Final energy

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