In reply to Jed Rothwell's message of Wed, 27 Feb 2013 21:11:11 -0500: Hi Jed,
What you didn't say in so many words, and I forgot to mention, is that using wind energy has a positive impact in as much as it reduces the amount of CO2 produced. [snip] ><[email protected]> wrote: > > >> ...one can only hope! However the truth is that most of the energy we use >> is >> returned to the environment as heat, so taking it out as wind power and >> putting >> it back as heat would probably have very little net effect. >> > >Two things about this are a little off: > >1. Nuclear power and fossil fuel combustion add heat to the earth's >atmosphere. Solar PV, solar water heating, hydro and wind do not. That is, >they add no net heat. They transfer it from one place to another. Hydro, >for example, reduces the heat in a river a little, and transfers it to the >city where it powers machines. It shows up there as waste heat. All energy >ends up as heat. > >Fossil fuel releases heat to the atmosphere that was collected from the sun >eons ago. > >2. The heat from energy production does not matter much. It is not the >cause of global warming. It leaves the atmosphere in about a half-hour. It >is true that urban "heat islands" from large numbers of automobiles are a >problem, but it is a separate problem from global warming, which is far >more serious. > >If we derive all of our energy from conventional nuclear power or cold >fusion we would still be heating the atmosphere at about the same rate we >do today, because cold fusion cars will probably not have hugely better >Carnot efficiency than today's models. If we get our energy from solar, >wind or even biofuel this will reduce short term atmospheric heating >somewhat. > >To get a sense of how much biofuel production reduces local heat . . . step >into a forest. It is a lot cooler than an open field, isn't it? All that >heat is being absorbed by the leaves, or reflected back into space I >suppose. Not much reflects from the trees to the fields. > >- Jed Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
