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Renewable/Alternative
• What are alternative or renewable
resources?
• What are common factors to consider in
their analysis
– Solar energy
– Wind energy
– Other renewable resources
- Ocean energy (tides, waves and temperatures)
- Geothermal energy
- Hydropower
- Biomass fuels
- Conservation as an alternative resource
The general theory of fossil fuels is that they were formed over millions of years from decay of organic material from dead plants and animals. In this sense, fossil fuels are renewable resources; they just take millions of years to renew themselves.
The general definition of renewable resources are those that are readily available in nature, such as solar energy and wind energy. It also includes resources that can be renewed in short periods of time such as biomass fuels. The latter include alcohols produced from agricultural products that can be used as a transportation fuel, municipal solid waste, agricultural waste, and crops grown for fuel use.
Hydroelectric power is also considered a renewable resource under this definition, however “new” technology is focused on the development of smaller hydroelectric projects.
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General Issues
• Cost
• Future technology development
• Incentives to provide experience with
using the technologies
• Environmental effects – usually a
benefit, but with some biomass fuels
there are environmental problems
• Global warming
• Availability of the resource
We will be discussing each of the topics covered here tonight in more detail. However, all the issues described here will be pertinent to those discussions. Many alternative energy technologies, such as solar, wind, geothermal, and tidal/wave power have the prospect of using zero cost fuels, but have high initial investment costs. All of these sources do not use any combustion and are valued as a way to reduce the emissions of CO (^) 2.
The resources mentioned above also have availability issues. Solar is available only during daytimes in skies that are not overcast. To be usable, a wind turbine must be located in a high wind area. Natural geothermal areas are limited, but hot rocks can be “mined” to produce geothermal energy; the cost of such production may be excessive, however. Wave energy is limited to costal areas and the methods for extracting it efficiently are not well developed.
The successful use of these alternative technologies requires cost reductions or such increases in the cost of fossil fuels that their present higher costs will become favorable in comparison.
US Renewable Energy Use 2001-
0.
0.
1.
1.
2.
2.
3.
3.
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Conventional Hydroelectric
Geothermal Energy
Biomass Solar Energy Wind Energy
Energy Type
Energy Use (quads)
2001 2002 2003 2004 2005 2006 2007
Plotted from data in spreadsheet on renewable consumption downloaded from http://www.eia.doe.gov/cneaf/solar.renewables/page/prelim_trends /rea_prereport.html on March 2, 2009.
Biomass includes: black liquor, wood/wood waste liquids, wood/wood waste solids, municipal solid waste (MSW), landfill gas, agriculture byproducts/crops, sludge waste, tires, biodiesel, ethanol, losses and coproducts from production of biodiesel and ethanol, and other biomass solids, liquids and gases. The growth in biomass is due, in large part, to the use of alcohol fuels for motor vehicles.
Solar includes solar thermal and photovoltaic electricity net generation.
Since the annual energy use in the US is about 100 quads, the data in quads shown here can be interpreted as a percent of the total energy consumption supplied by renewable sources. This slide also shows that solar and wind energies, which have received much attention, are seen to account for about 0.1% to 0.2% of the total energy use in the US.
Wind has the highest relative growth rate among alternative energy sources (although it is still quite small in an absolute sense) because it is cost competitive with conventional energy sources, especially when there is a tax incentive known as the Production Tax Credit (PTC) of 1.5 ¢/kWh.
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World Renewable Use 2004
Reference: Pamphlet available from IEA web site; it’s URL is http://www.iea.org/textbase/papers/2006/renewable_factsheet.pdf accessed February 29, 2008.
The majority of the renewable energy sources are from combustion; these typically include combustion of wood and waste as well as the use of biofuels. Conventional hydro makes up the second largest portion. This is the same ranking as in the US, but the combustible renewals are a larger fraction of the total for the world than in the US. The world use of solar energy and wind energy is 0.105% of the world total, which is less than in the the figure of 0.3% for the US.
Virtually all the tidal energy comes from a single source: the 240 MW tidal power station in La Rance, France.
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World Growth 1974-
Reference: Pamphlet available from IEA web site; it’s URL is http://www.iea.org/textbase/papers/2006/renewable_factsheet.pdf
Legend:
TPES = Total Primary Energy Supply
CRW = Combustion Renewables and Waste
The growth rates shown in this chart are the percent per year for the thirty- year period from 1974 to 2004. Although the percentage growth in “Other” or “New” renewables has been quite large, it is a percentage growth of a very small amount for each of these components in 1974.
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Power Generation Costs
Reference: Pamphlet available from IEA web site; it’s URL is http://www.iea.org/textbase/papers/2006/renewable_factsheet.pdf
The worldwide consumer cost of electricity shown on this chart is somewhat greater than that in the US. The costs for renewables shown here, the generation cost, is generally not competitive with that for wholesale power generation. The exceptions are small hydro and biomass. However, the upper range of the costs for these technologies are well above the range for wholesale power.
Small hydro and biomass are the most cost competitive. Geothermal and wind are next. A limited number of geothermal resources, such as the Geysers in Lake, County, California, are currently cost-competitive.
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Federal Incentives
• Energy Tax Act of 1978
• Crude Oil Windfall Profits Act of 1980
• Economic Recovery Tax Act of 1981
• Surface Transportation Assistance Act
of 1982
• Tax Equity and Fiscal Responsibility Act
of 1982
1978 Energy Tax Act of 1978 (ETA) (P.L.95-618) Residential energy (income) tax credits for solar and wind energy equipment expenditures: 30 percent of the first $2,000 and 20 percent of the next $8,000. Business energy tax credit: 10 percent for investments in solar, wind, geothermal, and ocean thermal technologies; (in addition to standard 10 percent investment tax credit available on all types of equipment, except for property which also served as structural components, such as some types of solar collectors, e.g., roof panels). In sum, investors were eligible to receive income tax credits of up to 25 percent of the cost of the technology. Percentage depletion for geothermal deposits: depletion allowance rate of 22 percent for 1978-1980 and 15 percent after 1983. 1980 Crude Oil Windfall Profits Tax Act of 1980 (WPT) (P.L.96-223) Increased the ETA residential energy tax credits for solar, wind, and geothermal technologies from 30 percent to 40 percent of the first $10,000 in expenditures. Increased the ETA business energy tax credit for solar, wind, geothermal, and ocean thermal technologies from 10 percent to 15 percent, and extended the credits from December 1982 to December 1985. Expanded and liberalized the tax credit for equipment that either converted biomass into a synthetic fuel, burned the synthetic fuel, or used the biomass as a fuel. Allowed tax-exempt interest on industrial development bonds for the development of solid waste to energy (WTE) producing facilities, for hydroelectric facilities, and for facilities for producing renewable energy. 1981 Economic Recovery Tax Act of 1981 (ERTA) (P.L.97-34) Allowed accelerated depreciation of capital (five years for most renewable energy-related equipment), known as the Accelerated Cost Recovery System (ACRS); public utility property was not eligible. Provided for a 25 percent tax credit against the income tax for incremental expenditures on research and development (R&D). 1982 Tax Equity and Fiscal Responsibility Act of 1982 (TEFRA) (P.L.97-248) Canceled further accelerations in ACRS mandated by ERTA, and provided for a basis adjustment provision which reduced the cost basis for purposes of ACRS by the full amount of any regular tax credits, energy tax credit, rehabilitation tax credit. 1982-1985 Termination of Energy Tax Credits In December 1982, the 1978 ETA energy tax credits terminated for the following categories of non-renewable energy property: alternative energy property such as synfuels equipment and recycling equipment; equipment for producing gas from geopressurized brine; shale oil equipment; and cogeneration equipment. The remaining energy tax credits, extended by the WPT, terminated on December 31, 1985.
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Federal Incentives (cont’d)
• Tax Reform Act of 1986
• Energy Policy Act (EPAct) of 1992
• Energy Conservation Reauthorization Act
of 1999
• Tax Relief Extension Act of 1999
• Energy Policy Act of 2005 (EPAct 2005)
• 2007 Energy Act
• 2009 Stimulus Package (HR 1)
- American Recovery and Reinvestment Act of 2009
Tax Reform Act of 1986 (P.L.99-514) Repealed the standard 10 percent investment tax credit. Eliminated the tax-free status of municipal solid waste (MSW) powerplants (WTE) financed with industrial development bonds, reduced accelerated depreciation, and eliminated the 10 percent tax credit (P.L.96-223). Extended the WPT business energy tax credit for solar property through 1988 at the rates of 15 percent for 1986, 12 percent for 1987, and 10 percent for 1988; for geothermal property through 1988 at the rates of 15 percent for 1986, and 10 percent for 1987 and 1988; for ocean thermal property through 1988 at the rate of 15 percent; and for biomass property through 1987 at the rates of 15 percent for 1986, and 10 percent for 1987. (The business energy tax credit for wind systems was not extended and, consequently, expired on December 31, 1985.) Public utility property became eligible for accelerated depreciation. Energy Policy Act of 1992 (EPACT) (P.L.102-486) Established a permanent 10 percent business energy tax credit for investments in solar and geothermal equipment. Established a 10-year, 1.5 cents per kilowatthour (kWh) production tax credit (PTC) for privately owned as well as investor-owned wind projects and biomass plants using dedicated crops (closed-loop) brought on-line between 1994 and 1993, respectively, and June 30, 1999. Instituted the Renewable Energy Production Incentive (REPI), which provides 1.5 cents per kWh incentive, subject to annual congressional appropriations (section 1212), for generation from biomass (except municipal solid waste), geothermal (except dry steam), wind and solar from tax exempt publicly owned utilities and rural cooperatives. Indefinitely extended the 10 percent business energy tax credit for solar and geothermal projects. 1999 Tax Relief Extension Act of 1999 (P.L. 106-170) Extends and modifies the production tax credit (PTC in EPACT) for electricity produced by wind and closed-loop biomass facilities. The tax credit is expanded to include poultry waste facilities, including those that are government-owned. All three types of facilities are qualified if placed in service before January 1, 2002. Poultry waste facilities must have been in service after 1999. A nonrefundable tax credit of 20 percent is available for incremental research expenses paid or incurred in a trade or business. 1978 Energy Tax Act of 1978 (ETA) (P.L.95-618) Excise tax exemption through 1984 for alcohol fuels (methanol and ethanol): exemption of 4 cents per gallon (the full value of the excise tax at that time) of the Federal excise tax on “gasohol” (gasoline or other motor fuels that were at least 10 percent alcohol (methanol and ethanol)) 1980 Crude Oil Windfall Profits Tax Act of 1980 (WPT) (P.L.96-223) Extended the gasohol excise tax exemption from October 1, 1984, to December 31, 1992. Introduced the alternative fuels production tax credit. The credit of $3 per barrel equivalent is indexed to inflation using 1979 as the base year, and is applicable only if the real price of oil is bellow $27.50 per barrel. The credit is available for fuel produced and sold from facilities placed in service between 1979 and 1990. The fuel must be sold before 2001. Introduced the alcohol fuel blenders’ tax credit; available to the blender in the case of blended fuels and to the user or retail seller in the case of straight alcohol fuels. This credit of 40 cents per gallon for alcohol of at least 190 proof and 45 cents per gallon for alcohol of at least 150 proof but less that 190 proof was available through December 31, 1992. Extended the ETA gasohol excise tax exemption through 1992. Tax-exempt interest on industrial development bonds for the development of alcohol fuels produced from biomass, solid waste to energy producing facilities, for hydroelectric facilities, and for facilities for producing renewable energy.
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Renewable Portfolio Standard
• An RPS is a requirement that electricity
producers in a state or other area have
a fixed percentage of their generation
as renewable energy
• California RPS is to increase by 2% per
year (starting in 2003) to reach 20% by
• Governor and PUC working on goal of
33% by 2020
See http://www.dsireusa.org/ (accessed March 2, 2009) a web site entitled Database of State Incentives for Renewables and Efficiency for a list of various incentives programs. The site also contains a limited list of Federal incentives.
Renewables include Solar Thermal Electric, Photovoltaics, Landfill Gas, Wind, Biomass, Hydroelectric, Geothermal Electric, Municipal Solid Waste, Anaerobic Digestion, Tidal Energy, Wave Energy, Ocean Thermal, Fuel Cells using Renewable Fuels
The California Public Utilities Commission (PUC) is responsible for implementing the RPS for investor-owned utilities (IOU) and municipal utilities are required to implement their own renewable portfolio.
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RPS States
Map and data table downloaded March 2, 2009 from http://apps1.eere.energy.gov/states/maps/renewable_portfolio_states.cfm,
State, Required RPS Amount, Deadline for amount
Arizona 15% 2025 California 20% 2010 Colorado 20% 2020 Connecticut 23% 2020 District of Columbia 11% 2022
Delaware 20% 2019 Hawaii 20% 2020 Iowa 105 MW
Illinois 25% 2025 Massachusetts 4% 2009 Maryland 9.5% 2022
Maine 10% 2017 Minnesota 25% 2025 Missouri* 11% 2020
Montana 15% 2015 New Hampshire 16% 2025
New Jersey 22.5% 2021 New Mexico 20% 2020 Nevada 20% 2015
New York 24% 2013 North Carolina 12.5% 2021 Oregon 25% 2025
Pennsylvania 18% 2020 Rhode Island 15% 2020 Texas 5,880 MW 2015
Utah* 20% 2025 Vermont* 10% 2013 Virginia* 12% 2022
Washington 15% 2020 Wisconsin 10% 2015
*Denotes states with voluntary RPS
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Solar Energy
• Used to provide heat in solar collectors
• Direct conversion to electricity via
photovoltaic cells
• Focusing solar collectors produce high
temperatures that can drive steam
power cycles
• Collectors can be fixed or tracking
– Simplest is fixed, facing south, with tilt
equal to latitude
Solar energy is available only during daylight hours and provides much more energy during summer months than during winter months. Although much of the early application of solar energy is for domestic heating purposes (heating water for household use and for swimming pools, heating room air) the temporal profile of solar energy is similar to the demands for electricity, which are higher in the summer than the winter and are higher during the day than at night. Thus there has been much research and development projects on using solar energy for electricity generation.
Solar electricity can be generated directly by photovoltaic cells. However, the cost of electricity produced by such cells is currently greater than the cost of producing high temperature heat from solar collectors and using this heat to generate steam in a conventional power generation cycle.
Because the orientation of the sun changes during the day and during the year, the most solar energy can be captured if the collector is mounted on two axes to follow the sun throughout the year. However, such tracking is expensive and most home solar collectors use a fixed orientation and tilt. The best position for maximizing solar collection year-round is a south facing collector tilted at the angle of the local latitude. Other fixed orientations can be used to optimize collection for a particular season.
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Renewable Fuels
• Naturally occurring materials either
used directly or converted to other fuels
– Wood
– Alcohol fuels from corn, cellulose, sugar
– Biodiesel from natural oils
• Waste products
– Direct incineration of waste
– Conversion of waste to other fuels
– Solids and gases produced by waste
Direct combustion of wood has long renewal time. It also has limited resources.
Alcohol fuels for automobile and truck engines can be made from a variety of natural sources but are not economical without government subsidy. They are more common than biodiesel. which is made from heavy vegetable oils or food waste.
Agricultural waste can be used for combustion. However, this waste has large transportation costs leading to a large number of small generating facilities.
Municipal solid waste power plants directly burn municipal solid waste (MSW) with minimal processing and some amount of pilot fuel
Refuse-Derived Fuel Refuse-derived fuel (RDF) typically consists of pelletized or "fluff" MSW that is the by-product of a resource recovery operation.
Pyrolysis/Thermal Gasification produces gaseous fuels from waste. The process is similar to the ones used to produce gaseous fuels from coal.
Animal and human waste can be converted to methane gas in anerobic digestion plants.
Fischer-Tropsch liquids are produced from coal or natural gas. They have been used for gasoline and fuel oil.
Alternative and RenewableAlternative and Renewable
Energy ResourcesEnergy Resources
Mechanical Engineering 483 Alternative Energy Engineering II Larry Caretto February 17, 2010 20
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Geothermal Power Plants
- Dry steam preferred, but resource is rate
- Flash steam is most common
- Binary cycle can use largest resource, but needs more research to become economic http://www1.eere.energy.gov/ geothermal/powerplants.html
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US Geothermal Resources
http://www1.eere.energy.gov/geothermal/geomap.html
Estimated subterranean temperatures at a depth of 6 kilometers
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US Geothermal Heat Flow
http://geothermal.id.doe.gov/publications/future_of_geothermal_energy.pdf
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CA Geothermal Resources
http://geothermal.id.doe.gov/maps/ca.pdf 26
MIT Report
- Future of Geothermal Energy (2006)
- http://geothermal.inel.gov/publications/ future_of_geothermal_energy.pdf
- Interdisciplinary assessment of resource, production, and use, focusing on electric power production - Enhanced geothermal systems (EGS) - Develop technology to use energy from hot rock geothermal energy
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MIT Report II
- States that 100,000 MWe of geothermal power could be developed over 50 years with additional R&D funding - $300–400 million required over 15 years
- Need commercial demonstration of plants using water injection to hot rock - Total public/private investment of $0.8– billion over 15 years
- EGS can be significant by 2050 28 http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf
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Size Requirements
http://geothermal.inel.gov/publications/future_of_geothermal_energy.pdf 30
http://geothermal.inel.gov/publications/future_of_ geothermal_energy.pdf
Well Drilling Costs
