Low-tech Magazine

Invention & Technology Magazine

2008-07-02T18:45:49+02:00

Low-tech Magazine will take some time off during summer, but this does not mean we will leave you without anything to read. The online archives of Invention & Technology Magazine (1985-2007) should keep you busy for quite some time (thanks a lot for the tip, David). This spin-off of American Heritage Magazine is dedicated to the history of technology. Very recommended. We keep moderating comments here at LTM, but there might be some delay in publishing them.

Carbon sequestration: bury the idea, not the CO2

2008-06-29T16:04:22+02:00

Why introduce yet another expensive, energy-intensive and risky technology if there are so many other and better ways of fighting global warming?

Capturing CO2 from the smokestacks of power stations with the intention of storing it in underground reservoirs, oceans, rocks, consumer products, chemicals or fuels has gained a lot of credibility recently. Many experts believe that we will burn the world's remaining fossil fuels anyway, and we should therefore try to lower the impact if we are to prevent a catastrophic climate change. Yet capturing, transporting and storing carbon dioxide raises energy consumption considerably and brings with it serious health and environmental problems. The benefits, on the other hand, are shadowed in doubt.

© Picture pipeline bridge in Alaska: Travis S.

--------------------------------------------------------------------------------------------------------

"A 50 percent increase in energy consumption is the last thing that the world needs."

--------------------------------------------------------------------------------------------------------

Earlier this month leading science and energy institutes advocated strongly for the development of carbon capture and storage technology. The science academies of the world’s 13 major economic powers called the implementation of carbon sequestration a “top priority”. Around the same time, the International Energy Association (IEA) argued for an energy technology revolution, of which carbon capture and storage forms a vital component. Meanwhile, many spin-offs and start-ups are presenting all kinds of "innovative" ideas that seem to differ substantially from the traditional approach of storing CO2 in underground reservoirs.

Attractive idea

The idea of carbon capture and storage (CCS) – first introduced in the 1970s - is attractive at first sight. To begin with, it is a natural occurrence. There are many natural reservoirs of CO2, which have kept this gas contained for many millions of years. Secondly, the potential for storage is significant. The available storage space in underground reservoirs (depleted oil and gas reserves, coal formations and especially saline formations) is probably large enough to store all the carbon dioxide still contained in earth's remaining fossil fuel reserves. It will take more research to find out which reservoirs are suited to this and which ones are not, but finding the actual storage space does not seem to be a fundamental obstacle. To add to this, the technology for capture, transport and storage of CO2 is available.

--------------------------------------------------------------------------------------------------------

CO2 can be transported in gaseous, liquid and solid form, the latter called dry ice - picture above. It can be kept at a temperature of minus 70 degrees Celsius and transforms directly to gas when it melts (hence the name). One cubic metre of dry ice equals to 1.5 tonnes of carbon dioxide, in gaseous form the same amount of CO2 takes up more than 500 m³. For transportation in pipelines, CO2 gas is compressed. For transportation by ships, CO2 can be transported in any form. (Picture source)
--------------------------------------------------------------------------------------------------------

Technology is available

Capturing CO2 from smokestacks has been a common practice for many years, for the purification of natural gas or at ammonia production facilities for instance. Injection and storage of carbon dioxide is already happening in the North Sea, in Algeria and in Texas. In these cases, CO2 is injected into oil and gas reservoirs in order to extract more fossil fuels than would otherwise be possible, a process called Enhanced Oil Recovery (EOR). For some of these applications, carbon dioxide is transported by pipeline or by ship.

A complete CCS infrastructure has not been demonstrated yet (all CO2 used for enhanced oil recovery is commercially produced or originates from other sources than power plants, and present capture techniques do not capture CO2 for storage but emit the gas in the atmosphere). Yet, since all the individual parts exist, this does not seem to be an obstacle either.

Energy penalty

The problem at hand is that the process of capturing, transporting and storing carbon dioxide requires a vast amount of energy. If this energy were to be derived directly from fossil fuels the benefits of the CO2-savings by capture and storage will be offset by the very same energy intensive process. If the energy were to come from renewable sources the technology is rendered unnecessary as it would be much more efficient to generate electricity directly from the renewable source.

--------------------------------------------------------------------------------------------------------

"If fuel use of electricity generation rises by 50 percent, the same goes for air pollution from coal plants and for the ecological consequences of coal mining. Storing the CO2 does not solve that."

--------------------------------------------------------------------------------------------------------

Capturing CO2 from smokestacks is the most energy-intensive part of the process. According to the International Panel of Climate Change (IPCC), which devoted a comprehensive study on the technology 3 years ago, capturing technology (including compression for further transport and storage) raises the energy consumption of a coal plant by an average of 32 percent.

A coal plant equipped with CO2-capture technology would thus need 32 percent more coal and other resources like water, chemicals and reagents to produce the same amount of electricity than the same power plant without this technology. Carbon capture technology forms a symbiosis with coal as a fuel (“clean coal”), since burning coal emits twice as much greenhouse gasses than burning gas. Capturing CO2 from a gas power plant requires less energy but is of not much use.

Pipeline infrastructure

This 32 percent does not include the energy needed to mine, process and transport the many thousands of tonnes of extra coal, and it does not include the energy needed for the construction of the capture, transportation, storing and monitoring infrastructure either.

It is insufficient to simply place the smokestacks of a coal plant upside down as suitable underground reservoirs do not necessarily lie beneath the world's power stations. A carbon capture and storage infrastructure requires a transport infrastructure consisting of pipelines (and tankers) that rivals the existing oil and gas network.

--------------------------------------------------------------------------------------------------------

© Picture of pipeline infrastructure in the US : Ken Flannery. Carbon capture and storage requires a pipeline network that rivals the existing oil and gas infrastructure.
--------------------------------------------------------------------------------------------------------

Manufacturing and installing these thousands of kilometres of stainless steel pipes will require a substantial amount of energy. Also, the transport by ship or pipeline itself requires energy, and so does the injection of the CO2 in underground reservoirs and the monitoring of the whole transport network (today’s pipelines are patrolled by plane every two weeks).

Everything taken together, CCS will probably raise energy consumption by as much as 50 percent (this is an estimate as to my knowledge nobody seems to have investigated this yet). Even if all of the CO2 is eventually stored, a 50 percent increase in energy consumption is the last thing that the world needs.

Coal mining

In addition, it is impossible to store all of the carbon dioxide. Capturing technology can only capture 80 to 90 percent of CO2 from smokestacks. Taking into account an additional energy use of 50 percent this comes down to a reduction in CO2 emissions of only 70 to 85 percent compared to a coal plant without carbon capture technology (and only if all emissions coming from the additional energy use are captured as well).

--------------------------------------------------------------------------------------------------------

"Carbon capture and storage requires a transport infrastructure that rivals the existing oil and gas pipeline network."

--------------------------------------------------------------------------------------------------------

There are losses during transport, too. According to the IPCC these are 1 to 2 percent per 1,000 kilometres of pipeline transport and 3 to 4 percent per 1,000 kilometres of ship transport (the ship's fuel use included). Carbon dioxide is also not the only harmful effect of power generation. Burning coal brings with it serious air pollution and produces waste, both of which will also rise by at least 30 percent. The same goes for the ecological damage of coal mining, which is devastating. Storing the CO2 can never prevent this.

Artificial trees

Because of all these disadvantages, researchers and entrepreneurs try to invent all kinds of other ways to keep carbon dioxide out of the atmosphere, like storing CO2 in consumer products, converting it to fuel or fixing it in rocks. Yet until now, all these proposals face – at best – a similar energy penalty.

That is mostly because the first step of the process is always the same: capturing CO2 from the smokestacks of a coal plant will raise fuel consumption by about 30 percent. The only alternative to this capture technology – sucking carbon dioxide out of ambient air by means of "artificial trees"– consumes even more energy because the concentration of CO2 in ambient air is much lower than the concentration of CO2 in smokestacks.
--------------------------------------------------------------------------------------------------------

Artificial trees, a technology proposed by Klaus Lackner of Columbia University. Copyright Illustration Stonehaven CCS, Montreal (via).

--------------------------------------------------------------------------------------------------------

Turning CO2 in plastics

Besides, the storage potential of most of these alternative proposals is very limited compared to that of the traditional CCS-concept. A strategy that is getting a lot of attention these days is to store CO2 into consumer products based on polymers like plastic bottles or DVD’s, or in chemicals like those used in fertilizers, refrigeration or food packaging.

The idea is that it is better to do “something useful” with captured CO2 instead of just storing it underground. However, even though the amount of chemicals and plastics we produce is enormous, as a carbon sink they are all but meaningless.

--------------------------------------------------------------------------------------------------------

"If all polycarbonates and polyurethane would be produced by means of CO2 this would only store the emissions of 3 coal power plants."

--------------------------------------------------------------------------------------------------------

According to the IPCC, producing all polycarbonates and polyurethane by means of carbon dioxide would store 3.3 million tons of CO2 – comparable to the annual emissions of just 3 coal power plants. China is building one coal plant per week (in large part to produce cheap goods for us to buy) and there are more than 100 coal plants on the drawing board in the US.

What makes this approach even more useless is that these consumer products and chemicals have a relatively short lifespan, from a few months for fertilizers to a few decades for plastic products. When the fertilizers are used, or when the DVD’s end up in the incinerator, the CO2 goes back into the atmosphere.

Burning algae

Using CO2 as a feeding stock for algae and then turning it into biofuel - another idea that is hyped these days - faces the same problem. It only delays CO2-emissions for a very short time. The carbon dioxide is converted into fuel which is subsequently burned in a car engine.

It is impossible to capture CO2 from car engines since the gas is too heavy (your car would gain serious weight while driving, and it would have to pull a trailer to store the large volume of carbon dioxide).

--------------------------------------------------------------------------------------------------------

"Turning CO2 into algae could be an interesting strategy if we bury the algae instead of burning them in our car engines. However, that’s not on anyone’s mind."

--------------------------------------------------------------------------------------------------------

One could argue that at least the CO2 is recycled and that we are using the by-product of electricity generation to make fuel – which means that we don’t have to dig up more fossil fuels to make gasoline. However, this argument does not take into account the fact that much energy (and water) is lost in the conversion process.

Firstly, there is again the energy penalty of CO2 capture from the smokestacks, on average 30 percent. Next, you have to build a huge infrastructure to produce algae (since their energy efficiency is 100 times smaller than that of solar panels) and furthermore there is the energy that gets lost during the process of turning algae to fuel. If there is net energy gain in the end, it will be small.

Turning CO2 into algae could be an interesting strategy to reduce CO2-emissions if we store the algae underground instead of burning them in our car engines (thus avoiding the energy-intensive process of converting them into fuel). However, that’s not on anyone’s mind.

Fixing CO2 in rocks

The only alternative approach that really could store a significant amount of CO2 is mineral carbonation: fixing carbon dioxide in rocks (limestone). This method is also based on a natural process. Under the influence of weathering, the surface of rocks combines with carbon dioxide. Earth has no shortage of rocks, so the potential of this method is large enough to store all possible future CO2-emissions.

But if we want the strategy to be useful for us, this natural chemical reaction has to be accelerated considerably and that is again a very energy-intensive process (rocks have to be crushed to powder in order to provide more rock surface, and then treated with chemicals and heated). According to the IPCC this method would raise energy consumption by 60 to 180 percent.

--------------------------------------------------------------------------------------------------------

© picture limestone mine: the stone company

--------------------------------------------------------------------------------------------------------

Capturing carbon dioxide in rocks would also require a mining and transport infrastructure that is comparable (and which would supplement) today’s coal industry. To fix a tonne of CO2, you need 1.6 to 3.7 tonnes of rock. These rocks have to be mined and transported to coal plants (some industrial wastes and mining tailings can also be used, for example fuel ash from coal plants or de-inking ash from the paper industry, but their total amounts are way too small to substantially reduce CO2-emissions). The process also generates large amounts of waste materials (apart from the carbonised rocks themselves). For every tonne of carbon dioxide stored in rock, you are left with 2.6 to 4.7 tonnes of disposable materials.

Atomic waste, meet your rival

Carbon capture technology is expected to become more energy-efficient in the future. But that would hardly make the whole scheme more attractive. Storing carbon dioxide in underground reservoirs (the only realistic option) is risky, not unlike the storing of atomic waste.

CO2 can escape. High concentrations of the gas are lethal to plants, animals and humans. Eventually the gas thins in the atmosphere but during escape concentrations can build up fast, especially since CO2 is denser than air. At concentrations above 2 percent in ambient air, carbon dioxide has a strong effect on respiration (the normal concentration in fresh air is 0.033 percent). At concentrations from 7 to 10 percent, it kills.

--------------------------------------------------------------------------------------------------------

"If CO2 escapes from storage reservoirs, the whole energy-intensive operation of capturing, transporting and storing it was all for nothing."

--------------------------------------------------------------------------------------------------------

Small impurities in the gas make it lethal at even lower concentrations. Similar amounts in the soil kill vegetation and make groundwater unsuitable for drinking or irrigation. And of course, if CO2 escapes from storage reservoirs, the whole operation of capturing, transporting and storing it was all for nothing. The result is a considerable rise in emissions, because of the energy penalty involved (the energy use of the whole process can go down, but it will never come close to zero).

Cement cork

As can be seen in the drawing below, storing CO2 in essence resembles storing a gas in a stone pot. When an underground reservoir is filled up, all injection wells are closed by a cement "cork". This cork has to keep the gas inside for thousands of years.

Now zoom out and you are looking at a planet with thousands of holes, each one sealed with a cork to keep inside a potentially deadly (and climate warming) gas. Reassuring, no? Yet, this is considered a high-tech solution. You also have a network of thousands of kilometres of pipelines, transporting the same gas and connecting power plants with these reservoirs.

--------------------------------------------------------------------------------------------------------

How big is the chance that leaks or sudden bursts will cause damage? According to the IPCC, the risk is low, at least if all pipelines and storage sites are monitored closely. Leaks will occur, they also occur through cracks in natural CO2-reservoirs (sometimes killing vegetation, animals and people), but if watched closely (by means of sensors and computers) they could be stopped in time. Earthquakes or accidental drilling operations in a former storage site could release large clouds of the gas in a short time, but that should be prevented by using carefully chosen locations and painstaking indexing of storage sites.

Oxygen supply

All these risks might be manageable in the short term, but storing CO2 is – just like storing atomic waste – a very irresponsible thing to do in respect to future generations. Will people in 2178 still know where CO2 was stored? Will the corks hold until that date? Risk analysis does not seem to look too far ahead. Carbon capture will also bury a part of our oxygen supply, by the way. After all, we would not only store the C but also the O2. Oxygen is abundant in the atmosphere compared to carbon, so this might not be a big problem, but again, nobody seems to have investigated this yet.

--------------------------------------------------------------------------------------------------------

"Carbon capture will also bury a part of our oxygen supply. After all, we would not only store the C but also the O2."

--------------------------------------------------------------------------------------------------------

Carbon storage in the oceans was radically disapproved of by the IPCC because of the even larger risks, yet the idea returned last week and seems to be gaining support even with green thinkers.

Real solutions, please

Why introduce yet another expensive, energy-intensive and risky technology if there are so many other and better ways to solve the energy crisis? If we choose to build a whole new infrastructure of pipelines comparable to that of the existing oil and gas industry, why not build something like an extensive underground tubular freight network instead? This would be a real solution, which would considerably lower transport energy use and CO2-emissions.

Why not channel the huge amounts of money needed for the development of CCS to countries with tropical rainforests, so that they have a very good reason to protect them fiercely? Stopping deforestation, especially in tropical forests, would contribute more to the fight against global warming than carbon capture technology could ever do. Tropical forests store enormous amounts of carbon and they are not prone to natural forest fires.

--------------------------------------------------------------------------------------------------------

"Halting deforestation in tropical forests would contribute more to the fight against global warming than capture technology could ever do."

--------------------------------------------------------------------------------------------------------

Why not put into force a regulation that prohibits the construction of any more power plants that burn non-renewable energy sources? There is already an enormous energy capacity in the world, why don’t we chose to do it with the energy plants that we have? This would at last make energy efficiency useful (because progress in energy efficiency is now always negated by new and more energy hungry products and services). Still want more energy? Build a solar plant or plant a windmill.

These are just 3 ideas that would be effective without the need to adapt our lifestyle (which is, of course, also the attraction of "clean coal"). They would not solve everything, but at least they would be very welcome steps into the right direction, towards a solution.

All high-tech carbon storage strategies described in this article are no solutions, they are just attempts to limit the problem. Let’s hope that the next appeal of the International Energy Association and of the Science Academies of the world (an awful lot of brains there) will contain a trace of innovative thinking.

--------------------------------------------------------------------------------------------------------

Related articles :

The world's factory hall : almost 30 percent of energy use and 35 percent of CO2-emissions in China comes from the production of export goods.

Leave the algae alone : while the first generation of biofuels is wreaking havoc on the environment and the food markets, the second generation is set to make things even worse.

Why the electric car has no (wireless) future : the e-car has a conceptual problem.

Nuclear reactors, but no fuel : already in 10 to 15 years time, there will be a severe shortage of uranium.

Main page / Site map / Subscribe to feed or email

The Citroen 2CV: cleantech from the 1940s

2008-06-06T20:38:49+02:00

If you sometimes wonder why more energy efficient technology does not bring about more energy efficient cars, you should take a look at this collection of Citroën brochures (most of them in foreign languages) from the fifties, the sixties, the seventies and the eighties (more here, here, here and here). These are all original, scanned leaflets of the legendary French hippie car "2CV" or "Deux Chevaux" (known as the "duck" or the "goat" in several European countries). In spite of all the high-tech that has been squeezed into cars since then, the 2CV from 1949 is still more energy efficient than the smallest model of the French car designer today. Why?

--------------------------------------------------------------------------------------------------------

"If we really want more energy efficient cars, the 2CV shows us that we need not more, but less technology"

--------------------------------------------------------------------------------------------------------

The 2CV was produced from 1949 until 1990 and sold almost exclusively in Europe. At the time of its introduction the car had an engine capacity of 375cc, a maximum power output of 8 horsepower (DIN-HP) and a top speed of 65 kilometres an hour (40 mph). In 1954 the power was tuned up to 10 HP, which brought the top speed at 80 kilometres an hour (50 mph). In 1974 the power output rose to 24 HP, with a top speed of 102 kilometres an hour (63 mph). Later models had an engine capacity of 602cc, a maximum power output of 30 HP and a top speed of 120 kilometres an hour (75 mph).

500 kilograms

In spite of the much higher performance (an almost doubling of engine capacity, 4 times as much power output and a top speed almost twice as high) the weight of the hippie car remained the same at about 500 kilograms (sources: 1,2,3)

Today, there is not one car which comes even close to these figures. The smallest model of Citroën now on the market, the C1, weighs 810 kilograms (despite the use of lighter materials). The Citroën C1 has an engine capacity of 998cc and a maximum power output of 68 HP, and it does 157 kilometres an hour (98 mph).

8 x more power

Compared to the first 2CV models, the weight of the smallest Citroën today has almost doubled, while the top speed more than doubled and the maximum power output rose by a factor of eight.

Surprisingly, the fuel consumption remained more or less the same. The C1 consumes 4.6 litres per 100 kilometres (61 miles per gallon), the 2CV consumed on average 4.4 litres (64 miles per gallon).

More efficient

It is obvious that the engine of the C1 is many times more energy efficient than the engine of the 2CV, since the latter needed the same amount of fuel to power a much lighter and much slower vehicle.

In other words: if we would apply this modern technology in a car that is as light and slow as a 2CV from the fifties, we would now drive cars that scarcely burn any gasoline. Unfortunately, all technological progress was devoured by more weight, more power, more speed, more comfort and more electronics.

Safety belts

Part of the extra weight is the consequence of safety measures. Car manufacturers always hammer at this and of course more safety is a good thing. But, because at the same time the speed of the vehicles has raised substantially, and higher speeds mean more serious accidents, part of this progress is negated - just like the higher energy efficiency is negated by the higher performance. Moreover, safety belts are still the most important reason why traffic deaths plummeted since the seventies, and the weight of that mechanism is limited.

Comfort

Another reason for the higher weight and energy consumption is the advancement of comfort and electronics. The first 2CVs hardly had a dashboard that was worthy of the name. The vehicles had no heating or air-conditioning - there was not even a fuel gauge.

If you wanted to know how much gasoline you had left, you had to stop and poke a dipstick into the fuel tank. Until the sixties, the windscreen wipers were driven by the wheels - and therefore did not work when the car was not moving (unless you powered them by hand).

The windows of the 2CV could not even be opened mechanically, let alone by electricity: they were pushed open with your elbow. In today's cars all these applications (and dozens of new applications) are run by their own electric motor.

These electronics push up energy consumption because they raise the weight of the car and because they consume energy themselves (electricity which is delivered by the combustion engine).

If we really want more energy efficient cars, the 2CV shows us that we need not more, but less technology.

Brochures found via Tecnología Obsoleta

--------------------------------------------------------------------------------------------------------
Links :

These sites have more information on the Citroën 2CV (in English).

Also check out the brochures of the Panhard, the Hoffmann 2CV, the Dyane, the AMI, the plastic Mehari and other Citroën models.

--------------------------------------------------------------------------------------------------------
Related :

Solar powered cars
Cars on hot air
Why the electric car has no (wireless) future
Leave the algae alone

Main page / Site map / Search / Subscribe to feed or email
--------------------------------------------------------------------------------------------------------

Life without airplanes: from London to New York in 3 days and 12 hours

2008-06-04T14:31:04+02:00

Rising fuel prices are slowly killing airline companies. Can ocean liners save long distance travel and tourism?

Flying has become cheaper than taking a train or driving a car. Yet, environmental concerns, dwindling fuel reserves and fast rising kerosene prices are threatening to turn airline travel into a privilege for the rich again. This should not mean the end of mass travel or tourism, however. Before mass air travel took off in the 1960s, people crossed the globe in majestic passenger ships. Reintroducing ocean liners would be more than a nostalgic move: it could be a much more energy efficient (yet slower) way to travel.

--------------------------------------------------------------------------------------------------------

"If we would stuff people in the 'Queen Mary 2' like we fold passengers into airplane seats, the ship could transport more than 500,000 people"

--------------------------------------------------------------------------------------------------------

Airlines all over the world are struggling to lower the energy consumption of their machines - by designing lighter planes and more efficient engines, by getting rid of needless weight inside the cabin, or by flying at lower speeds. At the same time, they started investigating alternative fuels like algae, coconut oil, hydrogen and solar power. None of these things will save cheap airline travel when kerosene prices keep going up, though. There is a limit to energy efficiency, and alternative fuels for airplanes are highly speculative; maybe we should first try and see if we could run our cars on “green” fuels without destroying the environment before we try to implement them in jumbo jets. There is no alternative for kerosene.

Ocean liners

It has been said that there are no alternatives to airplanes either, when it comes to long distance travel. This might be true, but this alternative once existed and it disappeared because of planes. From the mid-19th century to the 1960s, millions of people crossed the oceans on passenger ships. Many hundreds of ocean liners were built. Most of these passenger ships were rather small and slow, but the superliners travelling the North Atlantic between Europe and North America were fast vessels with a much larger passenger capacity than that of a present plane (these sites have a good overview of historical ocean liners).

Motorised ships (first running on ~~steam~~ coal, later on diesel) brought a spectacular improvement in speed and reliability. While a sailing ship needed one to two months to cross the Atlantic, the first steamships made the journey in just 15 days. Steamships also made travelling times predictable, so that regular services could be established.

Both speed and passenger capacity went up fast during the following one hundred years. The SS United States (illustration above), which was in service from 1952 to 1969, still holds the record for the fastest ocean liner ever built: she (ocean liners are female) crossed the Atlantic in 3 days and 12 hours, at a speed of more than 54 km/h. That’s 10 to 20 times faster than a sailing ship.

Contrary to present cruise ships, ocean liners were built for speed. Nations were in a constant race to possess the fastest passenger ship.

The end

Ocean liners brought thousands of European immigrants to the US, Australia and Canada. They caused a modest tourist boom in the 1920s and they served as the most important means of transportation between European countries and their colonies. Yet, the fast growth of ocean liner traffic came to a rather abrupt end when cheap and fast air travel took off.

Propeller driven aircraft like the DC-3 , which were used in the 1930s and 1940s, revolutionised travel at medium distances, but their speed (240km/h) and range (1,650 km) were still too limited to present a danger for transatlantic ocean liners. With the arrival of jet powered planes at the end of the 1950s, however, ocean liners lost their reason for existence.

The death of distance

Most passenger ships were taken out of service in the 1960s - some were converted to cruise ships. Travelling at speeds of 900 km/h, jet powered planes lowered the travelling time between New York and London to less than 8 hours – 10 times faster than the SS United States. Jet engines killed distance: today, at least in theory, every place on Earth can be reached in less than 24 hours time.

However, it is interesting to note that distances shrunk at least as much by switching from sailing ships to ocean liners (which also introduced predictable travelling times) as they did by changing from ocean liners to planes.

90,000 kilowatts

Today, there is only one ship left that services transatlantic crossings: the Queen Mary 2. Taking this gigantic ship as an example, replacing air travel by ocean liners does not seem to make a big difference. At service speed, the ship has an engine output of 90,000 kilowatts. Since she can take 2,620 passengers, this comes down to 34 kilowatts per passenger.

A Boeing 747 has an average engine output of 65,000 kilowatts and can transport about 500 passengers. This comes down to 130 kilowatts per passenger (for comparison: cars can have a maximum engine output from 50 to 300 kilowatts and more).

Thus, to transport one passenger across the Atlantic, a plane needs 4 times more engine power than a ship.

--------------------------------------------------------------------------------------------------------

"Ferries take not only passengers on board but also their cars. Since the cars take more space and weigh more than the passengers, this is a very inefficient way of transporting people"

--------------------------------------------------------------------------------------------------------

Energy output does not say all there is to say about fuel consumption however, since it does not take into account the duration of the trip (see comments) and the fuel efficiency of the engines. It says even less about the emissions of toxic fumes and CO2, because marine engines burn much dirtier fuel than aeroplanes. Therefore, to make a case for a revival of ocean liners, more spectacular gains are needed. These are not hard to find.

Sardines

While passengers in a plane are squeezed together like sardines, the use of space on a ship like the Queen Mary 2 is far from optimal. The ship might have the speed of an ocean liner, but she is built like a cruise vessel. The Queen Mary 2 shows off 15 restaurants and bars, 5 swimming pools, a casino, a ballroom, a theatre and a planetarium, to give some examples. It has cabins with balconies. In a plane, each passenger is folded into a seat - and that’s it.

--------------------------------------------------------------------------------------------------------

A cross-section of the Queen Mary 2 compared to the Titanic and to the Airbus A 380, currently the largest passenger plane with a capacity of up to 850 people.
--------------------------------------------------------------------------------------------------------

500,000 passengers

How many passengers would fit in the Queen Mary 2 if they would have as less space and leisure options as the passengers of a large jumbo jet?

The ship has a gross tonnage of almost 150,000 GT – gross tonnage is a measure determining the internal volume (or enclosed space) of a ship, and comprises all spaces including engine rooms and crew cabins for instance. On the Queen Mary 2, this comes down to 57 gross tonnes per passenger.

A Boeing 747 has a gross tonnage of 129 GT – which comes down to 0.26 gross tonnes per passenger.

If we would stuff people in the Queen Mary 2 like we fold passengers in airplane seats, the ship could transport more than 500,000 people.

This would make transatlantic shipping definitely more eco-friendly than air travel, even without cleaner and more efficient engines. The Queen Mary 2 transporting 500,000 people would boil down to a power output of 0.18 kilowatts per passenger – comparable to the output of a well-trained cyclist and 700 times more efficient than the engine power per passenger of an airplane. Taking into account the duration of the voyages, the ship scores 70 times better than the plane.

Staten Island Ferry

Surprisingly, there are a few passenger boats that achieve similar figures. The best example is the Staten Island ferry, a passenger service that runs between Manhattan and Staten Island in New York. Ferries generally make far from optimal use of space, because almost all of them take not only passengers on board but also their cars.

Since the cars take more space and weigh more than the passengers, ferries are a very inefficient way of transporting people (some of them are also as luxurious as cruise ships). Yet, the Staten Island ferry does not take cars (anymore). These ferries – which have a passenger capacity of up to 6,000 people - have a gross tonnage per passenger of 0.38 to 0.55 GT. That’s only slightly more than the available space on a jumbo jet.

Of course, a trip on the Staten Island ferry only takes 25 minutes, and crossing the Atlantic folded in an airplane seat takes less than 10 hours. Stuffing 500,000 people in the Queen Mary would be a bit optimistic, because the trip would take more than 3 days – a bit of walking space might be very welcome. Transporting more passengers also means you have to take more food and more lifeboats, and it would mean significantly more garbage.

Therefore, let’s change those 500,000 theoretical passengers into only 30,000 passengers. This is not a random number.

A realistic option: 30,000 passengers

The Queen Mary 1, who sailed the Atlantic from 1936 to 1967, was just like many other ocean liners converted to a troopship in World War II, often transporting as many as 15,000 American soldiers. On one trip she took 16,082 soldiers – the largest amount of passengers ever transported on one vessel.

The gross tonnage of the Queen Mary 2 is almost two times larger than that of the Queen Mary 1, so it must be possible to transport 2 x 15,000 = 30,000 people on a ship like the Queen Mary 2. This would come down to 5 gross tonnes per passenger and 3 kilowatts of engine power per passenger.

These figures closely resemble those of the earlier ocean liners at the end of the 19th and the beginning of the 20th century.

The SS Kaiser Wilhelm der Große, a German ocean liner launched in 1896, had a gross tonnage of only 14,350 GT but could take 1,506 passengers, which comes down to a gross tonnage per passenger of only 9.5 GT. Even the infamous Titanic had a gross tonnage of only 18.5 tonnes per passenger. If the passengers of the Queen Mary 2 would have the same moving space as the passengers of the (luxurious) Titanic, the ship could still hold more than 8,000 people, three times more than its capacity today (more, in fact, since older steamships had much larger engine rooms).

Therefore, transporting 30,000 people on the QM2 is far from unrealistic or uncomfortable (this is uncomfortable). You would need 60 Jumbo Jets to transport 30,000 people.

Travel in a peak oil world

Every one of those 30,000 passengers on the Queen Mary 2 would have 20 times as much space than a passenger on a plane, while at the same time consuming 43 times less engine power (taking the view that both engines has similar efficiency). Taking into account the duration of the trip, the ship is 4 times more energy efficient than the plane.

Now this looks like an option that could be useful in a peak oil world. If flying would become too expensive for most of us, passenger ships might continue to provide mass travel and tourism at a democratic price.

We would pay another price, of course: the world would become bigger again. London and New York will be 3 days and 12 hours apart. Engineers could design faster ships, but only at the expense of much higher fuel consumption. The majority of fast ships (hovercraft, catamarans, hydrofoils) were taken out of service because of high fuel costs.

--------------------------------------------------------------------------------------------------------

"Unfortunately, governments and businesses prefer to keep up their faith in larger airports and faster planes as if there is no alternative"

--------------------------------------------------------------------------------------------------------

Switching back to ocean liners would surely lower long distance passenger travel and change life as we know it, but it would not be the end of modern civilization, nor the end of tourism or business. A weekend of shopping in Paris will be hard if you live in New York and only have 3 days free. But you could still get anywhere you want, if you take the time.

Unfortunately, governments and businesses prefer to keep up their belief in ever larger airports and ever faster planes (like the Lapcat) as if there is no alternative. We are running out of fuel, guys - time to change course.

Dirty fuel

One very important note: replacing planes by ocean liners would be an ecologically sound idea, but only if marine engines become cleaner. Most ships make use of very dirty (unrefined) diesel oil that needlessly poisons the air and heats up the atmosphere. This is not a technological but a political problem. All we need is (much) stronger regulation (which is on its way). Wind energy and solar energy can also help to lower the fuel consumption of ships (see this article on Low-tech Magazine).

Other issues to consider are wastewater treatment and garbage disposal – again things that should not be harmful, but at the moment they are because of a lack of sufficient laws and control (read more about the rather sickening practices of cruise ships here).

Pictures & illustrations: SS Normandie (intro) / SS United States & Mauretania / Wikipedia

--------------------------------------------------------------------------------------------------------
Related articles :

Green, slow air cargo
Kitesurfing cargo ships
Satellite navigation in the 18th century
Leave the algae alone
Planes on wheels

Main page / Site map / Subscribe to feed or email
--------------------------------------------------------------------------------------------------------