Energy Part 4 Energy Conservation and Renewables Energy

Energy Part 4 Energy Conservation and Renewables

Energy Star n n n Joint program between the US EPA and the US DOE Mission: to protect the environment through energy-efficient products and practices Saved enough energy in 2005 equivalent to 23 million cars and $12 billion in utility bills

Corporate Average Fuel Economy (CAFE) Standards n n Average fuel economy (mpg) of a manufacturer’s passenger cars and light trucks Testing follows EPA guidelines Result in an estimated 55 billion gallons annually and 10% reduction in carbon emissions Achieved through better engine design, effciency, and weight reduction

Corporate Average Fuel Economy (CAFE) Standards n Improvements to CAFE standards could be achieved by expanding the standards to include: q q q Streamlining Reduced tire-rolling resistance Engine improvements (ex: hybrid technology) Optimized transmission improvements Transition to high voltage automotive electrical systems Preformance-based tax credits

Cars n Cars should q q q Drive at least 300 miles between refueling Be refueled quickly Keep up with other traffic on the road (no moped effect) Gas Hybrid Electric Pros Meets above standards Almost no pollution Cons Poor gas millage Pollution Limited range between charges

Hybrid Electric Vehicles Attempt to increase mpg n while overcoming the shortcomings of an electric car Parts of a gas-electric hybrid: n 1. 2. 3. 4. 5. Gasoline engine (smaller than gas only cars) Fuel tank Advanced electronics allow electric motor to act as a generator Generator acting only to produce electrical power Batteries to store energy

Types of hybrid electric vehicles n n n Parallel: Fuel tank supplies gas to the engine and batteries supply electricity to the electric motor Series: gasoline engine turns a generator which charges the batteries and/or power the electric motor; the gasoline engine never directly powers the car Plug-in electric: hybrid cars with an added battery; can be plugged into a 120 volt outlet and charged; run on stored energy for up to (60 miles per charge)

Alternative Fuels (LNG and CNG) n Natural Gas Vehicle (NGV) uses compressed natural gas (CNG) n In 2010 there were 12. 7 million natural gas vehicles world wide q q q Pakistan had the most with 2. 7 million Asia-Pacific region – 6. 8 million Latin America – 4. 2 million

Alternative Fuels (LNG and CNG) n n n CNG require high compression and thick walled tanks (adds cost and weight) CNG is cheaper than oil NGV corrode and wear the engine parts less rapidly than gasoline (500, 000 miles) on one engine is not uncommon Emissions are cleaner There is less wasted fuel

Electric Cars n Uses an electric motor and electrical energy stored in batteries n Popular in the late 19 th and early 20 th centuries but were replaced by internal combustion engines n Renewed interest in electric cars due to climate change

Electric Cars Pros n Significant reduction of urban air pollution n Reduced green house gasses n Less dependent on foreign oil Cons n More expensive than conventional vehicles q n n Due to cost of lithium-ion battery Lack of private and public recharging stations Driver fear of running out of energy before reaching a recharging station

Mass Transit n Types: q q Rail Bus services Subways Ferries n Often determines where people live and work n How much air pollution people are subject to n n n US – only 3% frequently use mass transit Japan – 47% Land availability determines is cities expand vertically (no land – NYC) or horizontally (have land – LA) q Determines preferred mode of travel

Mass Transit n Use rises with population density n Development of system determines efficiency of mass transit system n Most efficient method: promote a user-pay approach, where all external costs are factored into license fees and/or vehicle taxes

Types of mass transit n Light rail: trains that share space with road traffic and have own right-of-way and are separated from road traffic n Bus rapid transit: separate lanes, turnouts, signals, etc. for all busses

Types of mass transit - Car sharing n short-term car rentals q q q Not limited by office hours, reservations, pickup and return are self -service Can rent by hour or day Locations are distributed throughout service area Insurance and fuel costs are included in rates Near public transportation n n 30% of households participated in car sharing Help reduces congestion and pollution Reduces demand for parking spaces Only in high density areas

Types of Renewable Energy Wind Energy n n Solar Hydrogen Fuel Cells Biomass n n Ocean Waves and Tidal Energy Geothermal

Solar n n Collecting and harnessing radiant energy from the sun to provide heat and/or electricity Can be generated at home or in industrial settings q q q Photovoltaic cells Solar collectors Solar-thermal plant

Solar Collectors n Active: collects and uses sun’s energy to heat water or air inside a home or business n Passive: structure is built to maximize solar capture q Large south facing windows

Solar Pros n Supply of solar energy is limitless (for our purposes) n Reduces reliance on foreign imports n Only pollution is in the manufacture of collectors n Can store energy during the day and release it at night n Small systems have a low impact on the environment Cons n Inefficient where sunlight is limited or seasonal n Maintenance costs are high n Systems deteriorate and must be replaced periodically n Current efficiency is between 10% and 25% n Large systems can threaten wildlife – vaporize birds, etc.

Hydrogen n 9 million tons of hydrogen is produce in US each day q Could power n n n 20 – 30 million cars 5 – 8 million homes Used by industry q q q Refining Treating metals processing foods

Hydrogen Fuel Cell n Operates similar to a battery q q q Two electrodes and a cathode separated by a membrane Oxygen passes over one electrode and hydrogen over another Hydrogen reacts with a catalyst that converts H 2 gas Hydrogen ions combine with oxygen Electrons pass out of the battery

Hydrogen Fuel Cell Pros n Waste product is pure water n Ordinary water can be used to obtain hydrogen n Does not destroy wildlife and has minimal environmental impact n Energy to produce hydrogen could come from a fusion reactor, solar, or less polluting source n Hydrogen is easily transported through pipelines n Hydrogen can be stored in compounds to make it safe to handle Cons n Takes energy to produce hydrogen from water or methane n Changing from a current fossil fuel based system to hydrogen based would be very expensive n Hydrogen is an explosive gas n It is difficult to store hydrogen gas for personal cars

Biomass n Any carbon-based, biologically active fuel source q q q n Wood Manure Charcoal Biodiesel Methane ethanol Approximately 15% of world energy is derived from biomass q Burned in large incinerators as an energy source n n Most common in developing countries Suitable plants for growing biomass q q n Switch grass Hemp Corn Sugar cane Can be used for building materials, biodegradable plastics, and paper

Biomass Pros n Renewable as long as used sustainably n Can be sustainable (control for deforestation and erosion) n Could supply half of world’s energy demand n Biomass plantations can be located in less desirable locations to reduce soil erosion and restore degraded land n Crop residue are available as biomass n Ash can be collected and recycled n Reduces impact on landfills Cons n Requires adequate water and fertilizer n Use of inorganic fertilizers, pesticides, and herbicides would harm the environment n Corn diverted to ethanol production raises food prices n Could cause massive deforestation n Inefficient burning methods could increase air pollution n Expensive to transport n Not efficient (70% of energy lost as heat) n CO 2 production would have impact on climate change

Case Study - Biomass n n n Bagasse: the fibrous material that remains after sugarcane and sorghum stalks are crushed to extract the juice Used for biofuel, paper, and building materials 10 tons of sugar cane yields 3 tons of bagasse High moisture content (40 – 50%) makes it hard to use as a fuel Used widely in Brazil n n Using agricultural byproducts for paper off sets commercial forestry reduces rate of rain forest conversion to commercial tree farms Bagasse can be used to soak up oil spills and make disposable food containers, replacing styrofoam

Wind Energy n n The wind turns blades that turn a turbine to generate power Wind farms: clusters of wind turbines

Wind Energy Pros n All electrical needs of US could be met by wind from (ND, SD, and TX) n Can be built quickly and built on sea platforms n Maintenance is low and farms are automated n Moderate – high net energy yield n No pollution n Land underneath turbines can be used for agriculture Cons n Steady wind is required to make investment in wind farms economical – few suitable places n Back up systems need to be in place when wind is not blowing n Visual and noise pollution n Interfere with flight patterns of birds and bats – killing some n May interfere with communication such as TV and cell phone

Small-scale hydroelectric n n n Utilizes small turbines connected to submerged power generators to create electricity 100 k. W or less capacity Factors to consider q q q Amount of consistent water available Amount of drop between intake and output Regualtory issues

Small-scale hydroelectric Pros n No pollution n Does not impede stream flow n Does not stop fish migrations n Many economic incentives for installing, grants, loans, tax incentives Cons n Low energy out put n Suitable more for remote areas than large scale energy production

Ocean Waves and Tidal Energy n n n Uses natural movement of tides and waves to spin turbines Only a few in operation world wide Pros: q q q n No pollution Minimal environmental impact Moderate net-energy Cons: q q q Construction is expensive Few suitable sites Equipment can be damaged by storms or erosion

Geothermal n n Heat contained in underground rocks and fluids from magma, dry-rock zones, and warm-rock reservoirs produce pockets of warm water or wet or dry steam Steam drives a turbine engine Supplies less than 1% of world energy Known resources tend to follow tectonic plate boundaries

Geothermal Pros n Moderate net-energy yield n Limitless and reliable source if managed properly n Little air pollution n Completive cost Cons n Reservoir sites are scarce n Source can be depleted if not managed properly n Noise, odor, and land subsidence n Can degrade ecosystem due to corrosive, thermal, or saline waste

Relevant Law n Renewable Energy Law, China (2007): q q Requires power grid operators to purchase resources from registered renewable energy producers Offers financial incentives and discounted taxes and lending practices for renewable energy products Designed to help protect the environment, prevent energy shortages, and reduce dependence on imported energy Includes penalties for non compliance

n n n Case Study – Bloom Boxes Collection of solid oxide fuel cells that use liquid or gaseous hydrocarbons to generate electricity on site 20% of cost savings results from avoiding transfer cost over grid Used by e. Bay, Google, Staples, Wal-Mart, Coca -cola, and Bank of America