The market
The International Energy Agency has calculated that it would be necessary to invest $ 10,000 billion in energy worldwide by 2030. The Chinese government has already planned to invest $ 1,300 billion in a additional electricity supply. These $ 10,000 billion represent the equivalent of 1 % of world GDP throughout the period. However, the share of Russian investments in GDP is closer to 5 %, and Africa exceeds 4 %, against only 0.5 %for OECD member countries. Half of all investments intended to increase electricity production capacity in the 27 Member States of the European Union is devoted to renewable energies. However, the challenge of renewable energies is that wind and solar, the two main sources of green energy, are unstable and require an investment in the basic supply. When there is no wind and the clouds block the sun on the European continent, the total supply of electricity from these two main sources which will represent 138 and 30 GW in 2030 respectively could fall by 20 GW in A day. This is why, for each additional renewable energy unit, energy suppliers calculate that they must invest 0.9 additional unit in the basic supply. Alternatively, they could invest in the storage of electricity, which tends to be more expensive. Basic electricity operates 365 days without interruption. The privileged energy sources for this stable supply are natural gas with combined cycle, at an investment cost of $ 1,000 / kW, 3,000 dollars / kW coal power plants and nuclear power at $ 5,000 / kW . Although hydroelectricity and geothermal energy can also be part of the basic energy portfolio, their availability is more determined by the location. The cost of investment in the basic supply is determined by the type of financing. Banks are wishing to finance the construction of basic production facilities with long-term sales contracts, as these have a low risk. However, an investment of $ 1 billion in a base station includes 65 % in construction costs and 35 % in financial charges and costs. If funding was based on capital investments, the yield could increase by at least a third.
Innovation
Since most of the basic electricity is supplied by coal and nuclear, there is a search for renewable energy which can provide not only intermittent electricity, but also basic electricity . Concentrated solar energy is one of the promising technologies of renewable energies. It can collect and store energy in pressure steam, melted salt or purified graphite. Wind energy has been combined with a wide variety of storage systems, including hydroelectric accumulation by pumping, batteries, regenerative fuel cells, ruffles and magnets. However, the most promising seems to be storage of compressed air energy (CAES) which stores air in underground (geological) structures. The challenge remains that these storage facilities require additional investment costs and increased maintenance, which further increases the cost per kWh. Stein Erik Skilhagen, Vice-President for Osmotic Power at the Norwegian statkraft observed the power of a sequoia which sucks water up to 100 meters. The tree uses the difference in concentration by pushing humidity to the top. When mountain fresh water flows into salted seawater, a large amount of energy is released by the change in concentration of salt. He observed that the flow of rivers in the ocean is an endless flow thanks to the natural cycles of evaporation, condensation and precipitation. Consequently, the energy released by the difference between a higher salinity which has higher pressure and lower salinity with lower pressure could work 365 days without any interruption. It is an ideal basic renewable energy source. The simple exploitation of concentration differences that generate pressure differences implies that the energy source comes from the field of physics, the type of innovations proposed by the blue economy. This source of energy is also known as osmotic power or power of the salinity gradient, exploiting the difference in salt concentration between river or rain fresh water and salt water. The electricity production technique from this gradient has been tested in the Netherlands by reverse electrodialysis (RED) and has been put into practice in Norway by delayed pressure osmosis (Pro). The membrane that separates the two types of water is the key to success. While fresh water migrates to the salt side, it creates a pressure difference. This pressure is used to run the turbine. Like reverse osmosis (OI), this pro generates a by-product. However, unlike the ii which produces brine with high salt content, the pro produces brackish water which could be used in the production of algae, which allows the co-location of energy plants based on 'Oi and algae farms. This grouping of economic activities makes it possible to generate multiple cash flows, another characteristic of the innovations proposed by the Blue Economy.
The first cash flow
Statkraft has decided to invest $ 8 million in a demonstration unit. A square meter of membranes currently produces 3W of electricity. We expect the introduction of a new type of membrane to increase power to 5W. Experts consider that this is the minimum required to make professional technology competitive. The operating cost must include filtration. The creation of a biofilm on the membrane quickly reduces its effectiveness. This is where the vortex, a Swedish technology proven and tested in Spain, could serve as a low -cost solution and further reduce investment and maintenance costs.
The opportunity
The application of osmosis to produce electricity is limited to places where fresh and salted water is abundant. This implies that any estuary that flows into the sea has potential. Experts have already established that the potential of osmotic energy in Europe is three times higher than the combined wind and solar potential. The fact that it can operate 24 hours a day, 7 days a week makes it as competitive as gravity. Hydro-Québec, the Canadian electricity company, calculated that the St. Lawrence estuary has a potential of 12 gigawatts. Countries with abundant rainfall and a long coastline all expect to exploit this potential. The Tokyo Institute of Technology and Kyowakiden Industrial Co. of Nagasaki began to test osmosis in Fukuoka. Stein Erik Skilhagen thinks that a few osmosis installations are in service, the world's main suppliers of membranes will apply their existing know-how in terms of reverse osmosis membranes for drinking water production to drinking membranes. from salt water. While Europe, North America and Japan have already engaged in the planning of installations, the real future is for large river deltas in the world where energy is rare and where an additional basic supply is Urgent: the yellow and yangtse rivers, mekong, ganging, pearl, brahmapoutre, nil, gambia, okovango, niger, volta, zambezi, orinoco, amazonia, parana, lena and yenisey.
