Ebio Exam #4

Challenges to Commercialization

Development of algal biomass production technology is in its infancy Algal biofuels are not economical to produce using the technology avaliable today Based on conservative estimates, algal biofuels produced in large volumes with current technology would cost more than $8 per gallon (in contrast to $4 per gallon for soybean oil today) R&D are needed to reduce costs- who pays for this?

Fuel

Material such as coal, gas, or oil that is burned to produce heat or power

Solar Energy Technology (types)

Photovoltaics (PV) Concentrating (CSP)

Cellulosic Ethanol

The sugars in cellulosic material are harder to release than sugars contained in starchy biomass The complicate matters, the process of releasing sugars from cellulosic material produces byproducts that inhibit fermentation Therefore, some of the sugars from cellulosic biomass are difficult to ferment Because of these reasons, cellulosic ethanol production is complicated and expensive In order to make cellulosic ethanol cost competitive (cheaper), NREL has been leading the way with research and development R&D at NREL is looking at both biochemical (chemical, enzymes, and fermentative organisms) and thermochemical (heat and chemical) processes Looking at heat and chemicals to get what they want from feedstocks Snake eating its tail

Benefits of biomass

The use of biomass energy has the potential to greatly reduce greenhouse gas emissions

Pumped Storage Power

When the demand for electricity is very low, a pumped storage facility stores energy by pumping water from a power reservoir to upper reservoir During periods of high electrical demand Water is released back to lower... Taum Sauk in Missouri

Impoundment continued

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1 kilowatt hour can allow you

1200 electric shaves (>3 years) dry your hair 15 times listen to 15 CDs use a small refrigerator for 24 hours microwave 20 meals 4 evenings of light with a a 60W incandescent lamps

Hydropower

30% of 9%= 2.7% of entire portfolio Electricity generated using the energy in moving water Streams Rivers Almost 1/5 globally of the world's electricity Widely used in China Russia US Canada One of the oldest sources of energy and has been exploited for centuries (grissmills, saw mills, transportation)

What is a Kilowatt Hour (KWh)

A KWh is a unit of electricity When you buy electricity they charge you by the kilowatt-hour When you use 1000 watts for 1 hour, that's one kilowatt-hour KWh= watts x time(inhours)/1000

CSP Dish/engine

A dish stirling system uses a much different technology than other concentrating technologies It does not use water or steam except for a very small amount to wash the concentrators System still falls under CSP... Components: Parabolic concentrator A solar receiver (dish) Stirling engine

Diversion Hydroelectric

A diversion sometimes called run-of-river, facility channels a portion of a river through a canal Usually without the use of a damn Anchorage Alaska

Biofuel

A fuel derived directly from living matter

Transesterification

A reaction of the oil with an alcohol to remove the glycerin

Recent news in Solar Energy

According to the Solar Energy Industries Association, photovoltaic installations continued to proliferate, increasing 41% over 2012 to reach 4,7251 MW Solar was the second-largest source of new electricity generating capacity in the U.S., exceeded only by natural gas The cost to install solar fell throughout the year, with average system prices ending the year 15% below the set mark The U.S. Solar market showed the first real glimpse of its path toward mainstream status in 2013 The combination of rapid customer adoption, grassroots support for solar, improved financing terms

Hemicellulose

Also a polysaccharide found in plant cell walls but is less complex than cellulose

Large Hydropower plant

Although definitions vary, DOE defines large hydropower as facilities that have a capacity of more than 30 megawatts

Photovoltaics

Are a method for generating electric power by using solar cells to convert energy from the sun into a flow of electrons Photons of light excite electrons into a higher state of energy, allowing them to act as charge carries for an electric current Electricity is moving electrons Photo cells are made of special materials called semiconductors, such as silicon, which is used most commonly When light strikes the solar cell, a certain portion of the light is absorbed within the semiconductor material This means that the energy of the absorbed light is transferred to the semiconductor The energy knocks electrons out of their electron "shells", allowing them to flow freely Blue wavelengths are very good at knocking electrons out of orbit in silicon

Dead Zones

Areas of the oceans, rivers, or lakes where oxygen in bottom water (or water on the sea floor/river bed) is very low- so low that the water cannot sustain life The creation of dead zones is the interplay between nutrient loading to a river (which creates eutrophication), bacterial break down of increased organic matter (the more nutrients you have the more phytoplankton it can support) AND decreased water movement (restricted flow) If water flow is restricted then the water that lacks oxygen is not being replaced by water with dissolved oxygen

Diffuse vs. Direct solar radiation

As sunlight passes through the atmosphere, some of it is absorbed, scattered, and reflected by: Air molecules Water Vapor Clouds Dust Pollution Forest fires Volcanoes This is called diffuse solar radiation The solar radiation that reaches the Earth's surface without being diffused is called DIRECT BEAM SOLAR RADIATION The sum of the diffuse and direct solar radiation is called GLOBAL SOLAR RADIATION Atmospheric conditions can reduce direct beam radiation by 10% on a clear day, dry days and by 100% during thick, cloudy days

Biodiesel Basics

Biodiesel contains no petroleum but it can be blended (like ethanol) with petroleum It can also be blended with ethanol It can be used in diesel engines with little or no modifications It is simple to use, biodegradable, nontoxic, sulfur free and renewable Biodiesel is made from vegetable oil, animal fat, or waste grease Biodiesel is not just raw vegetable oil- it goes through a refinery process called transesterification Most biodiesel produced at present is produced from waste vegetable oil sourced from restaurants, chip manufacturers, industrial food producers such as Birdseye Though oil straight from the agricultural industry represents the greatest potential source it is not being produced commercially simply because the raw oil is too expensive However, waste vegetable oil can often be sourced for free and then refined pretty inexpensively

Benefits of Biodiesel

Biodiesel is 'carbon neutral' - this means that the fuel produces no net output CO2 This effect occurs because when the oil crop grows it absorbs the same amount of CO2 as is released when the fuel is combusted Rapidly biodegradable and completely non-toxic, meaning spillages represent far less of risk than fossil diesel spillages Has a high flash point than fossil diesel in the event of a crash

Burning biomass

Burning biomass releases about the same amount of carbon dioxide as burning fossil fuels However, fossil fuels release carbon dioxide captured by plants millions of years ago An essentially "new" greenhouse has to our modern atmosphere Biomass, on the other had releases CO2 that is largely balanced by the CO2 captured in its own growth

Concentrating Solar Power (CSP)

CSP systems use mirrors or lenses to concentrate a large area of sunlight, onto a small area Electrical power is produced wen the concentrated light is converted to heat, which drives a steam turbine connected to an electrical power generator Three types of systems- Linear concentrator Power tower systems Sterling Engine

Biomass continued

Can be used for fuels, power production, and to make products that would otherwise be made from fossil fuels Many products, such as plastics and chemicals, that are typically made with petroleum, can be made with biofuels

CSP continued (dish)

Concentrated sunlight (800 times normal) heats a working fluid in contact with the receiver to a temperature of approx. 650 degrees C The thermal energy causes a cylinder piston engine to oscillate back and forth at 50 or 60 cycles per second The piston moves a magnet back and forth inside a coil of wire which generates an AC current

Fermentation

During fermentation, microorganisms (primarily fungi and bacteria) convert the sugars in biomass to ethanol Under ideal conditions, these "bugs" will work contentedly, consuming sugars and producing ethanol and other products But conditions in a cellulosic ethanol biorefinery are anything but ideal The hot soup= called hydrolyzate= generated after pretreatment and hydrolysis contains not only fermentable sugars, but also compounds (such as acetic acid) that are toxic to the bugs Other things that are toxic in the process and hydrolyzate are a high-solids concentration and a rising ethanol concentration Because microorganisms found in nature do not function well in this hostile environment, NREL is creating "super-bugs" that thrive in it NREL also pioneered the use of a yeast alternative, the bacterium Zymomonas Mobilis (Zymo). Zymo gives a high ethanol yield and tolerate high ethanol concentrations Using genetic and metabolic engineering, NREL developed acetic acid-tolerant Zymo strains as well ZYMO-BACTERIA

Ethanol Basics

Ethanol is pure alcohol It is produced by fermenting sugars, just like other types of alcohol we drink, with yeast Common feedstocks used to make ethanol include corn and sugar cane: -The term feedstock refers to whatever plant matter is being converted to fuel

Cons of hydropower (environmental)

Extensive submersion of lands upstream of dam Reduces flow downstream result in less habitat for aquatic wildlife Fishes, like salmon, who swim upstream to spawn have less habitat or are blocked completely from their journeys; some fishes are killed in the turbines Don't spawn Fish ladders: area to avoid going through the dam Increased erosion downstream, you have a long skinny river with V sides, drop level of water, then naked banks, no plants= erosion Create oxygen deprived "dead zones" Side note: Hydropower has decreased from 34 to 30 percent Submersion of Dry land: Merowe Dam on the Nile river in Dar al-Manasir, Nubia- Northern Sudan

Small Hyrdopower plant

Facilities that have a capacity of 100 killowatts to 30 megawatts

Pros of hydropower

Flexibility: Hydropower is a flexible source of electricity since plants can be ramped up and down very quickly to adapt to changing energy demands Hydoelectric plants have long economic lives, with some plants still in service after 50-100 years Serves multiple purposes: added with relatively low construction cost proving a useful revenue stream Low power costs elimination of the cost of fuel does not change with the price of fossil fuels The avg cost of electricity from a hydro plant larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour Reduces CO2 emission Other uses of the reservoir

Micro Hydropower

Has a capacity of up to 100 kilowatts A small or micro-hydroelectric power system can produce enough electricity for a home, ranch, farm

Thermochemical

Heat and chemicals are used to break biomass into syngas (CO and H2) and reassemble it into products such as ethanol This method is particularly important because up to 1/3 of cellulosic biomass- the lignin-rich parts- cannot be easily converted biochemically MUCH MORE COMPLEX Biomass is converted into syngas, and syngas is converted into an ethanol-rich mixture However, singes created from biomass is not "clean"- it contains contaminants such as tar and sulfur that interfere with the conversion of sygnas into products NREL has developed tar-reforming catalysts and catalytic reforming processes that can covert ip to 97% of tar into more syngas This not only cleans the syngas, it also creates more of it, improving process economics and ultimately cutting the cost of the resulting ethanol

Other uses of Solar Power

Heating your home South facing windows allow sun to come into your home where it is absorbed by special material in the floor As the sun goes down, heat is released from the floor into your home Solar hot water heating- widley used in Greece Turkey Israel Australia Japan Austria China

Types of Hydroelectric Power Plants

Impoundment Diversion Pumped Storage

Benefits...

In the near future- and with NREL- developed technology- agricultural residues such as corn stover (the stalks, leaves, and husks of the plant) and wheat straw will also be used Long-term plans include growing and using dedicated energy crops, such as fast-growing trees and grasses and algae These feedstocks can grow sustainability on land that will not support intensive food crops

History of hydropower

It was used thousands of years ago to turn a paddle wheel for purposes such as grinding grain A water wheel picks up the flowing water in and the.... Late 19th century= became a great source for generating electricity 1881- Niagara falls 1882- The world's first hydro electric dan was built across the Fox River in Appleton, Wisconsin Potential exists where ever is moving water Best states; Washington Oregon California Montana New York Biggest hyrdoplant in the U.S.: Located at the Grand Coulee Damn on the Columbia River in Northern Washington 6809 MW capacity Bad for the Salmon World's Largest Hyrdoelectric damn: Three Gorges Damn on the Yangtze River 21,000 MW installed capacity HUGE ENVIRONMENTAL ISSUES

Largest Solar energy Plant in the World

Ivanpah Solar Electric Generating System Located in the Mojave Desert, just inside southeastern California near the border with Nevada Project cost 2.2 billion 400-megawatt covering 5 square miles Concentrating Solar Power

Energy Density- Let's get compared Apples to Apples

LOOK AT POWERPOINT

Environmental Concerns

Land use: Utility-scale solar energy requires large amounts of land Unlike wind, there are far few opportunities for solar energy to share space with agriculture We might be able to site them in Brownfields Abandoned mining land Existing transportation Transmission corridors Rocky flats= un-used because of radioactive emissions in the soil, when we were enriching plutonium by making nuclear weapons We capped it off with cement Water use: PV requires water for manufacturing CSP uses large amounts of water Considering the best solar resources in the US coincided with our most arid regions water use is a concern Hazardous Materials: PV thin films use even more toxic chemicals including gallium....

Closed carbon cycle

Many biomass energy sources have a "closed" carbon cycle- the carbon dioxide released during burning is taken up by the next "crop" of whatever is growing (80%) not (100%) 1. Atmospheric carbon dioxide 2. Connected into new plant material through photo 3. Which is harvested and burned 4. Carbon released back into the atmosphere

Impoundment

Most damns in the U.S. are not hydroelectric power plants Impoundment facilities are the most common type of hydroelectric power plants A typical hydro plant has three parts....

BPI contiuned

NREL shown that high-solids operation- using a high ratio of biomass to water in the biorefining process- is one key to cutting ethanol costs The less water introduced in the pretreatment step the higher the potential sugar concentration and the less equipment and energy the process requires The result is lower-cost ethanol In a perfect world that would be enough, but high solids concentration can create problems elsewhere in the process (REMEMBER HIGH SOLIDS CAN BE TOXIC TO THE BUGS) Process integration is ongoing effort, figuring out what does and doesn't work in terms of creating the most ethanol for the least amount of money

Algal Biodiesel

Phytoplankton Numerous algal strains are made up of 50% lipids- 50% of their biomass is fat Chlamydomonas- Green unicellular algae, NOT A BACTERIA OR A PLANT ALGAE- PROTISTS The development of biofuels from traditional oil crops and waste cooking oil/fats cannot realistically meet the demand for transportation fuels If the entire 2007 US soybean oil yield, representing almost 3 billion gallons produced on 63.3 million acres of farm land were converted to biofuel it would replace only about 4.5% of the total petroleum diesel (-66 billion gallons) If that much land were used to cultivate algae, the resulting oil could (conservative projection) would replace, approx. 61% of the petroleum diesel used annually, as well as capturing approx 2 billion tons of CO2 in biomass Microalgae, as distinct from seaweed or macroalgae, can potentially produce 100 times more oil per acre than soybeans- or any other terrestrial oil-producing crop Non-competitive with Agriculture: Deserts, non-arable land Flexible on Water Quality: Fresh and Shit Mitigation of CO2 Broad Product Portfolio: The lipids produced by algae can be used to produce a range of biofuels, and the remaining biomass residue has a variety of useful applications: Combust to generate heat Use in anaerobic digesters to produce methane Use as a fermentation feedstock in the production of ethanol Use in value-added byproducts, such as animal feed

Enzymatic Hydrolysis

Plants have evolved over several hundred million years to be recalcitrant- resistant to attacks from the likes of bacteria, fungi, insects, and extreme weather Breaking down plants is no easy task For cellulosic ethanol production the primary challenge is breaking down (hydrolyzing) cellulose into its component sugars NREL is exploring the causes of biomass recalcitrance and ways to overcome it using different types of cellulase (enzymes that break down cellulose) The goals are to maximize the conversion of cellulose to sugar, accelerate the rate of conversion, and use fewer, cheaper enzymes Cellulose breaks down by cellulase To make contact with cellulose, the enzymes must get past a complex maze of plant structures. NREL is mapping this this labyrinth of plant structures as a first step toward overcoming it Microscopy tools and techniques in NREL's new Biomass Surface Characterization Laboratory enables researchers to image plant structures down to the molecular level Once cellulase makes contact with cellulose, the real work beings Howver cellulases act very slowly, this is why dead trees take years to decompose in the forest The most active known cellulases are derived from fungi NREL is conducting R&D on a cocktail of enzymes

Solar Energy benefits

Solar energy is an inexhaustible source of energy and is often noise free The sun can provide electricity in remote locations that are not linked to a national grid Space, where satellites are powered by high efficiency solar cells Solar panels can be installed on top of many rooftops, which eliminates the problem of finding the required space for solar panel placement

Solar Energy basics

Solar energy technologies produce electricity from the energy of the sun The amount of solar radiation that reaches any one spot on the Earth's surface varies according to: Cloud coverage Time of day Shade due to certain surroundings Seasons Latitude Pollution Particulates Water vapor Geographic location Altitude (suns rays are more direct in Colorado then Ohio)

Solar Energy Barriers to Deployment

Solar technologies are very expensive and require an enormous amount of land area to collect the sun's energy at rates useful to lots of people Although, price is coming down Solar energy doesn't work at night without a storage device such as a battery Pollution can be a con for solar energy, as pollution levels can affect a solar cells...

EB continued

Technological breakthroughs are allowing us to convert other types of plant material to ethanol Other types of plant material that can be used to make ethanol include corn stover (everything but the corn kernels), wheat straw, wood chips and switchgrass

Tower Power

The centralized receiver is located in the upper section of the tower The receiver heats water and delivers saturated steam at 250...

Biomass energy

The energy from plants and plant-derived materials Wood is the largest biomass energy resource Other types of biomass (type of biofuel) include food crops, grassy and woody plants and the fumes from landfills (which are methane, a natural gas), trash, grain spoils, yard waste

Cellulose

The major component in the rigid cell walls in plants It's linear polysaccharide polymer with many glucose monosaccharide units Basically a complex carbohydrate (sugar) Most abundant renewable carbon source on earth

EB 2 continued

The ratio of fossil fuel in and ethanol out of corn ethanol is about 1:1.3- which means that the net energy in corn ethanol is only slightly positive However the ratio of fossil fuel in and ethanol out from cellulosic ethanol can be as a high as 1:10

Lignin

The stuff that binds plant cells together in woody plants

What are biofuels?

The term refers to liquid fuel derived from biomass These liquid fuels are almost exclusively used for transportation and include: -Ethanol -Biodiesel

Benefits of biomass continued

The use of biomass can reduce dependence of foreign oil because biofuels are the only renewable liquid transportation fuels available Biomass energy supports U.S. agricultural and forest-product industries The main biomass feedstocks for power and paper mill residue, lumber mill scrap, and municipal waste For biomass fuels, the most common feedstocks used today are corn grain (for ethanol) and soybeans (for biodiesel)

Pretreatment

To break down cellulose- the primary source of sugar in fibrous biomass- you have to first get past hemicellulose and lignin, which surround the cellulose in a protective sheath

Biochemical Process Integration

To produce low-cost ethanol, biorefineries will need to link the refining steps into an integrated process However optimizing conditions in one step of the process can influence performance in other steps The challenge is to find the right combination of tradeoffs to find the right optimization

CSP Tower Systems

Tower systems have three main components; Ground heliostats Central receiver Tower Heliostat (Greek name helios which means sun).... Light is electromagnetic radiation, travels on waves, vacuum, through out space Also Heliostats track with the sun, sending wave lengths back to receiver

NREAL pretreatment

Typically uses a moderately high-temperature, high-pressure dilute acid pretreatment process to break down (hydrolyze) hemicellulose and disrupt or dissolve lignin NREL is also conducting research on potentially cheaper pretreatment methods including enzymes that enable milder pretreatment conditions NOT CHEAP

Hydropower is a...

asymptote, meaning everything that could be installed has already been installed We can retrofit them but no more to put in

Basics in hydropower

can provide base load power Base load power- the mim amount of power that a utility or distribution company must make available to its customers, or the amount of power required the min...

CSP Linear Concentrator

collectors capture the sun's energy with large mirrors that reflect and focus the sunlight onto a receiver tube Parabolic trough is a type of CSP linear concentrator system Kramer Junction uses this The receiver is a tube positioned directly above the middle of the parabolic mirror and filled with a working fluid The reflector follows the sun during the daylight hours by tracking along a single axis A working fluid (e.g. molten salt) is heated to over 900 degrees F as it flows through the receiver...