Sustainable Transport Fuels
See also Biofuels Home Page
Given the current UK government policy of electrical generation by renewables, buses and trains - public transport - will run on overhead power lines - if there is enough power left over after home heating and industry requirements are met. However, what of the energy required by ships for international trade, aircraft for trade and travel (you can say "goodbye" to most tourist facilities) and our own personal transport? For these, a concentrated and portable form of energy is required.
Electric energy storage batteries are still - after 140 years - under development. For a discussion paper on electric vehicles, refer to www.dewinne.freeserve.co.uk/electric.htm . This points out the disadvantage of having to carry around half a tonne of storage medium to achieve the range of a gallon of petrol or diesel fuel and the feeling of insecurity which this imparts, but also holds out hope for the future of this low pollution mode of transport if the battery life and recycling problems can be overcome.
Which leaves hydrogen and biofuels - currently methane, alcohols and biodiesel, all of which may be made from sustainable agricultural crops, producing valuable by-products in the process.
There is, however, a catch - the ability of the land to produce all the liquid transport fuels needed. It has been calculated that the USA has the facility to produce less than 10% of its current usage - there is about to be a revolution.
Contenders for Sustainable Transport Fuels
Hydrogen
The perfect ecological fuel, producing only water when used.
Realistically, the fuel could be produced by electrolysis, using surplus energy from electricity generators, and packaged into portable cylinders. A steady current of 42 kW would produce 200 cubic metres of hydrogen ( @ stp) per day, using 1 MWh of electricity. The energy content of this is 600 kWh - a 60% efficiency rating and the equivalent of about 65 litres of diesel fuel.
On a larger scale, a hydro-electric plant supplying a steady 90 MW would produce around 30 tonnes of hydrogen gas per day, but storage is a serious problem.
Typically, a 1460 x 230 mm K size industrial gas cylinder weighs 65kg and holds 7.2 cubic metres of hydrogen, which has to be compressed at 175 bar (c. 2500 psi) - a convenient size and weight (same as a 50 litre fuel tank) for one cylinder to fit into a car, but the actual weight of the hydrogen is only 0.6kg. The energy content of this is 21.6 kWh - equivalent to about two litres of petrol.
To quote known facts, in November, 2002, the US EPA tested a Honda FCX hydrogen fuel cell vehicle and certified the fuel consumption as being 51 miles (82km) per kilo of hydrogen in the city and 48 miles (77km) per kg on the highway. Hence, a vehicle with an operating range of 300 miles (480km) would need six cylinders weighing 400kg (880 lb) and occupying a space of some 0.45 cu m (16 cu ft).
Whilst the EPA quotes the cost of compressed hydrogen at "about £5 per kg", BOC (UK) are charging £29.32 (US$45) for a K size cylinder - £49 ($75) a kilo! Hence, including VAT (17.5%), the 300 miles would cost £207 ($316).
Oops! Somebody needs to do a cost-effectiveness analysis, when discussing the opiate "hydrogen economy".
Absorption of hydrogen by a metal hydride is possible, but this is a slow (20 to 30 minutes) and exothermic reaction requiring cooling whilst refilling an expensive container, four times normal fuel tank size.
Neither of these "storage solutions" is practical for the average motorist, and it must also be borne in mind that the industrial refilling of hydrogen containers needs the services of a specialised technician and stringent safety precautions.
One of the most ingenious methods of obtaining a supply of hydrogen to power transport was patented by Francois P Cornish (UK!) in 1982. Aluminium from a coil of 1.6mm welding wire was fed into a pressurised water tank and pressed onto a revolving aluminium drum. A 16000 volt 1 amp current from a capacitor was passed between the two, causing heating at the interface and liberating free hydrogen which was then fed into the intake manifold of a car engine - BMW tested the system and found it to work, using 1.8 metres of wire per minute to power a 2 litre engine with the one litre of hydrogen it produced.
Chemically, the equation is 2Al + 3 H2O = Al2O3 + 3H2
Aluminium, of course, is very energy intensive to produce from the bauxite ore, but most of this comes from hydro-electric plants so is sustainable. The aluminium oxide sludge produced proved to be an operating nuisance, but could be recycled (with more energy input) to recover both the Al and the pure oxygen. (That is, provided carbon-lined boxes are not used in the refining process, which produces CO2 - one of the very gases we are trying to avoid creating!)
Methane
With a weight for weight energy content three times that of hydrogen, methane may be organically manufactured by the anaerobic (without oxygen) decomposition of vegetation and sewage, reducing the volume of volatile solids by 75% over the course of five or six days and producing 85 cubic metres of gas per tonne of solid waste. The energy content of this is around 700 kWh, allowing for some gas being used to heat the reaction. The by-product, of course, makes a good natural fertiliser without the disadvantage of offensive aromatics.
Methane also occurs naturally as the product of waste in-filling and, as such, has been deemed a pollutant - until somebody had the bright idea of sinking pipes into the sub-soil, recovering the gas and using it in a district heating system.
More recently (1996), vast amounts of methane have been found in the form of methane hydrate in arctic and other sea sediments, trapped by sheer weight of water. Located at between 300 and 2000 m below sea level it will be very costly to extract but will be a necessary replacement for "natural" gas resources currently used in living and working space heating systems. For another 100 years or so, at any rate. Methane also works well in fuel cells to produce electricity.
Methane compresses cryogenically to provide a more convenient source of portable energy, but has only one third of that contained in, say, butane. It is also possible, by using a catalytic reformation process, to convert the gas into methanol.
(N.B. - Butane and propane are products of the petroleum industry; compressed or liquified "natural" gas is not sustainable.)
Alcohols
Ethanol - ethyl alcohol - grain alcohol - made organically by natural fermentation of carbohydrates and starches contained in sugar beet/cane, potatoes, etc., and the highly taxed potable variety. Apart from use as a behaviour-modifying leisure pursuit, it has been an additive of petroleum (Agrol, Gasohol or Petrohol) since the 1930's and has been the mainstay of Brazil's transport system for over 20 years.
It only takes three days to ferment a mash, after which the alcohol may be distilled out at reasonably low temperatures, thereby saving on the energy cost of production. It takes over 3 litres of mash to make 1 litre of ethanol, which may then be used for cattle feed.
Already a liquid at normal temperatures, the form of energy is therefore more concentrated - about 5.7 kWh per litre, or just over half that of petrol. With no requirement for specialised on-vehicle storage facilities, this makes it a viable transport fuel without the associated pollution, as well as being able to use existing technology and refilling facilities.
Methanol - methyl alcohol - wood alcohol - may be obtained organically by the distillation of hardwoods at high pressure and a temperature of around 350 deg C - itself a high energy-consuming process. With a far higher cumulative toxicity rating than ethanol, the energy content is around 3.7 kWh per litre (about one third that of petrol), making it a less attractive alternative transport fuel.
Trying to mix methanol with petrol brings problems - they are not entirely compatible, and the slightest amount of water absorbed by the fuel causes the alcohol to separate out in the bottom of the tank. Additives are commercially available, but this adds to the fuel cost.
Toxicity is a relevant factor - ethyl alcohol is rapidly oxidised in the body to form mainly carbon dioxide and water (and a splitting headache!), whereas methyl alcohol forms formaldehyde and formic acid, both of which are very slowly eliminated. The problem arises from the possibility of unburnt fuel particles being emitted from the exhaust.
Biodiesel
The essential element of biodiesel is oil - animal or vegetable; used or recovered; oil or tallow. Treated with alcohol and a catalyst, mixed for an hour then left to settle overnight, the result is a pure diesel fuel compatible with currently manufactured motor vehicle engines. That is a simplification of the transesterification process, but not overly so.
To use the fuel, simply retard the injection timing by a couple of degrees and check that there are no rubber seals or pipes in the vicinity - biodiesel melts them.
Practical oils depend on local availability - soybean oil in the USA, rapeseed oil in the UK and most of northern Europe, or perhaps sunflower oil in France - the economics depend on the amount of raw oil produced per hectare.
In round figures, one hectare of land (UK) should produce an average 3 tonnes of rapeseed at 40% oil content. Pressed at a 90% extraction rate, this gives 1100kg of oil, which is treated with 150 kg of alcohol to give in excess of one tonne (1100 litres) of biodiesel and 120 kg of the valuable by-product glycerol. It requires around 15% energy input to produce the biodiesel - almost exactly the same as for petrodiesel extraction and refining.
Biodiesel is rated (DETR figure) at almost 12kWh per litre (only 7.5% below that of fossil diesel), giving a yield of 13MW per hectare per annum.
Added to this, the 2 tonnes of oil-bearing meal produced contains an estimated 4kWh of energy per kg, resulting in an energy yield of a further 8MW per hectare.
The benefits of this sustainable fuel are tremendous - environmentally, for every tonne of biodiesel used to replace petrodiesel -
In addition, the fuel is biodegradable - 98% within 21 days (fossil oil - 50%) - and does not have an offensive, choking smell when used. A thought may occur - who approved the use of fossil diesel for transport in the first place?
Economically, there are also huge advantages -
UK Government Policy
The UK Government currently (2000) has no policy for the provision of sustainable transport fuels for the future, preferring to concentrate on the generation of electricity under the Non Fossil Fuels Obligation. That is, unless you count the punitive taxation of renewable biofuels as a policy.
Due to the fact that biodiesel contains about 7% less energy than petrodiesel (caused by the inclusion of oxygen, which provides many of the benefits) and the application of the full fuel duty rate, biodiesel in the UK is the highest taxed road fuel in the world!
Sources of energy approved by the government are restricted to wind, hydro and short rotation coppicing (SRC) of willow, as indicated by the Supporting Analysis to the consultation document "New and Renewable Energy; Prospects in the UK for the 21st Century", published by the Department of Trade and Industry as part of the New and Renewable Energy Programme. It was written by the Energy Technology Support Unit (or ETSU, as they now like to be known), based at the Harwell Atomic Energy Authority facility.
Unbelievably, the whole of current UK government policy is based on one incorrect figure in a document published in 1996 by ETSU - "Alternative Road Transport Fuels - A Preliminary Life-cycle Study for the UK, Volume 2". Using a totally wrong figure (twenty times the actual!) for the energy required to press the oil from rapeseed and quoting a nonexistent authority, this caused the emissions figures to be adversely distorted - to the disadvantage of biodiesel. It was not until the British Association for Bio Fuels and Oils commissioned ECOTEC to analyse this report that the error was discovered in November 1999.
The results may be found on www.biofuels.fsnet.co.uk/biocase.htm
EEC Policy
The EEC is very pro biofuels, and many member states are taking advantage of this. See -
http://europa.eu.int/geninfo/query_en.htm and search on biodiesel
Premature emission
Before the results of the "UK" consultation process had been published, the Department of Economic Development for Northern Ireland (still just about part of the United Kindom, as at today's date) also published a similar paper - this time, without the consultation element - "Renewable Energy in the Millennium; the Northern Ireland Potential". This, too, was written by ETSU, with assistance from the Northern Ireland based Western Region Energy Agency Network. Needless to say, many of the shortcomings of the UK paper (as subsequently published in the DTI "Analysis of the Responses") appeared in the NI paper.
This is despite the stated governmental policy of being "joined up".
What are we going to do when the oil runs out, Daddy?
It is an inescapable fact that, within our lifetime, the oil will run out. It is a finite resource, no matter how many more oilwells are drilled, most of which is used for transportation - cars, buses, lorries, ships, trains and planes. All use fossil fuels to move. What are we going to do without them?
According to the American Petroleum Institute www.api.org/consumer/runningout.htm there is not a problem - reserves are set to last another 63 to 95 years. Guess where the vested interest lies? The UK government - or, at least, Secretary of State Stephen Byers - evidently believes in this philosophy, to the extent of the Department of Trade and Industry putting £2m into a new initiative called LOGIC, the brainchild of the Oil and Gas Industry Task Force (September 1999). OK - so the question should be "What are we going to do when the oil runs out, Grandad?", but the threat of exhaustion of supplies is still there and is, in historical terms, imminent. Even energy guru Gregg Easterbrook says so, in his book "Beside Still Waters" - he gives it 60 years - and the International Energy Agency forecasts a crisis somewhen between 2010 and 2020.
Biodiesel - a direct replacement fuel - who says so?
What follows is a list of documents, papers, etc, of sufficient importance for the authors to want them made public. Some are valid academic research documents, others are quite tongue-in-cheek, but they are all deserving of respect in that they are accepting the inevitable prognosis and facing up to the future with realistic foresight.
A good background document on biodiesel has been published by the US Alternative Fuels Data Centre on www.afdc.nrel.gov/altfuel/bio_general.htm
Do It Yourself - as the Actress said to the Bishop
Convinced? If so, you may consider making your own - it is quite possible, using the minimum of equipment and using any vegetable oil - even used frying oil from your local chippie. One of the better recipes, written by American enthusiast Mike Pelly, is to be found on http://jtforever.org/biodiesel_mike.html
More refined procedures, using the University of Idaho bubble washing technique, may be found on the US National Renewable Energy Laboratories site http://rredc.nrel.gov/biomass/doe/rbep/biodeg/one.html
Please take careful note of the safety precautions.
Excellent research work has been carried out on diesel engine emissions evaluation by Marshall, Schumacher & Howell www.web.missouri.edu/~pavt0689/CUMMINS.htm This demonstrates that biodiesel definitely does improve emissions criteria, especially unburnt hydrocarbons, particulates and carbon monoxide. It also has an excellent bibliography, but none of these papers are thought to be published on the internet.
Confirmation of improved emissions criteria, as well as some useful fuel replacement statistics appear on www.biodiesel.org/sptbdrpt.htm
Commercially, the production of biodiesel from rapeseed oil is well presented by Dr.-Ing. Joosten Connemann in his paper "Biodiesel in Europe 2000" - www.biodiesel.de/biodiesel2000.htm To the forefront in technology and much-needed exploitation, Oelmuhle Leer Connemann GmbH & Co have taken advantage of the willingness of the German government in reducing taxation to zero as a means of pump-priming the biofuel economy - one spin-off, of course, being the massive regeneration of the agricultural sector. Lalor (Ireland) gives a figure of one job being created per ten hectares of land used for energy crops, and the figure used by the EU for (semi-continuous) biodiesel production is one new job per 60 hectares.
Update September 2001
Since the above was written, the UK Government has been persuaded to remove nearly half the duty payable on biodiesel, making the use of recovered vegetable oils commercially viable, but not fresh oils. Other papers on this site tell the sequel, but the picture is that HMG does not intend to support the production of biodiesel in any other way - this is being left to private enterprise.
However, if anybody wants to re-invent ethanol or the strangely prominent bio-oil, there are R&D monies available. Electric and fossil gas cars are financially supported (£5.1m to the so-called Energy Savings Trust), but not the production of methane as a viable road fuel. The successor to the NFFO scheme is still under discussion, the Foresight Group is dispersing and a new Non-food Crops Forum has been formed, starting up discussions and consultations all over again. MAFF has changed it's name, keeping the same personnel with different titles - thereby ensuring that everything is being done except anything. As Count Oxenstierne is reported to have said in 1649, I think it was -
Dost thou not know, my son, with how little wisdom the world is governed?
Come back to terry@biofuels.fsnet.co.uk
if you hear of anything different.
This site is in the course of development and will be added to as time permits.
The tax break being introduced in April 2002 allows me to start producing biodiesel commercially, scaling up my pilot demonstration project.
Copyright - Terry de Winne 2000