The Energy Storage Issue

When talk turns to alternative sources of power, one of the big issues that always tends to come up is the matter of storage. The reason so much discussion revolves around this is that the predominant alt energy sources — wind and solar — only generate power at certain times. Unlike hydro or coal/gas-powered utilities that are capable of continuous power generation as long as water is flowing downstream or fuel is available to stoke the fires, wind and solar energy are delivered periodically. When they’re “on” they can deliver more power than may be needed, when they’re “off” power may be needed that they aren’t capable of providing at that time. So the question has been how to store the excess power generated when the wind is blowing and the sun shining.

Brian MacLeery, principal product manager for Clean Energy Technology at National Instruments, says that this issue is quickly becoming less of a problem due to advances in battery technology, power electronics (especially IGBTs) and embedded controls (especially FPGAs). These technologies, he says,  are allowing grid level energy storage to becoming a reality and significantly drop associated costs.

Note: For those unfamiliar with the technologies noted above, IGBTs (insulated gate bipolar transistors) are three-terminal power semiconductor devices known for their high efficiency and ability turn on or off very rapidly. IGBTs are used in everything from electric cars and trains to variable speed refrigerators, air-conditioners and stereo systems. FPGAs (field programmable gate arrays) are integrated circuits that can be customized after manufacturing and programmed to perform complex, combined functions.

Putting alt energy storage into use as part of the energy grid is the next step in making alt energy a viable solution, and ABB recently announced one of the big steps it is taking in this direction. The company is partnering with EKZ, a Swiss distribution utility to build a one megawatt battery storage facility that will be integrated into the power distribution network in Dietikon, Switzerland (an industrial city that is the fifth largest city of the canton of Zurich). Evaluation of the energy storage project will be performed across key areas such as balancing peak loads, intermittent power supply and, obviously, the overall viability of such a solution for grid optimization.

ABB will supply and install the one megawatt lithium-ion battery-based solution with an initial capacity to store 350-500 kWhs (kilowatt hours) of electricity providing additional power to the grid on demand. EKZ will evaluate the connection and behavior of grid-linked battery storage and monitor various operational and economic parameters. The pilot is scheduled to be energized by the end of 2011 when EKZ will take over the operations.