New Storage System Innovation: Sun Energy's Final Hope

Online, July 19, 2013 (Newswire.com) - Sacha Fontaine
Author: Sacha Fontaine

The push for alternative energy sources has been greatly impacted by the hefty funding of solar panels resulting from the German Renewable Energy Act. The focus towards renewable energy has been assisted by the German Renewable Energy Act which has heavily funded the installation of solar panels; helping to lower the cost of production of photovoltaic (PV) panels. Efforts have been focused toward the development of renewable energy as a direct corollary of the subsidization of solar panels through the efforts of the German Renewable Energy Act. Outgrowths of this heavy funding include a conspicuous reduction in the supply price of photovoltaic panels. The German government hopes to expand its percentage of all energy production from green sources to 35% by 2020 and to 80% by 2050. With the intention of achieving its goals, the German government has put through a $2 billion a year outlay toward energy research. Globally, the German efforts have succeeded in influencing the cost of PV panel parts.

In the U.S., the Department of Energy (DOE) has implemented "SunShot", a global initiative to further lower the expense of PV energy systems by 75% before the end of the year 2020. Through the distribution of heavy government subsidies in the initial stages of research and development the initiative seeks to level the playing field between solar and traditional sources of energy in the hopes that once the prices reach comparable levels government subsidy can be phased out. At full implementation the cost of solar energy is projected to be as low as $.06 per kilowatt-hour, making it a viable alternative for consumers interested in being grid independent while maintaining minimal environmental impact. On the provider side, the initiative is an attractive solution for those companies with a desire to strengthen their grid redundancy while promoting an environmentally conscious image.

Increased unpredictability in the price of fossil fuels has also driven the push toward development of alternative fuel sources. The perilous footing of fossil fuels as a cost-effective source of energy looking to the future can only increase support for initiatives which push for more viable alternatives, including solar energy.

Assuming that the cost of solar energy equipment can be lowered to a competitive level, the intermittency of power continues to be one of the last obstacles to the widespread use of solar energy. Solar energy can go from 90% generation to less than 5% with the passing of one large cloud, putting the electrical supply and demand equilibrium completely out of sync. Such unpredictable fluctuation can be a serious problem in the maintenance of supply-demand equilibrium. Two of the biggest drawbacks to the use of energy storage systems include the prohibitive cost of large scale use as well as the high cost and limited lifespan of large capacity batteries.

DOE research and efforts have come to the conclusion that there is a large potential for a new battery design to mitigate these historic barriers to the cost-effectiveness of solar energy and assist in the mainstream adoption of PV by utilities and residential consumers internationally.

Dr. Yi Cui, an associate professor of Material Science and Engineering at Stanford University, has created a prototype battery that would regulate the natural fluctuations of renewable energies.

Traditional Redox flow batteries use two liquids, a cathode liquid and an anode liquid, separated by a membrane. The liquids interact via the membrane when undergoing the chemical reaction while generating or storing energy. A few problems arise from this design, the first being that regular maintenance is required for the membrane. The major hurdle is the very high cost of the materials needed to manufacture the membrane as well as the liquids which are typically made of dissolved vanadium, a rare metal.

The new battery designed by Dr. Cui's team is called a Lithium-Polysulfide Flow Battery and has numerous advantages over the traditional battery design. It uses only one liquid, a polysulfide cathode consisting mostly of lithium and sulfur which are both inexpensive materials. Additionally, the liquid is dissolved in an organic solvent which entirely sidesteps the corrosion issues found in today's batteries. The new design does not require a membrane, hence eliminating the frequent maintenance while rendering the entire design more compact. In place of a membrane, a plate of coated lithium metal precipitates the chemical reaction where lithium-polysulfide molecules absorb lithium ions when discharging and release them into the liquid when charging.

The team reports that in lab tests, the new design successfully cycled through 2,000 charges and discharges, showing that the prototype battery would have an ideal use coupled with solar or wind generation. The inexpensive, extended-life profile of this prototype battery might hold the key to widespread adoption of solar and wind energy.

Sacha Fontaine is the Head of Smart Grid Practice at Theorem Geo Associates, an engineering consulting firm focused exclusively on the electric utility industry. He has 13 years of Transmission & Distribution experience leading EMS/DMS and SCADA integration teams. He has helped utility clients prepare their DOE grant proposals and subsequently managed the projects through their entire lifecycle. Through Theorem Geo, Sacha has supported several of the largest Smart Grid initiatives including the 2 largest US power utilities, one of the largest engineering firms in the world and the 2nd largest Smart Grid Systems manufacturer. Sacha holds a bachelor's degree in Electrical Engineering from McGill University.

Sources:

German Renewable Energy Act: http://www.nature.com/news/renewable-power-germany-s-energy-gamble-1.12755

US Department of Energy's SolarShot Initiative: http://www1.eere.energy.gov/solar/sunshot/news_detail.html?news_id=16701

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