Californian Renewable energy firm Sperra has received funding from the US and German governments to advance its 3D printed subsea pumped storage hydropower (SPSH) technology.
The company’s 3D printed concrete spheres sit on the sea floor and generate electricity by pumping water to power a turbine. The resulting energy can be stored underwater near cities and released when needed. This process does not rely on critical battery materials constrained by supply chains, offering a sustainable solution for local electricity generation for coastal cities.
Sperra has been awarded a $4 million grant from the US Department of Energy’s Water Power Technologies Office to demonstrate the capabilities of its SPSH process. It will use the capital to design, fabricate, and test a 500 kW/600 kWh, 10-meter diameter energy storage unit off the coast of Southern California.
The company is also collaborating with Fraunhofer IEE and Pleuger Industries in a parallel pump and turbine development project. This initiative recently received $3.7 million (€3.4 million) from the German Ministry for Economic Affairs and Climate Action (BMWK).
According to Sperra, these collaborative efforts will support the development of low-cost subsea energy storage capabilities to enhance electrical grid decarbonization. The company believes its SPSH technology will allow the US to exploit its approximately 75 terawatt-hours of unused offshore energy potential. This is more than twice that of on-shore closed-loop storage alternatives.
“This project is a major step forward to realizing the full potential of energy storage to decarbonise our electric grid,” commented Jason Cotrell, CEO of Sperra. “Subsea pumped storage hydropower with 3D printed concrete will accelerate the energy transition, employing local labour and using immediately available materials.”
3D printed subsea energy generators
According to Sperra, long-duration energy storage supports the broader integration of renewable energy in the US. It reportedly improved grid reliability by locally providing energy on demand, reducing fossil fuel usage during peak demand. SPSH offers the ability to store sustainably generated electricity close to large coastal population centres.
This technology is engineered to deliver the advantages of traditional pumped storage hydropower while sidestepping many of the challenges related to land-based systems. Each unit features an underwater motor pump housed within a pipe. To generate energy, a valve opens, allowing seawater to flow through the pipe and into the sphere. This flow reverses the pump’s operation, turning it into a turbine that drives a motor to produce storable electricity.
SPSH reportedly eliminates the need for critical battery materials like lithium, which often come with complex supply chain issues, as well as environmental and social impacts. Additionally, the modular spheres can be 3D printed close to the point of need with locally sourced concrete. This process builds on Prof. Horst Schmidt-Böcking, Dr. Gerhard Luther, and Fraunhofer IEE’s “Stored Energy in the Sea” (StEnSea) technology, developed from 2013 to 2017.
In the DOE-backed project, Sperra will 3D print the large-scale concrete spheres at its Long Beach facility using locally sourced concrete. This will reportedly reduce transportation emissions and mitigate the environmental impact of materials like steel.
To scale its technology and commercialize SPSH for US wind energy applications, Sperra is working with research, engineering, and energy supply chain members. These include WSP USA, Purdue University, the National Renewable Energy Laboratory, Pleuger Industries GmbH, Fraunhofer IEE, and an advisory stakeholder panel.
“Pumped storage power plants are particularly suitable for storing electricity for several hours to a few days. However, their expansion potential is severely limited worldwide,” explained Fraunhofer IEE Senior Project Manager Dr. Bernhard Ernst.
According to Ernst, “Transferring their functional principle to the seabed” reportedly overcomes these challenges as “the natural and ecological restrictions are far lower there.” He added that locating these units on the ocean floor makes them more likely to be accepted by the local population.
The project builds on R&D funding from the California Sustainable Energy Entrepreneur Development (CalSEED) program and the New York State Energy Research and Development Authority (NYSERDA).
Looking ahead, Sperra will plan a grid-connected pilot demonstration. This will reportedly help to derisk SPSH technology and generate public and private funding to support more widespread deployments in the future.
Additive manufacturing enhances renewable energy
Additive manufacturing has experienced increased adoption within the energy sector, amid ongoing efforts to scale sustainable and renewable alternatives to fossil fuels.
Earlier this year, it was announced that the US Department of Energy (DOE)’s Oak Ridge National Laboratory (ORNL) is 3D printing hydropower dam components. The large metal runners rotate and convert the movement of water into electricity. Called Rapid RUNNERS, the project will receive $15 million from the DOE over three years.
Currently, hydropower turbines are almost exclusively manufactured outside the United States. ORNL hopes its initiative will revitalize American manufacturing and re-shore clean energy production to the US.
3D printing is set to reduce lead times for critical runner parts and accelerate growth in the energy manufacturing sector. “This has the potential to transform forging and casting of large-scale metal components,” explained Adam Stevens, an R&D staff member at ORNL and technical lead for the project.
Elsewhere, Saudi Arabia-based 3D printing service provider National Additive Manufacturing & Innovation (NAMI) acquired 3D Systems’ 3D printers to localize energy supply chains. The 3D printers are being used to produce parts for the Saudi Electricity Company (SEC), bringing the production of critical energy parts closer to the point of need.
According to 3D Systems, this deal will allow NAMI to capitalize on the $2.6 billion energy sector which is expected to grow to $17 billion by 2032.
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Featured image shows an artistic rendering of an SPSH storage park, connected to a substation and floating offshore wind farm. Image via Sperra.
