Ch. 20 Sustainable Energy

CH. 20 SUSTAINABLE

ENERGY

Matt ShillerMike Tarantino

Case Study: Sea Power The US had plans to

start build one off the coast of Cape Cod, MA. This project has been stalled for several years now due to people concerned over property value decreasing as well as marine life and the fishing industry.http://i.telegraph.co.uk/multimedia/

archive/01209/WindFarm_1209799c.jpg

Conservation Most of the energy we consume is wasted in the

form of heat. Not necessarily because of us, but mostly because

of the technology we use. Several European nations have higher standards

of living, yet use 30-50 percent less heat then us.

Conservation - lighting One technology that is

wasting energy is our ways of lighting

Florescent light bulbs produce 4 times as much light at the same wattage and last 10 times longer than incandescent bulbs

Light Emitting Diodes (LED’s) consume 90% less energy, and last a lot longer than ordinary bulbs.

Conservation - Insulation Energy losses can be

reduced by ½ to ¾ through better insulation

Double or triple glazing windows

Thermally efficient window coverings

Sealing cracks and loose joints

Cheapest way of saving energy.

Conservation - Appliances From 2001 to 2007, washing machines

will use 35% less water. This will cut water use by 10.5 trillion gallons (40 trillion liters) per year. Also saves about 4 times as much electricity per year as is used to light homes. This adds $240 to the price, but will back in about 7 years.

Air conditioners since 2001 have been required to be about 20% more efficient.

Conservation – Natural insulation Sod roofing. Good

insulation and protection from weather.

Straw bales are good for insulation and is cheap and easy to replace. However not as waterproof.

Conservation – Turn Off Stuff Unplug your devices when

your not using them. Even if they are off they are still drawing power TV Cable Box Video Gaming console Printer Chargers

By doing this the average American saved 25 percent on their monthly electrical bill.

Energy Efficiency – a measure of energy produced compared to energy consumed.

Conservation - Transportation Cars and light trucks account for 40% of the US oil

consumption. The US E.P.A. says that raising the MPG of every

auto by 3 would save Americans as a whole $25 billion. As well as reduce CO2 emissions by 140 million metric tons per year.

Most people in the US now drive even to places that are less than 2 km away.

The average MPG of the cars on the road in the US dropped 20.4 MPG in 2004 from 25.9 MPG in 1988.

Mostly due to the increased usage of SUV’s.

Conservation – Transportation Walking High efficiency mini cars

Smart Cars Hybrids Diesels Hydrogen fuel cell autos Net Energy Yield – total useful energy produced

during lifetime of system – energy required to make useful energy available. Expressed as ratio between output and energy costs for all parts of system. Yield to cost ratio

Solutions

Conservation – Negawatt Programs Alternative to

creating new power plants.

“nega-”watt – demand avoidance program to save money.

Conservation - Cogeneration Cogeneration – the

simultaneous production of both electricity and steam or hot water in the same plant.

Produces 2 useful sources of energy

Increases net energy yield from 30%-35% to 80%-90%

Small generators, in small neighborhoods, the size of about a small house are now using biomass as fuel.

Solar Energy Passive heat

absorption – uses natural materials or absorptive structures with no moving parts to simply gather and hold heat.

Greenhouse

Solar Energy Active solar systems

– pump a heat absorbing, fluid medium like air, water or an anti-freeze solution through a relatively small collector, rather than passively collecting heat in a stationary medium like a masonry.

High Temperature Solar Energy By having mirrors

make light point towards a more concentrated point, that would be centralized around a tube.

The fluid inside that tube then heats up.

Also could use solar cooker.

Gov’t incentives Energy policies in some states encourage

conservation and alternative energy sources. Distributional surcharges (small kWh charge

levied on all utility customers to help renewable energy finance)

Renewable portfolio ( standards to require power suppliers to obtain a minimum percentage of their energy from sustainable sources).

Green pricing – allows utilities to profit from conservation programs and charge premium prices for energy from renewable sources.

Photovoltaic cells Photovoltaic cells –

capture solar energy and convert it directly to electrical current by separating electrons from their parent atoms and accelerating them across a one-way electrostatic barrier formed by the junction between 2 different types of semiconductor material.

Storage It is difficult to store

electricity. Acid from batteries is

corrosive and can damage the battery.

Batteries are also expensive.

Temperature also effects batteries.

Flywheels are current experiments for storage of energy.

Fuel Cells Fuel Cells – devices

that use ongoing electrochemical reactions to produce an electric current.

Adds more fuel for the chemical reaction.

Case Study: Sea Power

These windmills average a height of 417 feet. (statue of liberty is 111 feet tall).

Saidaonline.com

Wind energy is currently the fastest growing source of energy in the world.

British and Swedish Government have both harnessed this source of power in there portfolio of conservation of energy.

The offshore wind projects off of the UK produce as much electricity as 6 nuclear power plants.

Electrolytes that can be used in Fuel Cells Proton Exchange Membrane: Organic

Polymer containing sulfuric acid allows Hydrogen Movement but blocks Electron and oxygen

Phosphoric acid immobilized in a porous ceramic matrix as an electrolyte

Energy From Biomass Wood, Wood Chips, bark, branches,

leaves, starchy roots Wood burning not used as much as

used to, can produce carbon monoxide Catalytic Combustors burn harmful

hydrocarbons and CO

Short Supply of Wood Fire would in very short supply in

developing countries Resorting to deforestation 40% of world relies on fuel wood to heat

homes and produce energy

Dung and Methane as Fuel Burning Dung is ineffective (90% of

potential heat is lost) Harvest methane from dung (6 mill.

Households in China use biogas) Swamps are methane digesters,

anaerobic Bacteria produce methane from waste

Fuel from Crop Plants Ethanol (grain alcohol), methanol (wood

alcohol) Crop residue can also be use (stalks,

cobs, wheat straw) Some plants produce hydrocarbons

which can be burned directly (sunflower oil)

Energy from Earth’s Forces Water energy accounts for 20% of total

energy Dams use water turbines Three Gorges Dam predicted to produce

power equal to 25 nuclear power plants Many problems with dams, floods, disruption

of ecosystems, degrading water quality Schistosomiasis caused by parasitic

flatworms can be transferred to humans by snails that live in weedy waters behind dams

Dam Alternatives Low-head hydropower: extract energy

from small head water dams Run-of-the-river flow: non obstructing

can produce energy off of slow moving streams

Micro-Hydro Generators: same as above but smaller

Wind Energy Large wind turbines can produce energy

for 5000 average American Households 3 cents/kWh Germany world leader in wind power,

then Spain then U.S Relatively cheap and much land

available in Great Plains Create many jobs

Geothermal Energy Heat within the Earth can be used,

produces steam such as geysers and hot springs

California's Geysers project, 200 steam wells, produce 1,300 MW of power

Long life span, relatively no waste, no transport of fuels

Earth loops underground (constant temp. of 10-20 degrees Celsius)

Tidal and Wave Energy Works like dam, turbines spin as tide

flows through Tides do not coincide with peak energy

use Drawbacks include heavy siltation,

flooding of aquifers, disruption of ecosystems

Waves could amount to 16% of worlds energy

Ocean Thermal Electric Conversion OTEC, warm upper level boils ammonia

or Freon, spins turbines, lower level then condenses

Needed temp. difference of 20 degrees Celsius