Within 10-15 years, it will be technically possible to produce sustainable and economically viable biodiesel from micro-algae on a large scale, say Dutch scientists.
They say that technological innovations during this period should extend the scale of production by a factor of three while, at the same time, reducing production costs by 90%.
Two researchers from Wageningen UR (University & Research Centre) believe this to be possible.
Energy has reported on the future potential of algae from time to time. What the Dutch duo has done is apply the principle to wastewater.
They say that, by producing microscopically small algae in bulk in large-scale installations, Europe should be able to become independent of fossil fuels in a sustainable way.
Algae could even contribute to the sustainable production of food. To cultivate algae on a large scale, fertilisers (nitrogen and phosphates) could be extracted from manure surpluses and wastewater, with CO coming from industrial residues.
The energy source for algae is sunlight. Biodiesel and an almost unlimited quantity of protein and oxygen are the sustainable products of this process. The amount of fresh water consumed in algal cultivation is minimal because seawater can be used.
In a nutshell, that is the idea put forward by Professor René Wijffels and Dr Maria Barbosa, of Wageningen UR.
According to calculations on energy consumption in transport in Europe, almost 0.4billion cu m of biodiesel would be needed to replace all transport fuels.
The cultivation of micro-algae would requires 9.25million hectares of land – equal to the surface area of Portugal – assuming a yield of 40,000 litres of biodiesel per hectare, to supply the European market.
Algae produce the maximum quantity of oily substances when growing under stress. Such conditions can, for instance, be induced by a shortage of nutrients such as nitrogen and phosphate.
Algae are much more efficient at converting sunlight and fertilisers into useable oily substances than agricultural crops such as oilseed rape. It is not even necessary to have full sunshine for algal cultivation, which is why it is possible to design reactors that look like vertical plates on to which the light shines from one side.
In this way, the Dutch duo argue that it is possible to produce 20,000-80,000 litres of oil per hectare. In comparison, one hectare of oilseed rape or oil palm yields only 1,500 or 6,000 litres, respectively.
The 5,000 tonnes of algae (dry matter) now produced annually in the whole world is very valuable.
The price is high because algae can make rare (and therefore expensive) substances such as carotenoids and omega 3 fatty acids that are converted into high-quality products such as food supplements.
It is s extremely expensive when compared with the cost of palm oil used as a fuel. However, palm oil and other fuel crops are controversial.
To investigate whether the use of algae as biofuel generators is possible, a feasibility study was carried out on scale enhancement in algal cultivation This showed that, presently, the cost price could be reduced, according to Wijffels and Barbosa
They say that, by making use of residues such as wastewater and CO from exhaust gases, by improving the technology and by shifting production to sunnier countries, it would even be possible to reduce the price to one-tenth of that level.
Even then, however, the production of bioenergy from algae would not be financially viable. To achieve that goal, the whole algal biomass would have to be utilised. This consists of roughly 50% oil, 40% proteins and 10% sugars.
Wijffels and Barbosa say that algal proteins offer interesting possibilities. If all transport fuels were to be replaced by algal oil on a European scale, 0.3billion tonnes of protein would become available as well.
That is 40 times more than the amount of protein in the soya that Europe imports each year.
Thus, algae would allow us to produce food and feed proteins as well as sufficient quantities of biofuel.
In order to manufacture biofuels from agricultural crops such as oilseed rape, 10,000 litres of fresh water are required to produce each litre of fuel.
This is an incredibly large volume, say the scientists. By cultivating algae in seawater, it is possible to achieve the same result with just 1.5 litres of fresh water/kg of product.
With the aid of sunlight, algal growth requires 1.3billion tonnes of CO (Europe produces 4billion tonnes per year, mainly from fossil fuels) and 25million tonnes of nitrogen (wastewater and fertilisers contain 8million).
In other words, algal cultivation would not normally compete with food production, which is very important given the concerns now being voiced about energy crops displacing food cropping.
A sustainable pilot-study facility, AlgaePARC (Algae Production and Research Centre), will soon be starting up in Wageningen.
Here, it will be possible to study the scaling up of algal production and to compare various technologies, taking into account energy costs for building, production and logistics during the production of biofuels from algae.
Wijffels and Barbosa say algae need to be interesting as a food source for fish and shellfish farming within five years. However, in that regard, they are more than 40 years out of date as this work was carried out in the UK by the White Fish Authority (now Sea Fish Industry Authority).
That said, the duo claims that, five years after that, it should be possible to achieve applications such as providing protein sources in foods as well as basic chemicals for the manufacturing industries. Then, in 10-15 years’ time, biofuels should be available.