Waste Not Want

In the natural world, waste from one process provides nutrients for another. Nothing is wasted. The human world, however, functions quite differently. For example, most of the world's power plants convert heat to mechanical energy to electricity; in the process, about two thirds of the primary energy fed into

An Enduring Energy Future these plants is released into the environment as heat. In Europe, losses from power generation are so great that if they were captured and rerouted they could meet the region's heat demand through district heating. Heat is just one form of waste that could be captured to dramatically increase useful energy without burning more fossil fuels.48 A 2005 study by the U.S. Lawrence Berkeley National Laboratory examined 19 different technologies at various scales that can recover energy from waste heat, manure, food industry waste, landfill gas, wastewater, steam and gas pipeline pressure differentials, fuel pipeline leakages and flaring, and numerous other sources. In the United States alone they offer the technical potential to profitably generate almost 100,000 MWof electrical capacity—enough to provide about 19 percent of the nation's electricity in 2002— in addition to useful heat or steam.49

Around the world, some of these "wastes" are already being tapped. For example, combined heat and power is used widely in much of northern Europe, with Denmark, Finland, and Russia leading in the shares of national power production. Finland meets about half of its heating needs with district systems, mainly CHP plants. District Energy in the U.S. city of Saint Paul, Minnesota, provides electricity, heating, and cooling to its customers; 70 percent of its fuel is local wood waste.50

The world's petrochemical, glass, metal, and other heavy industries offer enormous potential for using waste heat through CHP and through capturing and reusing "cascading" heat for lower temperature uses. Mittal Steel, on the southern shore of Lake Michigan in the United States, captures high-temperature heat released from 250 ovens used to produce coke for its blast furnace; this heat energy, which was formerly vented, today produces 93 MW of electricity plus useful steam. As a result, Mittal saves $23 million and avoids 5 million tons of CO2 emissions annually.51

In China, energy-intensive industries account for almost half of energy use. Nearly 30 percent of large steel furnaces and most cement manufacturers in this country do not capture and reuse waste heat, so the savings potential is enormous. Thus China has been called the "Saudi Arabia of waste heat." A large Baosteel furnace uses waste heat to generate 192,000 kilowatt-hours of electricity a day, enough to meet the needs of more than 43,000 average Chinese. In eastern China, CHP plants are gradually replacing individual kilns and boilers to heat industrial parks and residential facilities clustered with factories.52

Anaerobic digesters decompose organic matter in the absence of oxygen to produce biogas for cooking or transport fuel or to generate electricity, as well as create high-quality compost for fertilizer. Biodigesters, fed primarily with animal manure, are widespread throughout India, Nepal, China, and Viet Nam and provide cheap fuel while reducing pollution and diseases caused by untreated waste. On a larger scale, dozens of municipalities in Sweden convert human sewage to biogas for transport fuel; biogas is also available as vehicle fuel in Austria, France, Germany, and Switzerland.53

Fats and waste oils can be converted into renewable diesel and jet fuel, which can be transported through existing pipelines. Anything that contains carbon, oxygen, and hydrogen—including construction debris, waste paper, plastic, wood, and lawn trimmings—can be turned into some form of motor fuel today, which has the added benefit of extending the life of landfills. The challenge for many of these technologies is obtaining the capital to scale up and commercialize.54

While still in the early stages of develop

An Enduring Energy Future ment, algae can convert as much as 80 percent of the CO2 released from coal and natural-gas-fired power plants into biomass. Algae can be used in power plants as fuel or converted into bioethanol, biodiesel, or biogas and provide high-protein feed for livestock and aquaculture. It can grow in polluted or salt water, on nonarable land, or at wastewater treatment facilities. It requires far less water than most biofuel crops, produces several times the biofuels per hectare, and can be productive even in desert regions. Harvesting and processing algae is an energy-intensive process, but it offers the potential to "burn carbon twice"— providing additional energy for each unit of CO2 emitted and an alternative to long-term physical storage of carbon dioxide.55

Using energy more efficiently can reduce emissions even further. For example, lighting accounts for 19 percent of world electricity consumption, yet technologies available today, including compact fluorescent lamps and light-emitting diodes, could halve electricity use for lighting. Realistically, it is feasible to eliminate at least one third of global electricity consumption for lighting simply by changing lightbulbs—saving money and avoiding about 450 million tons of CO2 in the process. By reducing waste in the production and use of energy, more energy services can be provided with lower carbon dioxide emissions.56

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

Get My Free Ebook

Post a comment