Wanted: An inexpensive, efficient, and reliable energy storage device

Published on Tuesday, 07 May 2019

Published by Kelly Hewitt on Tuesday, 07 May 2019

Hot topic: Lithium batteries are one way to store energy generated from renewable sources, but overheating and other concerns limit their potential. Photo: ADB
Hot topic: Lithium batteries are one way to store energy generated from renewable sources, but overheating and other concerns limit their potential. Photo: ADB

While I understand the possibilities of renewables there are issues of storage that plague each. In fact, when it comes to the power sector, storage in general is an issue. Landfill gas, biomass and geothermal provide renewed fuel sources that can partially displace conventional fossil fuels – oil and gas – in power generation. Yet, landfill gas, biomass and geothermal – once captured – needs storage if not fed immediately and directly into a power generator.

However, storing landfill gas, biomass and geothermal in a safe environment and at a level where energy is not lost is a difficult undertaking. Wind, solar, and wave energy – like landfill gas, biomass and geothermal – also has limitations, primarily, due to storage constraints. Yet, wind, solar and wave pose different storage problems. These energy sources provide intermittent availability – and hence intermittent power delivery. And, once generated, there is a lack of long-term, durable and sustainable storage devices to contain wind, solar and wave energy. This is why the renewable energy technology with the greatest impact on the overall supply equation is a sound, small footprint, energy storage device that is inexpensive, efficient, and reliable.

  Today’s overheating energy storage devices need improvement 

While there is much activity in the global market to create a storage device for generated power, one has yet to be perfected. There are fuel cells, flow battery, and lithium battery technologies but they all have space for improvement.

Fuel cells generate electricity by chemical reaction. Hydrogen is the basic fuel combined with other power sources – including wind and solar-generated power. Fuel cells generate electricity with very little pollution. However, the efficiency range is 40% to 80%, requiring temperatures of up to 1,800 degrees Fahrenheit, depending on the input mix.

A flow battery is an electrical storage device that is a cross between a fuel cell and a conventional battery. It is made of vanadium salt with acid sulfur. Instant recharge capability, longer life cycle, and longer discharge creates an opportunity for its use as an affordable storage device for renewable power. But energy and power are separate. If you want more power, you add more flow battery stacks. However, like fuel cells the need for very high temperatures to catalyze chemical reaction required to release power plagues this technology’s advancement.

A lithium battery is often viewed as an energy source that is powerful yet not durable over the long-term. Lithium batteries have suffered from thermal run-away – excessive heat that keeps creating more heat. With improvement, lithium battery technology could provide sustainable storage capability. Yet, like fuel cells and flow battery – excessive heat issues have thwarted development. For now, the battery provides a generation ancillary service in some markets – improving frequency – through its quick discharge capability – allowing time for new generation to be brought online in response to surges in load demand.

  For energy storage devices, the solution might be small 

Many power supply storage devices have been examined from a utility scale perspective; that is, the research has focused on how such devices can be improved to meet utility scale power needs. While power generation utility scale storage is important it may be more advantageous if we look to telecommunications and information technology history for guidance in the energy sector. Technological disruption in these sectors are important guideposts. In short, when the end-user and the system become the focus, forward technological strides result.

Given, the overheating issues shared by fuel cell, flow battery, and lithium battery technologies, it appears sensible to examine opportunities separately for power storage improvement from an off-grid and on-grid perspective. Limiting improvements of power storage devices to the prerequisite of utility scale may constrain improvements and overemphasize excessive heat constraints. Like personal computers and laptops as compared to the mainframe, solutions may be more easily reached if we focus on the end-users and not the device for delivering solutions with the highest impact on the overall power supply equation. In the end, a small, inexpensive and reliable storage device might be the breakthrough needed.