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NEW DEDICATED ENERGY CROPS FORSOLID BIOFUELS
The resources from European forestry and by-prod-ucts from wood industry are not sufficient to meetthe objective of the EU for bioenergy, especially ifwe opt for second generation biofuels.
In the long term, bioenergy crops from agricultureprovide a significant potential for the biomass sup-ply. The environmentally-compatible bioenergypotential from agriculture can reach up to 142 Mtoeby 2030 compared to 47 in 2010 (EEA report). Sucha development will occur if the high yield crops areintroduced and their productivity is increased.
New dedicated energy crops for energy productionwould enable the EU to diversify its energy sources,provide an income to European farmers and reduceCO2 emissions.
1 Development of energy crops inEurope
In Europe, solid biomass energy crops cover about50 - 60 000 ha of land. It is rather a small area if
compared with traditional energy crops grown fortransport biofuels that amount about 2,5 million haof land. The largest areas of energy crops can befound in the UK (mainly miscanthus and willow),Sweden (willow, reed canary grass), Finland (reedcanary grass), Germany (miscanthus, willow, etc),Spain and Italy (miscanthus, poplar). The picturebellow provides an overview of energy crops devel-opment in Europe. However, this graph does notcover all the EU countries as the statistics of ener-gy crop plantations for solid biofuels are almostinexistent in most of them. Empty squares showthat the actual production of the crop is most prob-
ably higher; however, different sources indicate dif-ferent numbers.
2 Energy crops characteristics
The best biomass crops for energy production isone that can be harvested dry and has a perennialgrowth habit (no need for annual planting or tillage)to minimize cultivation costs. Low input of fertilizersand other chemicals when growing these plantshelps to reduce the environmental impact as well asto improve energy efficiency. It is also importantthat plants can convert solar energy efficiently. Twomajor pathways of photosynthesis are the C3 andC4 pathway. In general, the C3 assimilation path isadapted to operate under low temperature (15-20°C) whereas C4 metabolic pathway species aremore efficient converters in high light level and hightemperature situations.
Tropical grasses, such as sugar cane, maize, alsomiscanthus and sweet sorghum are C4 plants. C4plants can generate a theoretical maximum drymatter yield of 55 t/ha year compared with 33 t/hafrom normal C3 temperate crops. However, C4plants can only generate such a yield under hot cli-mate conditions. In temperate climate C3 plants
might be more suitable. For example, short rotationforestry suitable for energy production under tem-perate climate is mostly C3 species – willow, poplar,etc. Generally, the C4 crops such as Miscanthus aremore suitable for arable lands whereas C3 cropscan be grown on marginal land. In order to make thecrop growing process environmentally friendly, atransportation distance should be as short as pos-sible and should preferably not exceed 40 km.
Conversion
The primary product, in this case, Miscanthus,
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SE IR UK FR DK HU AT PO FI SK IT Baltics
Willow
Miscanthus
Reed Canary Grass
source: Aebiom
Solid biomass energy crops statistics, 2007
C4 - plant that prefaces the Calvin Cycle with reactions that incorporate CO2 into 4-carbon compound. C4 plants have a distinctive leaf anatomy. Thispathway is found mostly in hot regions with intense sunlight.
Poplar, Willow, Reed Canary Grass is converted tosolid biuofuels in the form of chips (using a chipper)or briquettes, pellets and bales using compactiontechnology and then can be used for electricity andheating purposes.
There are three types of plants that are suitable toproduce solid biofuels:
• annual plant species - planted and harvestedevery year - such as cereals, hemp, or kenaf;• perennial species – planted once usually every12 - 25 years and harvested annually - such asMiscanthus, reed canary grass and other reeds;• short rotation coppice (SRC) – planted once usu-ally every 20-30 years and harvested every 2 to8 years - such as willow, poplar, black locust orpaulownia with a perennial harvest rhythm.
Technical properties
In order to determine suitability of energy crops togrow them in a chosen area, the following factors
should be considered: the agronomic factors suchas crop yields, soils and climate, suitability of exist-ing machinery, energy input/output per hectare, andeffective utilization of all of the components of thecrop at the processing stage. Calorific value, ashcontent of the harvested plant and ash propertiessuch as ash melting point as well as moisture con-tent at harvest are of a crucial importance for ener-gy production.
Dry mass (DM) yield and the heating value of thecrops are the most important factors in determiningthe energy source potentials for solid fuels.Therefore, it should be noted that dry mass yieldlargely depends on soil and climate conditionswhereas the water content depends on the time ofharvest.
For comparison of the crops discussed bellow, theyield, medium energy content as well as ash andwater content are presented bellow:
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Division of Selected Energy Crops into Groups
Crops Dry mass yield Lower heating value Energy production per ha Water content at harvest Ash content
[tDM/(ha year)] [MJ/kgDM] [GJ/ha] % Weight %
Straw 2 - 4 17 35-70 14.5 5
Miscanthus 8 - 32 17,5 140-560 15 3.7
Hemp 10 - 18 16.8 170-300 n/a n/a
Willow 8 - 15 18.5 280-315 53 2.0
Poplar 9 - 16 18.7 170-300 49 1.5
Giant reed 15 - 35 16.3 245-570 50 5
Reed canary grass 6 -12 16.3 100-130 13 4
Switchgrass 9-18 17 n/a 15 6
Black locust 5 -10 19,5 100-200 35 n/a
Wood 3 - 5 18,7 74,8 50 1-1,5
Sources: AEBIOM “European Biomass Statistics 2007”; N.El Bassam “Energy plant species”; M J Bullard and others “Biomass and energy crops”
3 Miscanthus
Miscanthus speciesare perennial, rhi-zomatous grassescoming from Asia.Rhizomatous impliesthat it spreads natural-ly by means of under-ground storageorgans (rhizomes).Miscanthus x gigan-teus, is not invasiveand each plant growsto approximately 1meter in diameter,after which the plantsdo not continue tospread. Miscanthuscan grow up to 3.5
meters tall and theoreti-cally can give an annual harvest of up to 30 t/ha ofdry matter excluding the first couple of years. Likeother bioenergy crops, the harvested stems of mis-canthus may be used as fuel for production of heatand electric power, or in the future for conversion to2nd generation biofuels such as ethanol.Miscanthus is high in lignin and lignocellulose fibreand uses the C4 pathway.
Climate conditions and soil preferences
Miscanthus can be grown in a temperate climateand on many types of arable land. The yield of thecrop depends on sunshine, water availability andtemperature. Miscanthus does not grow at temper-atures below a threshold of 6oC. This is consider-ably lower than for maize which means that thegrowing season is longer.
The soil is an important factor for Miscanthus pro-ductivity. The yield on fertile soils can reach up to30 tons dry matter per hectare per year(DM/ha/year). However, the yield on less productivesoils can hardly reach 10t DM/ha/year. Increases in
productivity result in increases in water demand.For example, in order to produce maximum yields,Miscanthus x giganteus is able to utilize large quan-tities of water, up to 900 mm/year. Several conclu-sions can be made as regards to the soil preferenceof Miscanthus (D.G. Christian and E. Haase, 2001):
• Soil that is suitable for growing maize is alsolikely to be suitable for Miscanthus• The most suitable soil for growing Miscanthus isa medium soil such as a sandy or silty loam(brown earth or para brown earth) with a good airmovement, a high water-holding capacity andorganic matter content• Maximum yields are not achieved when the cropis grown on shallow soils in combination with longdry spells during summer although establishmentand survival are possible. • Cold and heavy waterlogged soils (e.g. clays) arenot suitable for growing Miscanthus (low tillernumber and plant height).• It is possible to grow Miscanthus in sandy soilswith a low water capacity but yields are low inthese circumstances.
Planting
It is important toestablish the cropcorrectly beforeplanting. The fiststep is the weedcontrol by sprayingthe site with anappropriate broadspectrum herbicide.The soil should besubsoiled if necessaryto remove compaction. After the crop is fully estab-lished, there is generally no need for further chemi-cal inputs.
Two methods of Miscanthus propagation are usedin Europe – micropropagation and rhizome division.The later one is used more often and is a more eco-nomically viable way to plant Miscanthus.
Rhizomes need to be planted to allow for someexpansion of the plant during the life of the cropand at a soil depth of 5-15 cm. Planting densitiesvary from 10,000 to 15,000 or more rhizomes perhectare. Miscanthus does not require a big input offertilizers due to good nutrient use efficiency and itsability to recycle large amounts of nutrients into therhizomes during the latter part of the growing sea-son (the maximum quantity of nitrogen is between50 and 70 kg N/(ha*year)) (Clifton-Brown J.C andothers, 2000).
The planting date should be late enough in the yearto avoid severe late spring frosts but early enoughto allow good establishment, growth and transloca-tion of reserves to the rhizome prior to the witherfrosts. Young plants and rhizomes can be very sen-
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Miscanthus, source : Deplanque
Miscanthus rhizome, source : Bical
Miscanthus, source : Bical
sitive to frost (when micropropagation plantingmethod is used) – if the temperature of the soildrops to less than 3,5°C during the first plantingyear, the rhizomes die. Nevertheless, Miscanthusplants grown from rhizomes can survive at least -5,5°C below freezing and potentially colder temper-atures.
Miscanthus is usually planted in March or April,
reaches 1-2 meters in height by late August, startsdrying by late July and is harvested in winter.However, in cold climates like in central and north-ern Europe Miscanthus dries after the first frost(which kills the tree cells) in winter and is harvestedin spring (March), just before the growth of the newshoots start so that the new shoots are not dam-aged. In warmer climates of southern Europe, theplant starts drying in November and can be harvest-ed from November to February, or in early March.
Planting can be carried out using semi-automaticpotato planters for plants, bespoke planters ormanure spreaders for crushed rhizomes (the leastfavored option). However, in the last 5 years specialplanting machines have been developed by compa-nies such as Bical enabling to plant Miscanthus atthe best daily rate possible. The planter has somesoil and seedbed requirements to enable it to oper-ate efficiently.
Harvesting
Once established, the crop can be harvested annu-ally for at least 15 years. Harvesting of Miscanthusshould be carried out after the crop has senesced,when the moisture content is lowest and beforeregrowth begins in the following spring. Miscanthusis not harvested in the first year due to the low yieldof the plant, however, the yield of the second yearcan reach maximum 10 t/ha of dry matter. From thesecond season onwards the crop can be expectedto achieve a maximum height of 2.5 - 3.5 m. By thethird year harvestable yields are between 10-15 tons of dry matter per hectare. Peak harvestable
yields of 20 t/ha have been recorded.
Harvesting can be carried out using a number of dif-ferent machines such as a mower conditioner, for-age harvester, maize harvester with a speciallyadopted head (kemper) to cut the grass, balers tobale the product, and transport with conventionaltransportation. Miscanthus can also be harvestedevery year with a sugar cane harvester.
The cutting part of the harvester should be adjusted
at the lowest possible way to avoid the yield losses.Some machines are especially adapted to cut andbundle the plant at the same time (developed byClaas and Deutz-Fahr).
In south Europe the humidity of Miscanthus at har-vest can be as low as 15%, however, in Germanyand in the UK it is between 16-25% if the plant isharvested when the moisture content is the lowest.
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Miscanthus planting machine, source: Bical
Bailing , source: Bical
Miscanthus harvesting, source: Bical
4 Short rotation coppice: willow andpoplar
Short Rotation Coppice (SRC) is densely planted,high yielding species such as willow, poplar andeucalyptus. It is harvested on a 2 to 5 year cycle,although commonly every 3 years. Willow andpoplar are well adapted to cool climates and toler-ate temporary wet conditions better than most ofother species.
Willow (Salix spp.)
Willow is mainly found in northern Europe, Asia, andnorth America as well as in the mountainous partsof China. There are about 300 species in the world,however, Salix viminalis is one of the most frequent-ly grown species for energy uses.
Climate conditions and soil preferences
Willow can be grown on a wide range of soil types,on light soils as well as on loamy soils, with a pHrange from 6.0 to 7.5 and an optimum pH of 6.5.However, mineral soils are more advantageous forgrowing willow. This is because it is easier to con-trol weeds on mineral soils than on organic soils.Furthermore, the later are more frequently found infrost-sensitive areas. On pure sand soils productionof willow may be low due to the water deficiency.Fine sand, loam, clay loam and heavy clay are suit-able for production of willow.
Salix species are more dependent on water thanany other agricultural crops; therefore, dry locations
should be avoided. Willow’s water consumptioncan reach 4,8 mm/day in June and July. Irrigation isnecessary if the yearly rainfall is less than600 mm/year. To a certain degree willows are toler-ant of waterlodging (not a permanent one). Theoptimal growing temperature of willow rangesbetween 15°C and 26°C. Minimum growing tem-perature is 5°C -10°C and maximum 30°C - 40°C.
Planting willow
The planting of willow, with 12 000 - 15 000 cuttingsper hectare, is done in spring once the soil hasbecome sufficiently warm (+5°C) to enable the cut-tings start growing. It grows rapidly in the first yearreaching up to 4 metres height. Specific varieties ofwillow are usually selected for their yield, ability toproduce long stems without branching as well astheir resistance to cold and rust. Good weed con-trol is very important during the first year for a gooddevelopment of the plant. Weed control can bedone by spraying a soil-applied herbicide on theentire field directly after planting. Additionalmechanical weed control can be done one or twomonths later. However, weed control is also possi-ble using only mechanical methods. Fertilisation islow due to the fact that harvesting occurs in winterwhen the leaves containing the biggest amount ofnutrients have fallen off the trees.
Willow is usually planted using a Step planter which
automatically cuts the whole-shoots into lengths of16-20 cm cuttings before they are pressed into thesoil. Another option is Frobbesta planter - preparedcuttings are fed automatically one at a time into anarrow furrow, after which the furrow is closed andcovered with soil. Autstoft planting machine and‘Lay flat’ planting system can also be used forplanting willow.
However, in Denmark, a more sophisticated theEgedal Energy Planter was developed by Ny VraaBioenergi and Egedal Maskinfabrik.
So far, the planter is operational in the UK,Denmark, Austria, Hungary, Slovakia, France, USAand Poland. If compared with a Step planter,
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Willow, source : Ena-Energi
Weed control, source: Ena Energi
besides the differences with cutting and plantingsystem, the Egedal Energy 4 row planter has a dou-ble capacity. The machine is developed to cut andplant willow cuttings in one operation. The 2-3 meters long willows are feed to the drum cut sys-tem of the machine, which cut the willows inapproximately 20 cm lengths and then plants thecuttings vertically into the plant furrow by means of
a hydraulic planting device. The machine (4 rows)has a capacity of approximately 1,5-3 ha/hour (12-13.000 cuttings per hectare), adjustable plant dis-
tance and standard a row distance of 75 cm. with aunique cutting system. The Energy Planter is adapt-ed to plant in almost all conditions and can plantdirect on set aside land or in stubble even on clay.
Harvesting
The harvesting of the wood takes place at the veg-etative rest (November to February). At this time ofthe year the wood has a water content of around50%. Performance of SRC depends on the selec-tion of species, environmental conditions, fertilizers,soil etc. and can reach up to 20 t/ha. However, usu-ally yield ranges from 8 to 12 t/ha of dry matter.
Harvesting can be carried out using 3 main meth-ods: the coppice is cut and bundled in bundles; thecoppice is cut and chipped in a single operation,then blown into a trailer; and an intermediate sys-tem where the coppice is cut into billets and blowninto a trailer.
For harvesting with direct chipping purposes, ClaasJaguar is the most widely used technology. Claasmachine was initially designed for maize and forageharvesting, however, adapted to willow harvestingby fitting a modified header. Willow shoots are cutoff by two circular saws and are processed intochips by a built-in chipper. The quality of chips issimilar to that of forest chips. Even though it is nomore widely used, the Bender machine can be usedfor harvesting. The harvesting unit of this machine ismounted on a large tractor. The shoots are cut fromthe stools with a chain saw and chipped by a discchipper. The Austoft 7700, another willow harvest-ing machine, initially designed for sugar cane har-vesting, is equipped with tracks that give themachine extremely good accessibility. The machineweights 12,5 tons and the chips produced areslightly coarser than forest chips. The shoots are cutoff at the stumps with circular saws. After harvest-ing, the chips can be stored and dried in piles in thefield.
The harvesting with direct chipping is the most costeffective way of harvesting, however, not the bestsolution for smaller heating plants due to the highmoisture content of the chips (unless the plant hasa steam condensation installation). If dry chips are
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Frobbesta planter, source : AEBIOM
Egedal planter, source: Ny Vraa Bioenergi
Claas machine, source: Styrian Chamber of Agriculture
required, the harvesting can be done using Empire2000 machine which is designed for whole shootharvesting. This harvester weights 12 tons. Theshoots are cut off from the stool by means of twocircular saws and are transported then to a storagehopper on the machine. The shoots are unloadedwith a built-in elevator and can be placed in piles upto a height of 2 to 3 meters. In this way, the shootscan be stored and dried in the field during thespring and summer. A plantation could be viable forup to 30 years before re-planting becomes neces-sary. However, Empire 2000 is not the most recentmachine for whole stems harvesting and themachines such as Mantis – a self-propelled wholerod harvester which is used by Nordic Biomass andStemster TR – tractor-trailed whole stem harvesterused in Ireland and Brittany (France) can be usedmore efficiently than Empire 2000.
Advantages of willow use
Willow is not only the source of bioenergy but alsohelps to solve certain environmental problems.Growing willow can be combined with purificationof urban or industrial water, can reduce the use ofpesticides, help to avoid further soil erosion, protectground water and increase biodiversity etc.
Purification of urban and industrial water. When irri-gated with wastewater, the SRC plantation acts asa biological filter and remove nutrients as well assome heavy metals from the wastewater. Such bio-
filtration can replace conventional tertiary treatmentwhile increasing the SRC biomass yield due to irri-gation and fertilisation. The system has manyadvantages such as recycling of nutrients, reducinghealth hazards as SRC is a non food crop, goodenergy balance, cheaper purification system forwater companies, higher profitability for growersdue to a lower cost for fertilisers and a higher yield.The main drawbacks are a lower purification poten-tial during winter and the extensive character of thesystem which needs relatively large areas. This typeof irrigation system for willow plantations is used inSweden, France and Ireland.
Reduction of pesticides use is another importantadvantage of willow plantations. Comparing withtraditional grain production, about 60% less pesti-cides are used for willow plantations.
Poplar (Populus spp.)
Poplars are usually planted in south Europeancountries such as Spain and Italy. Poplars are morefrost sensitive than willows and, therefore, are not
usually planted in northern European countries.
The plant is also grown in Central European coun-tries where it reaches rather high yields per hectare,up to 22 t DM/ha/y. Research has shown thatpoplar can often outperform willow in terms of yieldbut this appears to be site specific and highlightsthe fact that choosing the appropriate varieties for asite is essential. Unlike willow, poplar tends to pro-duce better yields when allowed to grow for fouryears or more from cutback.
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Stemster TR - whole shoot harvesting, source: AILE - Wilwater
Willow irrigation by pre-treated waste water, source: AILE - Wilwater
Source: Styrian Chamber of Agriculture
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Soil preferences
Poplar grows best in deep fertile soils, although itcan grow on wide range soils. However, shallowsoils and sites that remain waterlogged should beavoided. Soil pH should ideally fall in the range 5.5- 7.5. Preparation of the site should be the same asthat for willow SRC, including the weed control.Weed control is very important in the establishmentyear, so after planting and rolling a residual herbi-cide should be applied within 3-5 days. Cutbacktakes place late in the winter following planting.
The soil should be well cultivated to a depth of atleast 25 cm. Where compaction is present, sub-soil-ing should be carried out to a depth of 40 cm. Dueto its apical dominance, poplar will generally pro-duce only 1-3 shoots after cutback.
Planting
Planting should take place as early as possible inthe spring but avoiding frost. The density of plantinghas generally been lower than that for willow at 10-12,000 cuttings/ha. The planting and field manage-
ment in the establishing phase is very similar to wil-low cultivations.
The step planter (see page 14) is not suitable forplanting poplars for SRC because whole poplarrods are much more brittle than willows and liable tobreakage. Also the stem diameter of poplar rodstends to be much greater after one year’s growth
than the equivalent willow rods, and consequentlythey are generally too thick to enter the deliverytubes. However, the Egedal Energy Planter used forwillow (see planting willow) can be successfullyused for planting poplar. No fertilizer is applied inthe planting year because of the risk that the weedsbenefit more than poplars. Modified cabbageplanters can be also suitable to plant poplars butdue to the ridged nature of poplar stems, the cut-tings occasionally block the planter mechanisms.
Harvesting
The rotation period of poplar is usually 5-7 yearslonger than willow’s. Therefore, the harvest is car-ried out less frequently. Harvesting Poplar requiresheavier machinery as it produces fewer and heavierstems. Higher stem diameter, rigid stems can cause
problems with fully mechanized harvesters. If theharvesting operations are carried out every 5-7 years in which case the stem diameter of poplarreaches 10-15 cm, the forestry machinery used forthinning operations is the most suitable. However,the same harvesting machinery as for willow can beused if poplar harvesting is carried out every 3-4 years.
Source: Styrian Chamber of Agriculture
Source: Styrian Chamber of Agriculture
Felling head, Source: Allan Bruks
5 Reed Canary Grass (Phalaris arundi-nacea)
Reed canary grass isperennial C3 plant. Itusually grows indamp areas. Reedcanary grass is anative plant in tem-perate regions, likeScandinavia, which isused since around20 years for energyproduction. The plantis mostly grown inFinland with the totalestimated cultivationarea of 20 000 ha in2007. This rhizoma-tous grass grows
naturally to between60 cm and 2 m high and has hairless light green orwhitish green leaves 10-35 cm long and 6-18 cmwide.
Propagation and soil preferences
Reed canary grass spreads naturally by creepingrhizomes, but plants can be raised from seed.Flowering occurs in June to August, and seed isproduced. The plant frequently occurs in wetplaces, along the margins of rivers, streams, lakesand pools. The advantages of the species as ener-gy crop are its adaptation to poor wet soils, its abil-ity to be established from seed and its attainment ofhigh dry matter content. Reed canary grass needsrelatively little fertilizer.
Success of the crop depends on a sufficient supplyof nutrients and oxygen rich, non-stagnant water.Reed canary grass tolerates well both drought andwet conditions due to its excessive large root sys-tem. In the USA, where the grass is largely cultivat-ed for forage, it is mainly used because of its goodresistance to dry conditions in prairies. However,waterlogged soil is not suitable because of the defi-ciency of oxygen.
Harvesting, baling and logistics
The fuel properties are improved when the grass isallowed to dry for the following autumn or winter,during which the nutrients accumulate into theroots and water rinses out the harmful trace ele-ments to some extent. Reed canary grass (RCG) isusually harvested annually in spring with conven-tional technology either by mowing or baling usinga high density baler. The yield of this plant canreach 11 t DM/ha/year, however, an average yield of6-8 t DM/ha/year can be expected. Crop durationof 12-15 years is possible. Due to its low moisturecontent – 85-90% of dry matter at harvest, canarygrass (those harvested in spring) can be easily con-verted to pellets, briquettes and powder.
However, harvesting, baling and logistics need fur-ther improvement in order to make this plant morecost efficient. Harvesting losses can be very high upto 50-60% due to the light weight of the fuel, espe-cially in the chopped form. The transport of reedcanary grass can be economical only for short dis-tances, less than 80 kilometers. Also the efficiencyof the transport of round bales which is the mostcommon type of baling is relatively low. The prevail-ing agricultural choppers and industrial crushers ofpower plants are in most cases unsuitable for chop-ping of bales for fuel production. However, experi-ments carried out by VTT, showed that disc mowerand silage windrowers produce the lowest harvestlosses (20-30%). It was also shown that silagemower with conditioner can reach low losses (20%)if the adjustments are in optimum. A new type bigsquare baler reached maximum bale density201 kg/m3 (moisture content 15%). Although tightand optimum shaped big square bales are the bestsolution for long distance transport of reed canarygrass, round bales are better suited for shortertransport distances as they are significantly cheap-
er and lighter than big square baler. Another alter-native to reduce the high cost of transportation is tomix the grass with wood chips or peat before the
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Harvesting, source : Vapo
Round bales, source : Vapo
source : Vapo
long-distance transport.
As for chopping the reed canary grass, slow speedtwo–rotor crushers can be appropriate for choppingin certain conditions. This system under suitablefeeding speed which is one bale per two minutesdoes not cause dust problem and can be econom-ically viable. If the high speed crushers are used,dust can be reduced by using water spray or evenbetter solution is crushing the grass with moistwood simultaneously.
In Finland the plant is mainly used for co-firing withother type of biomass or in coal fired power plants.Due to the fuel properties, reed canary grass shouldbe used in mixtures with peat and wood chips oth-erwise it might cause blockages on conveyor sys-tems. Studies and practical experience has shownthat the optimum amount of RCG in the mixture canbe 10-20% (which is 20-30% in volume) dependingon the main fuel. Such amount of reed canary grasswill not provoke corrosion in boilers or increasefouling as it might be feared.
6 Other energy crops
Energy crops such as Miscanthus, Willow, Poplarand Reed Canary Grass are widely grown and arecommercially viable in Europe. However, these arenot the only energy crops that can be used forbioenergy production. At present, only small quan-tities of other crops such as Giant Reed,Switchgrass, Hemp are grown for biomass purpos-es. Further studies on these plants should enable toexploit them (and many more) on a larger scale.
Giant Reed (Arundo donax L.)
Giant reed is a wild C3 plant growing in southernEurope regions.
Although Giant Reed grows best in a warm climate,certain genotypes canbe adapted to coolerclimates and can begrown in countries likeGermany or the UK.
Giant Reed is one ofthe most productivecrops as its yieldreaches more than30 t/ha of dry matter(only in SouthernEurope) as well as one
of the most cost-ef fective energy crops because itis perennial with low annual inputs after establish-ment of the crop. The annual input consists of har-vesting, irrigation and/or fertilization costs. Giantreed is one of the largest grass species that can begrown in cool temperatures and it can grow up to5 meters tall and 3.5 cm in diameter. Giant Reed isusually harvested in late winter to make sure thatthe moisture content is not over 50%. Giant reed isusually established by planting rhizome cuttings;however, appropriate machinery for planting is notyet available. Propagation of the plant is also possi-ble through stem cuttings or whole stems; never-theless, further research is still needed. Plantingdensities of 12,500 plants per hectare (100 cm x80 cm) can be economically viable. Depending onits use, giant reed is either harvested each year orevery second year. Harvesting operations can becarried out using a mower-fodder–loader combin-ing machines with no rows cutter (KEMPER), gener-ally used for maize harvesting.
Hemp (Cannabis sativa)
Hemp is an annual short day, C3 plant with a highcellulose and lignin content in its stems and a highfat and protein content in its seeds. The entire plantconsisting of bast fibres, leaves, seeds, andprocessable remains can be used as a solid fuelwhen compacted. The stalk contains a very strongand durable fibre. The average height is 2.5 etersbut it can reach up to 4 meters height. For the ener-getic use the whole hemp crop is harvested. Directharvesting by a forage harvester was tested. Hempcan be easily planted and cultivated but its growingis prohibited in some EU countries as it can begrown as a drug. Theplants vegetative period isabout 100 days, with themain growth period in Juneand July, followed by flow-ering in August. Hempyields can reach up to 18 tDM/ha but the high plantmoisture content can cre-ate storage -problems. Theyields were tested in theNetherlands and reached10-17 t odt/ha (oven dry tonsper hectare), with the highest yields on clay soils. InAustria yields were lower and reached 6-14 odt/ha.Hemp needs low inputs of pesticides and fertilisers.
Two different harvesting technologies are availablefor the energy use of the whole hemp crop. The firstis the whole-fibre-technology where, with a modi-fied chopping technology, the hemp culm is cut into50 to 60 cm lengths. The straw stays for four weekson the field for drying before the bales are pressed.Another technology is wet harvesting. This technol-ogy includes the chopping of the crops followed bysilaging. For combustion it is necessary to press thehemp silage into bales to reduce the water contentof the fuel.
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Square bales, source : Vapo
Hemp, source: Wikipedia
Giant Reed, source : Hellabiom
Switchgrass (Panicum virgatum L.)
Switchgrass is a lignocellulosic perennial rhizoma-tous grass that uses the C4 pathway. Switchgrass isusually grown as a prairie grass in North America onmarginal lands not well suited for conventional rowcrops. Since the early 1990s the crop has been
developed as a modelherbaceous energy cropfor ethanol and electrici-ty production in the USAand in Canada.Switchgrass can growto more than 3 m heightand develop roots to adepth of more than3,5 m. A normal switch-grass stand has a lifespan of ten years.However, the grass isnot harvested in theseeding (establishment)year. The harvest activi-ties start in the second
year of the stand life ifthere has not been any reseeding. Harvesting activ-ities involve mowing, raking, baling, staging, andloading. Harvest is done during the autumn periodand in large square bales with a weight of about 400kg/bale. Yields of up to 18 tons dry matter/ha werefound in North West Europe and up to 25 tons drymatter/ha in Southern Europe. Switchgrass bio-mass can be used for thermal conversion to elec-tricity and heat and also has potential to be a fibresource for paper pulp production.
Sudangras (Sorghum sudanense)
Sudangrass is a C4 plant which origins lay in thetropics, where it is used very often as feed grass foranimals. But this plant can also be grown in south-ern and central regions of Europe, where the firstexperimental fields were planted in the past years.
Sudangrass requires a high quality of soil and theyields on bad soil decrease considerably. With goodmanagement practices and fertilizer this can be
counterbalanced.Sudangras has hightolerance for watershortage; thereforeit can be grown indrier regions like insouthern Europe.But the yields arehigher if sufficientwater can be pro-vided during thegrowing season.
Sudangrass is verysensitive to frost,therefore, the plant-ing site and time
should be selected carefully. A seeding rate of 15kg/ha should be planted at a depth of 2-3.5 cm in18-36 cm rows. The seeding is usually done in thebeginning of May with a distance between the rowsof 30 cm and a planting depth of 3 cm. At the begin-ning the plants are growing quite slowly, but after afew weeks the plant grows rapidly reaching a heightof up to 3 meters.
Sudangrass is harvested using traditional machin-ery like the one used for maize.
Sudangrass can yield in an annual harvest of up to30 t dry matter. For the moment Sudangras is usedfor bioenergy production mainly in biogas plantswith a similar biogas output like maize. But in thefuture it can be also used for the production of sec-ond generation biofuels.
Black Locust (Robinia pseudoacacia)
Black locust is a fast growing short rotation coppicewhich uses the C3 pathway and originates fromNorth America. In Europe, it is cultivated in coun-tries such as Hungary, France, Romania, CzechRepublic and Bulgaria. The plant grows on a largenumber of soils, but not on very dry or heavy soils.Black Locust prefers sites with loose structuralsoils, especially silty and sandy loams and is resist-ant to environmental stresses such as drought, high
and low temperatures, andair pollutants. Soil aerationand water regime are themost important soil charac-teristics for good blacklocust growth. Propagationof the plant is possiblethrough root cuttings,greenwood cutting,seedlings or micropropaga-tion. Propagation using rootcuttings and greenwood
cuttings provides a guaran-teed quality, but is more expensive than seed prop-agation. The best period for planting is April. As forharvesting, black locust is different to other fastgrowing trees such as willow and poplar. Blacklocust has thorns, which makesok it difficult to han-dle manually, and it is thus preferable to chip it in thefield. Black locust can sprout from the roots, soafter the third or fourth cut regrowth will also occursbetween the rows. In addition, black locust hasharder wood than other fast growing trees.Therefore, the cutting apparatus must be moredurable and powerful than that used normally. Thedry mass yield can reach from 5 to 10 t/ha by threeor four year rotations of black locust stands from10 000 trees/ha. However, the yield of this plantdepends largely on planting density, soil properties,fertilization, climate etc.
12
Switchgrass, source: switchgrass.nl
Sudangrass, source: Agnation.com
Robinia - Source: AEBIOM
7 EU legislation and national policies
European Union has adopted various energy andagricultural policies and measures to increase theuse of renewables/energy crops, however, the fur-ther establishment of energy crops in the EUrequires stronger measures and incentives at EUand national levels. Key EU renewable energy poli-cies indirectly affecting the growth of dedicatedenergy crops are summarized in the following table:
There are a couple major barriers for the develop-ment of energy crops for bioenergy production(technical, economic, local and those related tofarming issues and reforestation of set-aside land).First, the establishment costs are quite high due tothe fact that the crop cuttings and rhizomes arecostly and specific machinery has to be used forplanting. Second, varying climate conditions andsoil introduces the distortion in productivity yield.Harvesting, logistics can be rather expensive and,therefore, planting energy crops might becomesless cost efficient. Furthermore, farmers have diffi-culties to see long term stability for growing energycrops within the existing political framework. Animportant barrier is the commercialisation of dedi-cated energy crops. The farmer growing energycrops commits himself to grow it for at least 10-15years. It is rather a big risk because the farmerdoesn’t know whether dedicated crops will be com-petitive in 3 years time as compared with traditionalannual crops. In order to ensure the competitive-ness of these crops the contracts between farmersand processing industry should ensure the similarincome to farmers as growing traditional crops.These and many other obstacles can be overcomewith further efforts in research and developmentarea, legislation at EU level, and with additional
financial and legislative support to farmers willing toplant energy crops. Present situation in the cropmarket makes it more profitable for farmers to growtraditional crops. The European aid of EUR 45 is notsufficient to make it more competitive. Therefore,most European countries have a very slow growthof energy crops plantations with an exception ofthose where the European aid is backed by thenational support. Nevertheless, growing oil pricesmake the energy crops more cost competitive.
Common Agriculture Policy (CAP)
The CAP reform introduced an aid to encourage theproduction of crops for energy use. The reform pro-vides an encouragement for farmers to grow energycrops, via the energy crops aid and through the set-aside scheme (allowing growing of crops for manynon-food uses, one of which is energy production).An aid of EUR 45 per hectare is available to farmerswho produce energy crops. It is applied on a maxi-mum guaranteed area in the whole EU, of 2 millionhectares. Farmers qualify to receive the aid if theirproduction of energy crops is covered by a contractbetween the farmer and the appropriate processingindustry. This aid is additional to the SPS (singlepayment scheme) and SAPS (single area paymentscheme mostly applied in new member states) pay-ments.
However, the European aid of EUR 45 was reducedto EUR 31,5 in 2007 due to the fact that the maxi-mum area of 2 million hectares for which aid can begranted was exceeded. Furthermore, due to a poorharvest in 2006 and consequent increase of cerealsprice, the set-aside land was/is no more obligatoryfor autumn 2007 and spring 2008 sowings.
13
Directive/communication Date of publication Purpose
Directive 2001/77/EC on electricity pro-duction from renewable energy sources Published on 27 September 2001 The aim is to increase the share of renewable electricity
from 14% to 22% by 2010
Directive on transport biofuels2003/30/EC Published on 8 May 2003 To achieve a share of 5.75 % of biofuels for transport in the
total amount of fuels in Europe by 2010
Biomass Action plan COM (2005) 628final (BAP)
This Commission communication wasadopted 7 December 2005
Designed to increase the use of energy from forestry, agri-culture and waste materials in three sectors: heating, elec-
tricity and transport.
Directive on cogeneration 2004/8/EC(CHP) Published on 11 February 2004 Directive has the aim to promote cogeneration based on a
needed heat demand in the internal energy market.
Renewables roadmap COM(2007) 1Communication published on 10 January
2007 and approved on 8-9 March 2007 bythe European Spring Council
The aim is to increase the share of renewables in the cur-rent energy mix to 20% by 2020.
Renewables directive Proposal to be published on 23 January2008, and adoption is planned for 2009
The aim is to deliver concrete measures to achieve 20%RES share by 2020: proposal of the national RES targets,
strengthening the heat sector.
National aid
Council Regulation (EC) No 1782/2003 authorisesthe payments of national aid. Member states maynow pay state aid up to 50% for the establishmentof perennial energy crops on land for which a farmerhas applied for the basic energy crop aid.Additional support is possible with the agreement ofthe European Commission.
National policies
National policies are non sufficient and in manycountries non-existent for development of energycrops in the EU-27. Nevertheless, countries such asSweden, the UK, Ireland have introduced appropri-ate policy measures to enable the planting of dedi-cated energy crops.
Example of national support schemes - Sweden
Sweden has a highest share of willow plantation inthe whole EU and relatively high share of reedcanary grass. This is due to high taxation of fossilfuels and an appropriate national support for energycrops.
Support allowances in Sweden depend on the typeof the farm land. The support allowances for set-aside land dedicated for energy crops vary between€125 and €276/ha/year.
Support for plantation of energy forest
The farmer that is growing energy forest can applyfor an aid to plant short rotation forest (willows).Such energy forest can be planted on all types of
farmland except natural pasture (protected openlandscape fields with natural flora and fauna).
If the energy forest is to be planted on a non set-aside land, the special requirements are requestedfrom a farmer such as a specific education andexperience in cultivating energy forest. Farmersmust also provide the information on availablefinances for such plantations.
The support is approved as soon as the applica-
tions reach the county administrative board. Sincethere is a limited amount of money to be granted,the last applicants (each year) might be left withoutsupport if there were too many applicants before-hand.
The aid amounts SEK 5,000 (€ 536) per hectare. Ifthe plantation is on non set-aside land, the maxi-mum amount is SEK 480,000 (€51,482) per farm oragricultural company for a four year period.
Farm support for annual industrial crops andenergy crops on set-aside land (supportallowances)
Support allowances are not granted to cultivate rawmaterial for food or feed on set-aside land.However, farm support is available for energy cropson set-aside land.
All agricultural crops except hemp, sugar beet,Jerusalem artichoke (sunroot) and chicory canreceive this support. There are several rules to guar-antee that the crops are used for the right purpose:
• Contract with a buyer;• Copy of the contract must be sent to the countyadministrative board;• The buyer must submit a warrant of € 250 perhectare to the Agency of Agriculture;• After the harvest and delivery both the cultivatorand the buyer must each submit a delivery decla-ration to the county administrative board. The war-rant is released after the approval of both declara-tions.
Farm support for multi-annual industrial cropsand energy crops on set-aside land (supportallowances)
The contract between producer and buyer is notnecessary to receive the support allowances for cul-tivation of perennial energy crops on set-aside land.The only requirement is a declaration to the countyadministrative board (a signed document) that thepurpose of grown energy crops is for industrial or
14
Willow, source: AILE - Wilwater
Step planter, source: AEBIOM
energy production use.
Therefore, farm support is granted for willow andreed canary grass cultivation on set-aside land,however, it is limited to available supportallowances for set-aside land. One can apply for thespecial support for energy crop production from wil-lows or reed canary grass if the grown plantationexceeds the area covered by the supportallowances for set-aside land. However, in suchcase, the farmer must have a contract with a buyer.
Special support for energy crop production
This support is granted to energy crops grown onland that does not benefit from the support for set-aside land. It is applicable for all agricultural crops(except hemp and sugar beet) as long as they aregrown for energy production. This is usually ensuredby the contract between the farmer and the firstrefiner of energy crops. Beside the contract, the firstrefiner of the crop must submit a warrant of €60 perhectare to the Agency of Agriculture. After the har-vest, both the farmer and the refiner submit a con-firmation delivery and the warrant is released follow-ing the approval by the Agency of Agriculture.
15
Bioenergy crops scheme - provides establishment grants for approved energy crops
• Willow, poplar and miscanthus are amongst the eligible energy crops. • Funding available for the period of 2007-2013 • Short rotation coppice £1,000 per hectare • Miscanthus £800 per hectare
The Bio-energy Infrastructure - scheme helps develop the supply chains required to harvest,
store, process and supply energy crops and woodfuel to energy end-users
• A total of £3.5 M is being allocated UK-wide. Maximum of £200,000 per group or business. • A sliding scale for administrative set-up costs for producer groups of up to 100% in the first year,
80% in the second year and 60% in the third year• The same sliding scale for the rental costs of specialist machinery.• Up to 40% for specialist machinery and additional storage and hard-standing• Specific training costs - up to 35% for small and medium producer groups and businesses and up to
25% for large produces.
Bio-energy Capital Grants Scheme - supports the installation of biomass-fuelled heat and com-
bined heat and power projects in the industrial, commercial and community sectors in England.
Bioenergy scheme for Willows and Miscanthus
• 50% of the costs associated with establishing miscanthus and willow on set-aside land and on areaswhich have been subject to an aid for the EU Premium of €45 per hectare.
• farmers can receive up to €1,450 per hectare • €8 M is being allocated over the period 2007 to 2009
Top-up to Energy Crops Premium
• €80 per hectare in 2007 to support the growing of energy crops• €125 paid on top of € 45 aid for a period of 3 years • the current maximum area payable per producer over the three-year period is 37.5 hectares.
Support for energy crops in the United Kingdom
Support for energy crops in Ireland
RESTMAC project ’Creating Markets for Renewable Energy Technologies - EU RES technology marketing campaign’ aims at deve-loping and implementing a concise, well-targeted and thematic approach to ensure the dissemination and uptake of selected REStechnologies in the market. In other words the consortium works towards establishing a technology marketing campaign for thedifferent RE technologies involved. So far R&D formed a good basis for the outstanding industry development in the RenewableEnergy area. Nevertheless, the market uptake of these R&D results is not always happening in the best possible way and thereforeneeds to be improved. Lack of information and limited use of synergies between various stakeholders (industries, governments,investors..) are still the key critical barriers towards Renewable Energy Technologies. The renewable energy sectors to be marketed include: PV (photovoltaic), SHP (Small Hydro Power), Biomass, Geothermal, SolarThermal and Wind Power.
RESTMAC project Supported by
CONTACTS
About the project
Project partners located in Renewable Energy HouseRue d’Arlon 63-651040 Brussels, Belgium
CoordinatorEREC – European Renewable Energy CouncilMs Christine LinsTel: +32 2 546 19 33Fax: +32 2 546 19 34Email: [email protected]
AEBIOM –European Biomass AssociationMs Edita VagonyteTel: +32 2 400 10 22Fax: +32 2 546 19 34Email: [email protected]: www.aebiom.org
EWEA - European Wind Energy AssociationMs Zoe WildiersTel: +32 2 546 19 88Fax: +32 2 546 19 44Email: [email protected]
EPIA - European Photovoltaic Industry AssociationMs Eleni DespotouTel: +32 2 400 10 13Fax: +32 2 400 10 10Email: [email protected]
ESHA – European Small Hydropower Association Ms Gema San BrunoTel: + 32 2 546 19 45Fax: + 32 2 546 19 34Email: [email protected]
EUBIA – European Biomass Industry AssociationMr Stephane SenechalTel: +32 2 400 10 18Fax: +32 2 400 10 21Email: [email protected]
EGEC - European Wind Energy Association Mr Philippe DumasTel: +32 2 400 10 24Fax: +32 2 546 19 34Email: [email protected]
ESTIF - European Solar Thermal Industry FederationUwe BrechlinTel: +32 2 546 19 37Fax: +32 2 546 19 39Email: [email protected]
Project partners outside REH
ADEME – French Environment and Energy Management AgencyMr Stéphane PouffaryTel: +33 4 93 95 79 55Fax: +33 4 93 65 31 96Email: [email protected]
NTUA – National Technical University of AthensMr Arthouros ZervosTel: + 30 210 772 1030Fax: + 30 210 772 1047Email: [email protected]
ECB - Energy Centre BratislavaMr Roman DoubravaTel: +421 903 240 559Fax: +421 2 593 00097Email: [email protected]
GAIA - GAIA S.L. Consultores en gestion ambientalCipriano MarinTel: + 34 922 230 688Fax: + 34 922 200 951Email: [email protected]
