Calculating a Path to Net Zero

Article by Patrick Royce MIChemE

Two online net zero calculators have been launched to aid public understanding and engagement

MOST of us know about the UK commitment to achieve net zero greenhouse gas emissions by 2050, enshrined in the Climate Change Act. And I’m sure most of us know some of the things that will help us on the decarbonisation journey, such as more renewable electricity generation, electric vehicles and so on. But what does net zero really mean? And how much effort will we have to make in each area of the energy system in order to reach net zero?

To help people think about the choices we can make along our path to reaching net zero, the UK’s Department for Business, Energy & Industrial Strategy (BEIS) has developed two new online net zero calculators. As a Chartered Chemical Engineer working for the Government I’m really proud to have helped develop these tools and to have used my industrial experience to help inform the design, and am keen that the public, including this community, uses the tools to join the debate.

After all, achieving net zero will mean fundamental changes to the way our energy is supplied and used, and chemical engineering is central to what we will need to do.

The political space

The UK jointly holds the presidency for the UNFCCC Conference of Parties meeting in November next year (better known as COP26) to push for greater international commitment in the fight against climate change. So there is a now a lot of political focus on net zero.

In November this year, the UK Prime Minister announced a 10-point plan of action for 2030, including a commitment to reach 40 GW of wind energy generating capacity. And in early December, he announced the UK’s first Nationally Determined Contribution (NDC) to reduce greenhouse gas emissions by 68% by 2030, a large component of which will involve reducing fossil fuel use.

The online calculator tools

Back to the earlier question, what is net zero, and what do we have to do to reach it? To help everyone understand and engage, BEIS has developed two new online net zero calculators, a universal tool called My2050, and a detailed tool called the MacKay Carbon Calculator.

The tools were launched via an event on 3 December, with an opening keynote speech by the Minister of State for Business, Energy and Clean Growth, Kwasi Kwarteng, whose portfolio includes responsibility for net zero. The calculators model UK territorial emissions and differ from some other calculators by allowing you to create "pathways" to decarbonisation of the UK energy system. Both tools have "levers of decarbonisation" (15 in My2050, and 45 in the detailed tool) which you can set to one of four "levels of ambition" of decarbonisation effort, ranging from minimal effort (Level 1) to the maximum plausible effort (Level 4).

For example, in the case of the lever that controls the proportion of electric cars, minimum effort (Level 1) is for no cars to be electric in 2050, and maximum plausible effort (Level 4) is for 100% of cars to be electric.


My2050 is about helping the public and schools to understand what net zero is, the options for achieving it, and the ways in which individuals can help through their lifestyle choices. The tool has a greenhouse gas (GHG) meter expressed in "carbon dioxide equivalents" (CO2e) relative to 1990 emissions. This includes emissions of the main GHG (namely CO2) but also the other important GHG emissions (methane, nitrous oxide and fluorinated gases).

You're in control: The My2050 home page

My2050 invites you to choose levels of ambition for the 15 levers which cover both demand and supply sectors of the energy system such as transport, buildings and industry. Clicking the lever name opens an information page.

As you might imagine, 15 independent levers give you quite a lot of different possible combinations – however, only a few of them lead to net zero!

The MacKay Carbon Calculator

I expect many chemical engineers would want to interact with a more detailed tool, and for that, there is the MacKay Carbon Calculator, named in honour of the late Sir David MacKay, who was the driving force behind the original 2050 Calculator launched in 2010. This has 45 levers of decarbonisation grouped under category headings that you can expand or collapse, and also contains 30 interactive graphs for each sector of the energy system.

Detailed: MacKay Calculator offers 45 levers

With 45 levers, you have to choose between competing options. For example, should industry be decarbonised through energy efficiency, electrification, biofuels, shifting to a decarbonised gas grid, or using carbon capture? Or a mixture of all five? If you go too high on ambition for every option, the calculator only applies the ambition that is needed to satisfy industry, based on a priority order. The priority order follows the lever order, and is shown on the information sheet you can see by clicking the lever name.

If it all seems a bit daunting, you can start by opening the "Example Pathways" dropdown, and selecting the "ESC Net Zero Illustrative" pathway. This is a balance pathway to net zero created by partners Energy Systems Catapult (ESC).

What it means for chemical engineers

I think it’s a really exciting time to be a chemical engineer, because chemical engineering is at the heart of many of the changes required for net zero, and the innovations we are going to need. The core of chemical engineering is about scaling up and reducing cost for large-scale physical and chemical transformation processes, and net zero is full of them! In low carbon electricity generation, we have chemical engineers in the nuclear industry. Decarbonisation of the gas grid will require low carbon hydrogen from large scale electrolysis (‘green’ hydrogen) or carbon capture and storage of CO2 emitted by steam methane reformers (‘blue’ hydrogen) at massive scale. Aviation will need refineries to produce new low carbon fuels, to replace fossil fuel kerosene. And we need innovation for low-cost large-scale energy storage and to enable direct air capture of CO2.

If you want further information about the calculators, there is a Government carbon calculator page, to which both online tools have links. Or you can email the Calculator Team at We hope that the tools will help the wider public (and schools) to understand more about net zero,  and enable energy stakeholders to engage with Government on the way ahead. To support use of the tools in schools, the Royal Geographical Society has kindly created GCSE and A-level teaching resources which are available on its website, or via the page above.

If you’re starting your career, and are tempted by the salaries in the fossil fuel industry, maybe it’s time to think again?

Article by Patrick Royce MIChemE

Energy Engineer, Department for Business, Energy & Industrial Strategy

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