1. NEW Renewable Energy Alternatives
Chapter 21

2. CASE STUDY: Germany Goes Solar
Germany produces the world’s most solar power
Yet it is cool and cloudy
Its feed-in tariff system requires utilities to buy power from anyone who generates it
Homeowners and businesses have installed photovoltaic solar systems to generate energy
CASE STUDY: Germany Goes Solar

4. Conventional Renewables
Biomass
Hydropower
Can be depleted with overuse and exert some undesirable environmental impacts
Conventional Renewables

5. New Renewables Not truly new Solar
They are just beginning to be used on a wide scale
Their technologies are still in a rapid phase of development
They will play a much larger role in our future energy use
Solar
Wind
Geothermal
Ocean
Hydrogen
New Renewables

6. New Renewable Advantages
Benefits of the new renewables include:
Alleviating air pollution and greenhouse gas emissions
They are inexhaustible, unlike fossil fuels
They help diversify a country’s energy economy
They create jobs, income, and taxes, especially in rural areas
Green-collar jobs = design, installation, maintenance, and management of renewable energy technologies
New Renewable Advantages

8. Use of new renewables have started out low levels, so it will take some time to catch up to the other conventional sources
How do we hasten the spread of renewable energy?
Subsidies
Feed-in tariffs
Gov’t goals and mandates
Policy & Investment

9. Which approach is best? Subsidies Policy
Lowers price, increases demand
Inefficient? Skews market?
Policy
Implementation is key
Ex. Spain - adopted a generous feed-in tariff that led to many hastily built, poor designed/bad location plants… finally slashed tariff rates
Which approach is best?

10. Solar Energy Solar energy- energy from the sun Two methods
Passive solar energy collection-
Building design; max warmth in winter, minimal heat in summer
South facing windows, vegetation around building,
Active solar energy collection-
Makes use of devices to focus, move, or store solar energy
Solar Energy

11. Flat Plate Solar Collectors
Flat plate solar collectors = dark-colored, heat-absorbing metal plates mounted on rooftops
Water, air, or antifreeze runs through the collectors, transferring heat throughout the building
Heated water is stored and used later
It is not restricted to wealthy, sunny regions
Flat Plate Solar Collectors

13. Concentrating solar rays
Focusing solar energy on a single point magnifies its strength
Solar cookers = simple, portable ovens that use reflectors to focus sunlight onto food
Concentrated solar power (CSP) = technologies that concentrate solar energy
The most widespread is the trough approach
Uses curved mirrors that focus sunlight on synthetic oil in pipes
The heated oil creates steam that drives turbines to produce electricity
Concentrating solar rays

18. PV Cells Generate Electrcity Directly
Photovoltaic Cells- converts sunlight to electrical energy by making use of the photovoltaic effect
The photovoltaic (photoelectric) effect occurs when light hits the PV cell and hits a plate made of silicon
Electrons are released by the silicon and are attracted to the opposite plate
Wires connecting the two plates let electrons flow, creating an electric current
Small PV cells are in watches and calculators
On roofs, PV cells are arranged in modules, which comprise panels, which can be gathered into arrays
PV Cells Generate Electrcity Directly

20. Thin-film solar cells Lightweight Less bulky Less efficient Cheaper
Could be built into roofing shingles, highways, etc.
Thin-film solar cells

22. Solar Power Advantages Disadvantages
Sun is an inexhaustible energy source
Reduce greenhouse gas emissions
Solar cookers, inexpensive for developing nations
Sell back energy to the grid
Creates green-collar jobs
Location
Seasonality affects stand-alone units
Timing
Sun is intermittent
Costs
A lot upfront, save over time- 20 years?
Solar Power

24. Wind Power
Converts wind’s kinetic energy to electricity

25. Wind power: An overview

27. News clip: RI Deepwater Wind

29. LEEDCo & Lake Erie Offshore Site Project
onsultant-says-lake-erie-offshore-wind-poses- low-risk-for-wildlife/
LEEDCo & Lake Erie Offshore Site Project

30. Offshore Sites Wind speeds are 20% greater over water than over land
Also less air turbulence over water
Costs to erect and maintain turbines in water are higher
But more power is produced, and it is more profitable
Offshore Sites

31. First offshore wind farm expected to be the Block Island project in Rhode Island (pictured above) final closing stages, will be online by the end of the year.
Textbook correction: Cape Wind Project (Wind farm off of Cape Cod) construction has not begun.

32. Wind Power Advantages Disadvantages Many Jobs in the wind industry
Minimal costs over the lifetime of the turbine
Small scale and large scale use
EROI ~20:1
No emissions
Intermittent resource
Location limitations
Prime locations are often far away from people
Aesthetics
Pose a threat to birds and bats
Wind Power

35. Geothermal Energy
Thermal energy that arises from beneath the Earth’s surface

36. Radioactive decay of elements under extremely high pressures deep inside the planet generates heat
Heat rises through magma, fissures, and cracks or heats groundwater, which erupts as geysers or submarine hydrothermal vents
Geothermal power plants use hot water and steam for heating homes, drying crops, and generating electricity
Geothermal energy

38. Geothermal steam heats water piped in from a lake, piped out to residents

39. Enhanced Geothermal Systems (EGS)
Overcome the limitation of location
Areas where naturally heated ground water does not occur
Drills deep into the ground pumps in cool water that can then be used repeatedly
Safety, reliability, limits expansion
Could trigger minor earthquakes
Enhanced Geothermal Systems (EGS)

40. Ground-source heat pumps (GSHPs)- make use of the natural temperatures in the ground, warm in winter; cool in the summer
Heat pumps

41. Geothermal Benefits Limitations Reduce fossil fuel emissions
Renewable means of heating and providing electricity
Regional restrictions
Crust patterns shift overtime, puts a lifetime cap on plants
Maintain the water levels to continue use
Natural groundwater has minerals and salts that corrode equipment
Small amounts of CO2, methane, ammonia, and hydrogen sulfide
Geothermal

42. ICELAND: setting examples for the rest of the world

43. Homework: Hydrogen & Ocean Energy
Complete notes on pg , and the charts outlining the benefits/limitations of each source. DUE tomorrow FRI 11/18
Tomorrow: Energy Superhero/supervillain poster planning BRING BOOK
Homework: Hydrogen & Ocean Energy