Perhaps you had to walk along the seacoast at the end of summer, see the mountains of seaweed, carried by the surf to the shore, rotting, exuding an unpleasant smell … This experience is from the process known as fermentation, during which a huge amount of energy is released. Scientists ponder – why not use it, if the world ocean seems to offers this almost inexhaustible resource to man?
Japan: fermentation on an industrial scale
It is not surprising that the world first to set out to turn algae into a source of energy were the inhabitants of the island state – Japan, which, moreover, had a very practical interest in the use of alternative energy in all its forms. In a country that does not have its own reserves of natural hydrocarbons, wind, sun and ocean have become great sources of national welfare in the 21st century.
In short, Japanese technology includes the processes of harvesting algae, grinding them with the addition of water to the state of the liquid, and then its fermentation using microorganisms. As a result of this industrial fermentation, methane gas is released, which then enters the gas engine. It rotates the generator, which in turn produces electricity.
This is the way that Tokyo Gas power plant operates, erected with the participation of NEDO (New Energy and Industrial Technology Development Organization) experts. This plant processes tons of algae per day, turning them into twenty thousand liters of methane. To increase the generator’s power, pure natural gas is added to the methane produced from the algae. The generator’s output of ten kilowatts is enough to provide electricity for a dozen houses in the country’s capital – those that occupy the offices and production facilities of Tokyo Gas. It seems like too little to consider, but the company management sees an opportunity and government interest in clearing the seashore and putting the waste to best possible use.
Stanford Experiment and Minnesota Farms
Scientists of one of the most status-based universities in the world – Stanford – set out to get electricity directly from algae. Their cells produce electricity in the process of photosynthesis, in which plants convert sunlight into chemical energy and then into electric current. To get it, american researchers have made a microscopically thin gold nanoelectrode, which penetrated into the unicellular alga Chlamydomonas reinhardtii, namely, into its chloroplasts. At the same time, the experimental representative of the oceanic flora did not perish and gave up electrons excited by light, instead of habitually using them to synthesize sugars and polysaccharides.
The current strength obtained from a single cell reached 1.2 picoamperes.This is just an experiment, the results of which can be applied industrially, with the further development of technologies. However, algae,both sea and river, are also excellent for biofuel production.
Algae are ideally suited for biofuel production in terms of biomass yield per square meter of cultivated areas. They are decomposed easily by microorganisms – while not containing toxic substances, like sulfur. Finally, algae provide a high percentage of output of ready-to-use fuel – for many species it can easily exceed half of the original mass.
Here we need to remember that American scientists, perhaps the first in the world, have began to experiment with large scale algae growing as a source of energy – it happened in the seventies of the last century, during the oil crisis. It was then that within the framework of the ASP (Aquatic Species Program) the NREL laboratory decided to establish a list of subspecies of algae suitable for the production of biofuel. For its development, open-air transparent “tanks” were used, in which carbon dioxide was supplied from the neighboring CHP plant burning coal. As a result, a list of more than three hundred items containing the name of algae suitable for the production of biofuel was compiled.
These are mainly diatoms and green algae species (Chlorophyceae), which, when cultivated in optimal field conditions, can achieve a productivity of 1850 gallons per acre. For comparison, in rapeseed, especially widely used for biofuel production, the yield does not exceed 127 gallons per acre.
In our time at a sewage treatment plant in Minnesota, American scientists are experimenting, growing algae in a wastewater filtrate. The environment, rich in phosphates and nitrates and pernicious for the river, proved to be favorable and nutritious for algae. The required carbon dioxide can be obtained here – burning the sediment out of the drains.
Some species of algae have long been grown for the needs of the pharmaceutical and food industries (additives, components of dietary nutrition, etc.) – however, the volumes of this production are not comparable with those required for biofuel production.
It should be noted the fundamental difference in the collection of algae from their industrial production for further processing into biofuel. In the second case, a huge amount of water is required, which localizes this process in areas adjacent to large water bodies.As for the types of alternative fuels that can be produced from algae, there are many such: bioethanol, biodiesel, biohydrogen, biogas, biobutanol – and, finally, just biomass that can be burned to produce heat or electricity using the “Japanese” method.
“Hanging Gardens” of Israel
This Middle Eastern country with an abundance of sun and sea water is an ideal place for growing algae, as well as their subsequent processing into biofuel. The Israeli company UniVerve is developing a new project in Dimona. The goal is to develop an economically sound and technologically stable process of converting aquacultures into clean energy. Most algal strains selected during the development of the project already demonstrate a high content of oils and good growth in salt water with low operating costs for farm equipment. Although in this case it would be more correct to say – a garden, a hanging garden.
The Israeli company developed and patented the original algae growing system in V-shaped hanging tanks. The technology is called HAVP; Its feature is its ability to provide the maximum amount of light necessary for photosynthesis. In addition, HAVP allows you to significantly reduce the cost of production compared to traditional ponds – containers are easy to maintain, easy to clean; The collection of algae is much less labor-intensive. At the end of the growing cycle, the algae is dried and processed into biotops.
Bioreactors mounted on walls
Vertical landscaping of buildings, the so-called “living blinds” – is not only a trend of landscape design. Panels from living algae on the walls of homes can contribute significantly to their economic energy supply, acting as a kind of bioreactors. In addition to their obvious environmental friendliness, such systems are designed to generate electricity and partially reduce power consumption from the central network. The technology is still under development – it is actively engaged by specialists from Germany, France and a number of other countries.
One of their agencies developing such bioreactors is the French X-TU, under the patronage of the University of Nantes, the developing project Symbyo2, whose name indicates a symbiosis of «concrete and green jungles», to which urban development of the future should turn. Within the framework of the project in Saint-Nazaire, located near the university laboratory, the agency’s staff are installing special panels on building walls, containing algae, to which water is fed with all the nutrients necessary for the growth of microorganisms. Scientists argue that the use of such systems can at least halve the consumption of heat by buildings.
Currently, the project of French researchers is in the stage of scientific experiment. The next step is to install “green” panels on the facade of the local incinerator AlcéadeNantes – as scientists believe, the heat and carbon dioxide released during the thermal utilization of waste will create the best environment for the life of algae. On closer inspection, the system is not that complicated. It is a special frame, on which many containers without lids are attached. With the help of an automatic watering system, water and necessary minerals are supplied. The creation of “greenhouse” conditions for the growth of algae will allow us to understand what maximum energy yield from them can be expected in the future. For our country, vertical gardening systems using algae are something completely new: in Russia, “green panels” of this kind can be seen only as exhibits at international specialized exhibitions.
Prospects of biofuel from algae
On a historical scale, the idea of processing algae in biofuels is new: it is not yet fifty years old. In addition, its practical development began, by and large, only in the last decade. The benefits of such biofuels are obvious – a huge resource of unpretentious raw material with the possibility of almost complete processing, absolute environmental friendliness of the production process, low labor costs, and the opportunity to use industrial waste from other enterprises (primarily carbon dioxide). With regard to the cultivation of algae, it occurs very quickly – some of their subspecies double their volume every 48 hours.
Collecting this resource is also eco-friendly as humans will hardly be able to deplete the astounding volume of algae in the oceans.
Of course, with all the listed advantages, the production of fuel from algae is associated with a number of difficulties. Among them – the lack of an “ideal” culture, the need to improve technology, while associated with the use of large amounts of water, and, of course, irrational conservatism, sometimes hindering the attraction of the right amount of investment in a new promising direction. Be that as it may, the production of biofuel from algae year by year finds an increasing number of supporters in different countries. According to some expert assessments, by the end of this decade, the aggregate turnover from algae processing may reach $ 100 billion.