This comprehensive overview of small-scale [100 kilowatt - 10 megawatts (MW)] electric development using geothermal energy has been prepared primarily for financial investors as a guide to resource opportunities, commercial technologies, and financial incentives. California's geothermal resource in the 180°F to 350°F temperature range has been estimated to contain enough energy to generate over 1,000 MW. To assist in economically developing these resources, the guide summarizes important siting considerations, including resource requirements. Discussed are the three technologies--flashed steam, Organic Rankine Cycle (ORC), and total flow--which can convert the available energy in geothermal resources into electricity. Of the three, small-scale ORC systems have the greatest potential for commercial development in the immediate future. The technology involved in ORC systems is well established and has been proven in industrial operations. The overall performance (efficiency) of geothermal ORC is a function of resource characteristics, plant design, working fluid selection, and numerous other considerations. The guide discusses overall performance in detail.