Pig farming plays an important role in providing protein-rich food for consumers worldwide. Consumers increasingly are demanding food with diminishing negative impacts on the environment which encourages pig farmers to adopt renewable energy and more energy-efficient systems to reduce fossil fuel demand. Energy-smart pig farming systems can be realized in several ways. On-farm generation of electricity through solar photovoltaic arrays, and heat from geothermal systems or through biogas from manure, reduces reliance on fossil fuels. On-farm energy generation can require large capital investment that might prevent adoption on many farms. Optimizing pig performance improves energy efficiency by producing the most pork possible from a given quantity of energy inputs. Energy conservation measures in buildings can be implemented on most existing pig farms with small or moderate capital investment. Regardless of size or age, virtually all pig farms can implement some practices or technologies that improve their efficiency of energy use.