewables.
In detail, renewable energy sources (RES) contributed 5.2%, or 1.46 Mtoe, to the Greek
Total Primary Energy Supply (TPES) in 2000 (CRES, 2002).
3
Table 1. RES’ contribution to the Greek energy balance for 2000. (CRES, 2002)
E n ergy B alan ce 2000
Fo ssil Fu els
Liqu id Fu els
G as Fu els
RES:
S olar
kTO E
%
9038
32.11 %
15941
56.63 %
1703
6.05 %
1165.3
4.14 %
99
0.35 %
W ind
106
0.38 %
B iom ass - Industry
241
0.86 %
B iom ass - H ouseholds
705
2.50 %
0
0.00 %
B iom ass - Transport
S m all H ydro (0-10 M W )
Larg e H ydro (10+ M W )
To tal
14.3
0.05 %
303.3
1.08 %
28150.6
100.00 %
Of this, biomass (mostly wood consumed directly in the domestic/residential sector)
accounted for 67%, or 0.946 Mtoe. Domestic use of wood (burning of wood in open
heaths for cooking, water and space heating) accounted for about 74% (0.70 Mtoe) of
total biomass energy production.
The remaining 26% (0.24 Mtoe) was produced by the combustion of wood by-products
and agricultural residues, and the utilisation of biogas produced in landfills, agro-food
industries and municipal wastewater treatment plants. In total, approximately 2,730
plants operating on biomass resources have been recorded in Greece (2002).
A number of biogas-to-electricity installations, including a 240 kWe plant in a municipal
solid waste landfill in Thessaloniki and a 193 kWe plant in a municipal wastewater
treatment plant in Heraklion and a 166 kWe in Chania, as well as ten biogas-to-heat
installations (with a total heat production of 717.4 TJ), have been realised so far and
others are currently being planned.
The diverse topography of Greece combined with favourable climatic conditions favour
a wide range of agricultural activities. A large number of energy crops have been tested
in different soil climatic conditions, and good adaptability and high biomass yields with
relatively low inputs (water, fertiliser, etc.) have been demonstrated.
The main biomass resources in Greece, towards which RTD &D activities focus, are:
• Residues from: agriculture in-field; forestry activities (early thinnings, final fellings,
silvicultural treatments), agriculture processing/ agro- industries; by- products from
animal husbandry; by- products from forestry.
4
• Energy crops: During the last decades, several energy crops have been tested under
Greek climatic conditions. High biomass yields, up to 30 odt/ha/year, have been
observed in experimental trials. The main energy crops tested so far are:
• Sweet and fiber sorghum (Sorghum bicolor L. Moench),
• abessinian mustard (Brassica carinata),
• rapeseed (Brassica napus),
• kenaf (Hibiscus cannabinus),
• giant reed (Arundo donax),
• cardoon (Cynara cardunculus),
• eucalypts (E. globulus, E. camaldulensis),
• miscanthus (Miscanthus sinensis x giganteus),
• black locust (Robinia pseudoacacia),
• poplar and willow clones, and
• switchgrass (Panicum virgatum).
2.
National RES policy and role of bioenergy
The legislative and support framework affecting the penetration of RES includes the
following:
•
Law 2773/99 regarding the liberalisation of the electricity market in Greece. The
main points are:
- Priority is given by the system Operator to the electricity produced from RES
to cover the demand of electricity.
- A ten year contract will be given to the producers of electricity from RES by
the System Operator at a price which will be 90% of the existing medium
voltage tariff, at maximum, for the energy produced.
• Law 2244/94, regarding revisions on the electricity production code from RES, and
the implementing Ministerial Decision 8295/95, which broke new ground for the
promotion of RES in Greece. This was the necessary regulation tool for the
production of electricity by independent producers, making a distinction between
independent producers, selling the total of production to PPC, and auto-producers,
covering primarily their own energy needs and selling surplus energy to the Public
Power Corporation (PPC). This law remained in force only until the end of 2000,
5
when it was replaced by law 2773/99 (described above) for which it still acts as
reference.
•
The Renewable Energies Sub-programme of the Operational Programme for
Energy (1994-1999), which was the main funding mechanism for RES installations.
The programme had a total budget of 340 MEuro (139.6MEuro being public
funding and 200.4MEuro private funding), and supported mainly RES investments,
but also broad “infrastructure” work, such as the development of the National
Certification System, the assessment of the technically exploitable RES potential
and the determination of the optimum administrative and legislative framework for
RES.
•
The development law 1892/90 together with its amendment 2234/94, which was a
general “development law” that provided subsidies (40-60%) for investments by the
private sector, including renewables.
•
The new development law 2601/98, replacing 1892/90, which was expected to be
the main funding tool of RES applications in the future. The law foresees a
combination of subsidy options that is either a) capital investment subsidies up to
40%, interest subsidy up to 40% and subsidy for leasing up to 40% or b) tax
deduction up to 100% and interest subsidy up to 40% for investments in RES.
• Moreover, very high financial support for special biomass-to-energy investments (up
to 70% of total capital cost, depending on the particular region where the investment
is located) has also been provided, in the period 1994-1999, for the erection of
greenhouses, according to the Common Ministerial Decision 163/1995, issued by
the Ministries of Agriculture and Finance. According to this Decision, the
greenhouse installations eligible for funding must have a size between 0.3 and 0.5
hectares, and must cover their thermal requirements by biomass, solar or geothermal
energy.
The main financial instrument to support investment in RES was till 1999 the
Operational Programme for Energy and currently is the Subprogramme 2 of the present
Operational Programme for Competitiveness (OPC), under the third Community
Support Framework (2000-2006), as already mentioned.
In particular, during the two rounds of proposals submitted in the framework of the
OPE/Measure 3.2 (calls released on 04.12.96 and 22.07.97, respectively), twelve (12)
projects related to bioenergy applications were approved in total, the distribution of
which is further shown in Table 2 below.
6
Table 2. Distribution of biomass-to-energy related projects that were approved for
funding in the two rounds of proposals, submitted in the framework of the
OPE/Measure 3.2
st
1 round of proposals (04.12.96)
Biomass
83utilisation
technology
Number of
approved
projects
Budget
(million
Euro)
Installed
capacity
(MW)
2nd round of proposals (22.07.97)
Number of
approved
projects
Budget
(million
Euro)
Installed
capacity
(MW)
Heat production in
agro-industries
3
1.8
15.6 MWth
3
1.7
17.5 MWth
Biogas utilisation
1
11.1
7.4 MWth
7.4 MWe
2
16.5
13.5 MWe
District heating
-
-
-
2
7.8
22.3 MWth
Cogeneration
-
-
-
1
44
0.7 MWth
20.0 MWe
TOTAL
4
12.9
23.0 MWth
+ 7.4 MWe
8
70
40.5 MWth
+33.5 MWe
Similarly, in Measure 2.1 of Sub programme 2 of the current Operational Programme
for Competitiveness (OPC), under the third Community Support Framework (20002006), that is devoted to providing State support to private investments in RES and
RUE the grants are given following rounds of public calls. For biomass – biogas
investments, the public subsidy is 40% of the total eligible investment cost but
independent of geographical region (see also chapter 1.2.1.3).
In the frame of the first proclamation of Measure 2.1, private investments of 745.4
MEuro were approved by the Minister of Development on June 2002 following the
evaluation of proposals of RES, CHP and energy saving, that corresponded to 26% of
the total budget of actions of the Energy Sector and Natural Resources programme of
the OPC. The approvals concerned 201 investment proposals. Thirteen of the 95
approved initial RES proposals concerned biomass with a total investment of 53.3
million Euro. One project is for production of biofuels, seven projects are cogeneration
units and five projects refer to biomass utilisation for heat generation. The maximum
eligible costs set are for cogeneration with biomass between 1600 to 1320 Euro/kWe for
agricultural waste to sewage sludge and 440 Euro/tonne for biofuel production.
7
3.
Energy market and the role of biomass fuels
3.1
Agricultural residues
In Greece, the total agricultural land is about 3.8 million ha, from which 60% is arable
land, 25% is cultivated with trees and vines, 3% is garden area and 12% is fallow land
(NSS a).
Fallow land
12%
Trees
25%
Arable land
60%
Garden area
3%
Figure 1: Distribution of agricultural land in Greece.
Two large categories of field agricultural residues have been considered:
•
annual crop residues that remain in the field after the crops are harvested. The main
annual crops in Greece are winter cereals, rice, corn, cotton, tobacco and sugarbeet,
•
perennial residues that remain in the field after the pruning of trees and vineyards.
The quantities of residues from the annual and perennial crops cultivated in Greece, in
tonnes of dry matter per year, were estimated using data from the Annual Agricultural
Statistics, on the cultivated areas and the quantities of the main product produced per
year for each crop and for the years 1996 – 1998 (NSS a). Additionally coefficients that
indicate the ratio of residue quantity to product yield and the moisture content of each
type of residue were derived from literature (Apostolakis et al., 1987) and are presented
in Table 3.
In a further step, the theoretically available quantities were assessed taking into account
the percentages already used. From the total agricultural residues produced in Greece, a
part is already exploited and used in several energy and non-energy markets. Cereal
8
straw is used for various purposes such as animal feeding and animal bedding. There is
also a greenhouse in northern Greece using straw for heat production (250 MWh/year,
CRES, 2002). Therefore it has been assumed that only 15% is available for bioenergy
applications (Voivontas, et al., 2001). In the case of rice straw, cotton and corn stalks
and corncobs although no alternative markets have been reported, the availability
percentage was set to 60% due to difficulties in harvesting and handling. Olive prunings
(especially the large stems) are used in stoves and chimneys for residential heating and
their availability was estimated to 50%. Prunings from vines and other types of trees
are not preferred for this purpose and it was estimated that 80% of the total quantities
are available for bioenergy applications (Alexopoulou et al., 1999).
Based on the above it is estimated that approximately 3.8 million tonnes of field crop
and arboricultural residues are theoretically available for energy production.
9
Table 3. Characteristics of crop residues studied for Greece
Residue
Product/Residue
Moisture
Higher Heating Value
ratio
(%)
(MJ/kg)
Wheat straw
1.00
15
17.9
Rice straw
1.00
25
16.7
Barley straw
1.24
15
17.5
Oats straw
1.27
15
17.4
Corn cobs
3.75
50
18.4
Corn stalks
1.42
60
18.5
Sunflower straw
0.50
40
14.2
Cotton stalks
0.50
45
18.2
Sugar beet leaves
2.51
75
14.6
Tobacco stems
0.91
85
16.1
Vineyard prunings
1.20
40
18.3
Olive prunings
0.98
35
18.1
Peach prunings
2.51
40
19.4
Pear prunings
1.26
40
18.0
Apple prunings
1.20
40
17.8
Apricot prunings
2.84
40
19.3
Lemon prunings
2.22
40
17.6
Orange prunings
2.90
40
17.6
Cherry prunings
1.20
40
19.1
Tangerine prunings
1.55
40
17.6
Almond prunings
0.28
40
18.4
10
Table 4. Cultivated areas and produced quantities of agricultural residues in Greece.
Residue
Cultivated
Production
Availability
Available
area
(dry tons/year)
(%)
quantities
(ha)
(dry tons/year)
Soft wheat straw
245,019
536,103
15
80,415
Durum Wheat straw
612,047
1,229,189
15
184,378
Rice straw
27,982
157,200
60
94,320
Barley straw
144,884
238,274
15
35,741
Oats straw
43,853
55,383
15
8,307
Corn cobs
213,181
276,157
60
165,694
Corn stalks
213,181
583,431
60
350,059
Sunflower straw
26,818
47,671
60
28,603
Cotton stalks
412,727
1,463,015
60
877,809
Sugar beet leaves
42,585
246,169
50
123,084
Tobacco stems
67,070
23,767
60
14,260
Vineyard prunings
133,408
455,589
80
364,471
Olive tree prunings
749,522
1,468,857
50
881,314
Peach tree prunings
45,993
151,729
80
121,383
Pear tree prunings
4,213
38,409
80
30,727
Apple tree prunings
14,874
173,850
80
139,080
Apricot tree prunings
5,047
9,829
80
7,864
Lemon tree prunings
11,917
49,009
80
39,207
Orange tree prunings
40,050
190,505
80
152,404
Cherry tree prunings
8,613
24,256
80
19,404
Tangerine tree prunings
6,137
28,580
80
22,864
Almond tree prunings
23,613
104,902
80
83,921
TOTAL
7,096,331
11
3,825,309
Figure 2: Geographic distribution of the available quantities of agricultural residues in
Greece
Nowadays, the main volume of the aforementioned field crop residues are either
incorporated into the soil or burned on the field.
Although there are sufficient quantities of residues in the country, certain parameters
should be taken into account before making a strategy for their energy exploitation.
•
Small farming size (increases harvesting and transportation costs).
•
Environmental risks caused by the removal of the residues from the field (erosion in
sloping and low fertility areas, etc.).
•
Opportunity cost of the residue (e.g. cereals straw has already a market price as it is
sold for animal feeding purposes).
•
Lack of commercial harvesting machinery for certain residue types (e.g. cotton
residues).
12
3.2
Agro-industrial residues
The main types of agro industries in Greece are: rice industries, cotton-ginning
factories, corn industries, fruit industries, wine factories, seed oil industries, olive
industries, olive oil and olive kernel factories.
The main types of agro-industrial residues that can be used for energy production in
Greece are the residues from the fruit canneries, rice mills, olive oil and olive kernel
factories and the cotton ginning factories.
The evaluation of the quantities and geographical distribution of this category of
residues is more complicated because of the different processing technologies, size and
location of the processing plants and the characteristics of the final products (Blassi et
al., 1997). Further more there are no official data on the production of agro-industrial
products at a regional level in Greece that could facilitate the estimation of the produced
residues. Therefore, it was chosen to follow different methodologies, according to the
availability of data for each type of residue.
In the case of rice mill residues, rice husk was estimated as a percentage of the
harvested rice for which there are available data at a regional level. It is reported in
literature and has been confirmed by the engineers in the rice mills that rice husk is
approximately 20% of the processed rice, with average moisture content of 10% (CRES,
1996).
The same assumption was made for cotton, since all of the harvested cotton is sold and
processed in the cotton ginning factories. It has been reported that cotton-ginning
residues are 10% of the processed cotton, with average moisture content of 17% (CRES,
1996).
In the case of nutshells, the available data on the production of almond, walnut and
hazelnut shells are only at a national level (NSS b) and these data were used to estimate
the quantities of the produced hulls. The average shell/kernel ratios used were 1.2 for
almond shells, 1 for walnut shells and 0.8 for hazelnut shells (Pontikis, 1987).
13
Table 5. Characteristics of industry residues studied for Greece
Crop
Residue
Residue/
Moisture
Product ratio
(%)
Harvesting period
Rice mills
Rice husk
0.16
10
All year
Cotton ginning factories
Cotton ginning residues
0.1
13
September - April
Peach canneries
Peach kernel
0.0,4
20
July - September
Olive kernel factories
Olive kernel wood
0.21
30
November - July
Peeling plant
Walnut shells
1.5
8
All year
Peeling plant
Almond shells
0.95
5
All year
Peeling plant
Hazelnut shells
1.07
5
All year
There are no available data concerning the annual production of fruit canneries.
However, it has been reported that the total installed capacity at a national level is
200,000 tones/year for peach canneries and according to literature (CRES, 1996) peach
kernels is 4.5% of the total fruit.
Concerning olive kernel wood, the produced quantities were estimated based on the
annual regional production of olive oil producing varieties, and the assumption that
olive kernel is 23% of the olive fruit.
450.000
423.110
400.000
350.000
dry tons/year
300.000
250.000
200.000
132.079
150.000
100.000
30.311
50.000
6.400
1.842
Peach kernel
Nutshells
0
Olive kernel
wood
Cotton ginning
residues
Rice husk
Figure 3: Production of agro-industrial residues in Greece.
14
Most of the agro-industrial residues are being used for animal food production.
However, certain types of agro-industrial residues are being used for energy production
(mostly heat generation):
•
Several cotton ginning factories use their residues to produce the heat required for
cotton drying and space heating of their facilities. The total heat energy produced
has been estimated to 83,889 MWh/year (CRES, 2002).
•
The olive kernel wood produced in the olive kernel factories is being used for
greenhouse heating, space heating, etc. The total heat energy produced has been
estimated to 2,325,556 MWh/year (CRES, 2002).
•
Fruit kernels produced by fruit canneries and shells from almond, walnut and
hazelnut peeling plants are being used for greenhouse and residential heating. The
annual energy production from these types of residues has been estimated to 3,194
MWh/year (CRES, 2002).
•
Rice bark produced is used to produce the heat needed by the rice processing
factories and the thermal energy produced has been estimated to 18,333 MWh/year
(CRES, 2002). There is also a factory using rice husk for power production with an
installed capacity 0.44 MWe.
3.3
Forest biomass potential
The amount of biomass currently used for energy production in Greece is a small
percentage considering the available potential in the country. An accurate estimation of
the technically and economically exploitable biomass potential has not been carried out
yet. At present the available data concerning biomass potential are only indicative but
very promising. (general note for all biomass resources in Greece)
In particular, biomass of forestry origin is expected to play a complementary role in
biomass-to-energy supply schemes, in the short term. This is due to technical and nontechnical barriers affecting forest management today in Greece, while at the same time
biomass derived from agricultural activities consists a cheap and ready to use fuel, and
therefore competitive.
However forest biomass resources will represent the most important biomass resource
in the long term, after the overcoming of barriers. In general, the introduction of the
proper harvesting technology in forest operations, as well as the modification of the
15
unfavourable legal framework for forest exploitation, are expected to totally change the
biomass exploitation context, in Greece positively.
In the framework of the multifunctional management of the forests, the production of
forest biomass for energy purposes is considered as an efficient management tool for the
fulfilment of forest policy targets, in parallel with renewable energy policy targets,
regarding all ecological restrictions.
3.3.1
Forest biomass resources
Greece, located at the southern end of the Balkan peninsula, is mostly hilly or
mountainous and dry and rocky country.
Forestlands occupy an area of 6,513,068 hectares, which represent the 49.3 % of the
total land area of Greece. Industrial forests cover about 19 % (2,512,418 hectares) and
non-industrial forests 25 % (3,242,410 hectares) of the total country area. The
distribution of land-use classes is presented in Figure 4.
Industrial forests
3.33 %
2.10 %
13.30 %
2.07 %
5.57 %
24.56 %
Non industrial forests
Moor lands
Alpine lands
30.03 %
19.03 %
Range lands
Water
Bare lands
Crop lands
Figure 4: Land uses in Greece
Forest management is characterised as especially difficult, since the wooded areas are
sited in mountainous or remote regions with adverse pedo-climatic conditions, such as
poor and thin soil as well as drought. Forest’s condition is not satisfactory in terms of
density, quantity and quality of the growing stock, due mainly to human impact of the
past such as fires, grazing, land clearings, illegal fellings as well as lack of systematic
silvicultural treatment.
The main owner of the forestlands is the state. The 65.44 % of them are public owned.
The municipal forests cover an area of 301,527 hectares, the monasterial 109,946
hectares, the privately owned 199,870 hectares and the join-owned 245,845 hectares.
16
7.96 %
4.38 %
0.45 %
Public
M unicipal
9.79 %
12.00 %
M onastery
Foundation
Privately-ow ned
Join-ow ned
65.44 %
Figure 5: Forests ownership statement
The total forest area (industrial forests), of about 2.5 million ha, consist of 1 million ha
coniferous species and 1.5 million ha broadleaved species. The high elevation conifers
consist of black pine (Pinus nigra), scotch pine (P. silvestris) and fir (Abies borissi
regis), while the Mediterranean zone conifers managed for pine resin and recreation
functions consist of aleppo pine (Pinus halepensis) and calabria pine (P. brutia). The
broadleaved species compose forests of beech (Fagus silvatica), oaks (Quercus
pubescens, Q. conferta, Q. sessiliflora, Q. cerris etc.) and chestnut (Castanea vesca) as
well as shrublands of evergreen hardwoods (the so-called maquis).
Conifers occupy 38 % and broadleaved species 62 % of industrial forest areas,
respectively. In particularly, pines occur in an area of 612,824 hectares, fir 329,762
hectares, beech 219,070 hectares and deciduous oaks 747,490 hectares.
5.45 %
18.94 %
0.95 %
8.72 %
Fir-Spruce
4.05 %
A. Pine
B. Pine
Other conifers
Beech
13.13 %
29.75 %
Other broadleaved
Oak
19.01 %
Evergreen trees
Figure 6: Industrial forests cover
The major portion of forests is composed of sub-selection and selection stands while the
remaining of even-aged stands. The stand structure appears as one-storied, two-storied
and multi-storied. Forests managed as coppice totally consist of even-aged stands. The
length of rotation of these coppice forests is 25-35 years, depending on the site, the
climatic zone, and the species growing on the particular site. The main products of this
type of forest are fuelwood and charcoal.
17
Management data: According to management type, industrial forests are divided to
natural regenerated (872,363 hectares), coppice (1,207,343 hectares) and mixed
(432,812 hectares).
17.23 %
34.72 %
Naturally regenerated
Coppice
Mixed
48.05 %
Figure 7: Industrial forests management types
The mean growing stock of Greek industrial forests amount up to 45.2 m3/ha and is
composed of conifers (56.09 % of the total growing stock) and broadleaved species
(43.91 % of the total growing stock). It is compared to the mean growing stock of other
European countries, is considered as relatively low. This figure does not indicate the
real state of Greek forests, because there are many forest complexes which are wellorganized and managed for a long time which support stands with a mean growing
stock, ranging from 350 to 400 m3/ha. In particularly, the growing stock amounts to 19
m3/ha in pine forests, 76 m3/ha in fir forests, 84 m3/ha in beech forests, 19 m3/ha in oak
forests and 35 m3/ha in forests covered by other broadleaved species (ash, hop
hornbeam, plane-tree, elm-tree etc). The mean growing stock of the Greek nonindustrial forests amount up to 1 m3/ha. The mean growing stock has decreased
significantly because a high percentage of forests are coppice or over-thinned due
mainly to human actions of the past, as mentioned above.
90
84
76
75
60
45
41
33.21
43.28
27.69
30
m3/ha
35
,000,000 m3
24.15
19
15
8.92
0
Pine
Fir
Beech
Oak
Other
broadl.
Figure 8: Growing stock classification
18
The annual growth of the Greek industrial forests rises up to 3,812,538 m3 (1.14 m3/ha)
and represents the 2.76 % of the total growing stock. In fir forests represents the 1.92 %,
in pine forests the 3.04 %, in beech forests the 3.29 % and in oak forests the 2.49 % of
the growing stock.
Fuelwood production: The fuelwood production in 2000 rose up to 1,358,892 tones.
The 90 % (1,230,606 tones) derived from broadleaved species and the rest (128,286
tones) from conifers. The 53.68 % (729,394 tones) was available to the wood market (as
wood fuel or raw material for wood products) and the 46.32 % (629,498 tones) was at
the disposal of population living near by the forest areas.
800 000
600 000
Broadleaves
651 194
400 000
579 412
Conifers
200 000
78 200
50 086
0
Marketable
Domestic
Figure 9: Fuelwood production (in tones)
The energy content of the total fuelwood production is estimated up to 18.77 PJ. The
1.77 PJ equivalent derived from conifers and the 17.00 PJ from broadleaved species.
19
12
10
8
6
Broadleaves
9.00
8.01
Conifers
4
2
1.08
0.69
0
Marketable
Dom estic
Figure 10. Energy content of fuel wood (in PJ)
Industrial wood residues: Almost 747,000 m3 of round wood, harvested in Greek
industrial forests, conducted to wood industries. Fifty wood processing industries
(processing imported wood also) use wood residues for energy production by
themselves (to produce steam for heating, drying and steaming). The consumption of
residential wood for energy purposes amount up to 99,000 tones and the generated heat
estimated to 1.37 PJ.
Barriers: The General Secretariat of Forests and Natural Environment of the Ministry
of Agriculture is responsible for managing state forests, while non-state forests are
governed by various bodies. Management is carried out through 10-year management
plans, drawn up according specifications issued in 1953 and modified in 1965. New
specifications are under approval, which stress the principles of sustainability,
conservation of biodiversity and multiple-functional management of forests.
The main aims of national forest policy are the protection of forests and forest lands, the
enrichment and improvement of growing stock, the increase of forest production, in
terms of industrial wood, the enlargement of forest cover by reforestation, the
augmentation of production of other goods and availability of other services deriving
from the forests as well as the improvement of socio-economic conditions of the rural
population. The main factors determining the targets of forest policy in Greece are the
fulfilment of round wood production and fulfilment of services coming from the forest.
Greece has a rather small forest sector and a large share of its round wood production is
used as fuel. The wood of large dimensions is no more than fifty to sixty percent of the
total volume harvested from forests producing such wood. The rest is wood of small
dimensions, tops, branches and wood of low quality. While hardwoods are used mainly
for energy purposes, the softwoods are processed into sawn wood and particleboard.
The country imports all types of forest products, especially sawn wood and paper
products.
20
Concluding, the main forms of energy wood produced in the Greek forests are fuelwood
as well as logging residues. Other residues derived from early thinnings as well as from
clearing operations for the reduction of fire risk, are not produced at all, since such
operations are not or are poorly executed at present due to the lack of state financing.
Split and round fuelwood production is continuously declining from early 50’s up
today, being about 1.2-1.4 million tons nowadays, due to the expanded use of
conventional fuels and the drastic concentration of the population to large centres. The
production of fuelwood has been traditionally considered as one of the forest policy
targets since this product has both commercial and social value. The major part of
fuelwood produced (45-50%), is freely collected by the people living nearby the forests
to cover their domestic energy needs (for cooking and space heating).
Concerning logging residues, in forestry practice large amounts arise during the
harvesting operations (in the form of bark, tops, branches, leaves and needles) and are
left behind in the forest terrain. The potential of logging residues in Greece is roughly
estimated at 1.7 million tons (including stumps and roots), but only a part of them could
be utilised for energy purposes after the introduction of modern harvesting technology.
Both the state forest managers and the particleboard industry have encouraged removal
of logging residues for many reasons such as:
•
providing raw material the particleboard industry,
•
avoiding accumulation of biomass on the forest floor and reducing forest fire risk,
•
making room for reforesting and facilitating access during forest operations, as well
as
•
ensuring the forest health by avoiding fungi and insect attacks.
The existence of steep slopes, the lack of mechanisation in harvesting operations (horses
and mules are the standard form of power used to skid logs from the stump to the forest
road) and the inefficient legal framework that regulates the system of forest exploitation
through forest co-operatives, are the main reasons for not utilising forest residues.
3.4
Energy Crops
For nearly one decade R&D programs have been conducted in Greece aiming at
increasing the development and development of biomass energy sources and
21
technologies. The main topics, on which the R&D activities have focused on, are the
following:
Agronomic aspects:
The main aim of this field is to obtain optimum performance by matching topography,
soils, climate and location for a variety of species, varieties, hybrids, genotypes and
cultivars. Three major categories are distinguished depending on the measured
characteristics of each crop:
•
Adaptability under different pedoclimatic conditions and cultural practices such as
plant density, nitrogen fertilization applications, irrigation management, etc.
•
Growth characteristics such as LAI, height, number of tillers per plant, etc. As a
result, data sets for plant growth modeling are recorded.
•
Biomass production as well as biofuel production per plant and per plant part.
During the last decade more than sixty experiments have been conducted throughout
Greece in order to evaluate the biomass yielding potential of several energy crops. So
far, the following annual and perennial crops have been thoroughly studied:
I. Annual herbaceous crops:
1. Sorghum bicolor L. (sorghum)
2. Brassica carinata L. Braun (ethiopean
mustard)
3. Brassica napus L. (rapeseed)
4. Hibiscus cannabinus L. (kenaf)
II. Perennial herbaceous crops:
1. Cynara cardunculus (cardoon)
2. Arundo donax L. (giant reed)
3. Miscanthus x giganteus (elephant grass)
4. Panicum virgatum L. (switchgrass)
III. Short-rotation woody crops:
1. Eucalyptus globulus Labill. (eucalyptus)
2. Eucalyptus
camaldulensis
Dehnh.
(eucalyptus)
3. Robinia pseudoacacia (black locust)
22
Fuel characterization
The main aim of this research aspect is to categorize the energy crops according to the
calorific value, fuel origin and properties (e.g. ash characteristics). Chemical analyses of
various fuels include fuel proximate and ultimate analyses, ash stoichiometric analyses
and characteristic ash-fusibility temperatures. The expected deliverables of the above
research tasks are recommendations on the biomass type and ratio in the fuel blend.
Environmental aspects of biomass production
Environmental impacts of crop production and energy generation are the main targets of
the conducted research on this subject. Particularly, water and nitrogen balance, nitrate
leaching, soil erosion and agrochemical inputs are currently being examined in cropping
systems including some of the aforementioned crops. Furthermore, emissions and air
quality are carefully monitored.
Conversion to energy technologies
Biomass types are also categorized according to the suitable applied conversion
technology. Namely, the systems of Pulverised Fuel Combustion (PFC), Fluidized Bed
Combustion (FBC) and Pre-treatment Techniques (Gasification, Pyrolysis, and
Leaching) are used. Additionally, the preparation requirements like milling, particle size
and water content, as well as specific operational problems and restrictions set by the
combustion system are recorded.
Economic and social dimensions
The feasibility of energy crops to replace conventional ones is analyzed along with their
exploitation for energy purposes. The cost is analyzed per production factor such as land
use, farm size, agricultural income, conventional crops, energy market, etc. Table I
summarizes the factors taken into considerate for each type of energy crop.
3.5
Achieved results
In general, most of the studied crops performed high yielding potential under Greek
climatic conditions. However, differences have been observed so far depending on the
crop species, the climate and the cultural practices. A summary presentation of results
of the tested energy crops separated in annual and perennial herbaceous and woody
energy crops are presented in tables 6, 7, and 8, respectively. In particular, the recorded
results for each energy crop are presented below:
23
•
Sweet sorghum
Fresh biomass yields ranged from 45 to 141t/ha while dry matter yields ranged from 13
to 45t/ha, depending on site, variety and the cultural techniques. The bioethanol
potential under Greek conditions in well-watered and fertile fields was estimated at
6,750 l/ha. Water use efficiency (WUE) for sweet sorghum has been estimated in
central Greece at 181 to 206 kg water per kg dry matter while aerial radiation use
efficiency (RUE) at 3.5 gr dry matter per MJ intercepted.
•
Fiber sorghum
Experimental data obtained so far from central Greece indicate that fiber sorghum
exhibits high biomass yields, similar to that of sweet sorghum. Fresh biomass and dry
matter yields recorded in autumn, reached up to 90 and 27t/ha, respectively.
•
Kenaf
All the tested varieties performed good adaptability and high biomass yields. It should
be mentioned that the late-matured varieties were more productive than the early ones.
Varieties and maturity types presented fresh biomass ranged from 33.8 to 88.6t/ha and
dry matter from 7.6 to 23.9t/ha. Seed production was always feasible for the early
varieties while the late ones were occasionally able to produce seed, depending on the
prevailing climatic conditions during autumn.
•
Rapeseed and ethiopean mustard
Experimental data indicate that dry matter yields ranged from 3 to 8t/ha and seed yields
could reach up to 1.4t/ha, depending on the variety and the site.
•
Spanish thistle artichoke
The final plant height reached up to 2.6m, while dry biomass yields, depending on
plantation density, ranged from 17 to 30t/ha. Calorific values for the various plant
components ranged from 14.6 to 21.6MJ/kg d.m. Respective values for the energy
potential ranged from 6.9 to 12.9toe/ha/year.
•
Giant reed
Dry matter yields reached up to 30t/ha from unimproved wild populations and
conventional cultural methods. Calorific value of 17.1 MJ/kg was determined and based
on this value an energy potential up to 12.9toe/ha/year, was estimated.
24
•
Elephant grass
The average height of the plantation reached up to 3m, while dry biomass yields ranged
from 11 to 34t/ha and the estimated energy potential was 13.8toe/ha/year. The mean
calorific value and ash content of stems were 4,360kcal/kg d.m. and 2% d.m.,
respectively, while leaves seem to be a rather inferior fuel due to the higher ash content
(8% d.m.) and the lower calorific value (4,056 kcal/kg d.m.). The RUE obtained was
4.03 gr dry matter per MJ intercepted.
•
Switchgrass
Experimental data from experimental fields referring to 3-years results reported dry
matter yields that ranged from 14-25t/ha depending on variety and cultural practice.
•
Eucalyptus
Depending on soil fertility and cultural practices, dry matter yields up to 35t/ha/year
were obtained. The mean gross calorific values ranged from 16 to 19 MJ/kg d.m.
depending on the plant part (leaves, stems) and the respective energy potential was up to
15toe/ha/year.
•
Black locust
Dry biomass yields ranged from 5.6 to 17.1t/ha/year. The averaged value for energy
potential was8toe/ha/year.
Table 6: Annual herbaceous energy crops.
Sowing season
Sweet sorghum
Fiber sorghum
Kenaf
Rapeseed
May
May
April – July
Sep-Dec (early var.)
ο
ο
T > 15 C
T > 15 C
Pre-sowing
Pre-sowing
Pre-sowing
Pre-sowing
Post-emergent
Post-emergent
Post-emergent
Post-emergent
70,000-286,000
70,000-286,000
170,000 –320,000
130,000
250-500
250-500
300-400
-
0-240
30-50
0-120
30-100
Flowering season
September
September
July (early var.) - Sep. (late var.)
March – April
Harvesting season
September - October
September
November – January
June – October
13-45
27
7.6-23.9
3-8
Bioethanol
Bioethanol, solid
Solid
Bioethanol, solid
Herbicide
Plant density (pl/ha)
Irrigation (mm)
Fertilisation (kg N/ha)
Dry
matter
yields
March-April (late var.)
(t/ha)
Biofuel type
25
Table 7: Perennial herbaceous energy crops.
Propagation material
Cardoon
Giant reed
Elephant grass
Switchgrass
Seeds
Rhizomes, stem
Rhizomes, stem cuttings, seeds
Seeds, rhizomes
cuttings
Sprouting season
April – May
March
April
March
Herbicide
Pre-planting
Pre-planting
Pre-emergent in the first 2 years
pre-planting
10,000 –50,000
12,500-28,500
28,500-40,000
4,000,000
-
400
60-700
200
Fertilization (kg N/ha)
0-100
40-120
40-240
0-150
Flowering season
Spring
September – October
August - September
June – July
Harvesting season
June - July
February
February
December – February
17-30
20-30
11-34
19 – 30
Solid
Solid
Solid
Bioethanol
Plant density (pl/ha)
Irrigation (mm)
Dry
matter
yields
(t/ha)
Biofuel type
Biodiesel
Solid
Table 8: Perennial woody energy crops .
Eucalyptus
Black locust
Seedlings, Stem
Seedlings, Stem
cuttings
cuttings
Herbicide
post-planting
post-planting
Plant density (plants/ha)
10,000-40,000
10,000-20,000
2-3
2-3
18 – 24
14
Solid
Solid
Propagation material
Rotation cycle (y)
Dry matter yields (t/ha)
Biofuel type
3.6
Animal wastes
The Greek livestock system constitutes of sheep, goats, lambs, cows, calves, swine,
broilers, layers and pullets breeding. Poultry farming, sheep and goats breeding
represent the highest percentage of livestock industry, amounted for the 90% of the total
units in the years 1999/2000 (National Statistical Service). However, sheep and goats
26
breeding are extensive and thus the produced manure is spread all over the grazing land.
Intensive livestock consists of cattle, brood sows and poultry farming.
During the previous decade (1991-2000) there was a tendency towards more intensive
livestock farming as a result of Greek agricultural policy. Thus, as presented in Table 9,
except for pig breeding, the total number of units decreased but in the same period the
number of breeding heads increased. This change was more pronounced in cattle
farming. In 2000 there were approximately half the units in comparison to the year 1991
but the number of breeding animals increased about 9.8%.
Table 9: Inventory of Greek livestock system for the years 1991 and 1999/2000 (NSS).
Cattle
Ships
Goats
Swine
Poultry
Year
Units
Heads
Units
Heads
Units
Heads
Units
Heads
Units
Heads
1991
53,070
594,183
160,560
8,269,691
202,720
5,188,044
32,296
975,848
398,048
34,994,980
1999/2000
28,313
652,604
128,235
8,743,366
137,452
5,322,755
36,159
971,030
325,474
39,492,096
% Change
-46.6
9.8
-20.1
5.7
-32.2
2.6
12.0
-0.5
-18.2
12.9
Exploitation of animal wastes for energy production through anaerobic digestion (AD)
process would be feasible only in cases of medium-large scale livestock units. The
number of medium and large-scale livestock units was defined in an inventory of the
Greek Agricultural Bank (31/12/1995). Depending on these figures, the total number of
breeding animal heads and the medium-large scale units for cattle, pig and chicken
breeding are presented in the following Table 10.
27
Table 10: Total number of medium-large livestock units, animal heads and daily
production of wastes.
Waste Volume
Units
Heads
Cows
77
12,582
462.89
Dairy Cows
242
36,265
1331.33
Calves
37
19,243
546.19
Swine
281
100,793
371.09
Broilers
79
16,110,000
1305.26
Layers
72
4,180,900
443.56
Pullets
20
1,233,500
130.86
(m3/day)
It is estimated that the intensive livestock farming in Greece results in a daily
production of 2,300, 370 and 1,880 m3 of animal wastes from cattle, pig and poultry
breeding, respectively. Figure 11 depicts the distribution of daily animal waste
production resulted from the medium-large scale livestock. Regions that concentrate
daily production of animal excrements of more than 5% of the total national amount are
Ioannina, Imathia, Evia, Thessaloniki and Attiki with corresponding percentage 8.2, 9.6,
10.1, 12.3 and 15.4%, respectively.
28
0 - 2 6488
26489 - 99 248
99249 - 22 1418
22141 9 - 4 7081 2
47081 3 - 7 1591 9
Figure 11: Spatial distribution of animal wastes in Greece.
In addition, it is estimated that the total methane yielding potential of these wastes could
be 0.5 million m3/day and energy potential over of 400 TOE. In the Table 11, the
volume of volatile solids, estimated gas yields and energy potential for these livestock
units are presented.
Table 11: Volume of volatile solids (VS), estimated gas yields and energy potential per
day of the medium-large scale livestock units in Greece (Chatziathanassiou and Boukis,
2001).
Category
Volume of VS (m3/day)
Gas yield
(103 Nm3 CH4)
Energy Potential (TOE)
Cattle
291
195
155
Brood sows
24
5
4
Chickens
980
300
255
1,295
500
414
Total
29
3.7
Biogas Production
At the beginning of the decade 12 biogas plants were in operation in Greece. The
characteristics of these plants as well as their production in biogas and energy are
presented in Table 12. In total the electricity produced, in a year, was calculated to
amount for 174,249.64MWhe while the heating energy was 717.40TJ. The majority of
biogas plants (7 of 12) used the sewage sludge of Municipal Waste Water Treatment
(MWWT), 3 were agro-industries and in the rest 2 the biogas was collected from pipes
established in landfills. The biggest part of the generated energy was produced in the
region of the Greek capital due to the operation of MWWT of Psytallia and Landfill of
Ano Liosia, which treat the liquid and solid municipal wastes of Athens, respectively.
30
Table 12. Greek AD plants.
Plant
Feedstock
Amount
3
(m /day)
Gas production
Installed
Installed
Produced
Produced
3
Capacity (kWhth)
Capacity
Electricity
Heat (TJ)
(kWhe)
(MWhe)
(Nm /day)
Data
MWWT of Chania
Sewage sludge
130-140
461
n.a.
166
44
3.6
2000
MWWT of Larisa
Sewage sludge
18,800
1,008
570
no
no
8.6
2000
MWWT of Heraklion
Sewage sludge
47,089
2,606
250
193
0.64
15.3
2001
MWWT of Chalkida
Sewage sludge
n.a.
958.9
640
no
no
8.6
2000
MWWT of Alexandroupoli
Sewage sludge
n.a.
n.a.
756
no
no
9.7
2000
MWWT of Volos
Sewage sludge
n.a
120
500
353
2,100
15
estimation
MWWT of Psyttalia
Sewage sludge
600,000
72,000 (consumption)
2,700
7,370
64,000
252
estimation
Sanit. Landfill, A.Liosia
Landfill gas
no
16,800 (consumption)
16,550
13,000
107,000
392
estimation
Sanit. Landfill, Tagarades
Landfill gas
no
3,936 (consumption)
no
240
1,105
no
ALIBRANTIS
Residues from alcohol
150
99
141
no
no
1.0
2000
500
219
756
no
no
2.6
2000
400
882
650
no
no
9.0
2000
174,249.64
717.40
industry
TASTY FOODS
Residues from chips
industry (potatoes)
ZANAE
Residues from yeast
industry
TOTAL
n.a.: non available / no: not applicable
Source: Survey carried out by CRES (Information Systems Division and Biomass Department)
31
3.8
Bioenergy in heat market
In Greece the concept of district heating is not widespread. Because of the hot climate it
is necessary to heat houses less than 6 months per year (exceptions exist but it’s a niche
market). Therefore there is no specified price for heat.
The only district heating schemes that exist in Greece are the ones using the waste heat
of some lignite thermal plants listed in table 10. In the mid-1990s Public Power
Corporation- PPC (the only power generating utility till 2001 and still the largest one)
converted electrical energy production stations to cogeneration facilities with district
heating projects for the cities of Ptolemais and Kozani (northern Greece). Three more
stations are being converted to CHP (Amyntaio, Megalopoli, Florina). In 1993, PPC
began to construct power stations with the capability of district heating.
Table 13: District heating schemes in Greece
Thermal Plants
Installed thermal capacity
Condition
Ptolemaida
50 MWth
Operational
Kozani
67 MWth
Operational
Amyntaio
40 MWth
Under development
Megalopoli
20 MWth
Under development
Florina
70 MWth
Under development
117 MWth installed capacity
130 MWth additional potential capacity
Due to the above reasons the thermal energy produced from biomass in Greece concerns
either domestic use or industries that produce biomass residues and have at the same
time thermal needs. Under these conditions the efficiency of the conversion is
determined by the needs and is not always the best possible. The thermal energy
produced from biomass in Greece per sector is presented in Table 14, and the
32
proportional contribution of each sector is presented in Figure 12. These data do not
include the thermal energy produced from co-generation plants (see next chapter).
Table 14: Units producing thermal energy per sector in Greece in 2000 (CRES, 2002)
Type
Number of
Consumption
Thermal energy produced
units
(tonnes)
(MWh/y)
1,298,520
8,163,508
FUEL WOOD COMBUSTION
Domestic use
BIOGAS COMBUSTION
6
21,495
Food industry residues
3
8,667
Sewage treatment plants
3
12,828
RESIDUE COMBUSTION
2,720
2,811,500
Wood residues
58
99,138
380,278
Cotton ginning residues
18
28,138
83,889
2,633
500,000
2,325,556
Husks/Kernels
3
612
3,194
Rice residues
7
4,330
18,333
Straw
1
56
250
2,726
632,274
2,832,995
Dry olive kernels
TOTAL
33
R ic e
re s id u e s
0 .6 5 %
Food
in d u s try
re s id u e s
0 .3 1 %
S tra w
0 .0 1 %
Sewage
tre a tm e n t
p la n ts
0 .4 5 %
W ood
re s id u e s
1 3 .4 2 %
H u s k s /K e rn
e ls
0 .1 1 %
C o tto n
g in n in g
re s id u e s
2 .9 6 %
D ry o liv e
k e rn e ls
8 2 .0 9 %
Figure 12: Contribution of the various industrial sectors in the thermal energy
production (Greece)
3.9
Bioenergy in the electricity market
From 1950 to 1994 the Public Power Corporation (PPC) was the only company
producing, transmitting and distributing electrical energy in Greece. The PPC
generation system consists of the interconnected mainland system (some nearby islands
are also connected there), the systems of Crete, Rhodes, and the independent systems of
the remaining islands. From 1994 it was allowed to auto-producers and independent
producers to generate electrical energy from renewable energy sources while from 1999
the deregulation of the electrical energy market was established.
The first attempts to produce electricity from biomass in Greece were focused in
projects that were undertaken for environmental reasons (sewage treatment plants,
landfill gas from sanitary landfills). There is one demo plant that produces only
electricity (Table 15) and several others that also produce heat (co-generation units,
Table 16). The latest co-generation unit (Agrino) is the only industry that consumes
agricultural residues to produce electricity. Although all the cogeneration units produce
heat, once more the consumption of heat is determined by the needs and is not the
maximum possible.
34
Table 15: Units producing electricity from biomass in Greece
COMPANY
Activity
Municipality of
Installed capacity
Electrical energy
(MWe)
produced (MWh/y)
0.24
1,105
Landfill gas
Thessaloniki
Table 16: Co-generation units using biomass in Greece
COMPANY
Activity
Installed
Installed
Electrical
Thermal
Data
electrical
thermal
energy
energy
capacity
capacity
produced
produced
(MWe)
(MWth)
(MWh/y)
(MWh/y)
7.37
2.7
64,000.00
70,000.00
estimation
Water Entity,
Sewage treatment
Psyttalia
plants
Consortium
Landfill gas
13.00
16.55
107,000.00
109,000.00
estimation
Munic.Ent.,
Sewage treatment
0.35
0.5
2,100.00
4,200.00
estimation
Volos
plants
Munic.Ent.,
Sewage treatment
0.19
0.25
0.64
Partial use
2001
Heraklio
plants
Munic.Ent.,
Sewage treatment
0.17
Non available
44.00
1,000.00
2000
Chania
plants
Agrino
Rice industry
0.44
Non available
1,033.00
22,500.00
estimation
21.75
20.61
(munic.+
private)
TOTAL
35
174,177.64 206,700.00
Table 17. Biomass CHP projects that have received production permits (www.rae.gr)
REGION
INSTALLED
FUEL
TECHNOLOGY
CAPACITY
MW
Tebloni, Kerkyra
4
landfill gas
2*2,7 MW engines
Thermi, Thessaloniki
8
landfill gas
6*1,35 ΜW engines
Liosia, Attiki
9.5
landfill gas
3*1,4 ΜW engines
Metamorfosi, Attiki
0.92
sewage treatment biogas
anaerobic digestion
Patra, Achaia
0.9
sewage treatment biogas
anaerobic digestion
3
fruit peels and fibres
anaerobic digestion
Fillipiada, Preveza
4.09
pig manure
anaerobic digestion
Xanthi
9.5
MSW
gasification
Rodos, Dodekanisa
0.5
MSW
Meligalas, Messinia
8.14
prunings
gasification, 6*1,356 ΜW engines
Meligalas, Messinia
5
Dried olive stones
fluid. bed combustion, steam turbine
Sparti, Lakonia
53.55
22 MWe are already installed, while future projects for another 53.5 MWe from
biomass CHP have already received power production permits from the Regulatory
Authority of Energy (Table 17) (www.rae.gr). Industries are trying anaerobic digestion
for the production of electricity for the first time, and also other technologies are taken
under consideration.
36
4.
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