Lithium batteries: Powering future smart grids

Lithium batteries: Powering future smart grids

Renewable energy is creating the need for utilities to capture and store electricity for later use

BY TOM LARSEN
Palladium Energy
www.palladiumenergy.com

From Burlington, Vermont, to Bangalore, India, the global electrical grid is based on decades-old technology and for years has suffered from low levels of investment. All of that is changing as the industry enters an unprecedented era of innovation, and it is no coincidence that lithium battery pack technology advancement is happening simultaneously.

With the global growth of renewable energy, such as that produced by solar collectors and wind turbines, the need for utilities to capture and store electricity for later use is becoming increasingly important. According to a recent report by the Renewable Energy Policy Network, renewable energy now accounts for 20% of global electricity. As demand for power-generating capacity continues, lithium battery technology is playing a major role in meeting this need through stationary (large format) storage batteries and smart metering systems.

A modern electricity network

Primarily driving this demand is the smart grid, which has been in development since 2005. According to recent industry reports, in the period between 2009 and 2014, the United States’ smart grid industry revenues will double, and global revenue is projected to skyrocket to over $150 billion by 2014.

Increasingly, smart grids are delivering clean power from regions that have an abundance of sun or wind, which is why governments are offering incentives for building out new transmission lines and replacing aging ones with superconducting high-voltage direct-current power lines, which are super-chilled to boost capacity and can carry gigawatts of electricity.

The smart grid, using a computerized demand response program, pulls energy from distributed-power projects, like solar panels (that use photovoltaics to generate electrical power) and wind turbines, and from energy stored in lithium-ion batteries, then feeds it back into the grid and compensates the power generators accordingly.

Such a modernized electricity network is being promoted by many global governments and utilities (including those in developing countries) as a way of addressing energy independence, global warming and emergency resilience issues. It also presents these governments and utilities with an unprecedented need for storing large amounts of clean energy.

Li-ion: Stationary applications in smart grid

With about a dozen or so technologies vying for a segment of the smart grid’s stationary, large format energy storage market, many experts agree that the greatest potential lies within advanced battery technologies especially those that are lithium-based (see Fig. 1 ). Depending on a variety of market drivers, such as government intervention, global green movements, utility/grid energy requirements, infrastructure costs and consumer demand, revenue projections for lithium-ion large format energy storage applications are expected to grow up to 50% within the next few years.

Fig. 1: Lithium-based batteries target the energy storage market

Driving the utilities’ demand for reliable and scalable energy storage is so-called needle peaks in electricity usage that only occur for a small number of hours each day. It is expensive and inefficient to size capacity to these peaks. Therefore, large format energy storage is playing a significant role in supplanting peaking generation by leveling the loads and time-shifting periods of peak demand on the grid. Lithium-ion’s high energy density (storage) capabilities allow it to efficiently supply power and dampen power fluctuations during these daily needle peaks in electrical usage.

In addition to lithium’s long life span, low maintenance costs, ease of installation and space-saving attributes, which are all very important in the development of micro-grids, utilities are becoming increasingly attracted to this technology. In addition, expected price drops stemming from increased worldwide production capabilities and technology improvements will likely increase lithium-ion stationary battery pack use within smart grids and other large scale energy storage applications.

End users and lithium-ion

While utilities manage peak energy storage, they also try to reduce consumer demand during peak usage periods. Machine-to-machine technologies communicate with smart meters in homes and offices, allowing consumers to monitor when energy demand is high and track how much electricity is used at certain times. To motivate consumers to cut back, electricity prices are increased during high-demand periods and decreased during low-demand periods.

Due to peak leveling, electric smart meters need reliable backup power in order to maintain their real time clock and avoid disruption in the grid’s unique two-way communication. Lithium thionyl chloride (Li-SOCl2 ) is one of the ideal chemistries for smart meters because it can operate in a range of global climates with solid reliability and minimal maintenance.

Li-SOCl2 cells are likely to be cylindrical in shape and light-weight due to their metallic lithium anode. In addition, the cell’s liquid cathode is comprised of a porous carbon current collector filled with thionyl chloride. With a voltage of 3.6 V, Li-SOCl2 batteries are available in ½ AA to D format, and feature bobbin construction for extended discharge as well as spiral electrodes for power applications such as smart meters.

Key specifications for Li-SOCl2 :

Operating temperatures from 40 to 85C.Inherent long life from 10 to 20 years without maintenance or replacement.End-of-life indicators built into the smart battery design.High energy density: 3.6 V/19 Ah.Low self-discharge: <1%/year

In 2008, there were 46 million smart meters worldwide, but Pike Research predicts that by 2015, more than 250 million smart meters will be installed across the globe, representing a penetration of 18% of all electrical meters. In addition, over the next couple of decades, billions of electrical measuring devices alone could be replaced by smart meters worldwide.

The increase in smart meters can be attributed to global government incentives and mandates, such as the American Recovery and Reinvestment Act, in which the Obama administration called for the installation of 40 million smart meters by allocating $4.5 billion for direct investment in the smart grid. Considering that every meter must be equipped with reliable backup battery power, the market presents a strong opportunity for lithium battery technology.

Powering the future grid

Recently, the industry has seen an increase in end user innovation, which is continuing to fuel consumer demand for the smart grid. For example, automobile manufacturers are beginning to connect lithium-ion-powered electric vehicles (EVs) to the smart grid.

General Motors and OnStar recently launched a pilot program to wirelessly track and direct the EV’s charging behavior, which could potentially lower the costs to extend smart grid management features to EVs. In addition, private companies such as People Power are offering smart meter users the ability to manage home energy remotely using smart phone applications.

As the smart grid continues to proliferate and provide consumers with added functionality, one thing is certain: Lithium battery technology will expand alongside this new electrical grid to power a more sustainable global future. ■