Asked in Environmental IssuesEarth SciencesRenewable Energy
Are Solar nuclear wind water and geothermal energy renewable?
May 13, 2012 7:27AM
Simplistically, yes, these sources of energy (plus wave and tidal-stream power) are renewable, sustainable and carbon neutral. However investment of non-renewable resources is required to build and instal the energy capture devices: Nuclear fuel needs to be mined and refined, solar panels require "trace" elements in manufacture, any form of power plant (including wind or hydro turbines) require steel and concrete to build, and in every case copper or aluminium conductors are required to transport the energy produced to consumers. Energy captured throughout an entire project's life-cycle can be compared to energy invested (and possibly recovered by end-of-life recycling) to calculate and compare the carbon cost of different technologies. Nuclear power presents particular challenges because its "fuel" is fossil-energy expensive to mine and the "spent" fuel requires management long after its use in energy generation. The "embedded energy" in the steel tower of a wind turbine is recovered quite quickly, within a few years of it being built. Life cycle energy- and carbon-budgets, together with global availability of minerals should inform strategic decisions and it is certainly not true that nuclear is 100% carbon neutral even with no stack emissions. Wind is, of course, "solar-driven" through differential heating of land and sea masses whereas; tidal is driven principally by lunar gravity effects and geothermal by radioactivity within the earth's core. All of these so-called "renewable resources" are finite (in that they are subject to the laws of thermodynamics) in the very long term.