2. As the world struggles to get more of its power
from renewable sources amid rising demand for
electricity, renewable energy projects are growing.
This is especially true in China, which has plans
for a solar thermal farm, a solar photovoltaic farm
and a wind farm that are five times to 30 times
bigger than the world's current largest. In the U.S.
and elsewhere in the world, building bigger plants
can be tricky. Though economies of scale help to
reduce the cost per watt of bigger projects, bigger
projects are riskier to finance. Here are today's
biggest projects, from highest capacity to lowest,
by type of generation.
3. Three Gorges Dam, China
Capacity: 18,000 MW
Year completed: 2008
This isn't just the biggest renewable energy project in
the world, it's the biggest electricity-generating project,
period. It has 32 main generators. More are being
added, and final capacity will be more than 20,000
MW. All that power comes at a cost: More than a
million people are said to have been displaced by its
construction.
4.
5. The Geysers, Northern California, U.S.
Capacity: 1,000 MW
First power produced: 1921
"The Geysers" aren't actually geysers, but an
underground steam reservoir nestled in mountains 70
miles north of San Francisco. The steam powers 22
power plants at the site, 15 of which are owned by
Calpine. The Geysers' steam first started producing
power in 1921, but the field wasn't developed
commercially until the 1960s.
6.
7. Roscoe Wind Farm, West Texas, U.S.
Capacity: 782 MW
Year completed: 2009
Roscoe, now run by the German utility E.On, overtook
another West Texas farm, the Horse Hollow Wind
Energy Center, last fall. It will soon be overtaken itself-
-if it hasn't been already. China is developing a wind
corridor in western Gansu province that is planned to
ultimately grow to a staggering 20,000 MW. By the end
of this year, it is scheduled to reach 5,000 MW.
8.
9. Solar Energy Generating Systems, Mojave Desert,
Calif., U.S.
Capacity: 354 MW
Year completed: 1990
This system, known as SEGS, is a collection of nine
plants that redirect the sun's heat to tubes of synthetic
oil. The heat in the oil is transferred to water,
producing steam that turns a turbine. Bright Source
Energy is planning a bigger 440 MW solar thermal
project, also in the Mojave Desert. But these plants
seem quaint compared with a Chinese plan announced
this month to build a series of solar thermal plants in
the Mongolian desert designed by eSolar that could
reach 2,000 MW.
10.
11. Jakobstad Biomass Power Plant, Ostrobothnia, Finland
Capacity: 240 MW
Year completed: 2001
Biomass plants are simple--they burn vegetation for
heat that is used to spin a turbine. What keeps them
small is simple, too: logistics. It's hard to gather and
transport the amount of biomass it would require to
power a plant the size of, for example, a coal plant.
12.
13. Rance Tidal Power Station
Brittany, France
Capacity: 240 MW
Year completed: 1966
Tide mills have been employed for centuries. A tide
coming or going turned a water wheel that powered a
mill. The Rance station produces power more like a
hydroelectric plant--the pressure of water flowing turns
cylindrical turbines. A newer approach calls for
submerging huge spinning blades that look a lot like wind
turbines, called axial turbines. But the next big tidal power
station will likely be South Korean, and work like the
Rance plant: A 254-MW project called the Shiwa Lake
Tidal Power Station is scheduled to be completed this
year.
14.
15. Horns Rev 2 Farm, Denmark
Capacity: 209 MW
Year completed: 2009
This farm, owned by Denmark's Dong Energy, became
the largest offshore wind farm in the world when it
was completed in the blustery North Sea last fall. It's a
small part of Europe's much bigger hopes for offshore
wind. The European Wind Energy Association is
targeting 40,000 MW of offshore wind in Europe by
2020, up from 1,500 now.
16.
17. Rozenburg Waste-To-Energy Plant, Netherlands
Capacity: 108 MW
Year completed: 1972
The simple way to turn trash into power is to burn it
and use the heat to turn a turbine, the same way you'd
burn coal or biomass. The problem with trash is that
it's, well, trash. The emissions from these can be nasty
and must be scrubbed hard to clean them. Other trash-
to-energy approaches include gasification that can
produce either electricity or ethanol
18.
19. Olmedilla Photovoltaic Park , Olmedilla, Spain
60 MW
2008
A solar photovoltaic cell is a wonderfully elegant
device. Without any moving parts it simply transforms
the photons emitted from the sun into electrons that
can run our lives. The problem, however, is gathering
enough photons. The world's biggest field is just 60
MW. That's about to change. Several larger plants are
planned, both in the U.S. and abroad. The really big
plans, of course, are Chinese. The first phase of a
gargantuan project that is expected to create a 2,000-
MW field of First Solar thin film panels by 2019 gets
underway this summer
20.
21. Aguçadoura Wave Farm, Portugal
2 MW
First installed: 2008
This was the first and only commercial wave energy
power plant, consisting of connected sections of tubes
that, when jostled by the waves, created hydraulic
pressure which was used to create electricity. That was
before the devices broke. Now they are awaiting
repairs that have been delayed because the plant's
owner, Babcock & Brown, is being liquidated. Pelamis,
which builds the devices, now has its sites on tastier
waves: It has teamed with Sweden's Vattenfall to build
a 20MW project off the Shetland Islands.