A few weeks ago, on June 8, an event took place at the Berlin Air Show that could be significant. There was the first-ever flying demonstration powered by 100 per cent algae biofuel.

Such fuel has a number of advantages over the traditional petrol, diesel or kerosene, as there is less nitrogen and sulphur oxide in the exhaust gases and far fewer soot type particles.

Like all biofuels, it is carbon-neutral, unlike the fossil fuels from crude oil, as the carbon dioxide taken from the atmosphere to grow the plant is returned when the fuel is used.

We need to remember, though, that algae are just underwater plants that capture carbon from the atmosphere through photosynthesis, and in normal conditions they are no more successful than oil palm, or grasses, or rape seed or maize, the main vegetable sources for conventional biofuels. They do have the advantage, though, of being able to use polluted waste-water and land that is unable to support agriculture.

However, algae plants are able to grow much faster than normal if the amount of carbon dioxide they absorb is increased above the general level and there have been some impressive results from ponds close to power stations where waste CO2 is available and the land is not used for other purposes.

High yields also need additional phosphorous, either mined or as a product from human waste, and so perhaps the ideal site for algae farming is between a coal-fired power station, or cement works, and a sewage works.

It is possible to grow algae in open water, in the sea, or in coastal lagoons, but in these cases it is difficult to supply extra CO2, keep out strains of unwanted algae that reduce the yield or maintain a stable water temperature, and so at the moment, it is proving very difficult to scale-up production to industrial levels.

Algae certainly has an advantage over other biofuels, as food crops are not involved, so it has little influence on the price of foods eaten by millions of humans and animals worldwide.

Similarly, it grows very quickly under the right conditions, allowing ten or more crops a year, but the restrictions on optimum growth mean that while it can make a small contribution to the fuel needs of the future, it certainly isn’t a direct replacement for fossil crude oil.

The future fuel needs of internal combustion engines will likely be a combination of reducing the demand, through much more efficient engines, slower driving and a variety of bio fuels, but the most significant contribution will be from electric motors topped up using renewable and nuclear power sources.