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Chapter 13 Achieving Energy Sustainability

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Page 1: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Chapter 13Achieving Energy Sustainability

Page 2: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Objectives• Define renewable energy sources

• Describe strategies to conserve energy and increase efficiency

• Compare and contrast various forms of biomass energy

• Explain the advantages and disadvantages of hydroelectric, solar, geothermal, wind and hydrogen as energy sources

• Describe the environmental and economic options we must assess in planning our energy future

• AP: Renewable Energy (Solar energy; solar electricity; hydrogen fuel cells; biomass; wind energy; small-scale hydroelectric; ocean waves and tidal energy; geothermal; environmental advantages/disadvantages)

Page 3: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

What is renewable energy?• Energy sources have evolved from primarily biomass (wood and

animal manure, etc.) to fossil fuels and nuclear power.

• Energy sources formed over millions of years.

• Depleted much faster than they can be replenished.

• Regenerate rapidly• Renewable as long as we do not

consume them faster than they can be replenished

• Biomass must be used sustainably

• Cannot be depleted, no matter how much we use

Page 4: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

What is renewable energy?

• Global energy use in 2007

• Although renewable energy is more sustainable than nonrenewable, using any form of energy has impact on environment

• Best approach is to minimize use through conservation and efficiency

• United States energy use in 2008

Page 5: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

How can we use less energy?

• Energy conservation

• finding ways to use less energy. For example, lowering your thermostat during the winter or driving fewer miles.

• Energy efficiency

• getting the same result from using a smaller amount of energy.

• Tiered rate system

• “Setsuden”

Page 6: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Benefits of Conservation and Efficiency

• Conservation and efficiency efforts save energy that can be used later.

• Demand for energy varies with day, season, weather, etc.

• Energy companies must provide enough energy to meet peak demand.

• Many energy companies have an extra backup source of energy = natural gas-fired generators

• Variable price structure- utility customers can pay less to use energy when demand is lowest and more during peak demand.

• Consider the losses: the amount of energy we save is the sum of energy not used and energy that would be lost in converting energy into its consumer product (2nd law)

“The best energy choices are the ones you don’t need.”-- Amory Lovins

Page 7: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Sustainable Design• Improving the efficiency of the buildings and communities

in which we live and work• Leadership in Energy and Environmental Design (LEED)

Page 8: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Sustainable Designs

• Using passive solar energy can lower your electricity bill without the need for pumps or other mechanical devices.

• Examples:

• Building the house with windows along a south-facing wall which allows the Sun’s rays to warm the house.

• Using materials with a high thermal inertia

• Double-paned windows

• Window shades

Page 9: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Sustainable Designs• Green Roofs

• Cool and shade the buildings and the surrounding environment

• Improves air quality

Page 10: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency
Page 11: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Biomass is energy from the Sun• The Sun is the ultimate source of almost all types of energy

• Solid fuels: Wood and charcoal, animal products and manure, plant remains, and municipal solid waste

• Liquid fuels: Ethanol and biodiesel

Page 12: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Modern Carbon vs. Fossil Carbon

Is it really better for the environment to replace fossil fuels with biomass?

The (modern) carbon found in biomass was in the atmosphere as carbon dioxide, taken in by the tree, and by burning it we put it back into the atmosphere

As long as the biomass is harvested sustainably

Burning coal is (fossil) carbon that has been buried for millions of years and was out of circulation until we began to use it. This results in a rapid increase in the concentration of carbon dioxide in the atmosphere.

In theory, biomass is the better choice because the net change in atmospheric CO2 concentrations should be zero = carbon neutral

Page 13: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Solid Biomass• Wood, Charcoal and Manure- used to heat homes

throughout the world.

• Globally, 2-3 billion people use wood for heating and cooking; in the U.S., ~3 million homes rely on wood for heating

What are the consequences of unsustainable tree removal?

• In addition, particulate matter, CO, and NOx are released

Page 14: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Charcoal Production• Sustainable production and use of charcoal

through proper management and planning of supply sources, together with rational trade and marketing infrastructures and efficient use, can have a significant positive impact by helping to conserve resources, reducing migration from rural or forested areas and improving people’s incomes.

• In places where high charcoal consumption and weak supply sources put strong pressure on existing trees resources (because of high population density, low income and/or severe climate conditions), deforestation and devegetation problems are still of great concern.

Page 15: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Some figures regarding economic and environmental issues

Mass yields from a Casamance kiln and a well-managed traditional mound kiln are about 25 percent. In other words, 1 ton of wood will give 250 kg of charcoal. With poorer techniques, however, yields often do not exceed 15 to 20 percent, in other words about 150 to 200 kg from 1 ton of wood. Many charcoal makers, for example, use green wood, and the energy needed to dry it is provided by part of the load, reducing yields to 15 percent.

The carbon content of wood and charcoal is 50 and 90 percent respectively, giving the following carbon equivalents:

• 1,000 kg of wood → 500 kg of carbon;• 250 kg of charcoal → 225 kg of carbon;• 150 kg of charcoal → 135 kg of carbon.

When a ton of wood is carbonized, 365 kg are released into the atmosphere with a poorly managed technique and 275 kg with improved methods. Improved technique thus prevents the emission of 90 kg of carbon per ton of carbonized wood, equivalent to 300 kg of carbon or 1.1 tons of CO2 per ton of charcoal consumed.

For the city of, Abidjan, Côte d’Ivoire, which consumes about 300,000 tons of charcoal per year, the annual savings amount to:

• 330,000 tons of CO2 emission avoided;• 800,000 tons of wood not consumed as a result of the increased yield.

Page 16: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Liquid Biomass Ethanol and Biodiesel (biofuels)- used as substitutes for

gasoline and diesel fuel.

Ethanol is made by converting starches and sugars from plants into alcohol and CO2

In U.S., 90% comes from corn and corn by-products, and is heavily subsidized

Brazil uses sugarcane, which unlike corn needs to be replanted every year, is replanted every 6 years and harvested by hand

Flex-fuel vehicles can run on gasoline or E-85

CTI Journal: Discuss the advantages and disadvantages of using ethanol as a fuel source in

the U.S. (Use textbook p. 352 and one VALID scientific

source)

Page 17: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Liquid Biomass Biodiesel is direct replacement of petroleum-based diesel fuel

Produce less emissions than petro-diesel

Commonly made from vegetable oils or animal fats

Usually more expensive and typically diluted to “B-20”

Any diesel vehicle can be converted to 100% straight vegetable oil (SVO)

Waste product obtained from restaurants with deep fryers

Algae produces 15-300 times more fuel per area than conventional crops

Page 18: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

The kinetic energy of water can generate electricity

Hydroelectricity- electricity generated by the kinetic energy of moving water. This is the second most common form of renewable energy in the world.

> ½ of hydroelectric generated in U.S. comes from WA, CA, and OR

How it works:

Page 19: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Types of hydroelectric power systems Run-of-the-river systems - water is held behind a dam and runs

through a channel before returning to the river.

Water impoundment - water is stored behind a dam and the gates of the dam are opened and closed controlling the flow of water. (ex. Glen Canyon Dam in AZ)

Tidal systems - the movement of water is driven by the gravitational pull of the Moon.

Page 20: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Is Hydroelectric Sustainable? While hydroelectric projects generate a large amount of

electricity without direct air pollution, waste products or CO2 emissions, and provide recreational and economic opportunities there are negative environmental consequences:

Free-flowing river is held back and floods 100’s-1000’s of hectares

Submerges ancient cultural and archeological sites

Displaces people

Impounded water holds more heat and contains less DO

Destroys downriver ecosystems (ex: canyon cottonwoods, salmon, trout, shellfish, etc.)

Siltation – accumulation of sediments on reservoir bottom

In recent years, some dams are removed due to environmental concerns or heavy siltation

Page 21: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency
Page 22: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

The Sun’s energy can be captured directly

Passive solar energy

Sustainable building design

Solar cookers

Page 23: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

The Sun’s energy can be captured directly

Active solar energy- capturing the energy of sunlight with the use of a pump or photovoltaic cell and generating electricity.

1. Solar Water Heating Systems - cold water is heated as it passes through a solar collector, the into an insulated reservoir.

Page 24: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

2. Photovoltaic systems – captures light energy and convert to electricity

a. Use thin, ultra-clean layers of semiconductors

b. 12-20% efficient

Page 25: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

3. Concentrated solar thermal electricity generation - capable of generating 35 MW, but use large amounts of land

Page 26: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Earth’s internal heat produces geothermal energy

• Geothermal energy- using the heat from natural radioactive decay of elements deep within Earth as well as heat coming from Earth.

• Heat from magma warms groundwater, which can be used as a direct heat source or as a means to generate electricity.

• The heat source is non-depletable, but the groundwater it heats is nonrenewable if not used sustainably.

• Ground source heat pumps can be used to heat and cool residential and commercial buildings.

Page 27: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency
Page 28: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Wind energy is the most rapidly growing source of electricity

Winds are the result of uneven heating of the Earth’s surface by the sun

Wind energy- using a wind turbine to convert kinetic energy into electrical energy.

U.S. has largest wind generating capacity in the world; yet, we obtain <1% of electricity from wind

Page 29: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Generating Wind Energy

Page 30: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Pros of Wind Energy

1.Wind energy is a green energy source and does not cause pollution.

1.The potential of wind power is enormous – 20 times more than what the entire human population needs.

1.Wind power is renewable and there is no way we can run out of it (since wind energy originates from the sun).

1.Wind turbines are incredible space-efficient. The largest of them generate enough electricity to power 600 U.S. homes.

1.Wind power only accounts for about 2.5% of total worldwide electricity production, but is growing at a promising rate of 25% per year (2010).

1.Prices have decreased over 80% since 1980 and are expected to keep decreasing.

1.The operational costs associated with wind power are low.

•Good domestic potential: Residential wind turbines yields energy savings and protects homeowners from power outages.

Page 31: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Cons of Wind Energy

1.Wind is a fluctuating (intermittent) source of energy and is not suited to meet the base load energy demand unless some form of energy storage is utilized (e.g. batteries, pumped hydro).

1.The manufacturing and installation of wind turbines requires heavy upfront investments – both in commercial and residential applications.

1.Wind turbines can be a threat to wildlife (e.g. birds, bats).

1.Noise is regularly reported as a problem by neighboring homes.

1.How wind turbines look (aesthetics) is a legitimate concern for some people.

Page 32: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Hydrogen fuel cells have many potential applications

Fuel cell- a device that operates like a common battery where electricity is generated by a reaction between two chemicals.

In a hydrogen fuel cell, electricity is generated by the reaction of hydrogen with water:

2H2 + O2 2 H2O

What are some inherent problems of hydrogen fuel cells?

Is it a viable energy alternative?

Page 33: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency
Page 34: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

The challenge of Renewable Energy

• New energy sources may be the key to energy independence.

• This largely depends on the willingness of governments to commit to the development of renewable energy technologies.

• In the US, wind and solar only account for less than 1% of energy produced.

• The creation of a Smart Grid and decentralized “energy parks” will help to meet the ever increasing energy demands of US citizens.

• Research facilities like the Schatz Energy Research Center at Humboldt State University are leading the way to develop new applicable green energy solutions.

• Visit http://www.schatzlab.org/about.html to explore the Schatz lab projects.

Page 35: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

FOR IB STUDENTSResources – Natural Capital

• Ecologically minded economists describe resources as “natural capital”. If properly managed, renewable and replenishable resources are forms of wealth that can produce “natural income” indefinitely in the form of valuable goods and services.

• This income may consist of marketable commodities such as timber and grain (goods) or may be in the form of ecological services such as the flood and erosion protection provided by forests (services). Similarly, non-renewable resources can be considered in parallel to those forms of economic capital that cannot generate wealth without liquidation of the estate.

Page 36: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Natural Capital

Three broad classes of natural capital:

•Renewable natural capital, such as living species and ecosystems, is self-producing and self-maintaining and uses solar energy and photosynthesis. This natural capital can yield marketable goods such as wood fiber, but may also provide unaccounted essential services when left in place, for example, climate regulation.

•Replenishable natural capital, such as groundwater and the ozone layer, is nonliving but is also often dependent on the solar “engine” for renewal.

•Non-renewable (except on a geological timescale) forms of natural capital, such as fossil fuel and minerals, are analogous to inventories: any use implies liquidating part of the stock.

Page 37: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Sustainability

Any society that supports itself in part by depleting essential forms of natural capital is unsustainable. If human well-being is dependent on the goods and services provided by certain forms of natural capital, then longterm harvest (or pollution) rates should not exceed rates of capital renewal. Sustainability means living, within the means of nature, on the “interest” or sustainable income generated by natural capital.

Page 38: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Sustainable Development

• The term “sustainable development” was first used in 1987 in Our Common Future (The Brundtland Report) and was defined as “development that meets current needs without compromising the ability of future generations to meet their own needs.” The value of this approach is a matter of considerable debate and there is now no single definition for sustainable development. For example, some economists may view sustainable development as a stable annual return on investment regardless of the environmental impact, whereas some environmentalists may view it as a stable return without environmental degradation.

• Consider the development of changing attitudes to sustainability and economic growth, since the Rio Earth Summit (1992) leading to Agenda 21.

Int: International summits on sustainable development have highlighted the issues involved in economic development across the globe, yet the viewpoints of environmentalists and economists may be very different.

Page 39: Chapter 13 Achieving Energy Sustainability. Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiency

Sustainable YieldSustainable yield (SY) may be calculated as the rate of increase in natural capital, that is, that which can be exploited without depleting the original stock or its potential for replenishment. For example, the annual sustainable yield for a given crop may be estimated simply as the annual gain in biomass or energy through growth and recruitment. See figures 1 and 2.