environmental science: toward a sustainable future richard t. wright renewable energy ppt by clark...

Environmental Science: Toward a Sustainable Future Richard T. Wright

Renewable Energy

PPT by Clark E. Adams

Chapter 14

Renewable Energy

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

Renewable-energy Use in the United States

Examples of Renewable Energy Sources

Putting Solar Energy to Work

Principles of Solar Energy

ConstantAbundantFreeEverlasting

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 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 Work: Part 2

Kinetic energy from sunlight dislodges electrons from lower layer – creates an electric potential between the two layers.

How Photovoltaic Cells Work: 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.

The Market for PV Cells

Concentrating Solar Power

PV power plants Solar-trough

collectors Power towers Dish-engine

system

The Solar-trough Collector

Power Tower

Solar Dish Engine System

Disadvantages of Solar Energy Technologies Expense Only works during the day Requires backup energy sources, e.g.,

batteries Some climates not sunny enough

Hidden Costs of Traditional Energy Sources Air pollution Strip-mining Nuclear wastes

Indirect Solar Energy

Hydropower Wind power Biomass energy

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

Biomass Energy

Burning firewood Burning wastes Burning biogas

(methane)

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: ethanol and biodiesel Hydrogen: the fuel for the future

Hydrogen–Oxygen Fuel Cell

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 7,000 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 A clean energy blueprint

A Clean Energy Blueprint

Supply side Establish a Renewable Portfolio Standard Maintain production tax credits Extend net metering 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