GEOTHERMAL PROJECT COST ESTIMATING By Lorie M. Dilley

Go / No Go Decision Temperature and Depth of Resource Drilling success rate ~60% Costs per well can easily exceed 2M$ $200+/kW Drilling success rate<25% Confirm Size of the Project Drilling success rate 70 – 80% Generating Plant ~ $1300-$6000/kW Transmission Line, Access Roads, piping, etc add to costs... HDL Geothermal Projects Flow-Chart Construction Management Civil, Geotechnical & Transportation Design & Engineering Project Management Planning Cost Estimating Permitting Geochemistry Geology Hydrology Prefeasibility Studies Environmental Feasibility Go / No Go Decision Temperature and Depth of Resource Drilling success rate ~60% Costs per well can easily exceed 2M$ $200+/kW Drilling success rate<25% Confirm Size of the Project Drilling success rate 70 – 80% Generating Plant ~ $1300-$6000/kW Transmission Line, Access Roads, piping, etc add to costs... HDL Geothermal Projects Flow-Chart Construction Management Civil, Geotechnical & Transportation Design & Engineering Project Management Planning Cost Estimating Permitting Geochemistry Geology Hydrology Prefeasibility Studies Environmental Feasibility

Exploration – chemical, geophysical, aerial photos

Drilling Costs Wells –Wells – Determine # of wells based on temperature, flow rate, and production required. MW/well = F/50 – 3.5 (temp. > 175 F) –200 F: 0.5 MW –400 F: 4.5 MW Low temperature 0.1 to 0.4 MW/well Drilling success rate 25% to 80% increase as knowledge of field increases

Temperature “Gradient” holes

Drilling Costs Slim hole/temperature gradient Drilling: 3 to 4 inch –3,000 ft: $1.5 to $2 M Production Drilling: 9 to 12 inch –3,000 ft : $3.9 to $4.3 M –5,000 ft: $4.5 M – 30 to 40 days of drilling –8,000 ft: $7.5 M Alaska Factor: 1.25 to 2 times

Infrastructure Needs Construction – camp, access, skilled workforce Plant – power generation, piping, geothermal wells, waste fluid disposal – trained operators Support Facilities – transmission line, road, living quarters, water supply & storage, wastewater treatment, maintenance shop, drilling equipment/ core shop, Facilities: greenhouses, pools, rooms

Power Production

Plant Costs UTC System : 200 to 250 kW is about $1,300 per KW $260,000 Binary System: $1,600 to $2,400 per kW : 1 MW to 5 MW -$1.6M to $2.4M Steam Plants: $1,500 per kW 5 MW to 25 MW - $7.5M to $37.5M

Support Facilities Roads – equipment, access wells,: gravel sources estimated cost is $30 to $250 per cubic yard depending upon material source location and quality – route selection critical Site Development – pads for plant, shops, living quarters, greenhouses – gravel, placement Transmission line – route selection – closer to village – power use $200,000 to $400,000+ per mile

Costs < 1 MW: UTC - $7M to $30M 1 MW to 10 MW : Binary - $40M to $100M Greater than 10 MW: Steam - $100M to $400M Based on drilling depths, gravel costs, temperature of resource, flow, size of project.