GWP and hydropower methane Flashcards
What does GWP stands for?
Global warming potential: How good is a gas in trapping heat?
How is the atmospheric composition built up?
- 78% N2
- 20.9% O2
- Ar, CO
- Ne, He, Methane, H20, Kr, H, Xe, O3 < 1%
What is the greenhouse effect?
Radiative forcing of a gas. Greenhouse gases can trap heat from the sun which results in overall temperature increase. Radiative forcing is calculated in watts per square meter, which represents the size of the energy imbalance in the atmosphere. Earth receives more incoming energy from sunlight than it radiates to space. This net gain of energy will cause warming.
What other factor than radiative forcing [W/m^2] relates to the GWP of a GHG?
The lifetime
How is GWP related to RF?
The GWP is the time-integrated radiative forcing due to a pulse of emission of the pollutant, over a given time horizon (lifetime of the GHG)a, relative to a similar pulse in CO2 emission.
Is H2 a GHG?
No, its not a direct GHG but H2 emissions impact the life time of other GHGs and indirectly increases the global temperature. (estimated at 12 CO2,eq on 100Y)
What uncerntainties exists concerning H2 in the future?
Uncertainty to what level H2 will leak from our industrial assets and to what level H2 will reach the upper atmosphere to react with OH radicals remains uncertain!
A clear benefit for climate arises from a transition to a hydrogen economy. Assuming a leakage of 1-3% of green H2 would imply a 1-6% reduction in the CO2 emission avoided (GWP) when switching from a fossil economy to a hydrogen economy. Hydrogen supply and the leakage rate appear as key leverages to further mitigate the climate impact through an H2 economy transition.
