The market
The International Energy Agency has calculated that $10 trillion will need to be invested in energy globally by 2030. The Chinese government has already planned to invest $1.3 trillion in additional electricity supply. This $10 trillion represents the equivalent of 1% of global GDP over the entire period. However, Russia's share of investment in GDP is closer to 5%, and Africa's exceeds 4%, compared to just 0.5% for OECD member countries. Half of all investments aimed at increasing electricity generation capacity in the 27 member states of the European Union are dedicated to renewable energy. However, the challenge with renewable energy is that wind and solar, the two main sources of green energy, are unstable and require investment in baseload power. When there is no wind and clouds block the sun over the European continent, the total electricity supply from these two main sources, which will represent 138 and 30 GW respectively in 2030, could drop by 20 GW in a single day. Therefore, for every additional unit of renewable energy, energy providers calculate that they must invest an additional 0.9 units in baseload power. Alternatively, they could invest in electricity storage, which tends to be more expensive. Baseload power operates 365 days a year without interruption. The preferred energy sources for this stable supply are combined cycle natural gas, at an investment cost of $1,000/kW, coal-fired power plants at $3,000/kW, and nuclear power at $5,000/kW. While hydroelectric and geothermal energy can also be part of the baseload energy portfolio, their availability is more location-dependent. The investment cost in baseload supply is determined by the type of financing. Banks are keen to finance the construction of baseload generation facilities with long-term power purchase agreements (PPAs) because these carry low risk. However, a $1 billion investment in a base station comprises 65% construction costs and 35% operating and financial charges. If the financing were based on equity investments, the return could increase by at least a third.
Innovation
Given that most baseload electricity is supplied by coal and nuclear power, there is a search for renewable energy sources that can provide not only intermittent but also baseload power. Concentrated solar power (CSP) is one of the promising renewable energy technologies. It can collect and store energy in pressurized steam, molten salt, or purified graphite. Wind power has been combined with a wide variety of storage systems, including pumped hydro storage, batteries, regenerative fuel cells, flywheels, and magnets. However, the most promising appears to be compressed air energy storage (CAES), which stores air in underground (geological) structures. The challenge remains that these storage facilities require additional capital investment and increased maintenance, further raising the cost per kWh. Stein Erik Skilhagen, Vice President for Osmotic Power at Norwegian State Energy Corporation, observed the power of a redwood tree that draws water up to 100 meters. The tree harnesses the difference in concentration by pushing moisture upwards. When fresh water from the mountains flows into salty seawater, a large amount of energy is released by the change in salt concentration. He observed that the flow of rivers into the ocean is a continuous flow thanks to the natural cycles of evaporation, condensation, and precipitation. Therefore, the energy released by the difference between higher salinity, which has higher pressure, and lower salinity, which has lower pressure, could operate 365 days a year without interruption. This is an ideal basic renewable energy source. Simply harnessing the concentration differences that generate pressure differences implies that the energy source originates from the realm of physics—the kind of innovation proposed by the Blue Economy. This energy source is also known as osmotic power or salinity gradient power, harnessing the difference in salt concentration between fresh river or rainwater and salt water. The technique of generating electricity from this gradient has been tested in the Netherlands using reverse electrodialysis (RED) and has been implemented in Norway using delayed pressure osmosis (PRO). The membrane separating the two water types is key to its success. As the fresh water migrates to the saline side, it creates a pressure difference. This pressure is used to rotate the turbine. Like reverse osmosis (RO), this PRO process generates a byproduct. However, unlike RO, which produces highly concentrated brine, PRO produces brackish water that could be used in algae production, enabling the co-location of RO-based energy crops 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. One square meter of membranes currently produces 3W of electricity. The introduction of a new type of membrane is expected to increase the power output to 5W. Experts consider this the minimum required to make the PRO technology competitive. Operating costs must include filtration. The formation of a biofilm on the membrane rapidly reduces its efficiency. This is where the vortex, a proven Swedish technology tested in Spain, could provide a low-cost solution and further reduce investment and maintenance costs.
The opportunity
The application of osmosis to generate electricity is limited to areas with abundant fresh and salt water. This means that any estuary flowing into the sea has potential. Experts have already established that the potential of osmotic power in Europe is three times greater than the combined potential of wind and solar power. Its ability to operate 24/7 makes it as competitive as gravity-fed energy. Hydro-Québec, the Canadian electricity company, has calculated that the St. Lawrence Estuary has a potential of 12 gigawatts. Countries with abundant rainfall and long coastlines are all looking to tap into this potential. The Tokyo Institute of Technology and Kyowakiden Industrial Co. of Nagasaki have begun testing osmosis in Fukuoka. Stein Erik Skilhagen believes that once a few reverse osmosis plants are operational, the world's leading membrane suppliers will apply their existing expertise in reverse osmosis membranes for producing drinking water from saltwater to reverse osmosis. While Europe, North America, and Japan have already begun planning such facilities, the real future lies in the world's major river deltas where energy is scarce and an additional basic supply is urgently needed: the Yellow and Yangtze Rivers, Mekong, Ganges, Pearl River, Brahmaputra, Nile, Gambia, Okovango, Niger, Volta, Zambezi, Orinoco, Amazon, Paraná, Lena, and Yenisey.
