Report on Repurposing Retired Coal Facilities for Thermal Energy Storage in Alignment with Sustainable Development Goals

Executive Summary

A novel energy storage solution proposes retrofitting retired coal-fired power plants to serve as grid-scale batteries, utilizing heated dirt as the storage medium. This innovative approach directly supports the achievement of several United Nations Sustainable Development Goals (SDGs) by promoting clean energy, fostering economic growth in transitioning communities, and encouraging sustainable industrial innovation. The technology leverages existing infrastructure to provide reliable backup power, thereby facilitating a greater integration of intermittent renewable energy sources like solar and wind.

Technological Framework and Process

The proposed system, referred to as a “heat battery,” operates by converting electricity into thermal energy and storing it in a common, abundant material: dirt. This process is designed to align with the principles of sustainable infrastructure and resource management.

1. Energy Input: During periods of low electricity demand and low cost, surplus energy, preferably from renewable sources, powers industrial heaters placed within a large, insulated pile of dirt located at the site of a former coal plant.
2. Thermal Storage: The heaters raise the temperature of the dirt to approximately 600°C. Materials commonly found in dirt, such as silicon dioxide and aluminium oxide, are robust and can withstand these high temperatures, making it a cost-effective storage medium.
3. Power Generation: During periods of high electricity demand, the stored heat is extracted via pipes containing a heat-transfer fluid.
4. Infrastructure Repurposing: This extracted heat is used to boil water, creating high-pressure steam. The steam then powers the coal plant’s original turbines and generators to produce electricity for the grid, replacing the combustion of coal with a zero-emission heat source.

Contribution to Sustainable Development Goals (SDGs)

SDG 7: Affordable and Clean Energy

This technology is fundamental to advancing SDG 7 by enhancing the reliability and accessibility of clean energy.

• It provides a long-duration energy storage solution, which is critical for stabilizing grids that rely heavily on intermittent renewable sources.
• By using dirt, it offers a more affordable and widely available storage medium compared to lithium-ion batteries or hydrogen.
• It creates a pathway to decarbonize backup and emergency power generation, directly contributing to Target 7.2 (increase the share of renewable energy).

SDG 8: Decent Work and Economic Growth & SDG 11: Sustainable Cities and Communities

The repurposing of defunct coal plants offers a “just transition” for communities historically dependent on the fossil fuel industry.

• It provides new, local employment opportunities in the clean energy sector, helping to replace jobs lost from coal plant retirements.
• The continued operation of the site generates local tax revenue, supporting public services and community resilience (Target 11.B).
• This initiative revitalizes industrial sites, preventing them from becoming derelict and contributing to sustainable community development.

SDG 9: Industry, Innovation, and Infrastructure & SDG 12: Responsible Consumption and Production

The project is a prime example of sustainable innovation, focusing on retrofitting and reusing existing industrial assets.

• It upgrades existing infrastructure (turbines, generators, grid connections) for a sustainable purpose, reducing the need for new construction and associated resource consumption (Target 9.4).
• The use of dirt as a storage medium represents a circular economy principle, utilizing an abundant, low-cost natural resource.
• This model promotes sustainable production patterns by enabling a more efficient use of generated renewable energy, reducing curtailment and waste (Target 12.2).

SDG 13: Climate Action

By providing a fossil-fuel-free method for grid stabilization, this technology is a direct measure for climate action.

• It facilitates the displacement of coal and natural gas peaker plants, which are significant sources of greenhouse gas emissions.
• It supports the broader transition to a low-carbon energy system, essential for meeting national and international climate targets.

Implementation Context and Challenges

The United States presents a significant opportunity for this technology, with nearly 300 coal plants retired between 2010 and 2019 and more retirements anticipated. While the concept is promising, successful implementation requires addressing key challenges.

• Economic Viability: According to the Electric Power Research Institute, minimizing the costs associated with advanced piping and electrical systems is essential for the financial feasibility of such projects.
• Commercialization: Start-ups like Standard Thermal are actively working to commercialize this technology, focusing on sites with co-located solar or wind power generation to maximize efficiency and economic return.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

1. SDG 7: Affordable and Clean Energy
   • The article focuses on a new energy storage technology using heated dirt to provide backup power. This directly supports the transition to cleaner energy systems by supplementing intermittent renewable sources like wind and solar, and replacing fossil fuels like coal. The text states the technology allows for the use of “cheap electricity” during low-demand periods to store energy, addressing affordability, and it is a clean alternative to burning coal.
2. SDG 8: Decent Work and Economic Growth
   • The article highlights the economic benefits for communities affected by the closure of coal plants. It explicitly mentions that repurposing these facilities “provides a way for local communities to participate in the clean energy transition by providing jobs and additional tax revenue to help displace the retirement of the coal plant.” This addresses the need for a just transition and sustainable economic growth.
3. SDG 9: Industry, Innovation, and Infrastructure
   • The core of the article is about an innovative technology (“heat battery”) and the retrofitting of existing industrial infrastructure (retired coal plants). This aligns with upgrading infrastructure to make it sustainable and resilient. The article describes how the “coal plant’s turbine blades and connected generator could then turn that heat into backup energy,” demonstrating the retrofitting of old industrial assets for a new, clean purpose.
4. SDG 11: Sustainable Cities and Communities
   • By providing a new economic purpose for defunct industrial sites, the technology helps communities manage the transition away from fossil fuels. The article notes this provides “jobs and additional tax revenue,” which contributes to the economic and social sustainability of local communities that were previously dependent on coal.
5. SDG 13: Climate Action
   • The technology is a direct climate action strategy. By replacing the need to burn coal for power generation and enabling greater use of renewables, it helps reduce greenhouse gas emissions. The article frames the technology as a solution for a post-coal era, where coal’s share of electricity production has peaked due to competition from “cheaper natural gas and renewables.”

2. What specific targets under those SDGs can be identified based on the article’s content?

1. SDG 7: Affordable and Clean Energy
   • Target 7.2: “By 2030, increase substantially the share of renewable energy in the global energy mix.” The dirt battery technology is presented as “necessary to supplement renewable power sources, such as wind and solar, which only provide energy intermittently,” thereby enabling a higher share of these renewables in the grid.
   • Target 7.a: “By 2030, enhance international cooperation to facilitate access to clean energy research and technology… and promote investment in energy infrastructure and clean energy technology.” The article discusses research from Stanford University and a start-up, Standard Thermal, which is “looking to commercialise this ‘heat battery’ technology,” exemplifying the development and promotion of clean energy technology.
2. SDG 8: Decent Work and Economic Growth
   • Target 8.2: “Achieve higher levels of economic productivity through diversification, technological upgrading and innovation…” The article describes a technological innovation that diversifies the energy sector and upgrades old infrastructure, leading to new economic activity.
   • Target 8.5: “By 2030, achieve full and productive employment and decent work for all…” The article directly addresses this by stating the project can provide “jobs… to help displace the retirement of the coal plant.”
3. SDG 9: Industry, Innovation, and Infrastructure
   • Target 9.4: “By 2030, upgrade infrastructure and retrofit industries to make them sustainable… with greater adoption of clean and environmentally sound technologies…” The entire concept discussed is about retrofitting “retired coal-fired power plants” with a clean technology that stores energy in dirt instead of burning fossil fuels.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

1. Implied Indicators for SDG 7 & 9
   • Number of retired coal plants repurposed: The article provides a baseline by stating “nearly 300 coal-fired plants retired between 2010 and 2019 alone.” Tracking the number of these facilities converted to the new technology would be a direct indicator of progress.
   • Gigawatts of coal capacity replaced: The article mentions “an additional 50 gigawatts of coal plant capacity is expected to reach the typical retirement age… by 2030.” Measuring the amount of this capacity that is replaced by clean energy storage would be a key performance indicator.
2. Implied Indicators for SDG 8 & 11
   • Number of jobs created in transitioning communities: The article explicitly mentions “providing jobs.” A direct indicator would be the number of new employment opportunities created at the repurposed sites.
   • Amount of tax revenue generated: The article states the project can provide “additional tax revenue.” This is a quantifiable metric to measure the economic benefit to local communities.
3. Implied Indicator for SDG 13
   • Reduction in CO2 emissions: While not quantified, replacing coal-fired power with a system that supports renewables leads to a direct reduction in greenhouse gas emissions. The amount of coal not burned can be calculated and converted into an emissions reduction figure.

4. Summary Table of SDGs, Targets, and Indicators

Source: newscientist.com