Seite - 180 - in Water, Energy, and Environment - A Primer

• This is consistent with the historical pattern over the past few centuries tomove to lower and lower carbon content fuels, fromcoal to oil, to natural gas. • Other long-term energy options are to move to both renewable energy andnuclear power, subject to resolution of the concerns associated with nuclear power discussed inChapter 7. • A2015 interdisciplinaryMIT study, ‘The Future of Solar Energy’, in its Summary for Policymakers, concluded that ‘massive expansion of solar generationworldwide by mid-century is likely a necessary component of any serious strategy tomitigate climate change.’ • The MIT report goes on to state: ‘Fortunately the solar resource dwarfs current and projected future electricity demand. In recent years, solar costs have fallen substantially and installed capacity has grown very rapidly. Even so, solar energy today accounts for only about 1% of US and global electricity generation. Particularly if a substantial price is not put on carbon dioxide emissions, expanding solar output to the level appropriate to the climate challenge likely will not be possible at tolerable cost without significant changes in government policies.’ • Another possible goal is an energy economy that makes extensive use of hydrogen. Sometimes, hydrogen is referred to as ‘the hydrocarbon without the carbon.’Not only can it be burned cleanly (its principal combustion products arewater and heat), it can also serve as a source of clean electricity via its use in fuel cells if it is produced via electrolysis of water (H2O), using electricity sources (renewables, nuclear) that do not put carbon in the atmosphere. • Hydrogenmayalsoplayacritical role inenergy storage. It canbestoredingaseousandliquidform,andinrecoverable form in solid-statematrices. Water,Energy, andEnvironment–APrimer180