Four ways to store sunlight

Heat Storage

Heat storage presents a promising opportunity in energy systems with high renewable penetration. Andy Lubershane highlights the potential of repurposing retired coal-fired power plants into thermal storage systems, utilizing existing infrastructure like steam turbines and grid interconnections 1. This approach not only leverages surplus renewable generation but also supports local economies by retaining jobs in communities affected by plant closures 1.

I'm actually convinced that there is an opportunity for thermal storage, even in this power to power mode and relatively high renewable penetration systems.

--- Andy Lubershane

Additionally, the conversion of electricity into heat and its subsequent use can achieve high round-trip efficiency, making it a cost-effective solution for energy storage 2.

   

Thermal Challenges

Despite its potential, thermal energy storage faces significant challenges, particularly with the use of molten salts. Andy Lubershane explains that while molten salts can store energy effectively, they pose operational risks due to their corrosive nature and the difficulty in maintaining safe temperatures 3. These challenges have made companies hesitant to pursue innovative projects in this area 3.

The challenge with molten salts is that it's just proven to be extremely operationally risky and difficult to work with.

--- Andy Lubershane

However, simpler power-to-heat systems that deliver heat directly show promise, though they still face efficiency limitations when converting stored heat back into electricity 2.