Renewable energy’s place on the grid is increasing across the globe. Lower production costs and technology improvements coupled with policy changes have driven both adoption and urgency for clean energy alternatives.
The transition to renewables is not completely straightforward, however. The variability of solar and wind, for example, calls for grid management solutions that ensure reliable and resilient electricity supplies. Technologies such as Energy Storage Systems (ESS) can be utilized to capture renewable energy generation for future use.
Energy storage technologies
There are four groups of energy storage technologies with advantages and disadvantages that vary across scenario, location, scale and other factors.
- Thermal energy storage systems use thermal energy to store and release electricity and heat, such as molten salt.
- Mechanical energy storage stores potential or kinetic energy for future use; think solutions like pumped hydro storage, for example, which can be limited by geography.
- Electrochemical storage systems, such as batteries, rely on different battery chemistries that store energy; this includes the growing popularity of lithium-ion solutions on grids today.
- Chemical energy storage stores electricity through the creation of chemical bonds; this is where hydrogen storage solutions enter.
Storage duration – the length of operational time that the system can back-up – is a critical factor. Lithium-ion batteries are the most popular energy storage option today and suited for hour-to-hour grid balancing. Even with other battery technologies such as iron-air offering up to 100 hours of electricity storage, a significant improvement over the eight hours provided by lithium-ion batteries, it is still insufficient to support what is termed ‘seasonal storage’.
Hydrogen: A Long Term Storage Solution
Seasonal storage is critical to support the few but significant occasions where grids dominated by solar and wind power face weeks (not hours) of lower natural resource availability or, indeed, when resilient, back-up support is needed following extreme weather or other unpredictable events.
Paired with batteries, reservoirs of hydrogen can be stored and filled-up during periods of excess solar and wind resources. Then, these pools of hydrogen can be deployed when needed, much like the natural gas or diesel backups in use today. Building the equivalent battery capacity – suited for more regular, shorter-duration grid balancing – would be costly in comparison for such occasional use.
For now, in many cases, cost is still a barrier for low carbon intensity hydrogen production and large, long-term storage, too. In reality, iron and zinc are the more cost-effective alternatives in terms of the capital expense amount needed for many utility scenarios.
Seasonal energy storage is critical to support the occasions where grids dominated by solar and wind power face weeks of lower natural resource availability.
However, when we think more about time and the inevitable increase of renewable integration into our electric grids, seasonal hydrogen storage alongside selling hydrogen to other adjacent energy off-takers becomes a more compelling commercial scenario.
Download this ebook learn more about realizing the potential of hydrogen, advanced battery technologies and making hydrogen energy storage a reality, including project details of a large hydrogen production and storage project currently under construction.
