New York City to Use Only Hybrid Taxis

Hybrid vehicles, by design, return the best fuel economy and produce the lowest emissions when they are driven in a city environment. Naturally, this makes them ideal for use as taxi cabs in heavily congested urban areas where vehicles are trapped in never-ending gridlock. The majority of cabs used in this country, however, are traditional American sedan gas hogs.

That will change dramatically in the next five years in one of our nation's biggest cities: New York. Mayor Bloomberg recently announced a plan to convert the city's entire fleet of 13,000 taxis to hybrid vehicles by 2012. This change will greatly assist in the mayor's plan to reduce carbon emissions by 30% by 2030. As of mid-2007, hybrids comprise only 375 of the 13,000 vehicles used as taxis in New York. And of those 375 hybrids, the majority is the Ford Escape Hybrid.

The Escape Hybrid was the first hybrid to be used in taxi fleets across the country. The bulk of Escape Hybrids are serving in New York, and they have been holding up remarkably well, given the extremely harsh conditions faced day in and day out. Ford reports that the first batch of vehicles have accumulated around 175,000 miles (since late 2005!) and have had no major mechanical problems. City EPA estimated mileage for the Escape Hybrid is 34 mpg, compared with 14 mpg for the Crown Victoria. We expect the Escape to be chosen as the most popular model in the fleet.

Whichever model prevails, the savings in fuel costs alone will be significant - regardless of the environmental advantages - when the fleet runs entirely on hybrid power.

Biodiesel

Biodiesel refers to a diesel-equivalent, processed fuel derived from biological sources (such as vegetable oils), which can be used in unmodified diesel-engine vehicles. It is thus distinguished from the straight vegetable oils (SVO) or waste vegetable oils (WVO) used as fuels in some diesel vehicles.

In this article's context, biodiesel refers to alkyl esters made from the transesterification of vegetable oils or animal fats. Biodiesel is biodegradable and non-toxic, and typically produces about 60% less net carbon dioxide emissions than petroleum-based diesel, as it is itself produced from atmospheric carbon dioxide via photosynthesis in plants. Pure biodiesel is available at many gas stations in Germany.

Some vehicle manufacturers are positive about the use of biodiesel, citing lower engine wear as one of the benefits of this fuel. However, as biodiesel is a better solvent than standard diesel, it 'cleans' the engine, removing deposits in the fuel lines, and this may cause blockages in the fuel injectors. For this reason, car manufacturers recommend that the fuel filter is changed a few months after switching to biodiesel (this part is often replaced anyway in regular servicing). Most manufacturers release lists of the cars which will run on 100% biodiesel.

Biodiesel is a light to dark yellow liquid. It is practically immiscible with water, has a high boiling point and low vapor pressure. Typical methyl ester biodiesel has a flash point of ~ 150 °C (300 °F), making it rather non-flammable. Biodiesel has a density of ~ 0.88 g/cm³, less than that of water. Biodiesel uncontaminated with starting material can be regarded as non-toxic.

Biodiesel has a viscosity similar to petrodiesel, the current industry term for diesel produced from petroleum. It can be used as an additive in formulations of diesel to increase the lubricity of pure Ultra-Low Sulfur Diesel (ULSD) fuel, which is advantageous because it has virtually no sulfur content. Much of the world uses a system known as the "B" factor to state the amount of biodiesel in any fuel mix, in contrast to the "BA" or "E" system used for ethanol mixes.

For example, fuel containing 20% biodiesel is labeled B20. Pure biodiesel is referred to as B100.

Biodiesel is a renewable fuel that can be manufactured from algae, vegetable oils, animal fats or recycled restaurant greases; it can be produced locally in most countries. It is safe, biodegradable and reduces air pollutants, such as particulates, carbon monoxide and hydrocarbons. Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines.

Biodiesel can also be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems. The industry standard for the amount of time it takes to produce biodiesel used to be 4 hours, but a San Antonio based company is currently experimenting, and has claimed to produce biodiesel fuel in a fraction of what it formerly was, with a 1.4 minute contact time.

Production of Bioethanol

The production of ethanol or ethyl alcohol from starch or sugar-based feedstocks is among man's earliest ventures into value-added processing. While the basic steps remain the same, the process has been considerably refined in recent years, leading to a very efficient process. There are two production processes: wet milling and dry milling. The main difference between the two is in the initial treatment of the grain.


Ethanol production - Dry Milling



In dry milling, the entire corn kernel or other starchy grain is first ground into flour, which is referred to in the industry as "meal" and processed without separating out the various component parts of the grain. The meal is slurried with water to form a "mash." Enzymes are added to the mash to convert the starch to dextrose, a simple sugar. Ammonia is added for pH control and as a nutrient to the yeast.


Ethanol production - Wet Milling



In wet milling, the grain is soaked or "steeped" in water and dilute sulfurous acid for 24 to 48 hours. This steeping facilitates the separation of the grain into its many component parts.

Ethanol production from Cellulosic Biomass

This process flow diagram shows the basic steps in production of ethanol from cellulosic biomass. Note that there are a variety of options for pretreatment and other steps in the process and that several technologies combine two or all three of the hydrolysis and fermentation steps within the shaded box. Chart courtesy of the National Renewable Energy Lab.

Bioethanol

What is Bioethanol?

The principle fuel used as a petrol substitute for road transport vehicles is bioethanol. Bioethanol fuel is mainly produced by the sugar fermentation process, although it can also be manufactured by the chemical process of reacting ethylene with steam.

The main sources of sugar required to produce ethanol come from fuel or energy crops. These crops are grown specifically for energy use and include corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants. There is also ongoing research and development into the use of municipal solid wastes to produce ethanol fuel.

Ethanol or ethyl alcohol (C2H5OH) is a clear colourless liquid, it is biodegradable, low in toxicity and causes little environmental pollution if spilt. Ethanol burns to produce carbon dioxide and water. Ethanol is a high octane fuel and has replaced lead as an octane enhancer in petrol. By blending ethanol with gasoline we can also oxygenate the fuel mixture so it burns more completely and reduces polluting emissions. Ethanol fuel blends are widely sold in the United States. The most common blend is 10% ethanol and 90% petrol (E10). Vehicle engines require no modifications to run on E10 and vehicle warranties are unaffected also. Only flexible fuel vehicles can run on up to 85% ethanol and 15% petrol blends (E85).

What are the benefits of Bioethanol?

Bioethanol has a number of advantages over conventional fuels. It comes from a renewable resource i.e. crops and not from a finite resource and the crops it derives from can grow well in the UK (like cereals, sugar beet and maize). Another benefit over fossil fuels is the greenhouse gas emissions. The road transport network accounts for 22% (www.foodfen.org.uk) of all greenhouse gas emissions and through the use of bioethanol, some of these emissions will be reduced as the fuel crops absorb the CO2 they emit through growing. Also, blending bioethanol with petrol will help extend the life of the UK’s diminishing oil supplies and ensure greater fuel security, avoiding heavy reliance on oil producing nations. By encouraging bioethanol’s use, the rural economy would also receive a boost from growing the necessary crops. Bioethanol is also biodegradable and far less toxic that fossil fuels. In addition, by using bioethanol in older engines can help reduce the amount of carbon monoxide produced by the vehicle thus improving air quality. Another advantage of bioethanol is the ease with which it can be easily integrated into the existing road transport fuel system. In quantities up to 5%, bioethanol can be blended with conventional fuel without the need of engine modifications. Bioethanol is produced using familiar methods, such as fermentation, and it can be distributed using the same petrol forecourts and transportation systems as before.

In a world of permanently declining oil & gas reserves, the search for alternative liquid transportation fuels has taken on a new and heightened sense of urgency.

From producers and consumers to the institutions that govern them, parties involved overwhelmingly agree that the fuel alternatives in question need to be economical, sustainable and capable of seamless integration into the existing commercial infrastructure while addressing two significant concerns: energy security and environmental impact.

A daunting task yet the solution is clear: BIOFUEL

Biofuels are recognized as the only liquid alternatives capable of mitigating the effects of peak fossil fuel decline while simultaneously addressing the world’s need for secure and environmentally friendly transportation.

The heavyweight of the biofuel industry is ethanol. A clear, clean burning, biodegradable alcohol used primarily as an oxygenate in reformulated gasoline. A superb motor-fuel in its own right, ethanol can be made domestically from renewable resources.

Typically fermented from corn or sugar cane, ethanol proponents have long sought a more economical and higher yielding ethanol production path utilizing green waste feedstocks such as biogas, wood waste and agricultural residues. This search, for what many in the scientific community have deemed to be the holy grail of energy production, has been difficult.

Considerable time and resources have been spent testing a host of competing technologies and production paths, however, the most promising technology to surface to date has been catalytic conversion of gasified carbonaceous material.