A2 CAMBRIDGE GEOGRAPHY: ENVIRONMENTAL MANAGEMENT - THE MANAGEMENT OF ENERGY SUPPLIES. It contains case studies in USA and China.

1. A2GEOGRAPHY
ENVIRONMENTALMANAGEMENT
12.2 THEMANAGEMENT
OFENERGYSUPPLY
CASESTUDIESUSAANDCHINA

2. USA AND ENERGY SUPPLY
The United States uses and produces many different types
and sources of energy, which can be grouped into general
categories such as primary and secondary, renewable and
non-renewable, and fossil fuels.
Primary energy sources include fossil fuels (petroleum,
natural gas, and coal), nuclear energy, and renewable
sources of energy.
Electricity is a secondary energy source that is generated
(produced) from primary energy sources.

4. ENERGY SOURCES
Energy sources are measured in different physical units:
liquid fuels in barrels or gallons, natural gas in cubic feet,
coal in short tons, and electricity in kilowatts and kilowatt
hours.
In the United States, British thermal units (Btu), a measure
of heat energy, is commonly used for comparing different
types of energy to each other.
In 2017, total U.S. primary energy consumption was equal to
about 97.7 quadrillion (97,728,000,000,000,000) Btu.

6. PRIMARY ENERGY
There are five major
primary energy consuming
sectors.
Their shares of total
primary energy
consumption in 2017 were:
• Electric power—38.1%
• Transportation—28.8%
• Industrial—22.4%
• Residential—6.2%
• Commercial—4.5%

7. THE PATTERN OF FUEL
The electric power sector generates most of the electricity in
the United States, and the other four sectors consume most of
that electricity.
The pattern of fuel use varies widely by sector.
For example, petroleum provides about 92% of the energy
used for transportation, but only 1% of the energy used to
generate electricity.

8. CASE STUDY IN ENVIRONMENTAL
IMPACTS OF HEP IN USA
Hydroelectric power includes both massive hydroelectric dams
and small run-of-the-river plants.
Large-scale hydroelectric dams continue to be built in many
parts of the world (including China and Brazil), but it is
unlikely that new facilities will be added to the existing U.S.
fleet in the future.
Instead, the future of hydroelectric power in the United States
will likely involve increased capacity at current dams and new
run-of-the-river projects. There are environmental impacts at
both types of plants.

9. The Hoover Dam
when completed
in 1936 was both
the world's
largest electric-
power generating
station and the
world's largest
concrete
structure.

10. LAND USE
The size of the reservoir created by a hydroelectric project can
vary widely, depending largely on the size of the hydroelectric
generators and the topography of the land.
Hydroelectric plants in flat areas tend to require much more
land than those in hilly areas or canyons where deeper
reservoirs can hold more volume of water in a smaller space.

11. HEP Sites

12. BALBINA HYDROELECTRIC PLANT
At one extreme, the large Balbina hydroelectric plant, which
was built in a flat area of Brazil, flooded 2,360 square
kilometres—an area the size of Delaware—and it only provides
250 MW of power generating capacity (equal to more than
2,000 acres per MW).
In contrast, a small 10 MW run-of-the-rive plant in a hilly
location can use as little 2.5 acres (equal to a quarter of an
acre per MW).

13. Balbina Dam has
hit populations of
mammals, large
gamebirds and
tortoises,
researchers say,
warning against
hydro push.
Widely hailed as
‘green’ sources of
renewable energy,
numerous
hydroelectric
dams have been
built worldwide,
but research
reveals they are
far from
environmentally
friendly.

14. FLOODING LAND
Flooding land for a hydroelectric reservoir has an extreme
environmental impact: it destroys forest, wildlife habitat,
agricultural land, and scenic lands.
In many instances, such as the Three Gorges Dam in China,
entire communities have also had to be relocated to make way
for reservoirs.

15. DAMMED RESERVOIRS
Dammed reservoirs are used for multiple purposes, such as
agricultural irrigation, flood control, and recreation, so not all
wildlife impacts associated with dams can be directly
attributed to hydroelectric power.
However, hydroelectric facilities can still have a major impact
on aquatic ecosystems.
For example, though there are a variety of methods to
minimize the impact (including fish ladders and in-take
screens), fish and other organisms can be injured and killed by
turbine blades.

16. WILDLIFE IMPACTS
Apart from direct contact, there can also be wildlife impacts
both within the dammed reservoirs and downstream from the
facility.
Reservoir water is usually more stagnant than normal river
water. As a result, the reservoir will have higher than normal
amounts of sediments and nutrients, which can cultivate an
excess of algae and other aquatic weeds.
These weeds can crowd out other river animal and plant-life,
and they must be controlled through manual harvesting or by
introducing fish that eat these plants.
In addition, water is lost through evaporation in dammed
reservoirs at a much higher rate than in flowing rivers.

17. HYDROELECTRIC OPERATORS
In addition, if too much water is stored behind the reservoir,
segments of the river downstream from the reservoir can dry
out.
Thus, most hydroelectric operators are required to release a
minimum amount of water at certain times of year.
If not released appropriately, water levels downstream will
drop and animal and plant life can be harmed.
In addition, reservoir water is typically low in dissolved
oxygen and colder than normal river water.

18. MITIGATING IMPACTS
When this water is released, it could have negative impacts on
downstream plants and animals.
To mitigate these impacts, aerating turbines can be installed
to increase dissolved oxygen and multi-level water intakes can
help ensure that water released from the reservoir comes
from all levels of the reservoir, rather than just the bottom
(which is the coldest and has the lowest dissolved oxygen).

19. CASE STUDY
CHINA AND ENERGY SUPPLY
China overtook the USA in total energy usage in 2009.
The demand for energy in China continues to increase
significantly as the country expands its industrial base.
In 2008, China’s energy consumption breakdown by traditional
energy sources was:
• coal – 70.2%
• oil – 18.7%
• hydroelectricity – 6.6%
• natural gas – 3.6%
• nuclear energy – 0.75%

21. THE THREE GORGES DAM
The Three Gorges Dam is a hydroelectric gravity dam that
spans the Yangtze River by the town of Sandouping, in
Yiling District, Yichang, Hubei province, China.
The Three Gorges Dam is the world's largest power station
in terms of installed capacity (22,500 MW).
In 2014 the dam generated 98.8 terawatt-hours (TWh) and
had the world record, but was surpassed by the Itaipú Dam,
which set the new world record in 2016, producing 103.1
TWh.

22. CHINA’S ENERGY STRATEGY
China’s energy policy has evolved over time.
As the economy expanded rapidly in the 1980s and 1990s
much emphasis was placed on China’s main energy
resource, coal.
China was also an exporter of oil until the early 1990s; it is
now a very significant importer.
Chinese investment in energy resources abroad has risen
rapidly.
Long-term energy security is viewed as essential if the
country is to maintain the pace of its industrial revolution.

24. A BALANCED APPROACH
In recent years China has tried to take a more balanced
approach to energy supply and at the same time reduce its
environmental impact through:
• energy conservation
• placing a strong emphasis on domestic resources
• diversified energy development
• environmental protection
• mutually beneficial international cooperation

25. NEW DIRECTIONS
The development of clean coal technology is an important
aspect of China’s energy policy. China has begun
constructing clean coal plants at a rate of one a month and
gradually retiring older, more polluting power plants.
China has recently built a small experimental facility near
Beijing to remove carbon dioxide from power station
emissions and use it to provide carbonation for beverages.
The further development of nuclear and hydropower is
another important strand of Chinese policy.
The country also aims to stabilise and increase the
production of oil while augmenting that of natural gas and
improving the national oil and gas network. China’s

26. CHINA’S PETROLEUM RESERVE
Priority was also given to building up the national oil
reserve.
In 2007 China announced an expansion of its crude reserves
into a two-part system.
Chinese reserves would consist of a government-controlled
strategic reserve complemented by mandated commercial
reserves.
The government-controlled reserves are being completed in
three phases.
This will protect China to a certain extent from fluctuations
in the global oil price, which can arise for a variety of
reasons.

27. TOTAL R.E. CAPACITY IN CHINA
Total renewable energy capacity in China reached 226 GW
in 2009.
This included:
• 197 GW of hydroelectricity
• 25.8 GW of wind energy
• 3.2 GW of biomass
• 0.4 GW of grid-connected solar PV

28. ENERGY TARGETS FOR 2020
Renewable energy contributed more than one quarter of China’s
total installed energy capacity, with hydroelectricity by far the
largest contributor. China’s wind power capacity grew 30-fold
between 2005 and 2009 to become the second largest in the world
behind the USA. China’s wind turbine manufacturing industry is
now the largest in the world. It is now also the largest
manufacturer of solar PV.
China’s current draft energy plan for 2020 sets targets of:
• 300 GW of hydroelectricity
• 150 GW of wind energy
• 30 GW of biomass
• 20 GW of solar PV
This would amount to almost one-third of China’s planned power
capacity of 1600 GW by 2020.

29. THE THREE GORGES DAM
The Three Gorges Dam across the Yangtze River includes the
world’s largest electricity generating plant of any kind.
This is a major part of China’s policy in reducing its reliance on
coal. The dam is over 2 km long and 100 m high.
The lake impounded behind it is over 600 km long.
All of the originally planned components were completed in late
2008.
Currently there are 32 main generators with a capacity of 700
MW each.
Six additional generators in the underground power plant are
being installed and should become fully operational in 2011.

30. MULTIPURPOSE SCHEME
The Dam supplies Shanghai and Chongqing in particular with
electricity.
This is a multipurpose scheme that also increases the river’s
navigation capacity and reduces the potential for floods
downstream.
There was considerable opposition to the dam for a number of
reasons.

31. MULTIPURPOSE SCHEME
The Dam supplies
Shanghai and Chongqing
in particular with
electricity.
This is a multipurpose
scheme that also
increases the river’s
navigation capacity and
reduces the potential for
floods downstream.
There was considerable
opposition to the dam
for a number of reasons.