E
R RADIANT C CHEMICAL T THERMAL
HOW MUCH E NERGY DOES IT TAKE TO POWER A 100-WATT LIGHT BULB FOR A YEAR?
R K E
FUELS NATURAL FLOWS NEEDS
R C T E
K KINETIC
E ELECTRICITY
E
FUELS
R RADIANT
NATURAL FLOWS
NEEDS
The most intuitive way to define energy is to describe what it does. Energy is the ability to do work or cause motion. A more inclusive definition of energy would be to define it as the ability to transform a system, a process that can involve any kind of energy.
C CHEMICAL SOLAR RADIATION, THE ULTIMATE SOURCE OF ENERGY
T THERMAL
K KINETIC
E ELECTRICITY
Not everything the earth is energized by solar radiation: it does not keep the planet on its orbital path, it does not drive the plate tectonics, and it does not power the metabolism of deep water bacteria. But, the whole pyramid of life rests on photosynthetic conversion of solar radiation to phytomass (plant biomass) while precipitation, ice, and wind—all just thermal and kinetic transformations of solar radiation that was absorbed by the atmosphere, land and waters— keep reshaping the planetary surfaces and are the key determinants of the food-producing potential of every civilization.
E
FUELS
NATURAL FLOWS
Fuels are primary sources for creation of electricity, that is, usable energy. each fuel is a chemical store of sun’s radiant energy which can be unleashed by combustion and converted into heat, kinetic, and finally electrical energy.
INPUT
coal
718 pounds
raw uranium
0.036 pounds
natural gas
186 pounds
amount of fuel needed to power the lightbulb
STORE
= 100 pounds = 20 pounds = 6 pounds = 0.036 pounds
NEEDS
E
FUELS
NATURAL FLOWS
Fuels are primary sources for creation of electricity, that is, usable energy. each fuel is a chemical store of sun’s radiant energy which can be unleashed by combustion and converted into heat, kinetic, and finally electrical energy.
INPUT
coal
1.22 kwh
raw uranium
70,000 kwh
natural gas
4.71 kwh
STORE energy stored in one pound of‌
= 5000 kWh = 1 kWh = 0.71 kWh = 0.22 kWh
NEEDS
E
FUELS NATURAL FLOWS
NEEDS
Natural flows are different from fuels, or energy stores, since they are direct conversions of solar radiation in the form of instantaneous / timedependent / ephemeral / fleeting phenomena such as wind, water flow, and solar light or heat. Natural flows, then must be captured as they occur.
INPUT
wind turbine A.
7 hours and 18 min
wind turbine B.
2 hours and 20 min
hydroelectric A.
2 hours and 48 min
hydroelectric B.
17 min
solar panel A.
8 days and 18hours
solar panel B.
18hours
amount of flow needed to power the lightbulb
SIZE
= 1 days = 1 hour = 48 min = 25 min = 19 min
E
FUELS
NATURAL FLOWS
NEEDS
Natural flows are different from fuels, or energy stores, since they are direct conversions of solar radiation in the form of instantaneous / timedependent / ephemeral / fleeting phenomena such as wind, water flow, and solar light or heat. Natural flows, then must be captured as they occur.
INPUT
wind turbine A.
33 meter diameter rotor
wind turbine B.
66 meter diameter rotor
SIZE
hydroelectric A.
4 meter water head small turbine
hydroelectric B.
40 meter water head small turbine
solar panel A.
one hundred 1m 2 panels
solar panel B.
one thousand 1m 2 panels
= 50 meters = 10 meters = 1 meter = 2 panels
E
FUELS NATURAL FLOWS
NEEDS
Fossil fuels are the energy source of modern civilization 105
Supplied Fuels
oil fields
coal fields 104
Need Supply Match by Fuels and Flows
power density (W/m2)
Supplied Natural Flows
Energy Needs
Preindustrial societies relied on instantaneous or minimally delayed and constantly replenished solar income. Modern civilization is withdrawing accumulated solar capital at rates that will exhaust it in a tiny fraction of the time needed to create it. We are living in an energetic interlude.
thermal power plants
103
102
101
100 10-1 10-2
100
102
104
area (m2)
106
108
1010
E
FUELS NATURAL FLOWS
NEEDS
Supplying energy to the world after fossil fuels are no longer an option 105
Supplied Fuels
104
Need Supply Match by Fuels and Flows
power density (W/m2)
Supplied Natural Flows
Energy Needs
We will never exhaust all the recoverable reserves of fossil fuels, the share of overall resources that can be produced with available techniques at a known cost. Long before reaching that point we will either go back to immediate solar flows harnessed in ways vastly superior to preindustrial practices, or we will put in place new arrangements dependent on another, more durable class of stores, such as advanced nuclear options or entirely new, as yet unknown conversions.
103
102
101
flat plate collectors central solar towers
photovoltaics
hydro
wind 100
hydro
plant biomass 10-1 10-2
100
102
104
area (m2)
106
108
1010
E
FUELS NATURAL FLOWS
NEEDS
Power Densities of Fuels and Energy Conversions 105
Supplied Fuels
104
Need Supply Match by Fuels and Flows
power density (W/m2)
Supplied Natural Flows
Energy Needs
A revealing way to illustrate the space demands of modern energy production and use is to focus on the disparity between the power densities of conversions that harness renewable energies and those that rely on fossil fuels. Most of the deployed or promising renewable conversions produce electricity rather than fuel, ad their comparisons show significantly lower disparities on overall power densities.
highrises 10
3
supermarkets
industry
steel mills, refineries
102 cities houses
101
100 10-1 10-2
100
102
104
area (m2)
106
108
1010
E
FUELS NATURAL FLOWS
NEEDS
Power Densities of Fuels and Energy Conversions 105
Supplied Fuels
oil fields
coal fields 104
Need Supply Match by Fuels and Flows
power density (W/m2)
Supplied Natural Flows
Energy Needs
A revealing way to illustrate the space demands of modern energy production and use is to focus on the disparity between the power densities of conversions that harness renewable energies and those that rely on fossil fuels. Most of the deployed or promising renewable conversions produce electricity rather than fuel, ad their comparisons show significantly lower disparities on overall power densities.
thermal power plants
highrises 103 supermarkets 102
101
industry
steel mills, refineries
flat plate collectors photovoltaics
central solar towers
houses
hydro
cities
wind 100
hydro
plant biomass 10-1 10-2
100
102
104
area (m2)
106
108
1010
E
FUELS NATURAL FLOWS
NEEDS
Power Densities of Fuesolar energy prospects and challenges
oil fields
coal fields 104
Need Supply Match by Fuels and Flows
power density (W/m2)
Supplied Natural Flows
Energy Needs
In order to energize the existing residential, industrial, and transportation infrastructures inherited from the fossil-fueled era, a solar-based society would have to concentrate diffuse flows to bridge power density gaps of 2-3 OM (“Orders of Magnitude” or “powers of ten”).
105
Supplied Fuels
thermal power plants
highrises 103 supermarkets 102
101
industry
steel mills, refineries
flat plate collectors photovoltaics
central solar towers
houses
hydro
The mismatch between the low power densities of renewable energy flows and the relatively high power densities of modern final energy uses means that a solar-based system will require a profound spatial restructuring with major environmental and socioeconomic consequences.
cities
wind 100
hydro
plant biomass 10-1 10-2
100
102
104
area (m2)
106
108
1010