Welcome to the North American Subaru Impreza Owners Club Friday July 25, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC General > News & Rumors > Non-Subaru News & Rumors

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 03-18-2013, 05:13 PM   #26
shikataganai
Scooby Specialist
 
Member#: 92634
Join Date: Aug 2005
Chapter/Region: RMIC
Vehicle:
2007 Land Cruiser
2013 LEAF

Default

Quote:
Originally Posted by sxotty View Post
Methane is a far more potent GHG than CO2 and there will be plenty of methane leaking to the environment if we have tons of CNG vehicles running around. They are better for the immediate area they operate in though. So local effects are lessened global effects see little change.
More on sxotty's point above via a National Geographic article on LNG truck refilling stations:

Quote:
Measuring the environmental benefit of the switch to natural gas is complicated, even though it's clear that burning of natural gas produces about 30 percent less carbon dioxide than diesel fuel. One of the primary issues is leakage of methane, the main component of natural gas, which is 25 times more potent than CO2 as a greenhouse gas over 100 years. The U.S. government says when methane leakage in the production process is accounted for, a switch from gasoline to natural gas as a vehicle fuel still cuts greenhouse gas emissions, but only 6 to 11 percent.

The issue is even more complex, however, because methane's global warming potential is far worse when examined over a shorter time frame; it is 72 times more potent than CO2 as a heat-trapping gas over 20 years. Many scientists say it is vital to consider this short-term impact. A study published last year in the Proceedings of the National Academy of Science concluded that based on estimated leak rates, the atmosphere would be worse off for 80 years before any climate benefit would be realized from a switch to natural gas for gasoline-powered cars. It could take even longer to see a benefit from a switch for heavy-duty trucks, the study said.

So the nonprofit Environmental Defense Fund, working with partners in industry, has begun a deeper study of methane leak rates when natural gas is used as a fuel for heavy-duty vehicles. Chief scientist Steve Hamberg said the group will gather data on methane leakage from incomplete combustion in trucks, leaks from fittings in the system for delivering and storing natural gas, and from the filling stations themselves. "If you are switching fuels in the transportation sector, you need to be especially careful about methane losses through the supply chain if you want to be sure you are not increasing climate effects," he said. "This is not to say it can't be done." But because the energy content of diesel and natural gas are relatively close, "it doesn't take a lot of leakage of methane to result in higher net emissions from methane," he said.
A 6-11% benefit is definitely too small to convince me that switching to CNG is a good idea, not to mention the whole bit about being worse off for the first 80 years.

I will now cease my proselytizing for the fuel.
* Registered users of the site do not see these ads.
shikataganai is offline   Reply With Quote
Old 03-18-2013, 11:05 PM   #27
sxotty
Scooby Specialist
 
Member#: 95600
Join Date: Sep 2005
Location: Pittsburgh
Vehicle:
2003 WRX wagon
Silver

Default

Hey though remember the local effects part I mentioned. If you take a place like LA and you convert to natural gas you help a lot of people who live right there. So there is a trade off, it just is not good for climate change. But you like EVs anyway, and I like PHEVs so we can both be happy making electricity from the huge amount of natural gas we have instead of using coal. (You probably get hydro, but not here).
sxotty is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 10:35 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.