Plant Biofuels and Green Technologies: Hope or Hype?

Announcements

• Final exam is approaching, covering primarily Unit III, Lectures 19-27.
• Course evaluations can be accessed at: https://courseexp.umd.edu/
• USBG paper assignment is due soon.

Biofuels and Green Technologies

• Introduction to biofuels: Discussion of fossil fuels and their environmental impact.
• Greenhouse effect and global warming: Examination of causes, consequences, and potential solutions.
• Common plants used for biofuels:
  • Bioethanol: Corn, sugar cane, switchgrass
  • Biodiesel: Soybean
• Green Technologies: Overview of green roofs, green walls, and green buildings, with the WaterShed House as an example.
• Food Waste: Consideration of the prevalence and implications of food waste in today’s society.

What are Biofuels?

• Biofuel: Fuel containing energy from recent photosynthesis.
• Renewable fuels produced from living organisms, contrasting with fossil fuels.
• The need for alternative fuels is emphasized.

Fossil Fuels

• Organic substances from underground deposits, formed in previous geologic periods from plants and animals, and are used as energy sources.
• Coal: Formed from Carboniferous Period; plant material did not decompose due to lack of oxygen, forming peat and eventually coal with heat.
• Oil and natural gas: Liquid and gaseous forms of fossil fuels.

Fossil Fuel Particles

• Burning fossil fuels releases particles into the atmosphere:
  • Sulfur dioxide ($SO_2$) - From burning coal.
  • Carbon monoxide ($CO$) - About 10% from fires, cars, and human sources.
  • Nitrogen oxides ($N_2O$) - From cars and power plants that burn fossil fuels.
  • Hydrocarbons (C$-$H) - 80% from natural sources, about 20% from cars.

The Need for Alternatives to Petroleum

• 130 billion gallons of fuels are needed globally for transportation.
• Gasoline and diesel are the most commonly used fuels, with existing infrastructure and benefits.
• 2019: The US used 142 billion gallons of gasoline
• Need for alternatives due to:
  • Limited supply of petroleum (oil production has peaked).
  • Energy security concerns related to imported oil.
  • Economic issues related to supply and demand.
  • Environmental issues, including greenhouse gases and spills.

Burning Fossil Fuels: Acid Rain

• Burning fossil fuels has negative environmental consequences:
  • Acid rain: Acidic deposition near areas with major emissions of sulfur dioxide and nitrogen oxides.
  • In the atmosphere, these react with oxygen and water to form sulfuric acid and nitric acid.
  • Effects: Changes the pH of soil and water, damaging plants and animals.

Acid Rain Formation

• Sulfur dioxide ($SO_2$) and Nitrogen oxide ($NO$).
• React with water ($H_2O$) through oxidation.
• $NO + H<em>2O ">" Nitric Acid (HNO</em>3)$
• SO2 + H2O ">" Sulfuric Acid (H2SO2)
• Results in acid particles and gases, leading to acid snow and acid rain.

Global Climate Change

• The most pressing environmental problem.
• Causes: Greenhouse effect, where carbon dioxide and other greenhouse gases (nitrogen oxides, ozone, CFCs, and methane) are released into the atmosphere from human activities.
• These gases trap infrared light, preventing heat from dispersing into space, thus trapping heat in the Earth’s atmosphere.

Greenhouse Gases

• Tropospheric warming percentages attributed to various gases (Hansen et al., 1989):
  • Carbon Dioxide: Significant percentage
  • CFCs, Methane, Ozone, Nitrous Oxide: Other contributors to warming.

Petroleum-Based Fuels and $CO_2$

• Petroleum-based fuels used in transportation release $CO_2$.

Greenhouse Effect Analogy

• Like leaving car windows closed in the summer sun, creating an oven-like effect.
• Carbon dioxide is a trace gas, less than 1% in the atmosphere.
• Result of respiration; plant photosynthesis helps remove it.
• The amount of carbon dioxide has been increasing in the past 200 years.

Increasing $CO_2$ Levels

• Levels of $CO_2$ are increasing worldwide (25% increase in 150 years).
• Atmospheric carbon dioxide at Mauna Loa Observatory, Hawaii (C.D. Keeling).

Seasonal $CO_2$ Fluctuations

• Seasonal variations in $CO_2$ levels are observed.

Reasons for Increasing $CO_2$

• Two main reasons:
  • Burning of fossil fuels releases excessive amounts of $CO_2$.
  • Deforestation removes trees which help to remove $CO<em>2$ through photosynthesis, resulting in more $CO</em>2$ in the atmosphere.

Effects of Increased $CO_2$

• By 2030, doubling of atmospheric $CO_2$ is projected, resulting in global warming.
• Approximately 3 to 8°F temperature increase in the next 100 years.
• 1997 and 1998 were the warmest year of the century and millennium, respectively.
• 2003 European heat wave resulted in 19,000 deaths; 2005 was the hottest year on record.
• Warmer waters expand, and ice melts, leading to a rise in sea levels, affecting South Pacific islands.
• Increases in the severity and frequency of storms in coastal areas.

Global Warming Trends

• Average global temperature increase from 1880-2004.
• Hottest years on record include 1998, 2002, 2003, 2001, and 1997.

Effects of Global Warming

• Expanding deserts in the interior of continents.
• Loss of water resources.
• Loss of species diversity.
• Changes in agriculture due to environmental change.
• Humans in coastal or drought areas becoming environmental refugees.
• Increase in tropical diseases.

Solutions to Climate Change

• Nations must cut back on emissions.
• Develop alternative, non-polluting energy resources (solar, hydrogen, wind).
• Planting more trees, reforestation.
• Develop energy-efficient products and conserve energy (compact fluorescent, LED bulbs, hybrid cars).
• Reduce automobile use, develop mass transit.
• Involve developing nations in global climate change efforts (Kyoto Protocol).

Fossil Fuel Solutions?

• Conserve existing resources.
• Find alternatives to fossil fuels: electric, hydrogen, ethanol, biodiesels.

Types of Plant Biofuels

• Two main types:
  • Bioethanol: Alcohol made by fermentation of sugars or starches, mainly from corn, sugar cane, or cellulosic biomass.
  • Biodiesels: Plant vegetable oils modified to produce diesel.

Bioethanol Production

• Grain (corn starch) -> Enzymes -> Glucose -> Fermentation -> Distillation -> Bioethanol + $CO_2$

Ethanol as Fuel

• 69% energy content of gasoline on a per-volume basis.
• High octane rating (105 vs 87) - compressible - Higher energy utilization (90%).
• Low vapor pressure – Works best in a blend.
  • E10: Suitable for all vehicles.
  • E85: For flex-fuel vehicles.
• Corrosive to aluminum and hygroscopic.

Ethanol from Corn

• Ethanol production process releases $CO_2$

Corn Ethanol Biofuel

• Pros: May reduce greenhouse gas emissions from fossil fuels and less reliance on foreign oil.
• Cons: May increase prices and affect corn consumption as food. Energy inefficient due to high input of water, fertilizers, and fossil fuels.
• Approximately 1 gallon of oil used = 1.2 gallons of ethanol produced.

Corn Ethanol Inefficiency

• Production requires lots of energy, water, and fertilizer and releases $CO_2$.

Sugar Cane Ethanol

• Pros: Yields more ethanol per ton; requires less energy to produce (1 gallon of fossil fuel = 8 gallons of ethanol).
• Cons: Limited to hot, wet, tropical climates. Ethanol does not transport well.

Cellulosic Ethanol

• Made from breaking down farm waste, wood chips, and non-food grasses, like switchgrass.
• Pros: Does not require use of cropland; enzymes are needed to break down tough cellulose.
• Cons: Costly and difficult to make, energy intensive. Better cellulose-digesting enzymes are needed to break down materials faster and more efficiently.
• Saccharophagus degradans: Bacteria that produces useful enzymes for this process.

Switchgrass

• Perennial grass native to North America.
• Researched as a bioenergy crop due to:
  • Grows well in marginal lands.
  • Provides high yields of biomass with low input of water, fertilizers, etc.
  • Low energy to produce, high energy output (1:20).

Bacterial Enzymes

• Help break down complex molecules but are currently too slow, specialized, sensitive to inhibitors, and expensive to produce.
• Used on waste paper, agricultural wastes (wheat straw, corn), processing wastes, and energy crops (switchgrass).

Biodiesels

• Soybean and canola vegetable oils can be made into biodiesels.
• Pros: Can provide up to 90% more energy than is required to produce it and can cut greenhouse emissions by up to 40%.
• Cons: Can boost up prices of soybean and other oil plants. Replanting rainforests with palm oil plantations has detrimental environmental effects.

Green Algae

• Algae can grow fast and produce up to 30 times more energy per acre than other biofuels.
• May be a great solution for future biofuel production.
• Biofuels: No single solution; more research needed.

Green Technologies: Sustainable Architecture

• Sustainable architecture reduces the negative environmental impact of buildings.
• Focus on efficiency of design, materials, and space.
• Two interesting ways plants are used: green walls and green roofs.

Green Walls

• Covered with plants, growing soil, and a watering system.
• Function: To reduce the temperature of the building by trapping heat.
• Also used for water reuse and absorption.
• Sometimes produce edible fruits or seeds.

Green Roofs

• A living system on top of houses and buildings.
• Roof covered with plants and a growing medium over a waterproof membrane.
• Function of green roofs:
  • Absorb rainwater.
  • Provide insulation.
  • Absorb heat and pollutants.
  • Provide habitats for wildlife.
  • Reduce energy usage (26%).

Solar Decathlon

• International competition challenging colleges to design and build the most attractive, energy-efficient solar-powered house.
• University of Maryland team won the 2011 competition with the WaterShed House.
• Virtual Tour of the sustainable WaterShed House.

WaterShed House Virtual Tour

• Quiz on a virtual tour of the WaterShed Solar House focuses on sustainability issues and the technology used to make this living space.
• Virtual tour link: http://explorer360.org/spheres/md/watershed/demo10.html

Food Waste

• Approximately 30% of food is wasted and/or lost.
• Food loss occurs at production, harvest, transport, and processing.
• Waste occurs at supermarkets, restaurants, and the consumer level.
• About 2.8 trillion lbs. of food wasted – a grave environmental issue, since it takes so much energy and resources to grow such food.

Preventing Food Waste at the Store

• Buy “ugly” produce.
• Shop smart and realistically - plan and buy what you’ll need and use.
• Buy frozen produce to reduce waste.
• Shop often and buy what you need.
• Buy fresh from local farmers' markets.

Reducing Waste at Home

• Don’t cook massive portions – save and eat leftovers, keep track of wasted food.
• Store food right.
• Donate extra produce.
• Freeze or can extras, blend into smoothies!
• FoodKeeper app.
• Compost extra food.

Reducing Waste at a Restaurant

• Skip cafeteria trays: will waste 32% more food than if you carry a single plate at a time.
• Take home leftovers.
• Share side dishes.
• Hold on extras, like bread or butter, if you are not going to eat them.
• Encourage restaurants or cafeterias to donate leftovers.

Reducing Food Waste in Your Community

• Businesses, schools, governments, etc., can find ways to waste less food:
  • Teaching others about this.
  • Joining USDA Food Waste Challenge.
  • Food scrap collection programs.
  • Share your garden’s produce bounty: ampleharvest.org, Food Pantries, etc.

Community Garden Ideas

• Donations to UMD Food Pantry?
• Donation to cleaning staff workers?
• Provide produce to community organizations?
• Donate to a Food Co-op?

Ten Life Lessons from Plants

• Embrace humble beginnings: the biggest tree always starts as a tiny seed.
• Have strong roots and never forget them; strong roots allow trees to survive the toughest storms.
• Plants have good defenses (thorns, allergenic or toxic compounds); plants know how to defend themselves.
• Plants under stress and challenge from the environment grow stronger; plants without any challenges grow very weak and flimsy.
• Always look for the light!
• Adapt to the seasons.
• A tree in winter may look dead, but it will come alive in spring!
• Plants don’t let their circumstances define them.
• Plants are persistent (weeds or dandelions).
• Be like bamboo: Strong, but flexible!