Pairing hydropower with battery storage—an innovative hybrid solution

By Francesca Ottoni, PE, MBA | July 17, 2021

In addition to wind and solar energy, the province of Ontario also has hundreds of small run-of-river hydro plants with limited re-regulation capability, and some of these facilities are located in remote communities providing them with carbon-free, affordable power. The ability to store energy during periods of low demand, to be used in periods of high demand, can be an important asset for managing the smaller run-of-river hydro plants reliably and efficiently.

Batteries are cost-effective at delivering small amounts of stored energy over a short time at high power levels. They also offer a flexible and modular solution and have few limitations on installation location. The fast response time and high versatility makes the combination of existing smaller hydro with batteries worth exploring. Energy storage systems are also easy to construct and have low environmental impacts.

Battery energy storage is a rapidly growing technology and is becoming known as the most versatile technology on the grid. With the falling cost of batteries, we can expect to see more hybridization of storage with any type of generation. By combining generation with storage, we can take advantage of the beneficial performance characteristics of batteries. Including fast response, high efficiency, low maintenance costs, and zero emissions, while using the generation asset to address the storage’s limited energy duration. Smart dispatch software technology can also help with the optimal use of the hydro-battery combination to meet the various changing conditions, deciding on the best timing, and amount to store, versus release energy at single or multiple locations.

The batteries can capture excess energy produced by the hydro turbines, which would have been otherwise spilled due to low demand or excess waterflow. Energy associated with spilled water used to recharge the battery can also be used during periods of high demand to serve the community or generate additional revenue during high price periods if there is a grid connection. In addition, storage offers the ability to provide operating reserve and other ancillary services, such as frequency and voltage support. This results in the overall facility having a more versatile offering to the grid operator, whether the grid is isolated or connected to the national grid. A main benefit of battery energy storage systems is the ability of a single installation to provide multiple services, value stacking, both at different times and simultaneously if market conditions allow. This value stacking approach significantly improves the project economics, as it allows for multiple benefits and revenue streams.

The integration of battery storage and hydro makes sense both economically and environmentally. Batteries have a relatively small physical footprint, and they can likely be housed within the hydro facility, saving space and helping preserve the surrounding landscape. Storage also saves the generator from start-stop operation, allowing it to run in more favorable conditions, and ultimately prolonging its life. The cost-benefit analysis of pairing hydro with battery technology must consider the many different elements indicated in this outline, however, as renewable energy generation continues to rise around the world more storage facilities will be required to harness the full potential of the renewable sources. With that in mind, more innovative hybrid projects will be developed, marking another positive step in creating global safe, clean energy generation.