Finding the balance Comparing water, energy and emissions patterns - PowerPoint PPT Presentation

Finding the balance Comparing water, energy and emissions patterns for irrigation in surface and ground water dependent irrigation regions Tamara Jackson , Shahbaz Khan, Mohsin Hafeez Australian Irrigation Conference & Exhibition 2010

The water-energy-emissions nexus The links between water, energy and emissions • Evident at many levels • • Characterised by current issues: - Growing population, therefore a need to increase food supply - Competition for water - Global warming and climate change - Rising energy prices - Rising energy prices - Increasing environmental awareness - Biofuel production

Energy use in irrigated agriculture • Direct energy use ~ 30% energy use in developed countries • Indirect energy use ~ 70% Direct energy consumption, dependent • on – Total dynamic head (watertable depth/lift height, pressure for system) system) – Water requirement of crop – System efficiency • Indirect energy consumption, dependent on – System type – Water source

Greenhouse gas emissions Contribution of various stages of maize • Major GHGs affected by production to GHG emissions agriculture: - CO 2 - CH 4 - N 2 O • Nitrogen fertiliser application and water pumping are largest source of emissions on-farm

Methodology • Selection of irrigation regions • Survey of case study farms • Energy and emission budgets constructed (land preparation – harvest) • Regionally accepted data sets used to predict the • Regionally accepted data sets used to predict the consequences of converting to pressurised irrigation methods • Model developed in Excel and linked to the @Risk software to determine the level of uncertainty

Study areas

Limestone Coast • Irrigated area ~79 118 ha (3.6% total land area). • ~ 459 007 ML pumped for irrigation (2003-04) • 70% of irrigation systems are pressurised • Dependent on groundwater for 95% irrigation water as well as for industry, stock & domestic and town industry, stock & domestic and town water supplies. • Currently moving from area-based allocation system to volumetric based system. • Groundwater depth and quality variable.

Coleambally Irrigation Area • Regional irrigated area ~79 000 ha (65% total land area) • Predominantly uses surface water • 98% of irrigation systems surface irrigation methods

Factors influencing the energy-water-greenhouse nexus

Steps to determine an energy or carbon budget 1. Determine a boundary around the process to be evaluated. Narrow boundaries may be necessary in order to allow meaningful results to be obtained by Step 5. 2. Identify and quantify all inputs crossing the boundary. 3. Assign energy and emission coefficients to all inputs, including both direct and indirect inputs. and indirect inputs. 4. Identify and quantify all outputs. 5. Relate total embedded energy to outputs. 6. Apply the energy analysis results.

Energy and CO 2 -equivalent emission equivalents Sequestered Input Unit Total emissions (gCO 2 /MJ) energy (MJ) Human labour hr 2.3 n/a Fuel Diesel l 38.6 75.2 Avgas l 33.1 72.4 Electricity NSW kWh 11.93 295.0 SA 272.0 Fertiliser N kg 66.14 50.0 P kg 12.44 60.0 K kg 11.15 60.0 S kg 5 60.0 Chemicals Herbicides kg 240 60.0 Insecticides Insecticides kg kg 200 200 60.0 60.0 Fungicides kg 92 60.0 Soil improvements Lime kg 0.6 720.0 Manure tons 303.1 0.025 Seed General kg 14 Rice kg 14.7 n/a Cereals & kg 25 n/a pulses Wheat kg 15.7 n/a Maize kg 15.7 n/a Oil seed kg 36 n/a Machinery hr 64.8 n/a

Energy and water relationships in surface and ground water irrigated regions

Water application patterns – surface water region 18 16 14 ater applied (ML/ha) 12 10 8 Wate 6 4 2 0 Lucerne Wheat Rice Oats Lucerne Rice Rice Maize Rice Maize seed hay CIA 1 CIA 2 CIA 3 CIA 4 CIA 5

Energy consumption patterns – surface water region 25,000 20,000 gy consumption (MJ/ha) 15,000 10,000 Energy c 5,000 0 Lucerne Wheat Rice Oats Lucerne Rice Rice Maize Rice Maize seed hay CIA 1 CIA 2 CIA 3 CIA 4 CIA 5

Emission patterns – surface water region 0.9 valent emissions (tCO2e/ha) 0.8 0.7 0.6 0.5 0.4 Carbon equiva 0.3 0.3 0.2 0.1 0.0 Lucerne Wheat Rice Oats Lucerne Rice Rice Maize Rice Maize seed hay CIA 1 CIA 2 CIA 3 CIA 4 CIA 5 Case study farm & crop type

Water application patterns – groundwater region 14 12 Water applied (ML/ha) 10 8 6 W 4 4 2 0 Flood Centre Pivot Drip Flood Centre Pivot Centre Pivot Flood Centre Pivot Lucerne seed Pasture Clover Pasture Lucerne seed pasture SESA 1 SESA 2 SESA 3 SESA 4 SESA 5

Energy consumption patterns – groundwater region 45,000 40,000 nergy consumption (MJ/ha) 35,000 30,000 25,000 20,000 15,000 Energ 10,000 5,000 0 Flood Centre Pivot Drip Flood Centre Pivot Centre Pivot Flood Centre Pivot Lucerne seed Pasture Clover Pasture Lucerne seed pasture SESA 1 SESA 2 SESA 3 SESA 4 SESA 5

Emission patterns – groundwater region 4.5 4.0 nt emissions (tCO2e/ha) 3.5 3.0 2.5 2.0 1.5 Carbon equivalen 1.0 0.5 0.0 Flood Centre Drip Flood Centre Centre Centre Flood Pivot Pivot Pivot Pivot Lucerne seed Pasture Haifa Pasture Lucerne seed SESA 1 SESA 2 SESA 3 SESA 4 SESA 5 Case study farm, crop and irrigation method

Energy consumption – groundwater region Seed 40,000 Human labor 35,000 Machinery 30,000 Diesel - machinery 25,000 Diesel - pumping 20,000 Avgas Electricity - 15,000 pumping 10,000 Chemicals Fertiliser Fertiliser 5,000 Soil 0 improvements Flood Centre Drip Flood Centre Centre Centre Flood Pivot Pivot Pivot Pivot Lucerne seed Pasture Haifa Pasture Lucerne seed SESA 1 SESA 2 SESA 3 SESA 4 SESA 5 Crop and irrigation method

Energy consequences of converting to pressurised irrigation systems Region Case Crop Flood Centre Pivot Drip study Irrigation Energy Irrigation Energy Irrigation Energy farm (ML/ha) consump (ML/ha) consumption (ML/ha) consumption tion (MJ/ha) (MJ/ha) (MJ/ha) % change % change % change % change from flood from flood from flood from flood CIA Farm 1 Lucerne 5.0 3,186 4.5 -10 8,392 163 4.5 -10 7,606 139 (Surface seed water) Wheat 3.0 5,157 1.1 -63 6,430 25 1.1 -63 6,238 21 Farm 2 Farm 2 Oats Oats 2.0 2.0 8,406 8,406 1.1 1.1 -45 -45 9,678 9,678 15 15 1.1 1.1 -45 -45 9,486 9,486 13 13 Farm 3 Lucerne 11.0 9,811 9.9 -10 21,264 117 9.9 -10 19,534 99 hay Farm 4 Maize 8.3 7,975 7.5 -10 16,651 109 7.5 -10 15,340 92 Farm 5 Maize 8.0 14,075 7.2 -10 22,404 59 7.2 -10 21,146 50 SESA Farm 1 Lucerne 11.0 20,325 5.6 -49 16,255 -20 3.8 -65 11,346 -44 (Ground seed water) Farm 2 Pasture 12.0 41,759 6.1 -49 36,779 -12 4.2 -65 31,476 -25 Farm 3 Clover 11.2 22,954 5.7 -49 18,316 -20 3.9 -65 13,377 -42 pasture Farm 4 Pasture 7.8 20,647 4.0 -49 17,392 -16 2.7 -65 13,926 -33 Farm 5 Lucerne 12.0 28,465 6.0 -50 22,907 -20 4.1 -66 17,708 -38 seed

Conclusions • There are strong links between irrigation water use and energy consumption, and water source and irrigation method impact on these relationships • Decisions made at the paddock level have wider environmental consequences • Pressurised irrigation methods can reduce energy consumption in regions where groundwater is used, while the opposite can be true in surface water regions • The identification of accepted trade-offs between resource inputs and environmental effects

Acknowledgements • Co-operative Research Centre for Irrigation Futures • CSIRO Land and Water • Farmer participants • Farmer participants