Batteries made of super-hot sand: for long-duration grid storage at $4 to $10 per kWh – Energy Post

Low-Cost Long-Duration Grid Storage Using Sand

The Sustainable Development Goals (SDGs)

1. SDG 7: Affordable and Clean Energy
2. SDG 9: Industry, Innovation, and Infrastructure
3. SDG 13: Climate Action

Our electric future requires low-cost long-duration storage solutions for grids. Traditional options such as pumped hydropower, compressed air energy storage (CAES), and lithium-ion batteries have limitations in terms of cost and duration. Wayne Hicks at the National Renewable Energy Laboratory (NREL) highlights the research into thermal energy storage (TES) using solid particles like sand, which is abundant worldwide. The experiments and subsequent modeling reveal that sand storage could cost between $4 and $10 per kilowatt-hour (kWh) and have a duration lasting hundreds of hours. This article explores the potential of sand as a sustainable storage solution and its alignment with the SDGs.

The Need for Long-Term Storage

TES using sand involves raising the temperature of sand particles using renewable energy sources like wind and solar. The heated sand is then stored in a silo for later use in generating electricity or providing process heat in industrial applications. NREL has developed a laboratory-scale prototype that validates the technology and shows that a commercial-scale device would retain more than 95% of its heat for at least five days. This long-duration storage is essential for achieving carbon reduction goals and aligns with SDG 7 (Affordable and Clean Energy).

Advantages of Sand Storage

Compared to other storage technologies, sand storage offers several advantages. It does not rely on rare-earth materials or complex supply chains, making it more sustainable than lithium-ion batteries. Additionally, sand is widely available, environmentally friendly, and stable across a wide temperature range. The use of sand as a storage medium aligns with SDG 9 (Industry, Innovation, and Infrastructure) by promoting innovative and sustainable solutions for energy storage.

Low Cost: $4 to $10 per kWh

Sand storage is also cost-effective. When compared to rival technologies like CAES, pumped hydropower, and batteries, sand storage proves to be the cheapest option. CAES costs between $150 and $300 per kWh, pumped hydropower costs around $60 per kWh, and lithium-ion batteries cost $300 per kWh. In contrast, sand storage costs between $4 and $10 per kWh. This low cost makes sand storage an economically viable solution for long-duration grid storage, contributing to SDG 7 (Affordable and Clean Energy).

Pilot Project in 2025

NREL plans to conduct a larger-scale sand TES pilot project in 2025. This pilot project aims to demonstrate the commercial potential of sand for long-duration energy storage. By showcasing the scalability and effectiveness of sand storage, NREL contributes to SDG 9 (Industry, Innovation, and Infrastructure) by promoting the adoption of sustainable and efficient storage technologies.

Advantages over Molten Salts

While molten salts are currently used for temporary energy storage, they have limitations in terms of temperature range. Molten salts freeze at about 220°C and start to decompose at 600°C. In contrast, the sand used in NREL’s research can retain considerably more heat, reaching temperatures of up to 1,100°C. This makes sand storage a superior alternative to molten salts, contributing to SDG 13 (Climate Action) by reducing the reliance on fossil fuels for industrial heat.

Deciding the Best Storage Medium

NREL researchers have examined various solid particles for their ability to flow and retain heat. While ceramic materials outperformed sand in terms of performance, their higher cost made them less favorable. Sand, on the other hand, is readily available in the Midwest and costs between $30 and $80 per ton. The ease of access and low cost of sand make it an ideal storage medium, aligning with SDG 9 (Industry, Innovation, and Infrastructure) by promoting sustainable and cost-effective solutions.

Ease of Scale-Up

One of the key advantages of sand storage is its ease of scale-up. Expanding the amount of energy that can be stored simply involves adding more sand. This scalability makes sand storage a flexible and adaptable solution for various energy storage needs. By enabling the storage of energy for durations ranging from multiple hours to two weeks, sand storage contributes to SDG 7 (Affordable and Clean Energy) by providing a cost-effective and sustainable alternative to traditional storage technologies.

Overall, the research into sand storage for long-duration grid storage demonstrates its potential as a low-cost, sustainable, and scalable solution. By aligning with the SDGs, sand storage contributes to the global efforts towards affordable and clean energy, industry innovation, infrastructure development, and climate action.

SDGs, Targets, and Indicators

1. SDGs Addressed or Connected to the Issues

• SDG 7: Affordable and Clean Energy
• SDG 9: Industry, Innovation, and Infrastructure
• SDG 11: Sustainable Cities and Communities
• SDG 13: Climate Action

2. Specific Targets Based on the Article’s Content

• SDG 7.2: Increase substantially the share of renewable energy in the global energy mix
• SDG 9.4: Upgrade infrastructure and retrofit industries to make them sustainable
• SDG 11.6: Reduce the environmental impact of cities, including air quality and waste management
• SDG 13.2: Integrate climate change measures into national policies, strategies, and planning

3. Indicators Mentioned or Implied in the Article

• Cost per kilowatt-hour (kWh) for different storage technologies
• Duration of energy storage in hours or days
• Retaining heat percentage over a specified period of time
• Temperature range for thermal energy storage materials

Table: SDGs, Targets, and Indicators

Note: The indicators mentioned in the table are based on the information provided in the article. Additional indicators may exist that are not explicitly mentioned.

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Source: energypost.eu

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