Ch 13 a: Non-Renewable Energy Resources & Energy Efficiency

Nonrenewable Energy Sources

U.S. primary energy consumption by source and sector, 2017

Total = 97.7 quadrillion British thermal units (Btu)

-Fossil fuels

• Buried, pressurized plant remains

• Oil, natural gas, coal

  -Nuclear fuels

  Fission & Fusion

Where does your energy come From

Petroleum

Natural gas

Coal

Renewables

Nuclear

Net Energy

• Net energy = energy output - energy input

• Valuable for evaluating long-term usefulness of energy resources

• What do we mean by energy inputs? -Energy input is the energy used to obtain and process fuel.

Oil Deposits & Oil Extraction

• Oil collects in porous rock

• How do we find it?- Seismic surveys and other methods are used to locate oil reservoirs.

• How do we extract it?

• Primary Extraction

•  Secondary Extraction uses solvents or water

Oil Shales and Tar Sands

• Oil Shale

•  Dispersed in shale rock

• Tar Sands

•  Mix of clay, sand, water, bitumen

• Shared Properties:

• Located under remote lands

•  Low net energy (HIGH energy input)

•  Highly polluting

Environmental Impacts of Oil Extraction

• Habitat alteration & pollution

• Drilling

•  Infrastructure

• Waste & sludge ponds

•  Oil spills

• Social justice

Where is the oil?

• Reserves are not distributed equally

•  OPEC controls 80% of reserves

•  Biggest producers?- Us, Saudi Arabia, Russia

• Biggest consumers?- Us, china, India

• Uses: transportation, heating, plastics production

Are We Depleting Our Reserves?

• Yes and No

• Depends on technology

•  Net energy remains high in some places

• There's a growing shortage of cheap oil

Natural Gas

• Located in underground deposits above oil

• Fastest growing fossil fuel

• Cleaner than oil and coal

• Uses: cooking, heating, industry, vehicles

Hydraulic Fracturing (Fracking)

• Water, sand, chemicals pumped through horizontal well pipe

• Fractures rock & frees gas

• Concerns:

•  Water-intensive

• Hazardous waste

• Leaks

• 2005 Energy Policy Act exempted fracking from the SDWA!

Coal

• Most abundant fossil fuel

• Types vary in energy content

•  Uses: electricity, heating

• Concerns:

• Mining

• Habitat loss

•  Air & water pollution

How Electricity is Generated

• Pulverize (coal)

• Combust

• Heat boils water

• Steam turns a turbine, generating electricity

Environmental Impacts: Emissions

• Combustion alters carbon cycle flux

•  From litho → atmosphere

•  Greenhouse gases (CO2 & CH4)

• Acid rain precursors

• Health concerns

•  Particulate matter

• Heavy metals

• Carcinogens

Making Coal Cleaner

• Clean Air Act '90

•  Scrubbers

• Incentives for adopting "clean" technologies

• Coal jobs are declining due to economics

Nuclear Power

• Relies on radioactive isotopes

• Reduced environmental impact

• Reputation clouded by nuclear weaponry, waste disposal, & meltdowns

Nuclear Fuel Cycle

• Uranium is mined as U-238 - we need U-235

•  Enrichment converts

•  Pelleted & incorporated into fuel rods

•  Rods function in a nuclear reactor

Nuclear Power Plants

• In the reactor:

• Control rods regulate rate of reaction

•  Heat generates steam

•  Steam turns a turbine, generates electricity

• Reactor is housed in a containment building

Fuel Cycle: Waste Disposal

• Half-life of U-235 is 700
  million years

•  Wastes stored in water, glass, or concrete

•  What is the long-term plan? -place to put all nuclear waste in country

• Yucca Mountain pros & cons

  Pro- no earthquakes, wouldn’t containment water, on federal land

  Con- people oppose this

Nuclear: Small Risks of Large Accidents

Three Mile Island, PA

•  Near-miss in '79

•  Coolant H20 leaked, temps rose, fuel rods began to melt

• '86: Chernobyl, Ukraine

• Explosions released radiation for 10 days

• '11: Fukushima

•  EQ + tsunami caused power loss & flooding

The Future of Nuclear

• Nuclear vs. Fossils

•  No air pollution

•  More energy by volume

•  Plants = safer for workers

• Drawbacks

•  Low net energy

• Radioactive waste

•  Risk of accident

• Thermal pollution

• What about fusion? -

What is the best way to conserve energy resources?

• Waste less!

•  Improve energy efficiency

•  Appliances and lighting

•  Buildings

•  Vehicle engines

• The electrical grid

• Industrial processes

Buildings & Green Architecture

• Goal: Net zero energy/water/carbon

• Practices:

• Energy efficient appliances & lighting

•  Natural lighting

•  Direct solar heating

•  Super insulation

•  Patch leaks (water and air)

•  Green roofs

•  Solar panels

Automobile Efficiency

• 1975 CAFE Standards improved fuel economy

• Energy efficient options

• Hybrid or hybrid electric

•  Fully electric

•  Lighter car bodies

Fusion and fus

Fusion- when two atoms slam together to form a heavier atom,

Fission- occurs when a neutron slams into a larger atom, forcing it to excite and split into two smaller atom

Improve Efficiency of the Electrical Grid

• Current is outdated and vulnerable

•  Smart grids

•  Digitally-controlled (reliable)

•  Ultra-high voltage

•  Super efficient transmission

Conclusions

• Fossil fuels have done wonders for our standard of living

• Nuclear showed promise but has experienced a number of setbacks

• Economics & negative environmental impacts are encouraging us to look elsewhere

•  Improvements in energy efficiency

•  Renewable resources