1 co.9.4 maletta et al.2012 oral presentation
DESCRIPTION
In Spain, as in the mediterranean basin, the development of herbaceous perennial energy crops in the extensive rainfed areas requires species that tolerate severe frequent droughts during summer. In a previous study (2011), it was shown that annual grasses like triticale or rye require annual biomass production about 8 odt/ha in order to achieve the GHG savings established for biofuels in the Renewable Energy Directive (RED) for 2018, when substituting natural gas in power plants underspanish conditions. In order to improve the results achieved with annual grasses, perennial grasses were evaluated as an alternative to supply sustainable biomass to power plants.Elytrigia elongata - called “Tall wheatgrass”- is a summer dormant perennial C3 grass native from Eurasia and has been tried in constraints environments all over the world. Its palatability forlivestock is low at the same time that it could have acceptable characteristics to use for combustion in industrial boilers to produce electricity power. The aim of this report is to demonstrate and evaluate the potential of Elytrigia elongata to avoid GHG emissions and obtain lower economic costs in marginal areas of Spain and the Mediterranean region. Our research built scenarios based on experimental plots (2 years growth) inthree locations of Spain with very different climate conditions The preliminary evaluation results suggest that the use of C3 drought tolerant perennial crops, like tall wheatgrass in marginal areas of Spain for electricity production might present a better performance in terms of energy yields, costs of the electricity and GHG savings, than utilizing annual grasses like triticale and C4 grasses like switchgrass than cannot be established because of spring and summer droughts.TRANSCRIPT
Perennial energy crops for semiarid lands in the Mediterranean: Elytrigia elongata, a C3 grass with summer dormancy to produce electricity in constraint environments
Emiliano Maletta*1, Carlos Martin-Sastre2, Pilar Ciria1, Aránzazu del Val1, Annabel Salvado4, Laura Rovira4, Rebeca Díez3, Joan Serra4, Yolanda González-Arechavala2 and Juan Carrasco1
1 CEDER-CIEMAT. Energy Department. Biomass Unit2 IIT. Institute for Research in Technology - ICAI School of Engineering - Comillas Pontifical University
3 ITACyL. Biofuels and Bioproducts Resarch Centre 4 IRTA, Mas Badia (17134) Girona, Spain. Phone: +34- 972780275, Fax: +34-972780517
* Corresponding author: [email protected]
INTRODUCTION
Introduction
Semiarid environments and marginal areas usually produce
•Low yields
•High economic costs
•Low GHG emissions savings
•Low energy balances
About 4M ha of arable lands available in Spain
Cereal-grains yield (national average): 1.8 t/ha
C4 perennial grasses require water for establishment and long droughts are the rule in that moment => C4 grasses need irrigation support
Traditional C3 perennial grasses limited to northern cold areas
Farmers grow winter cereals (grains+straw) to feed power energy plants
Drought tolerant AND productive species required for semiarid lands to supply biomass for industry
Marginal yields, marginal benefits
Previous study on rye and triticale for electricity in a real 25MW power energy plant (Northern Spain).
Need at least 8 odt/ha to reach 60% GHG emissions savings compared to natural gas electricity
Perennial grasses background in Spain
Background
Demonstration plot (2 ha)Power energy plant (25MW) for biomass combustion. 160,000 ton per year. Straw price for farmers: 75-85€/odt (mostly agricultural residues and rye/triticale/oats).
US Tall wheatgrass trials (Salon et al, 2009)
US Tall wheatgrass (Photo: USDA-NRSC, 2008)
Tall wheatgrass: Scientific names: Elytrigia elongata (Host), Thinopyrum ponticum (Podp)
•Origin: Eurasia
•C3: three photosynthetic metabolism pathway (a “cool season” grass)
•Perennial summer dormancy: resist long summer drought periods, through senescence and buds dormancy recommencing growth in autumn
•Deep root system / suited for alkaline soils
•From 50s in US, Argentina and Australia as feedstock for livestock on marginal areas and for re-vegetation (green covers)
•Biomass characteristics allow co-firing and 2nd generation biofuels
•Breeding programs and commercial seeds are available worldwide
•Productions in literature: 3-16 odt/ha.year
Objective
Tall wheatgrass performance regarding biomass costs at the farm level and LCA for power energy
Objective
Tall wheatgrass (TW): using data from 3 sites with experimental plots established in 2009 and 2010 to feed scenario building
LCA on 15 scenarios assuming future yields and lifetime (15 years) for three regions
Economic costs at the farm level for TW and cereals
Comparison: TW vs Rye/triticale/oats (GHG, energy balance and mean costs)
What we did?:
Locations – soil – climate
Materials and Methods
pH N (%)P
(mg/kg)K
(mg/kg)Organic
Matter (%)Texture
Girona 8,2 0,11 28 192 1,65 loamPalencia 8,5 0,09 50,4 0,22 1,37 Franc
Soria 6,8 0,03 6,6 61,2 0,6 sandy
Soil characteristics in 0-30 cm layer of the three sites used for scenario building in this study
Soria
010
20304050
6070
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Months
Tem
per
atu
re (
ºC)
020
406080100
120140
Average Temperature (ºC) Precipitation (mm)
Girona
0
10
20
30
40
50
60
70
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Months
Tem
per
atu
re (
ºC)
0
20
40
60
80
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120
140
Pre
cip
ita
tio
n (
mm
)
Palencia
0
10
20
30
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60
70
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Months
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atu
re (
ºC)
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Pre
cip
itat
ion
(m
m)
Soria
010
20304050
6070
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Months
Tem
per
atu
re (
ºC)
020
406080100
120140
Average Temperature (ºC) Precipitation (mm)
Girona
0
10
20
30
40
50
60
70
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Months
Tem
per
atu
re (
ºC)
0
20
40
60
80
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Pre
cip
ita
tio
n (
mm
)
Palencia
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Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
Months
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ºC)
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Pre
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(m
m)
Ombrothermic diagram for the period September 2010-
August 2011 in all three sites.
Palencia Soria
Girona
Rains: 400-700mm
Rains: 300-500mm
Rains: 300-600mm
Unfertile soil on a experimental parcel of wheatgrasses in Soria, (above: Jan 2009; below: regrowth 2nd year, March 2010).
Wheatgrasses strips re-growth (Palencia, March 2012)
Mowed biomass let in the ground in the first year (Soria, 2010)
Tall wheatgrass
Tall wheatgrass trials
Establishment year in Palencia
(2009)
2nd year in Soria, (plots established in 2010)
Small plots in Girona (May 2011)
Second year harvest (Soria, Aug 2010)
Materials and Methods
Tall wheatgrass scenarios
Regions Very low Low Middle High Very HighPalencia (odt/ha) 4,1 5,8 7,0 8,2 10,2Girona (odt/ha) 6,2 8,1 9,5 10,9 12,8Soria (odt/ha) 2,4 3,9 5,0 6,1 7,0
Yield scenarios (mean value for lifetime)
RegionsManagement and inputs 2009 2010 2009 2010 2009 2010Experimental plot Strips Strips small plots Strips small plots small plotsPlot size (total in m2) 5000 4500 225 135 90 90Tillage operationsBase (NPK in kg/ha)
1st yearSuccesive years 0 250
Sowing rate 40 20 30 20 20Sowing date Nov.2009 Nov.2010 Oct.2009 Oct.2010 Oct.2009 Oct.2010
pre-emergence none Glifosate nonepost-emergence none 2-4D 2-4D and MCPA
Weed control mowings 2010 2010 2009 and 2010 2010 and 2011Cut numbers 1 1 1 1 2 (june - Oct) 1Biomass yield range (odt/ha) 2.5 - 6 4 - 10 5 - 12 5 - 12 12 - 39 10 - 40
300
GironaPalenciaSoria
350 500 noneChisel, harrowing, rotary tiller
Herbicides
Top fertilizers NAC27% (kg/ha)nonenonenone
250
Tall wheatgrass scenarios
Evaluations:
•Economic costs data: Ministry of Agriculture and local farmer costs. No subsidies taken into account.•Energy balances and GWP: Simapro and Ecoinvent•GHG emissions savings comparing biomass electricity to replaced fossil reference (natural gas electricity in Spain)•Winter grasses vs tall wheatgrass under rain fed conditions
Biomass economic cost comparison
Results & Discussion
Winter cereals in best areas produced biomass costs of about 80€/odt
Tall wheatgrass could be competitive with yields as low as 4 odt/ha.year
Most frequent yields in the study regions
0,0010,7%
0,08550,7%
0,03621,3%
0,03521,0%
0,0116,4%
Seed and Pesticides Fertilizers
Field Works Biomass transport
Power Plant Operation
0,0020,8%
0,14659,8%
0,05120,7%
0,03514,4%
0,0114,4%
Seed and Pesticides Fertilizers
Field Works Biomass transport
Power Plant Operation
0,0021,0%
0,09846,0%
0,06731,5%
0,03516,5%
0,0115,0%
Seed and Pesticides Fertilizers
Field Works Biomass transport
Power Plant Operation
Soria Palencia
Girona
Energy inputs (TJ fossil per TJe)
Energy yields were higher in TW compared to winter cereals
In lower yields scenarios, TW can produce higher energy yields
Energy yields
0,20,6%
14,540,8%
13,437,6%
4,612,9%
2,36,4%
0,61,8%
Seed and Pesticides Fertilizers
Nitrous Oxide Field Works
Biomass transport Power Plant Operation
0,20,4%
21,750,2%
15,034,7%
3,58,0%
2,35,2%
0,61,5%
Seed and Pesticides Fertilizers
Nitrous Oxide Field Works
Biomass transport Power Plant Operation
0,10,4%
12,845,3%
10,035,4%
2,48,6%
2,38,0%
0,62,3%
Seed and Pesticides Fertilizers
Nitrous Oxide Field Works
Biomass transport Power Plant Operation
Soria Palencia
Girona
Global warming potential (mg CO2eq/TJ)
Global Warning Potential (GWP)
Results & Discussion
Tall wheatgrass produce less GHG emissions (mg CO2eq/TJe) at similar biomass yields compared to annual grasses when producing electricity
Results & Discussion
Minimum GHG emissions savings for tall wheatgrass: 50% for lowest yields (average above 70%) when replacing natural gas electricity
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
2000 4000 6000 8000 10000 12000 14000
GH
G S
avin
gs (
%)
Bio
mas
s C
omp
ared
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ctri
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fr
om N
atu
ral G
as a
s fo
ssil
ref
eren
ce
Yield (kg d.m. ha-1)
Oat
Lopsided Oat
Rye
Triticale
Tall wheatgrass(Soria)
Tall wheatgrass(Palencia)
Tall wheatgrass(Gerona)
Tall wheatgrass
GHG emissions savings compared to natural gas electricity
CONCLUSIONS
Conclusions
According to the obtained results, the mean production costs of TW at the farm level 40-60 €/odt for low and medium yield scenarios (5-7 odt/ha.year). These costs are lower than those of winter cereals. Under these conditions TW biomass could be suitable to supply power energy plants in Spain
Considering the explored range of crop yields and management conditions, GHG emissions savings when using TW biomass for producing electricity are significantly higher (50-90%) of those of winter cereals (5-70%). Energy yields ranged from 1.5-3 in winter cereals and 2.5-7.5 in TW.
These results suggest that TW can have a significant potential as energy crop in marginal lands in Spain.
Thank you for your attention !
Acknowledgements:
This work has been developed in the framework of the Spanish National and Strategic Project “On Cultivos” co-funded by the Spanish Ministry of Economy and Competitiviness and the European Funds for Regional Development under the dossier PSE-120000-2009-15.