Contents INTRODUCTION What is Energy? How Power Grids Work
6 8 12
FOSSIL FUELS Carbon Crunch Coal Oil Natural Gas Damage Limitation Carbon Capture and Storage Combined Heat and Power Smart Grids Carbon-Light
16 18 20 30 40 50 52 56 60 64
Nuclear The Future of Fusion Hydrogen The Geopolitics of Energy The Haves and Have Nots SUSTAINABLE SOURCES Planetary Renewables Solar Solar Thermal Photovoltaic Wind Hydro Rivers and Lakes Wave and Tidal
66 72 76 82 86 88 90 92 94 100 106 112 114 120
Geothermal Biomass
126 132
CREATING A CLEANER WORLD Ecovilles: The Urban Landscape Housing Workplaces Heating and Cooling Transportation Cars Buses Trams Trains Planes Ships
138 140 144 148 152 156 158 166 168 170 174 178
Embodied Energy Energy on Your Plate The Conscious Consumer
182 184 190
EXPLORATORY PATHS Space’s Sunlight Fire of the Stars: Cold Fusion Power of Plants: Artificial Photosynthesis Nano-engineering Micro-organisms
194 196 198 202 206 210
Further Reading Measurements and Terminology Index Picture Credits and Acknowledgments
214 216 218 224
The petrol- or diesel-driven internal combustion engine dominated the twentieth century, but at a price to the planet: transport accounts for approximately one-quarter of global CO² emissions, with 80% of that coming from road vehicles of all shapes and sizes. Pressures to reduce engine pollution, make fuels more environmentally friendly and reduce fuel costs have resulted in big design improvements to both engines and cars. However, revolutionary technologies, such as fuel-cell vehicles and battery–engine hybrids, herald an exciting age of cleaner energy and more efficient driving.
Despite its century-long dominance, the internal combusion engine
GOING NOWHERE
is a highly wasteful convertor of energy (see box, left). The four-
A modern car is a more reliable mechanical mover than it has ever been. However, despite its many advances the internal combustion engine and its conversion of chemical energy to kinetic energy remains highly wasteful. No more than 20% of a four-stroke engine’s fuel will be converted to reciprocating motion, with the rest lost in heat and cooling the hot engine. Thereafter significant proportions of the energy input will be lost – 5–10% in idling (most cars are used in urban areas), 2–3% in power steering and other tasks. Of the small percentage that makes it to the transmission, friction will claim about 5%. Overall this leaves between just 2% and 8% of the fuel being converted to kinetic energy.
stroke engine (intake, compression, combustion, exhaust) that of a crankshaft is an inefficient technology that is, by a number of
COMPACT HYBRID VEHICLE HYDROGEN FUEL CELL VEHICLE
CONVENTIONAL COMPACT GASOLINE VEHICLE
20%
30%
60%
measures, overdue for replacement. However, until recently there has been little to challenge its hegemony. While it is already clear that accommodating new fuel technologies (see below and box, opposite) presents a significant challenge to national infrastructures (dominated by petrol and diesel provision), that disruption could
Driving energy efficiency: A typical combustion engine only delivers 20% efficiency whereas some hydrogen fuel cells will improve that threefold.
be as nothing compared to the shake-up of the oil and carmaking industries that could result from innovation in how cars are powered. The advances already well under way in engine technology seem to be pointing the way to a future with fewer pure internal
combustion engines and more hybrids, batterypowered cars and fuel-cell vehicles. However, creating a wide-scale hydrogen infrastructure may not be viable and this is a crucial unknown at the heart of the energy debate. Partly for this reason, some of the emerging technologies will be more likely to succeed than others.
A plethora of fuels Although, ultimately, it is likely that the world will
40%
move away from the internal combustion engine,
WASTE
6% HEAT (ENGINE FRICTION)
20% MOTION
36% COOLING WATER
20%
38% WASTE HEAT (EXHAUST)
30%
0
The sun that heats our planet is a fiery gaseous ball containing about 70% hydrogen – the most abundant element in the known universe. With its thermonuclear connotations, hydrogen seems an obvious motive fuel, but it doesn’t exist naturally on Earth. However, it can be made anywhere (though at present this still uses fossil fuels); it burns cleanly, emitting only water; and it is less flammable than petrol vapour. Crucially, it is now possible to store and refill a large amount of fuel energy in a relatively small space as revealed by the first hydrogen fuel-cell production car, which can deliver 67mpg (8l/100km), a range of 270 miles (430km) and a top speed of 100mph (160kph), all through a 136bhp electric motor.
converts the reciprocating movement of pistons to the rotary motion
HOW ENGINES BURN UP FUEL ENERGY
10%
Hydrogen: the transport fuel of tomorrow?
in the short to medium term the emphasis has been on developing cleaner, more efficient and sustainable fuels that can be used in existing Rocket-fuelled: Hydrogen conjures up imagery of H-bombs and NASA’s Apollo lift-offs, where it was burned as a propellant, but cutting-edge use of hydrogen is in the form of fuel cells. The Morgan LifeCar (above), unveiled in 2008, uses just four integrated 6 kW cells rather than the 100–150 kW norm and is three times more efficient than any other vehicle of its type.
vehicles with little or no retrofitting required. As the chart, opposite, shows, there are many options available, each with particular advantages and drawbacks. For example, biodiesel is compatible
FUELS AT A GLANCE DIESEL Pros: 30% more fuel efficient than petrol; diesels are quieter and smoother than in the past Cons: A fossil fuel; soot and NOx emissions still relatively high (but lower than in the past)
D
BIODIESEL Pros: Theoretically carbon-neutral and renewable; can be used in most diesel engines Cons: Diverts land away from food production; higher NOx emissions; lower fuel economy BIOGAS Pros: Low emissions of greenhouse gases and smog-producing pollutants; cheaper than petrol Cons: Limited availability of vehicles and refilling outlets; relatively low range per tank of fuel ETHANOL Pros: Low emissions of pollutants; renewable Cons: Can only be used in flex-fuel vehicles; lower mpg than conventional fuels; limited availability; expensive to produce
E
COMPRESSED NATURAL GAS (CNG) Pros: Low emissions of pollutants; dual-fuel vehicles (petrol/diesel and CNG) available Cons: A fossil fuel; limited availability of CNGonly vehicles; extra fuel tank takes up space
CNG
C R E AT I N G A C L E A N E R W O R L D
Motor transport faces a greener future – without changing the basic formula of some form of engine powered by some form of fuel.
LIQUEFIED PETROLEUM GAS (LPG) Pros: Low emissions of pollutants; usually cheaper than petrol Cons: Limited availability of vehicles (although retrofitting possible); low range per tankful
LPG
15 8
Cars
HYDROGEN (INTERNAL COMBUSTION) Pros: Emits only NOx when burned in an internal combustion engine Cons: Currently produced using fossil fuels; expensive; low energy density, so low range ELECTRICITY Pros: Up to 75% energy conversion rate; good performance; no exhaust pipe emissions Cons: Only 150 mile range at best; recharging takes 4–8 hours; batteries heavy and bulky HYBRID Pros: More fuel-efficient than petrol-only car; better range than electric-only car Cons: Expensive; can be unreliable; battery and regenerative braking system heavy and bulky FUEL CELL Pros: Produces no air pollutants or greenhouse gases; technology is developing rapidly Cons: Vehicles prohibitively expensive (at the moment); infrastructure a major challenge
H
Perhaps the answer really is blowing in the wind: it is estimated that all of the world’s current electricity needs could be met by capturing just 20% of global wind power.
In the past decade the proportion of electricity produced by wind power has quadrupled. Despite this rapid growth, the overall percentage of the world’s electricity sourced in this manner remains tiny – around 1%. Most arguments against converting energy from the wind into electricity are based on charges either of inefficiency or expense. No one doubts that the potential resource is considerable: the world’s landbased wind energy is estimated at more than 53 TWh – and the potential for offshore wind is estimated at half that again.
WIND SPEED
Turbines will take only a proportion of available wind energy. There are two major reasons for this. The turbine blades are feathered to spill the wind above 13–15 m/s, resulting in flat power characteristics at that point. Above 25 m/s all the wind is spilled and the turbine goes into a controlled shutdown.
107 7 EW CO I N-D DRIVING
1066 ESCUOS-TDARI N I VAI N BG LE SOURCES
Wind
Wind is abundant, cheap, inexhaustible, widely
among renewable energy sources – and the gap
distributed, clean, and climate-benign. Only solar
is closing fast. Western European countries have
energy can challenge that, yet by 2008 the global
done much in the past decade to promote wind's
wind industry had a capacity of just 100,000 MW,
adoption but the most active installers of turbines
which is equivalent to 100 large coal-fired power
in recent years are China and the United States.
plants. The blades of change have been turning,
One reason for this fast growth is the steady fall
though, and wind-power installation has recently
in prices for wind-generated power, although they
grown at a rate of nearly 30% year on year, so that
still remain much higher than fossil fuel prices.
it is now second only to large-scale hydropower
Another reason is the Chinese and American
MONEY-SPINNER
“SMALL WIND”
POWER GRIDS
SEA BREEZE
CARBON SAVINGS
A wind farm offers farmers an alternative revenue stream to biofuels. A study by the Earth Policy Institute has shown that a farmer in Iowa who offered a quarter-acre of land to house turbines might earn $10,000 a year (3% of the value of the electricity produced). Growing maize for bioethanol on the same land would only yield about $300.
Wind and solar energy can both provide power on a small scale. Households or small communities can use wind power independently of grid-derived supplies. This was once common when we ground corn and pumped water. Today, solar panels, a wind generator and a battery system can be used in a domestic hybrid system.
Proper grid connections are vital for effective wind energy transmission. China is expected to have installed 10 GW of wind turbine power by the end of 2008 but only half will connect to the grid. The typical capacity factor of wind is 20–40% (nuclear is 90%), because the wind does not blow constantly, so a grid including wind requires a back-up source.
The London Array is set to become the world’s largest offshore wind farm. Such wind farms offer two major advantages: more wind and fewer complaints about the “visual pollution” of the turbines. When it is complete (the first phase is due in 2012), the London Array will generate 100 MW – enough to supply electricity to a quarter of London’s homes.
The carbon footprint of a wind turbine depends heavily on its location. A large modern turbine in a rural setting will typically avoid over 4,000 tonnes of CO emissions each ² year, whereas a poorly sited urban turbine could actually be responsible for more CO emissions in its ² manufacture, installation and maintenance than it saves in its operation.
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108
realization (see The Pickens Plan, left) that they have considerable
In 2008 Texas oil man T. Boone Pickens outlined his plan, supported by the American Wind Energy Association, to expand US wind power and wean the country off its addiction to imported oil, thereby strengthening its economic and energy security. The potential exists to generate the annual electricity needs of the US on 6% of its land area (340,000 sq miles/880,260 sq km). Only 5% of the area of a wind farm is occupied by turbines: the rest of the land can still be used for agriculture and grazing. Pickens has argued that his plan would revitalize rural America at a oneoff cost of $1 trillion compared to $0.7 trillion per year importing oil.
onshore and offshore wind potential.
The mechanics of wind power Wind power is extremely sensitive to wind velocity, because power is a cubic function of velocity: doubling the wind speed from 5 m/s to
ECO-DRIVING
S U S TA I N A B L E S O U R C E S
The Pickens Plan
BRAKE SYSTEM A wind-speed sensor activates the brake system to halt the rotor blades in dangerously high winds.
10 m/s increases the power output twelvefold – from 6% of capacity to 73%. When planning a wind farm a location needs to be found where local wind systems blow strongly, though not strongly enough to damage the turbines. A perfect site will be one where the wind can blow freely over the turbines from all directions, and normally these are to be found in flat, open expanses rather than built-up PITCH SYSTEM Adjusts the angle of the blades to make best use of the prevailing wind. (A yaw system at the top of the tower rotates the nacelle to face the wind.)
areas, or clifftops rather than valley floors. For this reason, offshore wind farms tend to be particularly productive, although bolstering the turbines against the ravages of the sea is an ongoing challenge. A typical turbine (see diagram, opposite) will have a multibladed rotor, a nacelle (the turbine housing containing the primary machinery components), a tower and a foundation unit. The latter
TOP WIND STATES IN THE USA
anchors the turbine firmly in the earth or the seabed. The rotor is
Year-by-year wind-energy potential in megawatts
attached to the front of the nacelle, which is fixed at the top of the tower, thereby positioning the nacelle high above the ground where the power of the wind is greatest – the largest towers are twice the height of the Statue of Liberty. The tower gives maintenance engineers access to the nacelle that crowns the turbine, as well as providing a protective structure for the cables that snake down from
CALIFORNIA
total installed capacity, 2006
4,356 MW
2,439 MW
1,299 MW
MINNESOTA
TEXAS
total installed capacity, 2007
Source: American Wind Energy Association
the nacelle to connect up with the grid in the ground. In modern wind turbine design, two configurations dominate: horizontal axis, predominantly of the axial-flow type, or HAWT; and vertical axis, predominantly of the cross-flow type, or VAWT. These range from micro-turbines, capable of providing a proportion of a
GEARBOX Gears scale up the relatively low rotational speed of the rotor shaft to the higher speed required to drive the generator.
WHERE THE WINDS OF CHANGE ARE BLOWING
By 2020 the European Union aims to have 20% of its energy from renewables – in Denmark wind alone delivers about 19%. Offshore wind farms nearing completion in the North Sea may provide 120 MW on their own. Across the Atlantic, based on the current rate of installation, the US might well get 15% of its electricity from wind by 2020. And in Asia the rapid industrialization of India and China is being tracked by similarly rapid expansion of windgenerating capacity.
Housed within a modern large-scale wind turbine is a sophisticated array of up to 8,000 components.
The world’s total installed wind turbine capacity GERMANY 22,247 MW PORTUGAL 2,150 MW UK 2,386 MW FRANCE 2,454 MW
USA 16,818 MW
ITALY 2,726 MW DENMARK 3,125 MW CHINA 6,050 MW SPAIN 15,145 MW INDIA 8,000 MW REST OF THE WORLD 13,019 MW
TOTAL top 10: TOTAL all:
81,104 MW 94,123 MW
Source: GWEC-Global Wind 2007 Report
86.2% 100.0%
TRANSFORMER The transformer converts the electricity generated to the higher voltage required by the grid.
GENERATOR The generator converts the mechanical energy from the turning of the rotor blades into electrical energy.
0.2% B
PP 6.7%
0.2% R
G 10.3% N 2.7%
63.8% C
H 16.1%
AN ENERGY-HUNGRY PLANET The Earth’s population consumes a huge amount of primary energy, much of which is converted into secondary energy in the form of electricity. Household bills are usually expressed in kilowatt hours (kWh), but a large-scale use of energy is expressed as a terawatt hour (TWh) – equivalent to a billion kWh. Demand for energy and electricity is unevenly distributed around the world – as are the fuels used to generate it. These six regional breakdowns (right) reveal how electricity is sourced in different parts of the world: in Latin America and the Caribbean hydro power supplies two-thirds, whereas in sub-Saharan Africa – as for the world overall – coal is dominant. Only a quarter or so of the world’s electricity is generated from oil or gas, yet these two fuels – used for heating and industry – have given rise to a vast global trade via a network of pipelines and shipping routes.
FORMER USSR & E. EUROPE 1,473 TWh
LATIN AMERICA & CARIBBEAN 763 TWh
1.6% R G 31.5%
21.2% C
G 12.5% N 2.8%
17.8% H
67.0% H
N 22.1%
OIL is produced in 123 countries but the top 20 provide some 83% of the total. The US is one of the big producers but it uses approximately double its own output.
OECD [W. EUROPE & N. AMERICA] 9,490 TWh PP 5.9%
SUB-SAHARAN AFRICA 306 TWh
1.6% B 0.7% R
0.3% R
N 3.8% 4.3% G 4.8% PP 5.5%
G 16.8%
ANNUAL GLOBAL PER CAPITA PRIMARY ENERGY USE
H 15.0%
37.9% C
GAS is moved around the world largely through pipelines or in ships (in its liquefied form, LNG). Russia and the US are the largest producers.
70.6% C N 24.1%
IN KILOWATT HOURS (KWH) PER CAPITA (TO NEAREST 1,000 KWH) 13.0% H
200 min Pat, consequis adit aut alissed PETROLEUM PRODUCTS (PP) 1,200 eugue vulla feu ugiamcommod.
200
GAS (G)
COAL (C)
MIDDLE EAST & N. AFRICA 649 TWh C 6.9%
2,800
4.8% H
Source: IEA, 2002 Source: World Energy Assessment (WEA)
NON-OECD ASIA (EXCL. CHINA)
2,600
49.4% G
5,900 PP 38.9% 2,500
CHINA
13,000
LATIN AMERICA & CARIBBEAN
19,000
MIDDLE EAST & N. AFRICA OECD EUROPE
19,000
40,000
NUCLEAR (N) HYDRO (H)
SUB-SAHARAN AFRICA
7,000
37,000
BIOMASS (B)
OTHER RENEWABLES (R)
7,000
11,000
GLOBAL ELECTRICITY PRODUCTION BY SOURCE The world’s electricity needs are approximately 15,400 Terrawatt hours (TWh), of which two-thirds is generated using fossil fuel sources. Primary fuels such as coal, natural gas and oil remain the cheapest for most nations.
1.6% B
PP 4.2%
1.9% R 3.0% C
B 1.9% PP 10.9%
FORMER USSR
NON-OECD EUROPE (ORGANIZATION FOR ECONOMIC CO-OPERATION AND DEVELOPMENT) OECD PACIFIC (AUSTRALIA, NZ, KOREA, JAPAN) FORMER USSR
OECD NORTH AMERICA (INC MEXICO)
OECD EUROPE OECD PACIFIC (AUSTRALIA, NZ, KOREA, JAPAN)
50,000 78,000
OECD N. AMERICA
Source: World Energy Assessment (WEA)
ECO-DRIVING
ECO-DRIVING
The Globalized Grid
11
10
ASIA PACIFIC 2,795 TWh ENERGY DIGNISITENIS: