High energy costs have always been an incentive for improving the energy efficiency of commercial buildings. Now that the threat of global climate change and record-high costs have ratcheted up the urgency, federal tax deductions originally passed in 2005 give commercial property owners, and in some cases, architects, engineers and contractors, generous allowances for the construction or renovation of energy-efficient buildings. These tax deductions are available for systems “placed in service” in U.S.-located commercial buildings from January 1, 2006 through December 31, 2013, even if the deductions were not originally taken in 2006 or 2007, they can generally be claimed
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.