DEEP SEA ENERGY STORAGE

Global energy demand is anticipated to double by 2050 driven by the growth of world population (2 billion more people) and the development of emerging economies.

Finite fossil and conventional nuclear energy reserves will be under increasing pressure to meet this demand and their operational costs stand to increase.

Renewable resources are inexhaustible and have the potential to progressively replace these conventional resources while offering a solution to the increasingly urgent need of reducing greenhouse gas emissions.

Wind and solar energy resources are inexhaustible, but they are variable. This is because they are driven by inherently variable meteorology. Power grid operators have the responsibility to match demand and supply at all times; therefore they must develop operational solutions if they are to integrate increasing amounts of renewables on their grids. These solutions include demand-side management and smart grid interconnection. However effective, these solutions, alone, will not be able to match supply and demand without one critical catalyst: energy storage.

Less than 3% of the electrical generating capacity in the world can be stored today using the following technologies:

• Pumped Hydroelectric Energy Storage (PHES). This technology, which exploits the transfer of water between two elevations, represents more than 99% of the global electrical energy storage market. For economical operation prospective PHES installations require a large height differential (mountainous terrain).  
• Compressed Air Energy Storage (CAES). The development of this energy storage technology—which uses underground caverns or external containers as pressure vessels to store compressed air—is still minimal today although the potential is large. Conventional CAES requires the heating of gasses during decompression and typically uses fossil fuels to achieve this.  Researchers are working hard to make this process adiabatic by reusing the heat generated during compression to heat the gasses during decompression.
• Electrochemical Batteries, this technology group is likely the most familiar because of their ubiquity in consumer products.  Although perfect for such applications because of their high energy density, modularity and efficiency, they have found more limited energy storage potential for stationary grid-scale applications due their high cost. Their modularity makes them well suited for demand-side applications.

Other storage technologies such as pumped thermal energy storage (PTES) or hydrogen-based technologies could become contenders for the massive future electricity storage market.

The rapid growth of variable renewables like wind and solar necessitates an equally rapid growth of the energy storage sector.  Significant R&D work focusing on reducing the economic and environmental costs of each of these technologies is currently being expended to meet this future demand.  A demand in which we are convinced MGH will play a major role.