Environmental Science Richard T. Wright Environmental Science Tenth Edition Chapter 14 Renewable Energy Copyright © 2008 Pearson Prentice Hall, Inc.

Scroby Sands Wind Farm

Putting Solar Energy to Work

Rooftop Water Heaters

Solar Thermal Power in Southern California

Renewable-energy Use in the United States

Renewable Energy Putting solar energy to work Indirect solar energy Renewable energy for transportation Additional renewable-energy options Policy for a sustainable-energy future

Examples of Renewable Energy Sources

Putting Solar Energy to Work Principles of solar energy Solar heating of water Solar space heating Solar production of electricity The promise of solar energy

Principles of Solar Energy Constant Abundant Free Everlasting

Hurdles in Using Solar Energy Collection Conversion Storage Cost-effectiveness

Terms and Definitions: Solar Heating Systems Active: moves water or air with pumps and blowers Passive: moves water or air with natural convection currents or gravity

Components of Active or Passive Solar Heating Systems? Flat-plate collector Water pump Blowers Heat exchanger Improved insulation Earthen berms

Solar Heating of Water: Flat-plate Solar Collector

Solar Water Heaters

Solar Space Heating

Solar Building Siting

Landscaping in Solar Heating and Cooling

Solar hot water Solar space heater Both Required Components? Flat-plate collector Water pump Blowers Heat exchanger Improved insulation Solar hot water Solar space heater Both

Solar Production of Electricity Photovoltaic Cell

How Photovoltaic Cells Work: Part 1 Each cell consists of two thin mylar layers. Lower layer has atoms with single electron in outer orbit – easily lost. Upper layer has atoms lacking one electron in outer orbit – easily accepts electrons.

How Photovoltaic Cells Works: Part 2 Kinetic energy from sunlight dislodges electrons from lower layer – creates an electric potential between the two layers.

How Photovoltaic Cells Works: Part 3 The potential provides the energy for an electrical current through the rest of the circuit. Electrons from lower layer flow through a device back to upper side.

PV System Inverter Connects PV panels to the electric grid. Converts direct current coming from PV panels to alternating current.

PV Power Plant 6.5 Mw at peak 34 foot panels 220 panels

Concentrating Solar Power PV power plants Solar-trough collectors Power towers Dish-engine system

Power Tower

Solar Dish Engine System

Disadvantages of Solar Energy Technologies Expense Only works during the day Requires back-up energy sources, e.g., batteries Some climates not sunny enough

Promise of Solar Energy (More or Less?) The use of solar electrical power will: create ____ reliance on coal or nuclear power. lead to significantly _____ acid rain. produce ____ electrical power for villages in developing countries.

Indirect Solar Energy Hydropower Wind power Biomass energy

Hydropower: Benefits or Drawbacks? Level of pollution generated Level of environmental degradation Amount of energy produced

Hoover Dam

Hydropower: Benefits or Drawbacks? Geographical distribution of energy produced Ecological impacts above and below dam Societal disruptions

Wind Power: Benefits or Drawbacks? Size limitations of wind turbines Megawatts of electricity produced Level of pollution generated

Wind Power: Benefits or Drawbacks? Level of environmental degradation Geographical distribution of energy produced Aesthetics

Wind Energy in the United States cost

Biomass Energy Burning firewood Burning wastes Burning biogas (methane)

Biogas Power

Biomass Energy: Benefits or Drawbacks? Availability of the biomass resource Access to the biomass resource Public acceptance and utilization of biomass energy Past history of human harvests within a maximum sustained yield

Renewable Energy and Transportation Biofuels Hydrogen? Hybrid Electric

Model U Ford

Hydrogen-oxygen Fuel Cell

Freedom Car

Fuel Cells: Benefits or Drawbacks? Substitute for fossil fuels Pollution factor Production technology Portability National distribution system

Additional Renewable Energy Options Geothermal energy Tidal power Ocean thermal-energy conversion (OTEC)

Geothermal Energy: Benefits or Drawbacks? Consistent source Level of pollution Cost-effectiveness Technology required for extraction Geographical distribution of energy produced

Geothermal Heat Pump System

Tidal Power: Benefits or Drawbacks? Consistent source Level of pollution Cost-effectiveness Technology required for extraction Geographical distribution of energy produced

OTEC: Benefits or Drawbacks? In an average day the heat absorbed by the surface water in only one square mile is equivalent to the burning of 7000 barrels of oil. Cost effectiveness to capture and distribute heat energy. Industrial interest in the OTEC alternative.

Policy for a Sustainable Energy Future National energy policy Energy Policy Act of 2005 A clean energy blueprint

A Clean Energy Blueprint Supply side Establish a Renewable Portfolio Standard Maintain production tax credits Extend net metering (paying solar cell owners for excess electricity) Substantially increase research and development on renewable energy and efficiency

A Clean Energy Blueprint Demand Side Improve efficiency standards Enhance building codes Provide incentives for combined heat and power facilities Raise fuel economy (CAFÉ) standards Increase research and development on high-efficiency vehicles (hybrid electric and fuel cell vehicles).

End of Chapter 14 PPT by Clark E. Adams