24. Conclusions

Renewable liquid fuels offer a pragmatic and low-carbon alternative to depletable crude oil with current vehicle technology and infrastructure, while serving a number of other domestic objectives as well, such as energy security and rural economic development. Biofuels are produced from plants that capture solar energy through photosynthesis and convert it to starch that can be converted to fuel and combusted. A dominant portion of the carbon emissions released from conversion of biomass to energy is carbon sequestered by plant growth in both above-ground and below-ground biomass, making this potentially a carbon neutral source of energy. The extent to which biofuels are actually carbon neutral depends on the amount of fossil fuels used in the production of the feedstock crop and in its conversion to usable fuel. While photovoltaic technology offers greater promise in its ability to provide usable solar energy per unit of land (Nelson), its high cost and the current status of battery technology limit its usefulness in the near future.