The key to achieving 100 percent renewable penetration for remote Arctic mines
Today, many mines are targeting 100 percent renewable penetration by integrating wind and solar power with energy storage to supply their required electricity. However, achieving full renewable penetration is not an easy feat, especially in the Arctic. The variability of wind and solar power makes long duration energy storage imperative. Depending on operations, a minimum of six to ten hours of storage capacity are required to achieve these high renewable penetrations, with even longer durations required if the load is inflexible.
The standard approach for long duration storage applications is to use a lithium-ion battery, but due to the limited power-to-energy ratio, this battery is often oversized. This oversizing can result in the lithium-ion battery being a costly option for providing long duration energy storage. Alternative technology options are desirable.
Pumped hydro and compressed air storage technologies are potential options for long duration energy storage technologies, however both have geographical constraints and moderate to low efficiencies. Flow batteries, on the other hand, are becoming increasingly practical for longer duration energy storage applications. Here are five unique advantages of flow batteries for Arctic installations:
- The ability to vary the power-to-energy ratio, leading to lower costs per megawatt-hour as storage duration increases—while also using lower-cost materials compared to other technologies.
- Comparable response time to other battery technologies, which is currently limited by inverter or controller response time, proving the capability of providing both short duration grid forming services and long duration storage.
- The ability to operate at 100 percent depth of discharge with minimal degradation for over tens of thousands of cycles. This means minimal vendor maintenance and intervention is required, reducing the need to access the site.
- Flow batteries are self-heating during operation, maintaining the system at the desired operating temperature—allowing them to operate in the harsh Arctic climates below -40°C. The electrolyte tanks also contain thermal energy, with the system cooling slowly if idling for short periods of time, usually over several hours.
- Finally, many vendors offer fully containerized, modular systems, minimizing on-site installation requirements and lowering the costs. The modular systems can be relocated at the end of a mine’s life to another site, allowing flexibility if the mine’s life is short.
Despite the many benefits of flow batteries, I’d be remiss not to mention the challenges that need to be addressed to achieve successful remote Arctic deployment. Flow batteries require three to four times the number of containers than a lithium-ion battery of similar capacity. The containers must be transported to the remote site, leading to higher initial delivery costs per megawatt-hour, and more complicated delivery logistics. The larger area required also ultimately increases the balance of plant costs. As with all battery technologies deployed in the Arctic, added heaters and insulation are required to prevent freezing during prolonged idling. Flow batteries also have a modest round-trip efficiency (70 to 80 percent). The impact of cold Arctic climates on system efficiencies remains relatively unknown, as there are few deployments in cold climates. As more systems are deployed, the effects of harsher Arctic conditions will become better understood.
Addressing these challenges is a key step towards enabling flow battery deployment at remote Arctic sites. Flow batteries are a unique energy storage technology that are currently positioned as a key enabler to achieving 100 percent renewable penetration. The increasing drive to reduce fossil fuel consumption and use local resources to generate electricity at remote mine sites presents an excellent opportunity.