Recent Trends in Water Use and Production for California Oil Production.

Recent droughts and concerns about water use for petroleum extraction renew the need to inventory water use for oil production. We quantified water volumes used and produced by conventional oil production and hydraulic fracturing (HF) in California. Despite a 25% decrease in conventional oil production from 1999 to 2012, total water use increased by 30% though much of that increase was derived from reuse of produced water.

Long-term shifts in life-cycle energy efficiency and carbon intensity.

The quantity of primary energy needed to support global human activity is in large part determined by how efficiently that energy is converted to a useful form. We estimate the system-level life-cycle energy efficiency (EF) and carbon intensity (CI) across primary resources for 2005-2100. Our results underscore that although technological improvements at each energy conversion process will improve technology efficiency and lead to important reductions in primary energy use, market mediated effects and structural shifts toward less efficient pathways and pathways with multiple stages of conversion will dampen these efficiency gains.

Life cycle water consumption and withdrawal requirements of ethanol from corn grain and residues.

We assessed the water requirements of ethanol from corn grain and crop residue. Estimates are explicit in terms of sources-green (GW) and blue (BW) water, consumptive and nonconsumptive requirements across the lifecycle, including evapotranspiration, application and conveyance losses, biorefinery uses, and water use of energy inputs, and displaced requirements or credits due to coproducts. Ethanol consumes 50-146 L/vehicle kilometer traveled (VKT) of BW and 1-60 L/VKT of GW for irrigated corn and 0.