Thermal Energy Storage vs. Electrical Energy Storage
Renewable energy technologies have been gaining popularity over the past decade. They have become more affordable and efficient, and they have the potential to replace traditional fossil-fuel sources.
One of the challenges with renewable energy technologies is their intermittency. Solar panels and wind turbines only generate electricity when the sun is shining, or the wind is blowing. This means that there can be times when there is excess energy, and other times when there is not enough. To address this issue, energy storage systems have been developed as a solution.
There are two main types of energy storage: thermal energy storage and electrical energy storage. Let’s take a deeper look at what each one entails and how they compare.
Thermal Energy Storage
Thermal energy storage systems store heat energy, which can then be used to generate electricity when needed. They use materials such as molten salt, which can hold onto heat for long periods of time. Solar thermal power plants use this technology to store heat during the day and then generate electricity at night.
An advantage of thermal energy storage is that it can store large amounts of energy with relatively low cost. According to NREL, the cost of thermal energy storage is around $14 per kWh. Additionally, thermal energy storage systems have a longer lifespan than electrical energy storage systems.
However, there are some drawbacks to thermal energy storage. It requires a lot of space, and the materials used in the storage can degrade over time. The efficiency of the storage can also decrease over time.
Electrical Energy Storage
Electrical energy storage systems store electricity in batteries or other devices. This energy can then be used at a later time when needed. Lithium-ion batteries have become popular in recent years due to their high energy density and low self-discharge rate.
One advantage of electrical energy storage is that it has a high round-trip efficiency, which means that it can store and release energy with minimal loss. Additionally, it takes up less space than thermal energy storage systems.
However, there are some drawbacks to electrical energy storage. The cost of the batteries can be high, and they have a shorter lifespan than thermal energy storage systems. Additionally, they can be hazardous and require special disposal procedures.
Comparison
The table below compares the two types of energy storage systems based on efficiency, cost, and lifespan.
| Efficiency | Cost ($/kWh) | Lifespan (years) | |
|---|---|---|---|
| Thermal storage | 75 - 90% | 10 - 30 | 20 - 30 |
| Electrical storage | 80 - 90% | 200 - 300 | 5 - 15 |
As the table shows, both types of energy storage have their advantages and disadvantages. The choice between the two will depend on the specific situation and the needs of the user.
Conclusion
Thermal energy storage and electrical energy storage are both viable solutions to the intermittent energy produced by renewable energy technologies. While thermal energy storage is cheaper and lasts longer, electrical energy storage has a higher round-trip efficiency and takes up less space. The decision to use one over the other will depend on the circumstances.
References:
- National Renewable Energy Laboratory. (2021). Thermal energy storage. Retrieved July 28, 2022, from https://www.nrel.gov/research/re-thermal-storage.html
- National Renewable Energy Laboratory. (2021). Energy storage. Retrieved July 28, 2022, from https://www.nrel.gov/research/energy-storage.html