Figures describing renewable energy implementation and use
Animal Power Slides
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Cost over 10,000 hr.
Traditional long-life incandescent bulb* $87.50
Standard incandescent bulb* $65.80
Compact fluorescent bulb** $17.76
E-Lamp - compact Fluorescent bulb** $16.40
Fluorescent bulbs can replace 25 incandescent bulbs and over their life
save $800-1200. Replacing incandescent bulbs with fluorescent bulbs could
save a potential $15-20 billion in electricity bills per year. (Energy Efficiency ratio: 22:5 ratio for Fluorescent:Incandescent)
*Incandescence - is method used in a device that results in visible light
caused by heating; These light emitting substances (usually a metal or conducting substance like tungsten, W) and the light emissions are controlled by black body radiation theory.
**Fluorescence - is when, for some elements, energy excites electrons of an atom to jump from an inner orbit of the atom to an outer orbit. Then, after a very short period of time, when the electron falls back to its original state (orbit), a photon of light is emitted.
Questions:
1. Does the US have a sound energy policy?
2. How can we use waste heat?
3. Can waste heat be recycled as high quality energy?
4. What is the real price of gasoline? Has it gone up or down?
Why?
Look at the Figure 13-10 as part of your discussion
The 2nd law of thermodynamics predicts that all waste heat cannot be captured
and recycled as high quality (high work capacity) energy. Nevertheless,
it can be used as space heating for low quality work.
Capturing waste heat from lights, computers etc. can be recycled and used to heat spaces if insulation factors of buildings are high enough to make it effective. This reduces the requirement for high quality electricity.
Cogeneration from waste heat in high quantities can be used to generate electricity in industrial settings.
Cogeneration can up the useful work of energy used from 33% to 90% when implemented to maximum theoretical and practical efficiency. (using waste heat as space heat for example)
Figure 13-7 from text
Figure 13-8 from text
Figure 13-9 from text
Figure 13-10 from text
Evaluate the capabilities in miles per gallon.
Evaluate public transportation.
Evaluate emissions.
Evaluate materials
Figure 13-17 Generating costs of electricity per kilowatt-hour by various technologies in 1992.
Note: It costs less to use available stored energy (until it is exhausted)
Figure 13-16 - Jobs generated per year by electricity-production technologies. (data from Worldwatch Institute)
Photographs and graphics demonstrating these principles are available when each of these concepts is discussed.
Alternative technologies for heating the home and water.
Passive Solar Heating Systems
2. It uses low quality heat directly for space heating
3. The solar energy must be stored in some manner for when the sun is not
available to produce an average energy availability
4. Uses concepts such as
Figure 13-18 from text
Passive solar heating and 
Active solar heating
Figure 13-19 from text
Direct Gain and 
Greenhouse, Sunspace, or Attached Solarium and 
Earth Sheltered
Figure 13-20 from text
Figure 13-21 from text
Figure 13-11 from text
Figure 13-22 indicates appropriate regions for solar energy applications
in the US.
House construction is more important for conservation
Other graphical depictions of solar use in the home.
Solar thermal systems convert heat to steam to drive turbines to produce electricity.
Thermal Solar Energy Devices
Photovoltaic cells is an estimated $1-5 billion a year market - (1993 through 2100)
Figures 13-24 and 13-25 show direct solar photovoltaic cells as implemented in a dwelling.
Slides of Photovoltaic systems in use
Potential energy storage is used by power plants but is not practical for photovoltaic electrical storage.
In some countries for example:
Country compared to the amount of power from hydroelectric
Examples: Figures from other sources are instructive
Dams that produce hydroelectric are the most efficient.
Figure 13-26 demonstrate positive and negative effects of dams.
Hydrogeneration from dams.
Not all technologies that are proposed and are theoretically practical are
economically practical. Examples of theoretical but as yet not practical
alternatives are:
Saline solar ponds - An Israeli solar pond in the Dead Sea was abandoned in 1989 due to high costs of operation and maintenance.
Wave power - Two functioning wave power plants exist (Bay of Fundy in Canada and La Rance in France
Tidal Power Plant and Wave Power Plant
Ocean Thermal Electric Plant
Saline Water Solar Pond and Freshwater Solar PondSailing ships have and still use this power source.
It is one of the oldest powered water pumping systems and is still used for this application. Holland virtually reclaimed its land from the sea with the aid of wind power. They now wish they had not replaced so many windmills with electric pumps as they now have incredible electric bills.
The positive side to wind electricity production:
-1% of California gets electric power from wind powered generators.
-This technology has been steadily growing since about 1980.
-Projects are planned in 12 states.
-Direct electrical production is one of its strongest recommendations
-Projections are that by 2050 10% of commercial electricity will be from wind power.
The down side to wind electricity production:
-However "visual pollution" the killing of birds and noise pollution
are a serious problem that may curtail the use of wind power in many states
that have the resources but may not have the space or other aspects to make
it the most viable alternative.
Figure 13-28 (Wind Turbine Diagram and Wind Turbine Picture)provides an idea of what a wind energy production farm may look like and how it functions. Other pictorial examples are also provided.
Wind work and electric generation devices.
Burning of Wood and Manure:
Wood was one of the first biomass energy source used by man.
Wood as fuel - Pictures
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13-36% of the world's energy for cooking and heating is from this source.
The ratio is much higher in LDC countries.
About 70% of LDC home heat is from wood and wood by-products and wood wastes. However natural supplies are dwindling and over 2 billion people do not have adequate supplies to meet current demands.
As long as trees are planted when others are cut and used as fuel (or as building materials), this can be a renewable resource.
Wood and agricultural wastes could produce as much as 30% of electricity needs according to some organizations such as "Worldwatch Institute".
Photographs of wood fuel use.
Currently a 10:1 ratio exists between biomass and photovoltaic cell electricity
production. But there are tradeoffs and other considerations such as the
production of oxygen while the biomass is growing and land use as well as
material cost and the quality of energy needed in certain parts of the world.
Biomass Gaseous Fermentation Reactors:
These reactors produce methane (CH4, the primary component of natural gas)
by fermentation in bioreactors operated in anaerobic conditions and produce
combination of 60% methane and 40% carbon dioxide. In CA 20,000 homes receive
electricity from this source.
Biogas Reactor 1
Biogas Reactor 2
Biogas Vehicle 1
Biogas Vehicle 2
More on Biogas
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Example India:
India has constructed over 750,000 biogas digesters. The final organic
residue material is then used as fertilizer for agricultural purposes eliminating
waste material with the exception of the carbon dioxide that was not converted
to useful fuel.
Figure 13-29 demonstrates how a Solid Biomass Fuel reactor might work in the abstract.
Gasohol Pictures
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Another use of biomass is its conversion through fermentation* to gaseous
and liquid fuels. Methane reactors is one source of gaseous products that
can be combined with natural gases and pumped through pipelines. Alcohol
is another fermentation product that is a high quality fuel. One use is
in a fuel additive known as gasohol.
*fermentation is the biological and enzymatic conversion of organic matter by bacteria, molds and yeasts. Yeasts, for example, convert simple sugars into alcohol by secreting the enzyme zymase that makes this transformation and is the basis of alcoholic beverages as well as industrial production of alcohols.
Gasohol is a blend of 9:1 unleaded gasoline and alcohol (ethanol and/or methanol; C2H5OH, or CH3OH respectively)
It is not new but alcohol was used as an interchangeable fuel with gasoline in the first internal-combustion engines in the 1870s. It has been used at various times as an alternative fuel, fuel extender and now as a fuel enhancer to reduce automobile emissions.
Coal and Oil were at one time biomass and were reduced by time, pressure, heat and nature to their current state. The time required is hundreds of thousands to millions of years.
In Brazil 1/3 of the automobiles use ethanol as fuel.
Predictions are that this will be one bridging fuel to sustain portable
fuel needs when oil is depleted.
Alcohol can only meet about 10% of liquid fuel needs and it is not a permanent solution.
Coal gasification is one alternative that will be discussed later that has a similar potential.
Photograph of corn production for alcohol fuel
Hydrogen gas (H 2) can be produced by passing electrical current through water (hydrogen and oxygen are produced in a 2:1 ratio).
Any electrical source can be used to produce hydrogen as demonstrated in Figure 13-30.
The combustion product is water which can be used again to make hydrogen and oxygen or it can be used as normal water.
Hydrogen must be stored in a form that does not permit it to be released immediately for safety reasons. It can be stored in pressurized metal tanks as hydrides or in sponge iron or activated carbon. The reason for this precaution is that hydrogen is a forgiving fuel that will either burn or explode in an mixture of air or oxygen between 1:96 or 95:1 ratio.
Hydrogen Fuel Cell
One of the most efficient devices for producing electricity is the hydrogen
fuel cell. This is also the electrical generator of a new car. Politics,
economics, oil companies, auto manufacturers and the will to change hold
up this technology.
A hydrogen fuel cell is 65% efficient and consists of an anode (to which fuel, hydrogen, is supplied) and a cathode (to which an oxidant, air or oxygen, is supplied). The two electrodes of a fuel cell are separated by an ionic conductor electrolyte.
In the case of a hydrogen-oxygen fuel cell with an alkali metal hydroxide electrolyte, the anode reaction is 2H2 + 4OH--->4H2O + 4e- and the cathode reaction is O2 + 2H2O + 4e--->4OH-. The electrons generated at the anode move through an external circuit containing the load and pass to the cathode. The OH- ions generated at the cathode are conducted by the electrolyte to the anode, where they form water by combining with hydrogen. The fuel cell voltage in this case is about 1.2V but decreases as the load is increased.
Currently about 20 countries have active geothermal energy production sites.
In the US, most are in California or the Rocky Mountains.
80% of homes in Reykjavik Iceland are heated by geothermal hot water. In
France over 200,000 Paris homes are heated with hot water from geothermal
wells.
Figure 13-31 demonstrates an example of one type of industrial geothermal tapping system using pumped water.
Geothermal drawbacks:
These efforts on an industrial scale can deplete sites of high heat value,
cause ground subsidence or cause unsightly construction on natural wilderness
areas.
Geothermal closed loop heat pump systems:
One type of excellent alternative is one that can be used almost anywhere
is a closed loop heat pump. Because the earth is a constantly between 55-60°C
down a meter or two, heat in the winter and heat exchange in the summer
can be used to pump heat against a constant heat gradient. This technique
is also known as geothermal but is only useful on a domestic scale.
It has a playback of about 5-7 years when compared to oil fired heat systems or in about 3-5 years when compared to all electric heating. It is more costly to install but has the potential to be very efficient and non-polluting.
This alternative is cost effective for most countries and continents.
Geothermal implementation pictures
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What are some other alternatives that are less in the main stream?
What if anything can you do about it?
Are you more aware of alternatives now than you were before we started?
Do you understand the alternatives?
Does the energy consumption pattern in the US make sense environmentally to you?
Does the US have a sound energy policy?
What is your concept of alternative energy after becoming familiar with some of the technology?
Has your attitude changed about energy and the environment after reviewing this material?
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