Article: Hydroelectric power's dirty secret revealed

[Guest guest]

This is some serious stuff we are all going to have to deal with - the

energy crunch! What is the answer?

 

Even what we thought were more benign methods of generating power aren't

necessarily without their problems. A while back I posted an article

about problem with the wind power turbines, now this ... Food for

thought ....

 

So, read up folks, and get educated, but don't get blinded by emotion -

emotions is not what is going to solve our world's energy issues. Smart

kids is truly what will <grinz>

 

Oh,and of course conserve where you can! Unfortunately, that's most

likely not going to be the only answer to this problem ... but if

everyone turned off that extra light bulb that didn't need to be on -

we'd have that much less energy that needed to be produced

 

*Smile*

Chris (list mom)

http://www.alittleolfactory.com

 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

http://www.newscientist.com/article.ns?id=dn7046

 

Hydroelectric power's dirty secret revealed

 

Hydropower polluters

 

Contrary to popular belief, hydroelectric power can seriously damage the

climate. Proposed changes to the way countries' climate budgets are

calculated aim to take greenhouse gas emissions from hydropower

reservoirs into account, but some experts worry that they will not go

far enough.

 

The green image of hydro power as a benign alternative to fossil fuels

is false, says Éric Duchemin, a consultant for the Intergovernmental

Panel on Climate Change (IPCC). " Everyone thinks hydro is very clean,

but this is not the case, " he says.

 

Hydroelectric dams produce significant amounts of carbon dioxide and

methane, and in some cases produce more of these greenhouse gases than

power plants running on fossil fuels. Carbon emissions vary from dam to

dam, says Philip Fearnside from Brazil's National Institute for Research

in the Amazon in Manaus. " But we do know that there are enough emissions

to worry about. "

 

In a study to be published in Mitigation and Adaptation Strategies for

Global Change, Fearnside estimates that in 1990 the greenhouse effect of

emissions from the Curuá-Una dam in Pará, Brazil, was more than

three-and-a-half times what would have been produced by generating the

same amount of electricity from oil.

 

This is because large amounts of carbon tied up in trees and other

plants are released when the reservoir is initially flooded and the

plants rot. Then after this first pulse of decay, plant matter settling

on the reservoir's bottom decomposes without oxygen, resulting in a

build-up of dissolved methane. This is released into the atmosphere when

water passes through the dam's turbines.

 

 

" Drawdown " regions

 

 

Seasonal changes in water depth mean there is a continuous supply of

decaying material. In the dry season plants colonise the banks of the

reservoir only to be engulfed when the water level rises. For

shallow-shelving reservoirs these " drawdown " regions can account for

several thousand square kilometres.

 

In effect man-made reservoirs convert carbon dioxide in the atmosphere

into methane. This is significant because methane's effect on global

warming is 21 times stronger than carbon dioxide's.

 

Claiming that hydro projects are net producers of greenhouse gases is

not new (New Scientist print edition, 3 June 2000) but the issue now

appears to be climbing up the political agenda. In the next round of

IPCC discussions in 2006, the proposed National Greenhouse Gas Inventory

Programme, which calculates each country's carbon budget, will include

emissions from artificially flooded regions.

 

But these guidelines will only take account of the first 10 years of a

dam's operation and only include surface emissions. Methane production

will go unchecked because climate scientists cannot agree on how

significant this is; it will also vary between dams. But if Fearnside

gets his way these full emissions would be included.

 

With the proposed IPCC guidelines, tropical countries that rely heavily

on hydroelectricity, such as Brazil, could see their national greenhouse

emissions inventories increased by as much as 7%. Colder countries are

less affected, he says, because cold conditions will be less favourable

for producing greenhouse gases.

 

Despite a decade of research documenting the carbon emissions from

man-made reservoirs, hydroelectric power still has an undeserved

reputation for mitigating global warming. " I think it is important these

emissions are counted, " says Fearnside.

 

http://www.newscientist.com/article.ns?id=mg18524911.000

 

 

Make use of methane

 

19 March 2005

M. P. Hughes Gravesend, Kent, UK

 

 

<http://adserver.adtech.de/?adlink|289|113568|1|170|AdId=309603;BnId=2;i

time=456981584;> Your article suggests that dams for hydroelectric power

contribute to the greenhouse effect (26 February, p 8). Surely all the

carbon that is released from a dam is derived from the atmosphere

anyway. Except for the original pulse of decay, any CO2 released will

have been taken quite recently from the atmosphere.

 

The problem is, of course, the methane. It must be worthwhile

considering the possibility of harvesting this more potent greenhouse

gas if it is produced in the quantities suggested in the article.

Perhaps what is needed is a transfer of technology from the researchers

who were the subject of the article " Making the best of garbage gas " (26

February, p 25). Then it would be possible to get two sources of green

energy from a given dam - from hydroelectricity and from a power station

fuelled by the methane from the biomass the dam contains.

 

 

 

 

 

 

 

[Guest guest]

Chris,

Besides the fact that those bulbs live forever, I have replaced all the

light bulbs in my house with energy efficient ones, especially the ones

that I like to have on a lot. and only use high wattage for where it

really has to be , than am careful on how much I use it.

Use energy efficient drapes to keep the heat in or out and use attic

fan's instead of air conditioning...

Many years ago, we figured out that if ust 399.999. people in Michigan

would turn off ONE light bulb we would not have needed the Big Rock

Point nuclear plant in my area...it's all the power it supplied to the

general power grid.....

C-M