ENVIRO Ch. 20
One of the areas in which most of us can accomplish the greatest energy conservation is in our
Transportation choices -how to travel
By 2020, Germany plans to ... the share of wind power
Triple -offshore turbines are in hands of large corporations -onshore turbines are in hands of midsize farms and communities and small investors
Passive housing principles #5
Triple-pane windows that reduce radiative heat loss or gain
The cheapest, least environmentally damaging, and healthier alternative for driving is
Walking or biking
Active solar systems
Pump a heat-absorbing fluid (air, water, or antifreeze solution) through a collector (like a flat, glass-covered black surface, or glass vacuum tubes) -water (or any other fluid) pumped through the collector picks up heat for space heating or to provide hot water -active solar thermal (heating) systems are usually located adjacent to or on top of buildings and can be retrofitted on exiting buildings
Distrusted production is also democratic
Rather than have a huge monopoly controlling power production and transmission, you could own your own system or join with your neighbors in a local cooperative
Plug-in hybrids
Reduce gasoline dependency still more -have larger battery arrays than an ordinary hybrid -recharge battery at charging station rather than depend only on the internal engine to do the charging -95 mpg -since most Americans only drive about 30 miles per day, they rarely have to buy gas -electricity is cheaper
The easiest and cheapest ways to avoid energy shortages and relieve the environmental and health effects of our current energy tech is to
Simply use less
The current from a fuel cell is proportional to the
Size of the electrodes, while the voltage is limited to 1.23 volts per cell -cells can be staked together until desired power level is reaches
Micro-hydro generators
Small enough to provide economical power for a single home -live close to a small stream or river that runs year-round, have sufficient water pressure and flow -> cheaper than solar/wind power
low-head hydropower
Small-scale hydro tech that can extract energy from small headwater dams that cause much less damage than larger projects -run-of-the-river flow
When a reformer is coupled to the fuel cell
Some pollutants are released, but the levels are less than conventional fossil fuel combustion in a power plant or automobile engine
Fuel cells are ideal for
Space exploration -small size, high efficiency, low emissions, net water production, no moving parts, high reliability
The fuel cell provide direct-current electricity as long as it is
Supplies with hydrogen and oxygen -oxygen provided by ambient air -hydrogen is supplied as pure gas, but storing hydrogen gas is hard and dangerous because of its volume and explosive nature -liquid hydrogen takes less space than gas, but must be kept below -250 Celsius -alternative device called reformer
Iowa's Revolving Loan Fund
Supported by a surcharge on investor-owned has and electric utilities -this fund provides low-interest loans for renewable energy and conservation
run-of-the-river flow
high efficiency turbines that are submerged directly into a river or stream without a dam. -small enough to not impede navigation -don't require a dam or diversion structure and can generate useful power with a current of only a few km/hr -cause little environmental damage and don't interfere with fish movement
Three Gorges Dam
hydroelectric dam spanning the Yangtze River in China -produces as much energy as 25 nuclear power plants -displaced 1.5 million people -block the seasonal floods that have sustained the fisheries and farms of the river's lower reaches
Oil, gas, coal, and nuclear cause more
Wildlife mortality tan renewables do -oil-> habitat destruction, oil spills
... power currently provides the world's largest amount of renewable energy
Wind -nearly 2.5 times as much as solar
What is the world's fastest growing energy source and could replace all the commercial we use now
Wind power
The need to move away from imported oil has created a corn-based ethanol boom in America
-200 new ethanol refineries have been built -US annual production capacity grew to 60 billion liters -US and Brazil now produce 95% of all ethanol in the world
Oscillating water columns
-Push or pull air through a turbine -floating buoys, barges, and cylinders that bob up and down as waves pass-> generator converts mechanical motion into electricity -hard to design system that survives storms
Dams in arid regions
-can evaporate river's flow, reducing resources for farms and cities
Suburban subdivisions have replaced
-compact downtown centers in most cities -harder to walk so people drive instead
Municipal landfills
-contain buried anaerobic organic waste -are also active sites of methane production (20% of annual output of methane to atmosphere) -waste of valuable resource and threat to environment
Ocean wave energy
-energy from waves -wave power could be 16% of the world's current electrical output -oscillating water columns
In the US, incentives like... are increasingly common
-faster permitting or tax breaks to building projects that meet passive standards
High-voltage direct-current lines
-make it possible to transmit electricity over long distances with little loss
Tidal station
-ocean tides and waves contain energy -station works like a dam with turbines spinning as tide flows through them
Distributed solar power generation can
-reduce the need for power lines, which are expensive and inefficient -eliminate disruptive and dangerous infrastructure like coal trains, oil and gas pipelines, and oil and gas terminals
Why are smart meters becoming more common
-they save money for utilities and consumers
Plants capture ... of all solar energy that reaches earth's surface
0.1%
Wind power takes about ... as much area and creates about ... times as many jobs to create the same amount of electrical energy as coal, when the land consumed by mining is taken into account
1/3 5 times
Distributional surcharges
A mall charge is levied on all utility customers to help finance renewable energy research and development
A benefit over individual rooftop ownership is that the
Association maintains the facility (washing off dust in the summer, cleaning off snow in the winter)
Power walls
Battery arrays large enough to supply a house with power for about 24 hours
Schistosomiasis
Caused by parasitic flatworms called blood flukes -transmitted to humans via snails that thrive in slow moving, weedy tropical waters behind dams
Most of the hydropower development in recent decades has been in
Dams -but they have social and environmental disadvantages -humans displacement, ecosystem destruction, and wildlife losses -can floods -sedimentation, which reduce usefulness
The largest PV installations in the US currently are the
Desert Sunlight and Topaz Solar Farms in southern CA -flexible roof tiles with amorphous silicon collectors layered on their surface can be installed on residential rooftops
Fuel cells
Devices that use ongoing electrochemical reactions to produce an electric current
In tropical regions, where vegetation is abundant, rotting trees and other organic material in reservoirs can have
Disastrous effects on water quality -too much sulfide-> kill fish -acid water ruins dam's turnblades -creates methane (GG)
Currently, there are no known ... for Miscanthus
Diseases or pests -however, the characteristics that make it an attractive energy crop (rapid growth, efficient photosynthesis, low need for nutrients, no known pests, high water-use efficiency) also make it a good candidate to become an invasive pest
Many colleges, universes, cities, and industrial facilities have a central heating plant that
Distributes steam or hot water -by reducing electricity from waste heat in these plants, the net energy yield from the primary fuel increased from 30-35% to 80-90%
In Europe, municipal solar systems provide
District heating and hot water for whole cities
In response to the 1970s oil price shocks, automobile-gas mileage averages in the US more than
Doubled from 13.3 mpg in 1973 to 25.9 in 1988 -falling fuel prices in the 1990s discouraged further conservation, and mileage hardly improved for 20 years
Where wood and other fuels are short in supply, people often
Dry and burn animal manure -efficient use of waste biomass, but can intensify food shortages if manure is needed to fertilize crops
The earth's warmth can help reduce
Energy costs early everywhere, despite the fact that few places have geothermal steam -pumping water through buried pipes can extract enough heat so that a heat pump can provide a space heating or hot water -in summer, the reverse process can provide air conditioning -horizontal tubes can be laid in shallow trenches -limited space: tubes can be dropped into vertical wells
Firewood and charcoal production is a dominant cause of
Forest destruction and habitat degradation
Methane captured from landfills and wastewater treatment plants could also be used as a
Hydrogen source -hydrogen could also be priced by hydrolyzing water using solar or wind-powered electricity
In 1900, half the electricity generated in the US came from plants that also provided
Industrial steam or district heating -cogeneration became less common with falling fuel prices and growth of electric utilities
High-temp solar thermal plants are suitable for
Industrial-size facilities
Conservation
Parity about behavior (turning off lights and adjusting thermostat) and a technological challenge
Distributed production can also be threatening to
Power utilities accustomed to monopoly control -large utilities have enormous sunk costs in power plants and transmission grids, and they resist competition from distributed and renewable power producers -many utilities charge for use of utility network, and some charge private wind or solar systems a fee to hook up to the utility grid even if they only use the connections for emergencies -these fees can be an obstacle to renewable energy production adoption
Cogeneration
Production of electricity from waste heat in a steam heating plant -aka combined heat and power (CHP) plants -one of the fastest growing sources of new energy
Renewable portfolio standards
Require power suppliers to obtain a minimum percentage of their energy from sustainable sources
Passive housing principles #2
Roof and wall insulation 24-32 cm thick
Passive hear absorption
Using natural materials or absorptive structures with no moving parts to simply gather and hold heat -simplest and oldest use of solar energy -people have built thick-walled stone and adobe dwellings that slowly collect heat during the day and adulation release that heat at night
When a passive building produces electricity (like with solar panels on the roof), it can become a
"Net-zero" building that uses no more energy than it produces -some "energy-plus" buildings that produce more energy than they consume on an annual basis
Investing ... per year now in clean energy will avoid 20 times that much in a few decades from damages of climate change
$700 billion
Water power is now ... of our total electrical generation
20% -some countries still depend on falling water for hydropower
Wind power could supply ... the current world electricity supply and ... all global energy consumption if all the potential were tapped
40 times 5 times
Automobiles and light trucks account for ... of the US oil consumption and produce ... of its carbon dioxide emissions
40% 1/5
As further research improves their lifespan, industry experts believe they could produce electricity for less than
5 cents per kilowatt-hr by 2020 -low price makes solar suitable for utility-scale baseload power arrays
Renewables could provide about ... of world cumulative energy consumption in 2030
60%
It takes a wind velocity between .... and .... to generate useful amounts of electricity
7 m/sec 27 m/sec
The capacity for cogeneration is now over
70 GW, or about 7% of US electric supplies
Although the theoretical efficiency of electrical generation of a fuel cell can be ...,
70% Actual yield is closer to 40-45%
Oil palms are ... more productive per unit area than soy or sunflower
8 to 10 times -but more expensive to harvest and transport
Germany gets ... of its electricity from wind turbines
8.6%
Though national polls in the US show that ... of the public supports additional wind power, the rate of support is less amount people who
82% Live close to the towers
With each tower taking only about 0.1 ha of cropland, farmers can continue to cultivate ... of their land while getting ... or more in annual rent for each wind machine
90% $2000 -better return results if landowner builds and operates the wind generator and sells electricity to local utility ($100,000 annual profit)
Indonesia and Malaysia produce ... of the world's palm oil
90% -but releases many GG -Indonesia is 3rd in world in human made GG emissions -many species are threatened by habitat loss due to palm oil expansion
Putting your computer to sleep saves about
90% of the energy it uses when fully on, but turning it off completely is even better
A collector with about 5 m^2 of surface can reach ...Celsius and can provide enough hot water for an
95 Average family
Norway depend on hydropower for ... of its electricity
99%
Jatropha curcas
A shrubby tree that is a good alternative to palm oil and soybean oil -has nuts with high (and toxic) oil content that can easily be converted to diesel fuel -might produce 15,000 liters of oil per hectare -India is setting aside land for the crop and hopes it will provide 20% of its diesel fuel -Air New Zealand flew an airplane using a blend of this oil and aviation fuel
Economical battery storage is an important goal of solar producers
-Elon Musk also built a giant battery factory in Nevada -he hopes to produce millions of "power walls" -if he can produce these batteries at a reasonable price and reliability, it could erase the intermittency of solar and wind energy, and make it possible to unhook from the utility grid
Harvesting, storing, and shipping biomass crops remains a problem
-Low energy content of straw or wood chips, compared to oils and sugars, make them expensive to more than 50 km to a refinery -may need many small refineries
Tidal station disadvantages
-a high-tide/low-tide differential of several meters is required to spin the turbines -variable tidal periods often cause problems in integrating this energy source into the electric utility grid
Individual households and PV cells
-a photovoltaic array of 30-40 m^2 will generate enough electricity for an efficient house -at $1 per watt, a rooftop array might pay for itself in five to seven years
Disadvantages of small-scale hydropower
-abuse of water resources
Silicon collectors and PV
-amorphous, noncrystalline, thin-film silicon semiconductors can be made into lightweight, paper thin films that require much less material than conventional crystalline silicon cells -cheaper to manufacture and can be made into different shapes and sizes
How are appliances becoming more energy-efficient
-appliances have timers so they can run overnight, when energy use is low -thermostats can automatically adjust temp when you aren't home or when you're sleeping -smart metering gives info on how much energy is being used and how much it costs
Why do European countries tend to have higher standards of living than US despite using about 1/2 as much energy per person
-better appliances, buildings, and vehicles are critical to efficiency improvements
Miscanthus x giganteus
-biofuel crop, perennial grass from Asia -aka elephant grass -sterile, hybrid grass that grows 3 or 4 meters in a season -can produce 5 times as much dry biomass per hectare as corn -starts growing 4 to six weeks earlier in the spring than corn and stays green a month or more longer in the fall -protect soil from erosion, and requires less fuel for cultivation -can grow on marginal soil with less fertilizer than corn needs -moves nutrients into underground rhizomes during fall -stores carbon in soil-> help climate change
Benefits of algae biofuel
-can be grown in facilities next to conventional power plants, where CI2 from burning either fossil fuels or biomass could be captured and used for algal growth-> carbon negative (provide a net reduction in atmospheric carbon while also creating a useful fuel)
Wind turbines and school and homes
-claims that low-frequency sound waves from moving blades cause headaches, insomnia, digestive problems, panic attacks, and other health issues -and to study this because of low-frequency sounds from wind, highway noise
Solar garden (or solar farm)
-community shared solar arrays connected to the utility grid -members buy power from the utility as usual, but they get a rebate for the garden based on their share of ownership -members can either pay up front of a share, or pay on a monthly basis
Solar City
-company founded by Elon Musk -largest residential solar company in US -offers 3 options -in first two options, you don't pay anything initially, but you also don't have equity
light-emitting diode (LED)
-cost more than a compact fluorescent light bulb but they use about 1/2 as much electricity, and last 5 times longer -use 1/10 as much energy and last up to 50 times longer than standard incandescent lightbulb -produce millions of colors and can be adjusted in brightness
How have some counties encourage the use of electric vehicles
-creating networks of charging stations in cities and along highways, and by offering owners of electric vehicles feee street parking and charging -hefty tax breaks, promotional leases, cheaper operating costs
Many utilities now offer green energy options
-customers agree to pay a couple of dollars extra on monthly bills, and utilities promise to use the money to build or buy renewable energy
Disadvantage of CSP
-desert sites are often biologically rich and vulnerable, and they recover slowly from disturbance
Cogeneration on the rise
-district heating systems are being rejuvenated, and studies have been done regarding burning municipal wastes -small power-generating units to service neighborhoods or apartment buildings are being built that burn methane, natural gas, diesel fuel
Deep wells for community geothermal systems
-drilling gets you into rocks above 100celsius -fracturing them to expose more surface area and pumping water in-> makes enough steam to run an electrical generator at lower cost than fossil fuel/nuclear power
geothermal energy
-earth's integral temp and high pressure -around edges of continental plates or where earth's crust overlays magma pools close to surface -hot springs, geysers, and fumaroles
Electricity: standby mode
-electronics and appliances draw power in an "instant-on" mode -these "vampire currents" can amount to a quarter of the monthly electric bill -plugging appliances into an inexpensive power strip allows you to switch them off when not in use
Gas-2-power
-form of storage being explored in Germany -excess electricity can be used to hydrolyze water to hydrogen and oxygen gas -hydrogen can be stored and burned for heat, or used in fuel cells to generate more electricity when the need arises
Cautions of deep well geothermal energy
-fracking can contaminate groundwater aquifers -earthquakes
Advantages of CSP plants
-heat from the transfer fluid can be stored in a medium (like molten salt) for later use -lets system to continue to generate electricity on cloudy days or at night -some plants can produce power 24/7 -if plants are near coastlines, waste heat from the turbines can be used to evaporate seawater to create pure drinking water
In wealthy countries, biomass also makes a contribution to renewable energy supplies
-heating biomass, both from agricultural wastes and biomass crops -burning these crops in an industrial boomer is easier to install and maintain pollution-control equipment than in individual stoves -most plant material contains little sulfur (no acid rain) -brush at lower temp than coal-> less nitrogen oxides -crops are carbon-neutral (absorb as much CO2 in growing as they emit when burned)
Wind farms and birds and bats
-high mortality, esp in CA since the generators are placed at summits of mountain passes, areas where wind velocities are high -new generator designs and better placement reduced this problem -shutting down turbines during migrations also help
Power tower
-high-temp system that uses thousands of smaller mirrors arranged in concentric rings around a tall central power tower -mirrors track sun and focus light on a heat absorber at the top of the power tower, where a transfer medium is heated to temps as high as 500celsius, which then drives a steam-turbine electric generator
Rooftop solar energy
-huge potential -in the US, more than 1000 mi^2 of roofs suitable for PV systems could generate about 3/4 of our present electrical consumption
Federal and state rules and incentives had led to a growing variety of efficient automobile choices
-hybrid gasoline-electric engines offer good fuel economy and low emissions
Germany
-increased its energy efficiency by more than 50% over last 25 years while desde easing its primary energy consumption -reduce its reliance on imported energy from distant and dangerous places
Swamps
-large methane digesters, basins of wet plants and animal wastes sealed from the air by a layer of water -organic materials are decomposed by anaerobic (oxygen-free) rather than aerobic (oxygen-using) bacteria, producing methane instead of CO2
Wind power limitations
-like solar energy, it is an intermittent source -not every place has strong/steady enough wind to make this an economical resource
Concentrating solar power (CSP) systems
-long trough-shaped parabolic mirrors to reflect and concentrate sunlight on a central tube contains a heat-absorbing fluid
Power lines
-many of the places with the greatest energy potential for renewable energy developments are far from urban centers where power is needed -we will need an increased network of power lines if we depend on wind or solar energy
Industrial energy savings are another important part of our national energy budget
-more efficient electric motors and pumps, new sensors and control devices, advanced heat-recovery systems, and materials recycling have reduced industrial energy requirements
Often our use of energy is extremely inefficient
-most energy used to operate internal combustion engines and conventional incandescent light bulbs is lost as heat, rather than producing motion or light
Green building
-most of innovation has occurred in large commercial structures, which have large budgets and more to save through efficiency than homeowners have -energy audits can show you where energy is being lost -sealing leaks with caulk or weather stripping is quick and cost-effective to save energy
Texas and wind power
-number one state in wind power -wind power is so plentiful, that sometimes the price has dropped into negative territory, so wind farms had to pay consumers to use their excess power
CSP and wind/sandstorms
-on days when storms are forecast, the mirrors can be rotated into a protective position
Biomass advantages
-renewable, accessible
Debates over ethanol from corn
-requires lots of water, pesticides, fertilizer, and causes soil erosion -argument that cellulosic ethanol would be better
Disadvantages of jatropha curcas
-requires more water and fertilizer -sensitive to pests and diseases -has a lower yield than promised
Artificial "swamps"
-same process can be reproduced artificially by placing organic wastes in a container and providing warmth and water -after gas is removed, the remaining solid material can then be used as clean fertilizer
Ecological scenario
-shift wealth from north to south
Can we get all our electricity from renewable, environmentally friendly sources in a short time?
-some believe yes: currently available wind, water, and solar tech could supply 100% of the world's energy by 2030 and completely eliminate al our use of fossil fuels -would take 3.8 million large wind turbines, 1.7 billion rooftop PV systems, 720,000 wave converters, 1/2 million tidal turbines, 89,000 concentrated solar power plants, 5350 geothermal plants, 900 hydroelectric plants worldwide
Ivanpah Solar Station
-southwest of Las Vegas -power tower -currently world's largest thermal solar installation
Passive House standards in Germany
-strict energy use limits -guidelines for building practices that can reduce energy consumption to just 10% of what normal buildings use
William Grove
-studied fuel cells in 1939 -suggested that rather than use electricity to break apart water and produce hydrogen and oxygen gases, it should be possible to reverse the process by joining oxygen and hydrogen to produce water and electricity
Armory Lovins
-suggested that accounting for negawatts should be a priority in energy policy -it's cheaper to conserve energy than to build new generating stations and transmission lines to meet demand
Biofuel oil limits
-takes a lot of land -diversion of these oils for vehicles deprives humans of an important source of edible oils
ocean thermal electric conversion (OTEC)
-temp differences between upper and lower layers of ocean -heat from sun-warmed upper ocean layers is used to evaporate a working fluid (ammonia or freon) which has a low boiling point -pressure of gas produced is high enough to spin turbines to make electricity -cold water is pumped from ocean depths to condense the gas
Modern wind turbines
-the largest wind turbines are 49 times more powerful than ones 29 years ago -each can generate 8 MW of electricity, or enough for 3000 typical American homes -mostly used offshore -can reduce power 90% of time
20 Native American tribes have formed a coalition to study wind power
-together, their reservation (great plains) could generate at least 350,000 MW of electrical power, equivalent to about 1/3 of current total US installed capacity
Farms and methane
-use methane digesters and manure to generate over for dairy operation
Property assessed clean energy (PACE)
-uses city bonds to pay for renewable energy and conservation expenses -bonds are paid off through a 20 year assessment on property taxes -lower utility bills can forest tax increases, so that switching to renewable energy is relatively painless for property owner
wind power advantages
-wind farms have shorter planning and construction times than fossil fuel or nuclear power plants -wind farms are modular and they have no fuel costs or air emissions
CA Mojave desert CSP
-withstands storms and winds -but, some of CSP plans were cancelled because of protests over land use -installations would harm or endanger species, like the desert tortoise or fringe-toed lizard -Native Americans said some areas were sacred cultural sites -wilderness advocates don't like intrusion of industrial families
Diesels make up about ... of cars sold in Europe because of their
1/2 Superior efficiency -claimed that recent advances have made diesels cleaner and quieter than a generation ago -however, it was revealed in 2015 that some ca companies rigged their engines to run more efficiently during tests than actually on the street -hurt customer confidence in diesel tech, but greater efficiency makes diesels advantageous
Using corn or switchgrass to produce enough ethanol to replace 20% of US gasoline consumption would take about ... of all current US cropland out of food production
1/4 -miscanthus could produce same amount on less than 1/2 or that area
A passive house can cost only ... more than a standard house and...
10% -that extra cost pays for itself in just a few years of reduced energy use -where building standards are more lax and housing is inexpensive, the cost difference can be much greater, but so can the savings
The amount of solar energy reaching the earth's surface is some ... times all the commercial energy used each year
10,000 -since this infusion of energy comes in a diffuse, low-intensity form, we only have recently learned to covert into to electricity with economical efficiency
By 2050, Germany expects to get ... of its electricity from renewables
100% -1/2 of all jobs are now in solar industry -price of PV panels have fallen faster than that for CSP facilities, so there are more PV installations
The average amount of solar energy arriving at the top of the atmosphere is
1330 watt per square meter -1/2 of the energy is absorbed or effected by atmosphere, but over course of a year, we receive about 2000 kilowatt-hrs per year per secure meter -this is about 1/5 the amount of electricity used by a US household every year, or 1/2 the electricity use if a household in Europe
Most experts estimate useful biomass production at ... to ... times the amount we currently get from all commercial energy sources
15 20
In 2012, the department of transportation and the EPA issued regulations requiring cars and light trucks to
Achieve an average of 54.5 mpg by 2025 -save consumers $1.7 trillion in fuel costs, reduce oil conspiring by 2 million barrels per day, and eliminate 6 billion metric tons of CO2 emissions by 2025
In 6 hours, the world's deserts receive more solar energy than
All humans consume in an entire year
Green pricing
Allows utilities to profit from conservation programs by charging higher prices for energy from renewable sources
If the electricity comes from renewable sources, then most of your transportation could be
Almost pollution-free
Biomass
Any organic material -photosynthetic organisms have been collecting and storing sun's energy as biomass
Algae
Aquatic, photosynthetic plants that produce lipids (oils), the basic substances that led to ancient oil deposits we use today -all algae need to grow are nutrients (like waste from a sewage plant), CO2 (like effluent from a power plant), sunlight, and water -could be a productive biofuel source
Switchgrass
A tall native to the Great Plains that is easy to plant mechanically -good potential for fuel source (ethanol) -it's a perennial with deep roots that store carbon (thus, capturing GG) -roots keep soil in place
You can drive a hybrid automobile twice as far on the electricity generated by burning a ton of
Biomass than you could on the ethanol fermented from that same ton -so bruising biomass may be better tan fermentation, if we move to hybrid engines
Biofuel around the world
Brazil: gets 40% of its transportation energy from ethanol from sugarcane Southeast Asia: tropical forests cleared for palm oil plantations US: 1/5 of corn crop is used to make ethanol
Flex-fuel boilers
Burn wood chips, agricultural waste, or other biomass fuels
Co-combustion of coal together with biomass can have benefits over
Burning either alone
Some of the oil-rich Persian Gulf states are building
CSP plants as they prepare for a fossil-fee future -258,000 mirrors in the Shams plant can provide enough electricity for 20,000 homes -Saudi Arabia has pledged $109 billion for solar power
Federal Energy Regulatory Commission (FERC) has ruled that negawatts
Can be traded as a commodity -company that avoids using energy can market its savings just as a power company would do with real megawatts
Photovoltaic (PV) cells
Capture solar energy and convert it directly to electrical current by departing electrons from their parent atoms and accelerating them across a one-way electrostatic carrier formed by the junction between two different types of semi-conductor material
Passive housing principles #4
Heat exchangers, to warm or cool fresh air as it is exchanged with stake air leaving the building
Smart meters
Electricity meters that record data rapidly, for example, every hour, and that communicate with the electric utility grid -rewards customers who use most of their energy when there is excess supply, and it is cheap -ex) middle of night (consumption if low), utility companies offer customers low rates to take unwanted power off their hands -smart house system: time appliances to run only when a certain price is available, or only when electricity comes from wind or solar sources
High efficiency buildings are becoming the norm in
Europe -some regions in Germany require that buildings conform to passive house standards; some countries are following Germany's lead
The sun serves as a
Giant nuclear furnace in space, constantly bathing our planet with a free energy supply
Some trombe walls are built of
Glass blocks enclosing a water-filled space or water-filled circulation tubes, so heat from solar rays can be absorbed and stored while light passes through to inside rooms
A carefully designed wind farm using VAWTs can have an output power ten times that of
HAWT machines
Solar gardens can also foster social justice by
Including people who don't have the cash to credit rating to own a solar system of their own
Over the past 25 years, the efficiency of energy captured by PV cells has
Increased from less than 1% of incident light to more than 15% under field conditions and over 75% in the laboratory -promising experiments are underway using exotic metal alloys (like gallium arsenide) and semiconducting polymers of polyvinyl alcohol, which are more efficient in energy conversion than silicon crystals
In Germany, more than 1/2 of all solar power is owned by
Individual homeowners or community cooperatives
Although the US does have good wind potential on the mid-Atlantic continental shelf, the built of North America's wind potential is situated on
Land -offshore installations are costly because they need to operate in deep water and withstand storms and waves -wind turbine construction on land is simple and cheap
Currently, what is the cheapest source of new power generation
Land-based wind farms -cost as little as 3 cents per kWh compared to 4-5 cents per kWh for coal, and five times that much for nuclear fuel
Vertical axis wind turbines (VAWTs)
Lighter and cheaper than horizontal axis wind turbines (HAWTs) -main components are located as base of machine-> lighter and easier to service and repair -can operate at slower wind speeds, and can be sized to be more appropriate for a single home or small business -price for a 3-kW turbine can be less than for an equal-sized solar array -in the past, blades had tendency to twist and break, but new materials solved that problem
There are now more vehicles (254 million) in the US than
Listened drivers (190 million) -these vehicles are used for an average of 1 billion trips per day
Alternative to dams and reservoirs
Low-head hydropower
cellulosic ethanol
Made from wood plant tissue -most plants put energy they capture from the sun into the cellulose and related polymers, like hemicellulose, which are made of long chains of simple sugars -woody plant add a stick glue, called lignin, to hold cells together -how do we release these sugars so they can be fermented into ethanol? -we had to chop and shred ions and treat it with bacteria or fungi
Methane
Main component of natural gas -produced by anaerobic digestion of any moist organic material -animal waste emits it
Passive housing principles #1
No thermal bridges (wood or metal components conduct heat through walls, roof, or foundation)
Better meters and smart electric systems would also enable us to take advantage of the potential of
Plug-in hybrids and electric vehicles, which could serve us as an enormous, distributed battery array -automobiles could be programmed to charge only at night when electric prices are at lowest
All fuel cells consist of a
Positive electrode (cathode) and a negative electrode (anode) separates by an electrolyte, a material that allows the passage of charged atoms, called ions, but is impermeable to electrons -hydrogen or a hydrogen-containing fuel (natural gas) is passed over the anode electric oxygen is passed over the cathode -at the anode, a reactive catalyst (like platinum), strips an election from each hydrogen atom, creating a positively charged hydrogen ion (proton) -hydrogen ion can migrate through electrode to the cathode, but the electron is excluded -electrons pass through an external circuit, and electrical current generated by their passage can be used to do useful work -at cathode, the electrons and protons are reunited and combine w/ oxygen to make water
Solar collectors could provide ... of global electricity in a decade
25%
Toyota Prius C
53 mpg in the city and 46 mpg on the highway
In 2016, the price of PV cells fell to
55 cents per watt, and some companies were offering installed panels for less than $1 per watt, a price that makes them competitive with fossil fuels and nuclear power
Electricity costs the equivalent of about ... per gallon of gasoline
59 cents
Negawatts
Amount of energy saved through conservation -Amory Lovins
Biofuels
Liquid fuels created from processed or refined biomass -ethanol and biodiesel
The first PV cells were made by
Slicing thin wafers from giant crystals of extremely pure silicon
What can you do if you don't own a suitable roof for solar energy?
Solar garden
Solar city three options: #1
They install solar panels on your roof and you buy electricity by the month
Colleges in the US have been using biomass and biogas to
Wean themselves off fossil fuels
Passive housing principles #3
Well-sealed windows and doors to prevent heat loss or gain
In developing countries, solar power could make electricity available to
Nearly 2 billion people who aren't served by a power grid
... of all workers commute alone in private vehicles. ... carpool, while less than ... use public transportation, and ... walk or travel by bicycle
3/4 20% 5% .38%
Some algal species growing in a photobioreactor might produce ... times as much high-quality oil
30 -because single-celled algae can grow 30 times as fast as higher plants -some algae species store up to 1/2 their total mass as oil
... Chinese homes get hot water and/or space heat from solar energy, and china no was more than ... of the solar hot water market
30 million 80%
It would take about ... less total energy to meet our needs with sun, wind, and water than continuing with fossil fuels
30% -because electricity is more efficient that brining dead plants and animals
Taking mass transit instead of driving a private car to work or school can reduce your energy consumption and GG emissions by
30% per year
One thousand megawatts of wind power can create more than ... permanent jobs, while paying about ... in rent to landowners and ... in tax payments to local govs
3000 $4 million $3.6 million
Currently, total world hydroelectric production is
3000 terawatt-hrs
OTEC works best where
Near islands that are the tops of volcanic seamounts, like Hawaii, of the edges of continental plates along subduction zones where deep trenches lie just offshore
The relatively uniform temp of the ground can be used to
Augment air conditioning in the summer
Fuel cells are similar to batteries except that
Batteries are recharged by adding electrical current, whereas fuel cells are recharged by adding fuel to power a chemical reaction
If we had a carbon "cap and trade" program as many European countries do, wind power could
Be cheaper than fossil fuels nearly everywhere
For trips less than 2 km, its often quicker to go by
Bicycle than to find a parking space for your car
What country has become the world's leading producer of wind turbines
China -US is second, Germany is third
Who produces 80% of the world's solar heaters
China -cost about $160 each and pay for themselves in two-three years
Operating a large fleet of electric vehicles could mean higher electricity demand, but producing electricity at a central power plant is
Far cleaner than burning gas in thousands of vehicle engines
There is growing demand for wind projects from
Farmers, ranchers, and rural communities because of the economic benefits that wind energy brings
Utilities usually resist
Feed-in tariffs, which divert some profits to homeowners and also complicate management of electric grid, since solar power can be variable
In 1980s, plans to build CSP plants in North Africa and Middle East were ended because of
Financing difficulties and political instability in the region
What regions have persistent winds suitable for wind power development
Great Plains and mountain states -Texas leads the nation
Glass-walled "sunspace"
Greenhouse in the south side of a building -massive energy-storing materials (brick walls, stone floors, or barrels of heat-absorbing water) collect heat to be slowly released at night -interior, heat-absorbing wall called a Trombe wall is an effective passive heat collector
Crops like sugarcane and sugar beets have a
High sugar content that can be fermented into ethanol, but sugar is expensive and yields can be low, esp in temperate climates
Stranded in grains, like corn, have
Higher yields and can be converted into sugars that can be turned by yeast into ethanol, butanol, or methanol
All-electric vehicles are even more efficient than
Hybrids -some get the equivalent of 100 to 120 mpg in combined city and highway driving
Residents say that passive houses are
More comfortable -even heating, better natural light, less noise
feed-in tariffs
Require utilities to buy surplus power from small producers at a fair price -these tariffs are essential to make small solar installations economical -rather than pay for an expensive energy storage system, your meter simply spins backward during the day when you sell surplus electricity to your local utility -at night, when solar panels don't make any electricity, you buy some back from your power company -might end up making money
How did Obama show his commitment to solar energy
Restored solar electric panels and a solar water water to the White House roof that was removed 30 years ago by Reagan admin
Reformer
Strips hydrogen from fuels such as natural gas, methanol, ammonia, gasoline, ethanol, or vegetable oil -many of these fuels can come from biomass crops
Since all the mirrors are focused on a single point (power tower)
The heat transfer medium has to be capable of absorbing much higher energy levels than in solar troughs -most of these plants use liquid sodium or molten nitrate salt for heat absorption -these molten slats are more corrosive and difficult to handle than lower-temp fluids suitable for a solar trough
Concentrating solar power (CSP) systems
Uses long-trough shaped parabolic mirrors to reflect and concentrate sunlight on a central tube containing a heat-absorbing fluid -fluid reaches very high temps-> passes through heat exchanger, where it heats water and generates steam to turn a turbine to produce electricity -systems are large and expensive to build, so they are sited in desert areas w/ lots of sunshine
A fuel cell run on pure oxygen and hydrogen produces no
Waste products except drinkable water and radiant heat
Passive housing principles #6
Windows well positioned to let in daylight
Solar heat drives
Winds and the hydrologic cycle -all biomass, and fossil fuels and food, results from conversion of light energy (photons) into chemical bond energy by photosynthetic bacteria, algae, and plants
What is the largest geothermal region in the US
Yellowstone National Park
Solar city three options: #2
You lease your rooftop system from them, and get to use or sell any energy it captures
Solar city three options: #3
You pay up front and own the system and it's output -you own the array and can sell it with the house if you move
