EnviroLink Forum

Community • Ecology • Connection
It is currently Wed Oct 01, 2014 4:14 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 2 posts ] 
Author Message
PostPosted: Mon May 21, 2012 1:17 pm 
Offline
Member with over 1000 posts!
Member with over 1000 posts!
User avatar

Joined: Tue Apr 18, 2006 2:09 pm
Posts: 1649
Location: Regina, Saskatchewan, Canada
Geothermal (the type where you drill down to the hot parts of the earth's crust) is pushed as a great way to reduce the emissions of CO2 and thus global warming. Someone said that it was adding heat to the atmosphere that would not have been added naturally. This is not entirely true in that the heat is in fact heading to the surface which is why we need to drill down so far. We do of course make it easier to get to the surface so that might have an effect but I doubt that volume is much and of course the heat naturally heading to the surface is reduced in the same proportions as the heat extracted. What got my attention though was the plumes of steam that some geothermal operations have from the cooling towers. To make turbines more effective, you increase the temperature difference on each side of the turbines so they spray water on the cooling pipes. The best geothermal locations generally are in places with little water resources so other options are being used (including less efficient turbines). The most influential greenhouse gases is not CO2 but rather water vapor. The difference is that clouds also reflect sunlight and shade the planet and thus counter some or all of their heat capturing effects. This still leaves some doubt in my mind that geothermal is as great a solution to global warming as it is touted to be.


Top
 Profile  
 
PostPosted: Tue Jun 12, 2012 12:36 am 
Offline
Member with 50 posts!
Member with 50 posts!

Joined: Wed Mar 14, 2012 5:33 am
Posts: 67
Ann Vole wrote:
Geothermal (the type where you drill down to the hot parts of the earth's crust) is pushed as a great way to reduce the emissions of CO2 and thus global warming. Someone said that it was adding heat to the atmosphere that would not have been added naturally. This is not entirely true in that the heat is in fact heading to the surface which is why we need to drill down so far. We do of course make it easier to get to the surface so that might have an effect but I doubt that volume is much and of course the heat naturally heading to the surface is reduced in the same proportions as the heat extracted. What got my attention though was the plumes of steam that some geothermal operations have from the cooling towers. To make turbines more effective, you increase the temperature difference on each side of the turbines so they spray water on the cooling pipes. The best geothermal locations generally are in places with little water resources so other options are being used (including less efficient turbines). The most influential greenhouse gases is not CO2 but rather water vapor. The difference is that clouds also reflect sunlight and shade the planet and thus counter some or all of their heat capturing effects. This still leaves some doubt in my mind that geothermal is as great a solution to global warming as it is touted to be.


The problem is not that we are adding to much heat to the atmosphere but that we are not allowing the natural heat from the sun to escape as easily due to the addition of greenhouse gases.

The average time for water vapour in the air is about 8 or 9 days before it is rained out. The only way in which the atmosphere can hold more water is by increasing the air temperature. So if we add water vapour to the atmosphere it will saturate the air in that location and prevent further evaporation. Further to that the amount of water vapour from any steam driven generators is tiny compared to that which is naturally produced by evaporation from the oceans. To put this into perspective the worlds oceans on average evaporate a layer of water some 50 ins thick per year which of course comes back down as rain. The greatest man made source of water vapour would in fact be from burning fossil fuels but again is too small a quantity to have any detectable effect on the climate. The exception is jet aircraft which add water vapour to the atmosphere at high altitude where the levels are naturally extremely low.

_________________
Pollution is not the solution


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: Bing [Bot] and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group