few months back during a brain storming session (with the know-it-all engineers - KIAE) came up the topic of sustainable energy vs renewable energy... well we were looking for a slogan... and one KIAE said to include sustainable energy and i said that renewable doesnt ALWAYS imply sustainable... may be it was irrelevant but what the heck its a brain storming session... so anyways the KIAE opposed by INSISTING that they are both the same, going by the logic that for something to sustain it must be renewable... and one of my friends there argued against it saying that its not... and the example he gave was that nuclear (fission) energy is sustainable but not renewable... and even during a booze binge these KIAEs still insist that they are botht he same...
lets look the "definitions" of these two phrases... these are not an exact definitions... different organizations and so called experts interpret and define them differently...
sustainable energy is energy obtained from a source which is not expected to deplete during the timeframe relevant to the human race...
renewable energy is energy obtained from a source where the energy is replenished during a relatively short cycle...
open pit uranium mine
nuclear fission is non-renewable but sustainable because the source of energy will not deplete for a long time... long enough for the humanity to go extinct... (and it doesnt contribute to global warming)... there is enough uranium to last a few billion years... read more...
upper kotmale project
major hydro power is renewable but not sustainable... usually major hydro power projects involved building a reservoir which would occupy a large area of land... this may change the natural environment so much that there could be long term effects such as change in rainfall etc... so whether the dam could replenish its energy for a long period of time (such as the end of humanity) is questionable... hence major hydro power is not considered renewable... but then again this is debatable... because there are major hydro projects which have not gone bad... it all depends on how nature adopts to the change i guess... well take the upper kotmale project... it would change the environment but if its going change in a way that would effect rainfall which replenishes water to the reservoir for a long period of time is debatable... so major hydro in general is not a sustainable source of energy but its renewable...
other types of renewable sources such as wind, small hydro, solar PV (solar cells) and solar thermal (solar powered hot water etc), geo thermal energy etc are all sustainable energy types...
ipil ipil energy plantation in the puttalum district
is biomass renewable and sustainable? well its like major hydro... say there is a tree and you cut it down for firewood... the tree COULD grow back to its original size in a few years so its renewable... but if you dont allow it to grow then you make the source non-sustainable... but there is a new concept called energy plantations where you allow trees to grow to its "harvesting" size and then "harvest" the entire tree or a part of the tree... and let the tree or part that you chopped off grow back to its "harvesting" size... and this is something i was involved in at enerfab... sri lanka has quite a potential for such energy plantations without exaggeration... just that we sucked at marketing it!
bowser unloading diesel fuel
oil, coal and natural gas are not renewable and not sustainable... because their replenishment time long exceeds the time frame we are looking at... and there isnt enough oil to last till the end of humanity... some claim that oil will run out in 50 years! which is bull crap but lets not get in to that...
any questions?