Malta Inc: “Our technology provides long-duration storage from 8 hours to 8 days”
As a child, Ramya Swaminathan experienced first-hand the consequences of an unstable electrical grid: in India and the Philippines (where she grew up), power outages at the school were constant. Now, named in 2020 one of Business Insider’s list of 21 Rising Stars in clean energy, in addition to advising public agencies dedicated to the electric grid in the United States, Swaminathan advices Malta Inc., a startup that spun out from Google X that could be key for achieving a stable electrical network powered by 100% renewable energy.
The company, named to Time magazine’s Top GreenTech Companies 2024, has developed a system that stores energy in the form of heat in molten salt and cold in a cooled water, which can be converted back into electricity as needed. In this interview, we talk to her about the main challenges of this industry, how to develop long-duration energy storage technologies for the electrical grid that are more cost-competitive and the role of public institutions to achieve this.
QUESTION: Energy storage is key to our path to a successful low-carbon emission future. In the last few years, we’ve advanced installing short-duration storage to support the generation of renewable energy, but we still need to develop long-duration storage technologies. What are the main challenges in this kind of energy storage?
ANSWER: To power our grids with clean, reliable, and affordable energy, we need a broad range of storage technologies tailored to each region’s specific needs and conditions and use case, which would be unachievable without long-duration energy storage (LDES) solutions. Incorporating LDES also enhances supply security, providing the grid with resilience and stability. One of the main challenges is securing the required initial investment in technology and infrastructure, which is higher than that of other storage solutions. This, combined with the limited commercial scale and deployment history of LDES, makes investors often view LDES projects as high-risk, deterring investment and leading to elevated return requirements. Another major obstacle is revenue stacking: existing revenue models in many markets do not yet provide adequate compensation for the range of services that LDES assets can offer, such as energy capacity and critical grid-support ancillary services. Also, regulatory frameworks must be adapted to recognize the value of LEDS in grid stability and renewable integration.
Q: Malta’s solution lies in thermo-electric energy storage. Why is this system so innovative, and what are its main keys?
A: It combines well-established thermodynamic principles with modern technological advancements to create a cost-effective, scalable, and efficient energy storage solution. The system stores energy as heat in molten salt and cold water, which can be converted back to electricity on demand. Molten salt storage systems like Malta’s can store energy at temperatures up to 540 °C, which is much higher than the maximum temperature of other thermal energy storage technologies, such as sensible heat storage or phase change materials. Malta’s system also achieves a power-to-power charge/discharge round-trip efficiency (RTE) of up to 60%, which is about 50% higher than other thermal storage systems without heat pump charging. In use cases where both the discharge power and the discharge heat are utilized, such as in district heating or industrial heat applications, the overall system efficiency can approach an RTE of up to 95%. Key features of our technology include its ability to provide long-duration storage from 8 hours to 8 days, its scalability for large-scale deployment of 300 MW and beyond, and its dual functionality in supplying electricity and heat, for industrial and district heating uses.
Q: How many times can the materials used in the storage system (such as salt or liquid) be charged and uncharged? Does the process generate waste?
A: A Malta storage unit can be charged and discharged 100% in unlimited cycles without degradation of the storage media. As the main storage medium, Malta has selected a natural thermo-solar salt sourced by solar evaporation (e.g., in the Atacama Desert of Chile). It does not degrade during charge/discharge cycles and therefore does not need to be replaced over the project lifetime. These nitrates are also commonly used as fertilizers in agriculture. At the end of the project, they may be reused in a follow-up storage project or as fertilizer. The mechanical components of the storage system (tanks, piping, heat exchangers, turbo-machinery) are made of various types of steel, which can also be recycled at the end of the project life. Compared to lithium-ion batteries, storage in molten salts has increased durability, with a lifespan of 25 to 35 years without degradation or the need for material replacement. Additionally, its storage capacity is easily scalable by adding more thermal storage volume.
“Compared to lithium ion batteries, storage in molten salts has increased durability, with a lifespan of 25 to 35 years without degradation or the need for material replacement”.
Q: These cutting-edge energy storage technologies, such as Malta’s, imply large investments. As many experts say, financing is one of the main impediments to advancing faster and reaching the 2030 goals. How can we reverse this situation and develop more cost-competitive technologies?
A: The main financing challenge for LDES projects is replacing fossil fuels with a technology that needs to be financed upfront before the start of commercial operation of the LDES projects. To overcome financing challenges, a multi-faceted approach is necessary. First, continuous technological advancements, efficiency improvements, and the development of standardized scalable solutions are required to drive down costs over time. Second, deploying these solutions requires innovative financing mechanisms beyond existing market structures. Additionally, public-private partnerships, government incentives and subsidies can play crucial roles in mitigating financial risks and encouraging investment in these cutting-edge technologies. By combining these strategies, we can create a more favorable financial environment for advancing energy storage technologies and achieving our 2030 energy transition goals.
“Instead of viewing China’s advancements as a threat, we should see them as an opportunity to accelerate the deployment of our energy storage solutions”
Q: You mentioned public institutions. Let’s explore their role in financing these kinds of projects.
A: They play a crucial role in financing energy storage projects by providing grants, subsidies and low-interest loans to reduce financial risks for developers.In the EU, the Horizon Europe program offers substantial funding for research and innovation in renewable energy technologies, including energy storage. The European Green Deal also provides financial mechanisms like the Just Transition Fund, which supports regions most affected by the transition to a green economy. Another important initiative is REPowerEU, which aims to reduce the EU’s dependence on Russian fossil fuels and accelerate the transition to a more resilient energy system. Governments can also support research and development initiatives to drive innovation and offer tax incentives to companies investing in clean energy solutions.
Q: In addition to direct funding support, what regulatory changes would be required in the power markets to attract investments in LDES projects?
A: The electricity sector agents agree on the need for new regulations and a stable framework to ensure and promote investments in LDES to replace gas-fired combined cycles. One very important mechanism is the introduction of capacity mechanisms to support renewable energy storage systems by providing an economic signal to attract investment in LDES projects. In a context where a significant increase in storage capacity is expected, capacity mechanisms provide the necessary stability and security for investments, enabling the growth of this crucial infrastructure to integrate intermittent renewable sources.
“We need a broad range of storage technologies tailored to the specific needs and conditions of each region and use case”
Q: According to the study How China became the global renewables leader, the country has become a leader in grid-connected energy storage. Should we take this as a challenge, especially nowadays that the US and the EU fear China’s unfair competition in the renewable market?
A: China’s leadership in grid-connected energy storage presents both challenges and opportunities. While it is essential to recognize the competitive pressure it places on other markets, it also catalyzes innovation and improvement globally. The fear of unfair competition highlights the need for a level playing field, where fair trade practices and intellectual property rights are respected. Instead of viewing China’s advancements as a threat, we should see them as an opportunity to accelerate the deployment of our energy storage solutions. We can enhance our capabilities by fostering international collaboration, promoting fair competition, and investing in regionally manufactured technologies.
