renewable energy
Lizzie Lokey Ph.D. Candidate in Environmental Studies [email protected]
Sustainable Energy Outline • Conservation and Efficiency • Renewable Energy • Solar • Hydrogen • Wind • Biomass • Hydropower • Geothermal • Ocean sources • Storage options
Energy conservation and efficiency • What is the difference?
versus
• We tend to focus on new sources of energy. • Maybe we should approach the problem in a different way.
Cost Comparison • Coal 3-4 ¢/kWh • Biomass 4-9 ¢/kWh • Hydro 2-3 ¢/kWh • PV 20-30 ¢/kWh • Wind 4-6 ¢/kWh • Geothermal 5-6 ¢/kWh • Energy Efficiency Measures 2-3 ¢/kWh saved • Amory Lovins’ notion of the Negawatt •
*Source: Paul Komor, Renewable Energy Policy. (iUniverse Inc, 2004).
Energy Efficiency Gains • The average house today uses ½ the fuel of a house in 1974 for heating. Better insulation! • Front-load washers cut power use by 35%
But, each person is using more energy!
* Causes average annual demand growth of 3%
Energy Conservation and Efficiency • Personal behavior: • As individuals, we control 1/3rd of all energy used. • Societal changes (examples among many): • Mandate efficiency via laws (CAFE standards for cars) • Pass laws/codes to require more insulation in buildings • Remove subsidies that support inefficient practices
Renewable sources today
Figure 18.1
Growth of renewable sources
Figure 18.3
Ways to Promote Renewable Energy
Production Tax Credit – 1.9 ¢/kWh given to generators Feed-in Tariff – distributors must buy energy for set price Renewable Energy Mandate – utilities must source a certain % of their energy from renewables Voluntary green power pricing – customers agree to pay more for renewable energy Tax breaks on equipment, . . .
Clicker Question: What percentage of the world’s energy is derived from nonhydro and non-biomass renewables? a) 13.8% b) 5% c) 18% d) 35% e) Less than 1% Enough energy strikes the roof of the average home to provide all energy for that home.
Solar energy Large potential: About 5,000 times more solar energy strikes land surfaces on Earth than current global energy demand.
Solar energy Passive solar = using absorptive materials to gather and hold heat with no moving parts through window placement, overhanging eaves, absorbent materials…
Active Solar Active solar = uses technological devices to focus, move, or store solar energy Solar hot water panels, photovoltaic cells, solar cookers
Solar energy: Active solar cooker
Figure 18.6
Solar energy: PV cells Photovoltaic cells (PV cells) convert solar energy directly into electrical energy. Photons of sunlight strike the top of PV arrays made of a doped semiconductor. Electrons are displaced and move. The movement of these electrons can be captured and used to power devices.
Solar energy: PV cells This movement of electrons happens because the top layer easily gives up electrons and the bottom layer accepts electrons.
Figure 18.8
New Types of PV
Concentrating Solar Thermal (CSP)
Focusing the sun’s light to produce electricity Parabolic Dishes Solar Power Towers Parabolic Trough
Parabolic Dishes
Solar Power Towers
Parabolic Troughs
Solar Ponds- for hot water use and electrical generation
The Next Frontier for Solar Energy? The Solar Chimney http://www.enviromission.com.au/project/video/ SolarTower%20Animation%20Metric.wmv
Pros and cons of solar power CONS: PROS: Renewable Sun’s energy very abundant No greenhouse gas emissions
Site specific Intermittent fuel source Currently 5-8x as expensive as coal Only about 15% efficient and require large land area
Dependability and energy storage Problems with renewable energy: 1. Dependability Intermittent Need baseline to supplement intermittent renewables Need storage system 2. Limited potential Site specific 3. Unknown environmental impacts Require energy to make and impact landscape
Storage Options
Flywheels –
Batteries – lithium ion and vanadium redox Compressed Air Energy Storage –
Storage option: Pumped Hydro Storage in Japan
Hydrogen: another storage option Hydrogen = most abundant element, but is almost always bound to atoms of other elements. Must isolate for use in fuel cell or engine. Electrolysis = pass current of electricity through water: 2 H2O 2 H2 + O2
Production of hydrogen fuel
How you isolate hydrogen and where you get it from is key… New experimental way to produce hydrogen – algae
Fuel cells • Electrons can’t pass through membrane • Travel around membrane and produce current of electricity
Figure 18.16
Ideas for Fuel Cell Vehicles
Hydrogen Barriers Energy Inputs to isolate Energy Inputs to store PEM Fuel Cell Problems – degrade after 5 years
Clicker Question:
What is the most efficient form of energy storage? A. Hydrogen B. Flywheels C. Super conducting magnets D. Pumped hydro E. Lead acid batteries
Sustainable Energy Outline • Conservation and Efficiency • Renewable Energy • Solar • Hydrogen • Wind • Biomass • Hydropower • Geothermal • Ocean sources • Storage options
Energy conservation and efficiency • What is the difference?
versus
• We tend to focus on new sources of energy. • Maybe we should approach the problem in a different way.
Cost Comparison • Coal 3-4 ¢/kWh • Biomass 4-9 ¢/kWh • Hydro 2-3 ¢/kWh • PV 20-30 ¢/kWh • Wind 4-6 ¢/kWh • Geothermal 5-6 ¢/kWh • Energy Efficiency Measures 2-3 ¢/kWh saved • Amory Lovins’ notion of the Negawatt •
*Source: Paul Komor, Renewable Energy Policy. (iUniverse Inc, 2004).
Energy Efficiency Gains • The average house today uses ½ the fuel of a house in 1974 for heating. Better insulation! • Front-load washers cut power use by 35%
But, each person is using more energy!
* Causes average annual demand growth of 3%
Energy Conservation and Efficiency • Personal behavior: • As individuals, we control 1/3rd of all energy used. • Societal changes (examples among many): • Mandate efficiency via laws (CAFE standards for cars) • Pass laws/codes to require more insulation in buildings • Remove subsidies that support inefficient practices
Renewable sources today
Figure 18.1
Growth of renewable sources
Figure 18.3
Ways to Promote Renewable Energy
Production Tax Credit – 1.9 ¢/kWh given to generators Feed-in Tariff – distributors must buy energy for set price Renewable Energy Mandate – utilities must source a certain % of their energy from renewables Voluntary green power pricing – customers agree to pay more for renewable energy Tax breaks on equipment, . . .
Clicker Question: What percentage of the world’s energy is derived from nonhydro and non-biomass renewables? a) 13.8% b) 5% c) 18% d) 35% e) Less than 1% Enough energy strikes the roof of the average home to provide all energy for that home.
Solar energy Large potential: About 5,000 times more solar energy strikes land surfaces on Earth than current global energy demand.
Solar energy Passive solar = using absorptive materials to gather and hold heat with no moving parts through window placement, overhanging eaves, absorbent materials…
Active Solar Active solar = uses technological devices to focus, move, or store solar energy Solar hot water panels, photovoltaic cells, solar cookers
Solar energy: Active solar cooker
Figure 18.6
Solar energy: PV cells Photovoltaic cells (PV cells) convert solar energy directly into electrical energy. Photons of sunlight strike the top of PV arrays made of a doped semiconductor. Electrons are displaced and move. The movement of these electrons can be captured and used to power devices.
Solar energy: PV cells This movement of electrons happens because the top layer easily gives up electrons and the bottom layer accepts electrons.
Figure 18.8
New Types of PV
Concentrating Solar Thermal (CSP)
Focusing the sun’s light to produce electricity Parabolic Dishes Solar Power Towers Parabolic Trough
Parabolic Dishes
Solar Power Towers
Parabolic Troughs
Solar Ponds- for hot water use and electrical generation
The Next Frontier for Solar Energy? The Solar Chimney http://www.enviromission.com.au/project/video/ SolarTower%20Animation%20Metric.wmv
Pros and cons of solar power CONS: PROS: Renewable Sun’s energy very abundant No greenhouse gas emissions
Site specific Intermittent fuel source Currently 5-8x as expensive as coal Only about 15% efficient and require large land area
Dependability and energy storage Problems with renewable energy: 1. Dependability Intermittent Need baseline to supplement intermittent renewables Need storage system 2. Limited potential Site specific 3. Unknown environmental impacts Require energy to make and impact landscape
Storage Options
Flywheels –
Batteries – lithium ion and vanadium redox Compressed Air Energy Storage –
Storage option: Pumped Hydro Storage in Japan
Hydrogen: another storage option Hydrogen = most abundant element, but is almost always bound to atoms of other elements. Must isolate for use in fuel cell or engine. Electrolysis = pass current of electricity through water: 2 H2O 2 H2 + O2
Production of hydrogen fuel
How you isolate hydrogen and where you get it from is key… New experimental way to produce hydrogen – algae
Fuel cells • Electrons can’t pass through membrane • Travel around membrane and produce current of electricity
Figure 18.16
Ideas for Fuel Cell Vehicles
Hydrogen Barriers Energy Inputs to isolate Energy Inputs to store PEM Fuel Cell Problems – degrade after 5 years
Clicker Question:
What is the most efficient form of energy storage? A. Hydrogen B. Flywheels C. Super conducting magnets D. Pumped hydro E. Lead acid batteries
