[Editor note: One of the great energy scholars of our time is Vaclav Smil, Distinguished Professor Emeritus of Environment and Geography at the University of Manitoba. This (modified) article remains as fresh today as it was when originally published in 2009.]
President Barack Obama has promised an energy revolution in the world’s largest economy, with renewable sources of power and “green” technologies breaking America’s – and ultimately the world’s – dependence on conventional fuels…. But how realistic is this vision?
Primary Energies: Unchanged
There is only one kind of primary energy (energy embodied in natural resources) that was not known to the first high civilizations of the Middle East and East Asia and by all of their pre-industrial successors: isotopes of the heavy elements whose nuclear fission has been used since the late 1950’s to generate heat that, in turn, produces steam for modern electricity turbo-generators.…
Editor’s note: This is the conclusion of the series that provides an essential basis for the understanding of energy transitions and use. The previous posts in this series can be seen at:
Part I – Definitions
Part II – Coal- and Wood-Fired Electricity Generation
Part III – Natural Gas-Fired Electricity Generation
Part IV – New Renewables Electricity Generation
America’s dominant mode of electricity generation is via combustion of bituminous and sub-bituminous coal in large thermal stations. All such plants have boilers and steam turbogenerators and electrostatic precipitators to capture fly ash, but they burn different qualities of coal that may come from surface as well as underground mines, have different arrangements for cooling (once-through using river water or various cooling towers) and many have flue gas desulfurization to reduce SO2 emissions.…
Photovoltaic Electricity Generation
Satellite measurements put the solar constant – radiation that reaches area perpendicular to the incoming rays at the top of the atmosphere (and that is actually not constant but varies with season and has negligible daily fluctuations) – at 1,366 W/m2. If there were no atmosphere and if the Earth absorbed all incoming radiation then the average flux at the planet’s surface would be 341.5 W/m2 (a quarter of the solar constant’s value, a sphere having four times the area of a circle with the same radius: 4?r…