ALTERNATIVE TECHNOLOGY

Presented By:

Robin K Francis

Kiran Chembilath

INTRODUCTION

Alternative technology is a term used by environmental advocates to refer to technologies

which are more environmentally friendly than the functionally equivalent technologies

dominant in current practice.

It is technology that, as an alternative to resource-intensive and wasteful industry, aims to

utilize resources sparingly, with minimum damage to the environment, at affordable cost and

with a possible degree of control over the processes. The term is, particularly related to the

importance of low cost and ease of maintenance for developing country applications.

Alternative technologies themselves are part of environmentalist politics. Common political

issues related to alternative technologies include whether they are practical for widespread

use; whether they are cost-effective; whether widespread adoption would produce negative

impacts on the economy, lifestyle or environment (production energy costs/pollutants); how

to encourage rapid adoption; whether public subsidies for adoption are appropriate; which

technologies government regulations should favor, if any, and how environmentally unsound

technologies and practices should be regulated; what technological research should be done

and how it should be funded; and which of a field of competing alternative technologies

should be pursued.

The term was coined by Peter Harper, one of the founders of the Centre for Alternative

Technology, North Wales, in Undercurrents (magazine) in the 1970s.

Some "alternative technologies" have in the past or may in the future become widely

adopted, after which they might no longer be considered "alternative." For example the use

of wind turbines to produce electricity. We can now analyze The use of Fuel Cell as an

Alternate Technology which has the scope to be widely used in future.

Alternate Technology

Alternative technologies include the following technologies like Anaerobic digestion,

Composting, Fuel cells, Solar panels, Mechanical biological treatment, Recycling, Urban car,

Wind generators etcFuel Cells are one of the main Alternative Technologies being used in

the modern world.

Fuel Cell

A fuel cell is an electrochemical conversion device. It produces electricity from fuel (on the

anode side) and an oxidant (on the cathode side), which react in the presence of an

electrolyte. The reactants flow into the cell, and the reaction products flow out of it, while the

electrolyte remains within it. Fuel cells can operate virtually continuously as long as the

necessary flows are maintained.

Fuel cells are different from electrochemical cell batteries in that they consume reactant,

which must be replenished, whereas batteries store electrical energy chemically in a closed

system. Additionally, while the electrodes within a battery react and change as a battery is

charged or discharged, a fuel cell's electrodes are catalytic and relatively stable.

Many combinations of fuel and oxidant are possible. A hydrogen cell uses hydrogen as fuel

and oxygen (usually from air) as oxidant. Other fuels include hydrocarbons and alcohols.

Other oxidants include air, chlorine and chlorine dioxide.

DESIGN

A fuel cell works by catalysis, separating the component electrons and protons of the

reactant fuel, and forcing the electrons to travel though a circuit, hence converting them to

electrical power. The catalyst typically comprises a platinum group metal or alloy. Another

catalytic process takes the electrons back in, combining them with the protons and the

oxidant to form waste products (typically simple compounds like water and carbon dioxide).

In the archetypal hydrogenoxygen proton exchange membrane fuel cell (PEMFC) design, a

proton-conducting polymer membrane, (the electrolyte), separates the anode and cathode

sides. This was called a "solid polymer electrolyte fuel cell" (SPEFC) in the early 1970s,

before the proton exchange mechanism was well-understood. (Notice that "polymer

electrolyte membrane" and "proton exchange membrane" result in the same acronym.)

On the anode side, hydrogen diffuses to the anode catalyst where it later dissociates into

protons and electrons. These protons often react with oxidants causing them to become what

is commonly referred to as multi-facilitated proton membranes (MFPM). The protons are

conducted through the membrane to the cathode, but the electrons are forced to travel in an

external circuit (supplying power) because the membrane is electrically insulating. On the

cathode catalyst, oxygen molecules react with the electrons (which have traveled through the

external circuit) and protons to form water in this example, the only waste product, either

liquid or vapor.

EFFICIENCY

The efficiency of a fuel cell is dependent on the amount of power drawn from it. Drawing

more power means drawing more current, which increases the losses in the fuel cell. As a

general rule, the more power (current) drawn, the lower the efficiency. Most losses manifest

themselves as a voltage drop in the cell, so the efficiency of a cell is almost proportional to

its voltage. For this reason, it is common to show graphs of voltage versus current (so-called

polarization curves) for fuel cells. A typical cell running at 0.7 V has an efficiency of about

50%, meaning that 50% of the energy content of the hydrogen is converted into electrical

energy; the remaining 50% will be converted into heat. (Depending on the fuel cell system

design, some fuel might leave the system unreacted, constituting an additional loss.)

For a hydrogen cell operating at standard conditions with no reactant leaks, the efficiency is

equal to the cell voltage divided by 1.48 V, based on the enthalpy, or heating value, of the

reaction. For the same cell, the second law efficiency is equal to cell voltage divided by 1.23

V. (This voltage varies with fuel used, and quality and temperature of the cell.) The

difference between these numbers represents the difference between the reaction's enthalpy

and Gibbs free energy. This difference always appears as heat, along with any losses in

electrical conversion efficiency.

FUEL CELL APPLICATIONS

Fuel cells are very useful as power sources in remote locations, such as spacecraft, remote

weather stations, large parks, rural locations, and in certain military applications. A fuel cell

system running on hydrogen can be compact and lightweight, and have no major moving

parts. Because fuel cells have no moving parts and do not involve combustion, in ideal

conditions they can achieve up to 99.9999% reliability. This equates to around one minute of

down time in a two year period.

A new application is micro combined heat and power, which is cogeneration for family

homes, office buildings and factories. The stationary fuel cell application generates constant

electric power (selling excess power back to the grid when it is not consumed), and at the

same time produces hot air and water from the waste heat. A lower fuel-to-electricity

conversion efficiency is tolerated (typically 15-20%), because most of the energy not

converted into electricity is utilized as heat. Some heat is lost with the exhaust gas just as in a

normal furnace, so the combined heat and power efficiency is still lower than 100%, typically

around 80%. In terms of exergy however, the process is inefficient, and one could do better

by maximizing the electricity generated and then using the electricity to drive a heat pump.

Phosphoric-acid fuel cells (PAFC) comprise the largest segment of existing CHP products

worldwide and can provide combined efficiencies close to 90%[20] (35-50% electric +

remainder as thermal) Molten-carbonate fuel cells have also been installed in these

applications, and solid-oxide fuel cell prototypes exist.

Since electrolyzer systems do not store fuel in themselves, but rather rely on external storage

units, they can be successfully applied in large-scale energy storage, rural areas being one

example. In this application, batteries would have to be largely oversized to meet the storage

demand, but fuel cells only need a larger storage unit (typically cheaper than an

electrochemical device).

One such pilot program is operating on Stuart Island in Washington State. There the Stuart

Island Energy Initiative has built a complete, closed-loop system: Solar panels power an

electrolyzer which makes hydrogen. The hydrogen is stored in a 500 gallon tank at 200 PSI,

and runs a ReliOn fuel cell to provide full electric back-up to the off-the-grid residence. The

SIEI website gives extensive technical details on it.

Suggested Applications for Fuel Cells

* Base load power plants

* Electric and hybrid vehicles.

* Auxiliary power

* Off-grid power supply

* Notebook computers for applications where AC charging may not be available

for weeks at a time.

* Portable charging docks for small electronics (e.g. a belt clip that charges your

cell phone or PDA).

* Smartphones with high power consumption due to large displays and additional

features like GPS might be equipped with micro fuel cells.

HYDROGEN TRANSPORTATION AND REFUELING

The first public hydrogen refueling station was opened in Reykjavk, Iceland in April 2003.

This station serves three buses built by DaimlerChrysler that are in service in the public

transport net of Reykjavk. The station produces the hydrogen it needs by itself, with an

electrolyzing unit (produced by Norsk Hydro), and does not need refilling: all that enters is

electricity and water. Royal Dutch Shell is also a partner in the project. The station has no

roof, in order to allow any leaked hydrogen to escape to the atmosphere.

The GM 1966 Electrovan was the automotive industry's first attempt at an automobile

powered by a hydrogen fuel cell. The Electrovan, which weighed more than twice as much as

a normal van, could travel up to 70mph for 30 seconds.

The 2001 Chrysler Natrium used its own on-board hydrogen processor. It produces hydrogen

for the fuel cell by reacting sodium borohydride fuel with Borax, both of which Chrysler

claimed were naturally occurring in great quantity in the United States. The hydrogen

produces electric power in the fuel cell for near-silent operation and a range of 300 miles

without impinging on passenger space. Chrysler also developed vehicles which separated

hydrogen from gasoline in the vehicle, the purpose being to reduce emissions without relying

on a nonexistent hydrogen infrastructure and to avoid large storage tanks.

In 2003 President George Bush proposed what is called the Hydrogen Fuel Initiative (HFI),

which was later implemented by legislation through the 2005 Energy Policy Act and the

2006 Advanced Energy Initiative. These aim at further developing hydrogen fuel cells and its

infrastructure technologies with the ultimate goal to produce fuel cell vehicles that are both

practical and cost-effective by 2020. Thus far the United States has contributed 1 billion

dollars to this project.

In 2005 the British firm Intelligent Energy produced the first ever working hydrogen run

motorcycle called the ENV (Emission Neutral Vehicle). The motorcycle holds enough fuel to

run for four hours, and to travel 100 miles in an urban area, at a top speed of 50 miles per

hour. It will cost around $6,000 Honda is also going to offer fuel-cell motorcycles.

There are numerous prototype or production cars and buses based on fuel cell technology

being researched or manufactured. Research is ongoing at a variety of motor car

manufacturers. Honda has announced the release of a hydrogen vehicle in 2008.

Boeing researchers and industry partners throughout Europe are planning to conduct

experimental flight tests in 2007 of a manned airplane powered only by a fuel cell and

lightweight batteries. The Fuel Cell Demonstrator Airplane research project was completed

recently and thorough systems integration testing is now under way in preparation for

upcoming ground and flight testing. The Boeing demonstrator uses a Proton Exchange

Membrane (PEM) fuel cell/lithium-ion battery hybrid system to power an electric motor,

which is coupled to a conventional propeller.

Fuel cell powered race vehicles, designed and built by university students from around the

world, competed in the world's first hydrogen race series called the 2008 Formula Zero

Championship, which began on August 22nd, 2008 in Rotterdam, the Netherlands. The next

race is in South Carolina in March 2009.

CONCLUSION

Before concluding, lets once again have a look on the main Benefits using Fuel cell

Technology. The main advantages are :

Fuel efficiencies of between 30% and 90% can be achieved by converting fuel

directly into electrical energy.

Fossil fuel combustion leads to byproducts that are known to damage the

environment. In fuel cell systems using hydrogen as the fuel, the only byproducts of

the electrochemical reaction are electricity, heat, and water.

Extracting fossil fuels from the earth comes with its own set of environmental

hazards, not found in the process associated with generating fuel cell hydrogen. The

environmental impact of fuel cell technology is pleasingly miniscule.

A fuel cell's simplicity of design, with no moving parts, offers the benefits of quiet

operation and reliability.

Hydrogen can be produced a number of ways domestically, relieving the stress of

overseas petrochemical dependence.

Use of Energy is increasing day by day. There is a limit to which we

can control the use of Energy without waste. So it is really important that we must develop

Alternate Technologies to generate Energy. This is where we must understand the

importance of focusing on alternate energy measures like fuel cells. China is the Worlds 2nd

largest producer of Energy. They have started a huge project on Fuel cell development and

Technology , which is to become the main Alternate Energy source for China. Its high time

that Developing countries like India focus on using such alternative technologies. Thus create

a Energy efficient and a brighter Nation..!