# HalZero by Norsk Hydro

Canonical page: https://technooptimist.io/materials/halzero
Frontier: [Materials](https://technooptimist.io/materials.md) · Field: Aluminium & titanium · Company: [Norsk Hydro](https://technooptimist.io/companies/norsk-hydro.md)
Stage: Proto (2 of 5: Research → Proto → Pilot → Deploy → Scaling)
Updated: last update 2023-12-05, facts checked 2026-10-11
Goal: Make primary aluminium with oxygen as the only exhaust. Today's smelters burn carbon anodes and release CO2 with every tonne; HalZero would remove those emissions from both electrolysis and anode baking.
Status: Being verified at test scale in Porsgrunn, Norway; industrial pilot aimed for around 2030.
Next milestone: Process verified at test scale, target 2026

## Milestones

| Status | Milestone | Date | Slip |
| --- | --- | --- | --- |
| Done | HalZero development starts at Hydro's Porsgrunn tech centre | 2016 |   |
| Done | Test facility approved with NOK 141m from Enova | Mar 2023 |   |
| Current | Process verified at test scale | 2026 |   |
| Planned | Industrial-scale pilot production | 2030 |   |

## Upcoming events

- **2026**: Process verified at test scale
- **2030**: Industrial-scale pilot production

## Most important updates

- **5 Dec 2023**: HalZero wins COP28 changemaker recognition as test-facility construction is about to start. Hydro's HalZero project was recognised as an energy-transition changemaker at COP28 in Dubai, as construction of its test facility in Porsgrunn was about to begin. ([our story](https://technooptimist.io/stories/halzero-wins-cop28-changemaker-recognition-as-test-facility-bf7a3096.md) · [original source](https://www.hydro.com/en/global/media/news/2023/hydro-wins-changemaker-recognition-at-cop28-as-zero-emission-halzero-project-reaches-new-milestone/))
- **8 Mar 2023**: Hydro commits to a HalZero test facility in Porsgrunn with Norwegian state support. Hydro moved HalZero, its zero-emission smelting process, into a new development stage by investing in a test facility in Porsgrunn, Norway. ([our story](https://technooptimist.io/stories/hydro-commits-to-a-halzero-test-facility-in-porsgrunn-with-norwegian-61ba1a94.md) · [original source](https://aluminiumtoday.com/news/hydros-halzero-technology-reaches-a-new-milestone))

## Current obstacles

- **Unproven beyond test scale**: Hydro says the lab results and models are positive but significant research is still needed, and the full process carries real risk.
- **Pilot needs outside money**: Scaling up pilot testing will take a large investment and public-private partnerships, which are not yet in place.

## Physics limits

- **Removing CO2 does not remove the power bill**: Design studies put HalZero's electricity use in the same range as today's electrolysis, so aluminium stays one of the most power-hungry metals to make; it needs clean power to be truly clean.
- **Only for new or rebuilt potlines**: HalZero is a different plant, not a retrofit: it suits greenfield smelters or the replacement of obsolete potlines, so existing capacity needs other fixes such as carbon capture.

## How it works

### Chlorination: Alumina becomes aluminium chloride

Alumina reacts with chlorine and carbon to form aluminium chloride. The CO2 this step makes is fed back into the reaction instead of vented.

### Electrolysis: Chloride split by electric current

Electricity splits aluminium chloride into molten aluminium and chlorine gas. No carbon anode is burned, unlike the Hall-Héroult cells used today.

### Closed loop: Chlorine and carbon go round again

The chlorine returns to the first step and the carbon is recycled, so the net output is aluminium plus oxygen.

## Spec sheet

| Spec | HalZero | Provenance |
| --- | --- | --- |
| Test facility investment | ~NOK 400 million | reported |
| Enova grant | NOK 141 million | reported |
| Hydro primary aluminium today | <4 kg CO2e per kg | reported |
| Industry average footprint | 16.7 kg CO2e per kg | reported |

Provenance: reported = stated by the company; estimated = our estimate; sample = a sample figure.

## About Norsk Hydro

Norwegian aluminium producer founded in 1905. Its primary metal already has about a quarter of the industry's average carbon footprint, and it is developing HalZero, a smelting route that emits oxygen instead of CO2.

- Hydro's primary aluminium averages under 4 kg CO2e per kg, against an industry average of 16.7 kg.
- HalZero has been in development since 2016; a NOK 400 million test facility in Porsgrunn is verifying it.
- Target: an industrial-scale HalZero pilot around 2030, alongside carbon capture work for existing smelters.

- Founded: 1905
- Headquarters: NO
- Status: public
- Website: https://www.hydro.com
- People: Eivind Kallevik (President and CEO)
- Partners, customers, investors: Enova (investor)

Company page: https://technooptimist.io/companies/norsk-hydro.md

## Related programs

Everything in Materials: https://technooptimist.io/materials.md

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