ENERGETIC AND WATER COST RELATED TO THE CULTIVATION OF ENERGY CROPS: GENERAL PERSPECTIVES AND A CASE STUDY IN TUSCANY REGION (CENTRAL ITALY)

Transcription

1 ENERGETIC AND WATER COST RELATED TO THE CULTIVATION OF ENERGY CROPS: GENERAL PERSPECTIVES AND A CASE STUDY IN TUSCANY REGION (CENTRAL ITALY) Dalla Marta A., Mancini M., Orlando F., Natali F., Maracchi G., Orlandini S. Department of Plant, Soil and Environmental Science University of Florence

2 THE GREENHOUSE EFFECT Solar radiation reaches the hearth surface and it is re-emitted as infra-red radiation. Some of this radiation is blocked by water vapor and by the so called GHG

3 Mainly due to fossil fuels Agriculture is one of the responsibles IDEA: to use agriculture for producing bio-fuels and for reducing GHG emissions

4 SUPPORT PROVIDED AT DIFFERENT POINTS IN THE BIOFUEL SUPPLY CHAIN SUPPORT TO INPUTS Fertilizer, irrigation and other inputs support General energy and water-pricing policies Land-tenure policies SUPPORT TO PRODUCTION RESOURCES PRODUCTION Domestic agricultural subsidies Farm income support Trade policies General support to agriculture FEEDSTOCKS PROCESSES AND MARKETING SUPPORT Production-linked payments Tax credits, incentives and exemptions Trade policies Subsidies for capital investments PROCESSING BIOFUELS CONSUMPTION SUPPORT TO CONSUMPTION Subsidies for purchase of biofuels Tax exemptions Subsidies for flex-fuel vehicle purchase What about the consequences? END USE Source: FAO, 2008 adapted from Steenblink, 2007

5 SUGAR CROPS Sugar cane Sugar beet Sweet sorghum FERMENTATION AND DISTILLATION Maize Wheat Barley STARCHY CROPS Rye Potato Cassava CELLULOSIC MATERIALS Switchgrass Poplar Miscanthus Crop stover Willow OIL CROPS Rapeseed Sunflower Oil palm Jatropha Soybean WATER SACCARIFICATION, FERMENTATION AND DISTILLATION WATER EXTRACTION AND ESTERIFICATION ETHANOL PVO BIODIESEL Source: FAO, 2008

6 ENVIRONMENTAL IMPACTS: WATER Many of the crops currently used for biofuel production (sugar cane, oil palm and maize) have high water requirements at commercial yield levels. The processing of feedstock into biofuels can use large quantities of water Biofuels production will affect also water quality due to soil erosion, sedimentation and excess nutrient runoff into surface waters and infiltration into groundwater from increased fertilizer applications CROP Annual obtainable fuel yield Energy yield ET equivalent Crop ETP Rainfed crop ET Irrigated crop water requirement (L/ha) (GJ/ha) (L/l fuel) (mm/ha) (mm/ha) (mm/ha) (L/l fuel) Sugar cane Maize Oil palm Rapeseed Source: IEA, 2007 and FAO

7 WATER USE The water use related to the bioenergy systems consists of: 1. ET connected to the energy crop production (CULTIVATION PHASE) UNPRODUCTIVE LOSS 2. Water consumption in the biomass feedstock connected to pre- and post-harvest drying, feedstock pre-treatment and processing, and final bioenergy end use 3. Water consumption that is withdrawn from water bodies for use in the post harvest biomass processing to produce electricity, biofuels and process heat Source: Berndes, 2008

8 WATER USE The influence of increasing human water use for biomass production on different components of the hydrological cycle depends on: FEEDSTOCK: energy crops differ in their water use and also in other aspects relevance for the water context such as infiltration capacity IRRIGATION SYSTEMS: the efficiency of irrigation greatly affect the quantity used water of of LOCATION: some regions with abundant water availability will not likely face water related difficulties while others may face an even more difficult water situation (i.e. semi-arid and arid regions) LAND-USE CHANGE: the net change in ET can be both negative and positive. Areas with sparse vegetation may experience increased ET when bioenergy plantations are established, while reforestation of dense forests for the purpose of cultivating crops such as soybean and corn for biofuel leads to reduced ET

9 PART II THE CASE STUDY

10 MATERIALS AND METHODS Verification and homogenization of 19 historical series of meteorological stations located in Tuscany (period ) Simulation of maize and sunflower productivity using previously calibrated CropSyst model Analysis of crop productivity Water balances calculation Energy balances calculation TWO IRRIGATION METHODS WERE CONSIDERED PIVOT (efficiency 72.5%, energy 0.64 kwh/m3) HOSE REEL IRRIGATORS (efficiency 60.0%, energy 0.73 kwh/m3). SET-ASIDE LANDS WERE CONSIDERED IN ORDER TO AVOID PROBLEMS OF COMPETITIVINESS WITH FOOD CROPS

11 PLOUGHING HARROWING SOWING WEED CONTROL CULTIVATION HOEING FERTILIZATION TREATMENTS HARVEST IRRIGATION SYSTEM 1 SYSTEM 2 SEEDS HERBICIDE FEEDSTOCK N FERTILIZER P FERTILIZER PESTICIDE TRANSORMATION/TRANSPOR PROCESSING T Agronomic needs and mean productivity of maize and sunflower MAIZE SUNFLOWER SOWING DATE 15 April 15 April FERTILIZATION (kg/ha) Different categories considered for the calculation of energy balances of the biofuel production chain N P HERBICIDAL 1 treat 1 treat IRRIGATION (m 3 /ha) Pivot (72%) 2580 Mobile (60%) 3118 none MEAN PRODUCTIVITY (tons/ha)

12 PRODUCTIVITY OF MAIZE MAIZE BIOETHANOL LOCATION P10 P90 P10 P90 St St St St St St St St St St St St St St St St St St St MEAN BIOETHANOL PRODUCTION RANGES FROM 2.03 TO 2.72 TONS/HA

13 PRODUCTIVITY OF SUNFLOWER SUNFLOWER PURE VEGETABLE OIL LOCATION P10 P90 P10 P90 St St St St St St St St St St St St St St St St St St St MEAN PURE VEGETABLE OIL PRODUCTION RANGES FROM 0.31 TO 0.60 TONS/HA

14 BIOETHANOL (Ton) PURE VEGETABLE OIL (Ton)

15 ENERGY BALANCES MAIZE ENERGY BALANCE (GJ/ha) 10th PERC 90th PERC PLOUGHING HARROWING SOWING CULTIVATION WEED CONTROL HOEING FERTILIZATION TREATMENTS HARVEST IRRIGATION SYSTEM SYSTEM SEEDS HERBICIDE FEEDSTOCKS N FERTILIZER P FERTILIZER PESTICIDE PROCESSING TRANSF/TRANSP TOTAL INPUTS REQUIRED ENERGY SYSTEM 1 REQUIRED ENERGY SYSTEM TOTAL OUTPUTS USABLE ENERGY SUNFLOWER ENERGY BALANCE (GJ/ha) CULTIVATION IRRIGATION 10th PERC 90th PERC PLOUGHING HARROWING SOWING WEED CONTROL HOEING FERTILIZATION TREATMENTS HARVEST SEEDS HERBICIDE FEEDSTOCKS N FERTILIZER P FERTILIZER PESTICIDE PROCESSING TRANSF/TRANSP TOTAL INPUTS REQUIRED ENERGY TOTAL OUTPUTS USABLE ENERGY INPUT/OUTPUT BALANCE SYSTEM BALANCE SYSTEM INPUT/OUTPUT BALANCE EROEI (Energy Returned On Energy Invested) =

16 ENERGY BALANCES MAIZE ENERGY BALANCE (GJ/ha) 10th PERC 90th PERC PLOUGHING HARROWING SOWING CULTIVATION WEED CONTROL HOEING FERTILIZATION TREATMENTS HARVEST IRRIGATION SYSTEM SYSTEM SEEDS HERBICIDE FEEDSTOCKS N FERTILIZER P FERTILIZER PESTICIDE PROCESSING TRANSF/TRANSP TOTAL INPUTS REQUIRED ENERGY SYSTEM REQUIRED ENERGY SYSTEM TOTAL OUTPUTS USABLE ENERGY SUNFLOWER ENERGY BALANCE (GJ/ha) CULTIVATION IRRIGATION 10th PERC 90th PERC PLOUGHING HARROWING SOWING WEED CONTROL HOEING FERTILIZATION TREATMENTS HARVEST SEEDS HERBICIDE FEEDSTOCKS N FERTILIZER P FERTILIZER PESTICIDE PROCESSING TRANSF/TRANSP TOTAL INPUTS REQUIRED ENERGY TOTAL OUTPUTS USABLE ENERGY INPUT/OUTPUT BALANCE SYSTEM BALANCE SYSTEM INPUT/OUTPUT BALANCE IN TUSCANY MAIZE 50% - 62% For 2020 the biofuel for transport demand will be Mtoe SUNFLOWER 4% - 9%

17 WATER BALANCES (L/ha) MAIZE WATER BALANCE (L/ha) 10th PERC 90th PERC IRRIGATION SYSTEM SYSTEM PROCESSING TRANSFORMATION TOTAL TOTAL BIOETHANOL (L/ha) SISTEM 1 SISTEM Liters of Water for Liter of bioethanol

18 WATER BALANCES (L/ha) IN TUSCANY The agriculture need of water is 150 million of m 3 IN SET-ASIDE LANDS ( HA) THE WATER NEED IS ABOUT million of m 3 FOR CULTIVATION OF MAIZE FOR ENERRGY PRODUCTION The number of farm ponds is 2462 The average dimension is m 3 The stored water is about 59 million of m 3

19 CONCLUSIONS Increasing the production of bioenergy from agriculture and forestry may offer significant opportunities to reduce GHG emissions and to diversify and secure energy supply Greater production of bioenergy could lead to a more intense use of agricultural land and forests, with negative environmental consequences The increase in biofuel production could result in a significant increase in demand for water to irrigate fuel crops, which could worsen local and regional water shortages A substantial increase in water pollution by fertilizers and pesticides is also a risk, with the potential to increase eutrophication and hypoxia in inland and coastal water

20 RECOMMENDATIONS Research and development of crops and cultivation systems (i.e. use of compost) Particular attention has to be addressed to agricultural residues from permanent crops (vines, olives, etc.) by incentivizing virtuous behavior and sustaining research Take into consideration that just a small part of rainfall water (about 10%) is used, so there is a need to sustain water storage practices (i.e. small ponds where possible) Most important will be analysis of a policy framework that is needed to avoid potential environmental drawbacks and increase potential benefits of bioenergy production Regional, national and EU policies have the important responsibility to support the use of renewables while protecting the environment, economic systems and society STANDARDIZATION LAND USE WATER CERTIFICATION of carbon footprint calculation (for energy balances) to avoid competitiveness and deforestation the use of marginal lands require a lot of water of agronomic phase

21 OIL Gulf of Mexico, 20 April 2010

22 NUCLEAR ENERGY Chernobyl, 26 April 1986

23 HYDROPOWER Vajont, 9 October 1963

24