Energy Transitions

These are good articles to read:

(1) Energy Transitions Past and Future

June 7th 2010

(2) 21st century, some sobering thoughts


5 challenges:

(a) Scale of shift

(b) Lower energy density of replacement fuels (energy content in unit of fuel)

Crude oil:    42 MJ/kg

Air dry crop residue:    12-15 MJ/kg

(c) Substantially lower power density of renewable energy extraction

Hydrocarbons:    100-1,000 W/m2

Biomass:    1 W/m2

Water & wind:    10 W/m2

Photovoltaic:    20 W/m2

US corn ethanol:    0.22 W/m2

(d) Intermittency of renewable flows

Coal fired power plant:  >75% load factor

Wind:     20-25% load factor

(e) Uneven distribution of renewable energy resources

Many major load centres far away from available sources

by Vaclav Smil, University of Manitoba