SCARABEUS · Project

CO2 Blend Technology That Cuts Solar Power Plant Costs by Up to 40%

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Concentrated solar power plants use mirrors to focus sunlight and generate heat, but the machinery that turns that heat into electricity is expensive and not efficient enough. SCARABEUS found that mixing small amounts of specific chemicals into supercritical CO2 — the fluid that carries the heat — lets the power cycle run at higher temperatures and condense more easily, squeezing more electricity from the same sunlight. Think of it like adding a tiny amount of antifreeze to your car's cooling system so the engine runs better in extreme conditions. The team tested these blends at a 300 kWth scale for hundreds of hours to prove they actually work and stay stable at temperatures up to 700°C.

By the numbers

32%

Targeted CAPEX reduction for CSP plants

40%

Targeted OPEX reduction for CSP plants

96 €/MWh

Target cost of electricity

700°C

Maximum operating temperature tested

5% points

Efficiency gain of TiCl4-blended CO2 over pure CO2 (simple cycle)

2% points

Efficiency gain in advanced sCO2 cycle configuration

300 kWth

Scale of experimental testing loop

2000 hours

Long-term thermal stability testing duration

300 hours

Blend testing duration in loop

The business problem

What needed solving

Concentrated solar power remains more expensive than photovoltaics and wind, largely because the power conversion equipment is costly and the thermal-to-electricity efficiency is limited by current steam or pure supercritical CO2 cycles. CSP plant developers need a way to dramatically cut both capital and operating costs to make solar thermal competitive again.

The solution

What was built

The team developed and tested specific CO2-blend formulations (including TiCl4-blended CO2) that raise the critical point of the working fluid, enabling condensing supercritical cycles at temperatures up to 700°C. They produced thermodynamic property tables, completed 2000-hour stability tests, and ran a 300 kWth experimental loop for 300 hours covering steady-state, part-load, and transient operation.

Audience

Who needs this

CSP plant developers seeking to reduce levelized cost of electricityTurbine and compressor manufacturers designing next-generation sCO2 equipmentIndustrial waste heat recovery companies working with high-temperature sourcesEnergy utilities evaluating dispatchable renewable power optionsEngineering firms designing thermal power plants in hot climate regions

Business applications

Who can put this to work

Concentrated Solar Power

enterprise

Target: CSP plant developers and operators

If you are a CSP developer struggling with high capital costs that make solar thermal uncompetitive against PV and wind — this project developed CO2-blend power cycles that can reduce CAPEX by about 32% and OPEX by about 40%, bringing the cost of electricity below 96 €/MWh. The blends were tested for 2000 hours of thermal stability and at 300 kWth scale, giving you a validated pathway to cheaper solar thermal electricity.

Power Cycle Equipment Manufacturing

mid-size

Target: Turbine and heat exchanger manufacturers for thermal power

If you are an equipment manufacturer looking for the next generation of power cycle technology — SCARABEUS demonstrated that CO2 blends with compounds like TiCl4 can boost cycle efficiency by up to 5 percentage points at 700°C compared to pure CO2. The project produced thermodynamic tables and experimental data for the most promising blends, which you can use to design compatible turbines, compressors, and heat exchangers.

Industrial Heat Recovery

any

Target: Waste heat recovery system integrators

If you are a heat recovery company seeking more efficient power conversion from high-temperature industrial waste heat — the CO2-blend cycles developed here operate at temperatures up to 700°C with higher thermal-to-electricity conversion efficiency than conventional steam cycles. The condensing cycle design works at a pseudocritical temperature of about 50°C, making it viable for warm climates and industrial settings where standard sCO2 cycles cannot condense.

Frequently asked

Quick answers

How much could this technology reduce my electricity generation costs?

The project targeted a cost of electricity below 96 €/MWh, which is more than 30% lower than current CSP electricity costs. This comes from a combination of about 32% CAPEX reduction and about 40% OPEX reduction through the more efficient CO2-blend power cycle.

Has this been tested at industrial scale?

The CO2 blends were tested in a loop at 300 kWth scale for 300 hours of operation, and long-term thermal stability was measured over 2000 hours. This is lab-to-pilot scale — not yet a full commercial plant — but the results include both steady-state and transient operation conditions.

What is the IP situation and how can I license this technology?

The project was a Research and Innovation Action funded under Horizon 2020, coordinated by Politecnico di Milano with 11 partners across 6 countries. IP rights are governed by the consortium agreement. Contact the coordinator to discuss licensing of the CO2-blend formulations and cycle designs.

How does this compare to standard supercritical CO2 cycles?

In a simple cycle configuration, the TiCl4-blended CO2 outperforms pure CO2 by 5 percentage points at 700°C. In the advanced sCO2 cycle, the efficiency gain is 2 percentage points, but with significant cost savings due to the condensing cycle enabling simpler equipment.

What temperatures can the blends handle?

The CO2 blends were investigated for stability at temperatures up to 700°C, which is 100°C above current CSP maximum operating temperatures. Long-term stability at these temperatures was confirmed through 2000 hours of dedicated testing with various materials and contaminants.

Is this only for solar power, or can it work in other applications?

While designed for concentrated solar power plants, the CO2-blend power cycle technology applies to any high-temperature thermal-to-electricity conversion. Based on available project data, the cycle operates efficiently at temperatures up to 700°C, making it relevant for industrial waste heat recovery and other thermal power applications.

Consortium

Who built it

The 11-partner consortium spans 6 countries (Austria, Switzerland, Spain, France, Italy, UK) with a strong balance of 5 industry and 5 university partners plus 1 research organization — a 45% industry ratio that signals real commercial interest. Politecnico di Milano coordinates, bringing deep thermodynamic expertise. The presence of 5 industrial partners means the technology was developed with manufacturing and deployment constraints in mind, though only 1 partner is classified as an SME. For a business looking to adopt or license this technology, the consortium offers both the scientific depth to trust the results and the industrial connections to move toward commercialization.

POLITECNICO DI MILANOCoordinator · IT
TECHNISCHE UNIVERSITAET WIENparticipant · AT
NUOVO PIGNONE TECNOLOGIE SRLparticipant · IT
CITY ST GEORGES UNIVERSITY OF LONDONparticipant · UK
LABORATORIO ENERGIA AMBIENTE PIACENZAthirdparty · IT
ABENGOA ENERGIA SAparticipant · ES
Quantis Sarlparticipant · CH
UNIVERSITA DEGLI STUDI DI BRESCIAparticipant · IT
UNIVERSIDAD DE SEVILLAparticipant · ES

How to reach the team

Politecnico di Milano (Italy) — reach out to the energy department's power cycle research group

Order a report on this consortium See POLITECNICO DI MILANO profile →

Next steps

Talk to the team behind this work.

SciTransfer can connect you with the SCARABEUS consortium to discuss licensing the CO2-blend technology or adapting the power cycle design for your specific application.

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