The full text of this Vital Signs Online article can be found here.

Smart meters are just one component involved in emerging smart grid networks. Smart meter deployments are increasing, with many nationwide installations planned worldwide. (Source: Wired)

Global investment in smart grid technologies rose 7 percent in 2012 from the previous year. On top of direct investments, numerous countries around the world are making headway on smart grid regulatory policies, development plans, and frameworks to support future grid infrastructure upgrades.  Smart grids consist of many different technologies serving different functions. Smart grids are commonly defined as an electricity network that uses digital information and communications technology to improve the efficiency and reliability of electricity transport. Such modernized grids are becoming more important as current grid infrastructure ages and regions begin connecting more variable generation from renewable energy sources into the electricity network.

The United States had the highest investment of all countries in 2012 despite seeing a 19 percent decrease in smart grid spending from 2011. While the U.S. federal government has funded smart grid development and supported deployment projects throughout the country, many individual utilities are contributing their own efforts to update grid infrastructure. At the beginning of 2012, U.S. smart grid development efforts had installed 37 million smart meters, covering 33 percent of American households. Continued efforts by utilities to deploy smart grid solutions will become increasingly important in the U.S. as federal funding initiatives enacted under the American Recovery and Reinvestment Act of 2009 begin to expire.

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electricity, energy, energy storage, Green Technology, smart grid, smart meters, Vital Signs Online

In a previous blog, I discussed the value of pumped-storage hydro systems, especially when it comes to integrating intermittent renewable energies like wind and solar into a power system. However, traditional pumped-storage hydro systems require two reservoirs of fresh water (one upper and one lower), which are not always available at locations that might otherwise benefit from an energy storage system. An exciting technology that tackles this problem – requiring only one on-land reservoir – and that has gained recent momentum is seawater pumped-storage hydro.

An aerial view of the seawater pumped-storage hydro system on Okinawa Island (Source: wastedenergy.net)

Seawater pumped-storage hydro works similarly to traditional systems. Excess electricity from fossil fuel, nuclear, or renewable energy power plants is used during periods of low power demand to pump water uphill to be stored in reservoirs as potential energy. Then, when demand peaks the reservoirs are opened, allowing water to pass through hydroelectric turbines to generate the electricity needed to meet power demand. The main difference for seawater pumped-storage is that instead of having a lake, river, or some other source of fresh water serve as the lower reservoir, these systems pump salt water uphill from the ocean to a land reservoir above. This lowers the system’s fresh water footprint and greatly expands the potential for pumped-storage hydro worldwide because seawater pumped-storage is much less site-specific than traditional systems.

There is currently one seawater pumped-storage hydro system operating in the world, on the northern coast of Okinawa Island, Japan. The system began operation in 1999 and has the potential to generate up to 30 megawatts (MW) of power. The hydropower plant has a total head – the vertical distance, or drop, between the intake of the plant and the turbine – of 136 meters and the upper reservoir is located just 600 meters from the coast.

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Caribbean, energy storage, hydropower, Innovation, pumped-hydro storage, renewable energy, wind power

The ability to store energy efficiently and cheaply would solve one of renewable energy’s greatest challenges. Many renewable resources, such as wind and solar, cannot provide steady energy output. This represents a challenge to distribution networks, which have been designed to be fed with a steady electricity supply from centralized power plants but which encounter problems when supply fluctuates.

From Renewable Energy to Methane - The Process explained

Energy storage would allow dispatchers to “flatten” power peaks and “fill” gaps that occur with use of renewable energy. In reality, this means that electricity is stored when too much of it is produced, and consumed later when not enough power is available.

Today, pumped hydropower is the most widely used energy storage technology, although other technologies also are available, including compressed air storage or electrical batteries. But the storage capacity of existing technologies is limited, and researchers and companies are working to develop alternatives. Some of them are really promising; others deserve at least the label “interesting”.

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energy, energy efficiency, energy storage, Fraunhofer Institute, Germany, natural gas, renewable energy, Renewable Methane, technology series

That's some heavy lifting (authorstream.com/Heindl)

One of the main barriers to the diffusion of renewable energy sources such as wind and solar power is their inherent variability. If excess energy produced could be stored cheaply and used during times of lower production, this issue could be largely mitigated. Several technologies are under development as possible options for storing energy from the grid, including batteries that store energy in chemicals, mechanical flywheels that store energy as rotational energy, and hydroelectric dams that convert mechanical energy into electrical energy by retaining and channeling rivers.

And, on the bizarre end of the spectrum, we can find a hydraulic water storage system proposed by physicist Dr. Eduard Heindl, a professor at Furtwangen University in Germany.

Heindl’s idea is to store potential energy by using water as a hydraulic fluid to transfer power underground. A project would involve carving out a gigantic cylinder of dense rock, such as granite, by drilling two underground circular tunnels with 500-meter radiuses, one tunnel several hundred meters deep and another at a 1-kilometer depth directly underneath the first. A saw mill would be lowered into the tunnels connected to a saw mill at the surface via a wire saw. The saw mills would work away at the rock to separate the cylinder from the deposit. A seal would then be placed within the first tunnel to close off the system to prevent the loss of potential energy.

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energy storage, grid infrastructure, technology series