ENERGY1212.4 ENERGY CONSERVATION

12.5 ENERGY FROM BIOMASS

Prepared by:AIRA B. BELLEN

BSEd 3-P

• One of the best ways to avoid energy shortages and to relieve environmental and health effects of our current energy technologies is simply to use less.

• Our ways of using energy are so inefficient that most potential energy in fuel is lost as waste heat, becoming a form of environmental pollution.

• Conservation involves technology innovation as well as changes in behavior.

12.4 ENERGY CONSERVATION

• 1970s - Oil price shocks happened which led to rapid improvements in industrial and household energy use

• Energy intensity - amount of energy needed to provide goods and services

• Many improvements in domestic energy efficiency also have occurred in recent decades.

• Reducing air infiltration is usually the cheapest, quickest, and most effective way of saving energy because it is the largest source of losses in a typical house.

• Mechanical ventilation is needed to prevent moisture buildup in tightly sealed homes.

Green building can cut energy costs by half

• Innovations in “green” building have been stirring interest in both commercial and household construction.

• Elements of green building are evolving rapidly, but they include extra insulation in walls and roofs, coated windows to keep summer heat out and winter heat in, and recycled materials, which save energy in production.

• Several utilities are experimenting with smart metering , in which you get information not only on how much energy any particular appliance is using at a given time, but also the source of that energy and how much it costs.

• New houses can also be built with extra-thick, superinsulated walls and roofs.

• Improved industrial design has also cut our national energy budget.

• Cities can make surprising contributions to energy conservation

Cogeneration makes electricity from waste heat

• Cogeneration - the simultaneous production of both electricity and steam or hot water in the same plant

• As power plants became larger, dirtier, and less acceptable as neighbors, they were forced to move away from their customers.

• 1970s - Cogeneration had fallen to less than 5 percent of our power supplies, but interest in this technology is growing.

• Plants capture immense amounts of solar energy by storing it in the chemical bonds of plant cells.

• Firewood is probably our original fuel source.• For more than a billion people in developing

countries, burning biomass remains the principal energy source for heating and cooking.

• An estimated 1,500 m3 of fuelwood is gathered each year globally.

12.5 ENERGY FROM BIOMASS

• Charcoal - form in which wood is often sold in urban areas of developing countries.

• Wood gathering and charcoal burning - important causes of forest depletion in many rural areas—although commercial logging and conversion to farms and plantations are more rapid and widespread causes of forest loss globally.

• In developed countries, where we depend on fossil fuels for most energy, wood burning is a minor heat source.

• Inefficient burning in stoves and fireplaces makes wood burning an important source of air pollution, especially soot and hydrocarbons, in some areas.

• Biomass burning provides an important fuel source for many medium-sized power plants, which produce steam for both heating and electricity.

• Many of these plants burn waste material such as urban tree clippings, which makes them an efficient, local, carbon-neutral source of energy.

Ethanol and biodiesel can contribute to fuel supplies • Biofuels , ethanol and biodiesel - by far the biggest recent

news in biomass energy.• Globally, production of these two fuels is booming:

from Brazil (which uses sugarcane) to Southeast Asia (oil palm fruit) to the United States and Europe (corn, soybeans, rape seed).

In the United States, both farm policies and energy policies have promoted biofuel crops.

• 2007- a bill was passed in the US Congress w/c required a four-fold increase in ethanol production in which provided an enormous boon to corn growers in the Midwest, where falling corn prices have plagued farmers for decades

• This change is important because corn is a relatively low-efficiency source of biomass , but most research and development have focused, until recently, on corn.

• Small amounts of ethanol have been added to gasoline for years, because oxygen-rich ethanol molecules help gasoline burn (oxidize) more completely.

• Ethanol helps reduce carbon monoxide (CO) emissions, by converting it to carbon dioxide (CO2).

• Ethanol is made by adding yeast to a liquid mix of water and ground grain, then fermenting it to produce alcohol.

• Biodiesel- derived from organic oils; can be burned in normal diesel engines–can be much cheaper to produce than ethanol

because it requires no fermentation• Currently, most biodiesel is being made from either

soybeans or rape seed (Canola), which compete with food production, or from palm oil grown in the tropics where creation of new palm plantations is causing massive deforestation.

Grasses and algae could grow fuel

GRASSES• Perennial plants hold soil in place, unlike annual corn

crops, which leave fields bare for much of the year.Switchgrass is a perennial species, with deep roots that store carbon (and thus capture atmospheric greenhouse gases).Miscanthus x giganteus - a perennial grass from Asia; can produce at least five times as much dry biomass per hectare as corn

• Where using corn to replace 20 percent of U.S. gasoline consumption would take about 1/4 of all curent U.S. cropland out of food production, Miscanthus could produce the same amount on less than half that much area, and it wouldn’t need to be prime farm fields.

• Miscanthus can grow on marginal soil with far less fertilizer than corn need, and the fall Miscanthus moves nutrients into underground rhizomes - means that the standing stalks are almost entirely cellulose and next year’s crop needs very little fertilizer

• Some studies suggest that mixed fields of perennial, native grasses could provide biofuels and wildlife habitat at the same time, while switchgrass is a native plant, a monoculture of this one species is little different for wildlife than other monocultures.

• A study in Minnesota found that mixed prairie grasses provided a biomass yield, and potential ethanol yield, comparable to switchgrass but with more drought resistance, because in a mixed field, different species flourish under different weather conditions.

ALGAE• Algae could be an extremely efficient source of oil, or

biodiesel, although this source remains experimental. • Researchers have found strains of algae that grow

rapidly under hot and saline conditions, producing abundant lipids (oils) that could be converted to biodiesel.

• Algae could be grown with recycled water, in containment ponds or chambers built on land that cannot be farmed.

• Other potential sources of biomass which includes:–urban sewage–waste products from meat packing plants–orange peels from Florida citrus growers, and–sawdust from lumber mills

New plants built for these sources are among the more than 100 facilities now in development.

Effects on food and environment are uncertain• In developing countries, more than 50 % of

household income may be spent on food.• Gary Becker - a Nobel laureate in

economics, calculates that a 30% rise in food prices would reduce living standards in rich countries by about 3%; in developing countries, living standards would drop by 20%.

• Although ethanol and biodiesel are renewable fuels, they are not necessarily friendly to the environment, that depends on what kinds of plants are used and where they are grown.

• Algae or mixed prairie grasses could provide a sustainable, wildlife friendly feed source with almost no soil erosion or water pollution, but these fuel sources are still hypothetical and experimental.

• In many areas, biofuel production has led to intensive cropping on erodible soils, as well as rapid clearing of grasslands and forest for crop fields

• Fertilizer-intensive crops, including corn and sugarcane, also increase nutrient runoff in rivers.

• Water shortages are also a concern. – With current technology, 3 to 6 liters of water is

needed to produce 1 liter of ethanol. – In many farming states, there isn’t enough water

for both agriculture and food production. Plans for some new processing facilities have been scaled back because of water shortages

Methane from biomass is efficient and clean

• Methane gas, the main component of natural gas, is produced when anaerobic bacteria (bacteria living in an oxygen-free space) digest organic matter; main by-product of this digestion

• CH4 has no oxygen atoms because no oxygen was available in digestion, but this molecule oxidizes, or burns, easily, producing CO2 and H2O (water vapor)

• Consequently, methane is a clean, efficient fuel which today, as more cities struggle to manage urban sewage and feedlot manure, methane could be a rich source of energy.

• Methane is a promising resource, but...– is harder to store than liquid fuels like ethanol– low prices for natural gas and other fuels have reduced

incentives for building methane production systems• Concerns about greenhouse gases may lead to

further development, because methane is a powerful agent of atmospheric warming.

THANK YOU!