Presentation on theme: "Achieving Energy Sustainability"— Presentation transcript:
1 Achieving Energy Sustainability Chapter 13Achieving Energy Sustainability
2 Objectives Define renewable energy sources Describe strategies to conserve energy and increase efficiencyCompare and contrast various forms of biomass energyExplain the advantages and disadvantages of hydroelectric, solar, geothermal, wind and hydrogen as energy sourcesDescribe the environmental and economic options we must assess in planning our energy futureAP: Renewable Energy (Solar energy; solar electricity; hydrogen fuel cells; biomass; wind energy; small-scale hydroelectric; ocean waves and tidal energy; geothermal; environmental advantages/disadvantages)
3 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 rapidlyRenewable as long as we do not consume them faster than they can be replenishedBiomass must be used sustainablyCannot be depleted, no matter how much we use
4 What is renewable energy? Global energy use in 2007United States energy use in 2008Wind and hydroelectric turbines kill birds and fishPV panels require a lot water and heavy metals to makeAlthough renewable energy is more sustainable than nonrenewable, using any form of energy has impact on environmentBest approach is to minimize use through conservation and efficiency
5 How can we use less energy? Energy conservationfinding ways to use less energy. For example, lowering your thermostat during the winter or driving fewer miles.Energy efficiencygetting the same result from using a smaller amount of energy.Tiered rate system“Setsuden”Least expensive and most environmentally sound
6 Benefits of Conservation and Efficiency “The best energy choices are the ones you don’t need.”-- Amory LovinsConservation 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 generatorsVariable 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)In 2009, Time magazine named Lovins as one of the world's 100 most influential people.
7 Sustainable DesignImproving the efficiency of the buildings and communities in which we live and workLeadership in Energy and Environmental Design (LEED)This project demonstrates how a simple plan can produce a project with the potential to transform over time. The space adjusts to become a larger home or a multi-generational living space by exploring modularity and production. The team took consideration in orienting the home in relation to the sun, as well as the use cost-effective manufacturing construction techniques. The green roof offers an inexpensive solution to storm water management and reducing cooling loads in the summer. It also provides an additional outdoor space for the home.The jury commended the design, describing it as a “handsome, visual notion of what a Habitat house could be”.
8 Sustainable DesignsUsing 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 inertiaDouble-paned windowsWindow shades
9 Sustainable Designs Green Roofs Cool and shade the buildings and the surrounding environmentImproves air quality
10 California Academy of Sciences in San Francisco
11 Biomass is energy from the Sun The Sun is the ultimate source of almost all types of energySolid fuels: Wood and charcoal, animal products and manure, plant remains, and municipal solid wasteLiquid fuels: Ethanol and biodiesel
12 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 atmosphereAs long as the biomass is harvested sustainablyBurning 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
13 Solid BiomassWood, 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 heatingWhat are the consequences of unsustainable tree removal?In addition, particulate matter, CO, and NOx are releasedDeforestation, erosion, increase CO2 in atmosphere, release carbon from soil, species loss, biodiversity loss,
14 Charcoal ProductionSustainable 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.Charcoal is lighter and contains twice as much energy, does not need to be tended and produces less smoke, BUT, you have to burn a lot of wood to get itIn 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.
15 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.Good example of how developing countries improve yields and reduce emissions through better carbonizing techniques and improved kilns
16 Liquid BiomassEthanol and Biodiesel (biofuels)- used as substitutes for gasoline and diesel fuel.Ethanol is made by converting starches and sugars from plants into alcohol and CO2In U.S., 90% comes from corn and corn by-products, and is heavily subsidizedBrazil uses sugarcane, which unlike corn needs to be replanted every year, is replanted every 6 years and harvested by handFlex-fuel vehicles can run on gasoline or E-85CTI 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)
17 Liquid BiomassBiodiesel is direct replacement of petroleum-based diesel fuelProduce less emissions than petro-dieselCommonly made from vegetable oils or animal fatsUsually 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 fryersAlgae produces times more fuel per area than conventional crops80% petro diesel, 20% biodiesel. Produce less emissions that
18 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 ORHow it works:
19 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.
20 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 hectaresSubmerges ancient cultural and archeological sitesDisplaces peopleImpounded water holds more heat and contains less DODestroys downriver ecosystems (ex: canyon cottonwoods, salmon, trout, shellfish, etc.)Siltation – accumulation of sediments on reservoir bottomIn recent years, some dams are removed due to environmental concerns or heavy siltationCottonwoods depend on sandbars to reproduce, salmon, trout and shellfish depend on seasonal flow of water
22 The Sun’s energy can be captured directly Passive solar energySustainable building designSolar cookerscan boil several liters of water in an hour, cook chicken and rice in 2-5 hours10,000 were distibuted in refugee camps in Darfur
23 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.Solar Water Heating Systems - cold water is heated as it passes through a solar collector, the into an insulated reservoir.Captures heat
24 Photovoltaic systems – captures light energy and convert to electricity Use thin, ultra-clean layers of semiconductors12-20% efficient
25 Concentrated solar thermal electricity generation - capable of generating 35 MW, but use large amounts of landEvaporates water to produce steam
26 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.
27 Uses 30-70% less energy to heat and cool buildings
28 Wind energy is the most rapidly growing source of electricity Winds are the result of uneven heating of the Earth’s surface by the sunWind 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 windWarm air rises; cooler, denser air sinks, creating circulation patterns similar to a pot of boiling water. The Sun drives this air circulation
30 Pros of Wind EnergyWind energy is a green energy source and does not cause pollution.The potential of wind power is enormous – 20 times more than what the entire human population needs.Wind power is renewable and there is no way we can run out of it (since wind energy originates from the sun).Wind turbines are incredible space-efficient. The largest of them generate enough electricity to power 600 U.S. homes.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).Prices have decreased over 80% since 1980 and are expected to keep decreasing.The operational costs associated with wind power are low.Good domestic potential: Residential wind turbines yields energy savings and protects homeowners from power outages.
31 Cons of Wind EnergyWind 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).The manufacturing and installation of wind turbines requires heavy upfront investments – both in commercial and residential applications.Wind turbines can be a threat to wildlife (e.g. birds, bats).Noise is regularly reported as a problem by neighboring homes.How wind turbines look (aesthetics) is a legitimate concern for some people.
32 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 H2OBasic process forces protons from hydrogen gas through a membrane, while electrons take a different path. The movement of protons in one direction and electrons in another generates an electric current.H is explosive, it is very rare in nature, currently H is commercially produced by electrolysis which involves applying an electric current to split water = counterintuitive. Bacteria and algae produce H gas through photosynthesis80% efficient with water as a by-productWhat are some inherent problems of hydrogen fuel cells?Is it a viable energy alternative?
34 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 to explore the Schatz lab projects.
35 FOR IB STUDENTS Resources – 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.
36 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.
37 SustainabilityAny 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.
38 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.The first United Nations Conference on Environment and Development (UNCED Earth Summit) was held in Rio de Janeiro in It represented a turning point in the way we look at environment and development. At the Earth Summit, world leaders adopted Agenda 21, a blue print to attain sustainable development in the 21st century. Agenda 21 includes Chapter 14, Sustainable Agriculture and Rural Development (SARD). At UNCED, nine major groups were designated to represent civil society’s concerns in the follow-up work, and the UN established a Commission on Sustainable Development to guide and monitor the follow-up process, which included a major global stock-taking event every five years.Agenda 21 provides a comprehensive action programme to attain sustainable development and address both environmental and developmental issues in an integrated manner at global, national and local levels. Chapter 14 of Agenda 21 recognizes and confirsm the importance of the sustainable agriculture and rural development (SARD) concept. Adopted at the Rio Earth Summit in 1992, it sets out the programmes and specific actions needed to promote SARD, and represents the commitment of UN member nations to implement these programmes and actions.
39 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.
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