Baking sustainability into the startup cake

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SETsquared Bristol

On 28 September 2021 we ran a workshop on how to embed sustainable practices into a startup. The session was led by Eleanor Akers, Director of Innovative Energy Consultants, whose focus is on helping businesses grow sustainably. Here we share our top tips from the session.

What is sustainability?

A useful way of thinking about sustainability is as a stool with three legs: economic, social and environmental. It’s important for sustainable businesses to understand their performance, progress and goals in each area.

Selecting some metrics to track in each area can help rapidly growing startups understand both their current impact and their potential future impact. Economic metrics tend to be fairly well understood: cashflow, operating profits/losses, investment raised, total addressable market etc. All tend to be well documented and understood by entrepreneurs. They also tend to be familiar with their businesses’ current operational social and environmental metrics such as: CO2 emissions, water usages, or percentage of employees paid above the national living wage.

Who cares about sustainability?

Public and private investment markets are increasingly using ESG (Environmental, Social and Governance) criteria in addition to traditional financial models to make investment decisions. By including forecasts on metrics such as high quality jobs creation and tonnes of waste to landfill avoided in an awesome investor deck, startups can ensure they stand out to ESG investors.

Telling your sustainability story

Startups often struggle with quantifying and communicating the potential social and environmental impacts of their technology or service. Just like with an early-stage financial valuation, there are lots of uncertainties and unknowns. Knowing how or where to start can seem like an enormous challenge, a good starting point can be to think about what product or service your startup is replacing. Thinking about how your product compares on some common sustainability metrics like emissions of CO2, tonnes of waste to landfill, water footprint, improved health and educational outcomes, and job creation can be a great place to start.

AMSU™ – A Carbon Displacement Story

SETSquared Bristol member, Airway Medical, has designed and developed a portable suction device to clear blocked airways: the AMSU™. This device uses a canister of compressed air to create the suction needed to clear sputum, replacing existing electric powered devices.

During the workshop, a Fermi estimate was made of the carbon emissions that could be avoided if every COPD patient in Britain switched from using an electric Laerdal LSU to an AMSU™. This method is named after the Italian physicist Enrico Fermi and is used by scientists and businesses worldwide to create order of magnitude estimates when perfect data is not available.

Step 1: Estimate Annual Suction Time

  • According to NICE, there are 1,000,000 diagnosed COPD suffers in the UK
  • BMJ recommends each COPD sufferer spends 15 mins/day clearing sputum

That’s 91,250,000 hours of sputum suction per year!

Step 2: Estimate the displaced electrical load

  • From the label on the electric LSU, it is rated at 240 W
  • The LSU is powered by mains electricity or a battery. For the purpose of this estimate, it is assumed the battery charging process is 100% efficient.

91,250,000 hours/year x 240 W = 21,900,000 kWh/year

Step 3: Estimate the displaced carbon emissions

The LSU is used in homes and hospitals around the country.

  • The 2020 carbon intensity of the UK grid was 181 gCO2/kWh (National Grid)

21,900,000 kWh/year x 181 gCO2/kWh = 3,964 tonnes of CO2/year

Step 4: Estimate operating carbon emissions from AMSU™

Airway Medical use a compressor to fill the canister. The compressor is powered by electricity. As the company scales up production, they plan to assemble the device and fill the canisters at a site powered by 100% renewable energy, so there will be no carbon emissions from operating an AMSU™ unit. (If this changes, they’ll need to update this step using their actual electricity usage and carbon intensity.)

Step 5: Communicating the benefits

“Treating Britain’s COPD patients using Airway Medical’s AMSU™ has the potential to knock 3,964 tonnes of CO2 off the UK’s carbon footprint” raises an obvious question – what does that mean in real terms?

Putting CO2 savings into an equivalent most people are familiar with is a great way to drive your environmental message home. Miles driven in a car is a metric most people are familiar with.

Carbon Independent have estimated that the average car emits 280 gCO2/mile driven. So a saving of 3,964 tonnes of CO2/year is equivalent to not driving 14.2 million miles each year – that’s about 570 times the circumference of planet Earth!

“(…)a thought-provoking stat we can use that everyone can relate to.” Simon Hall, CTO Airway Medical


Visit Innovative Energy Consultants to find out how they can help your business communicate its sustainability impact and goals.

Caveat Emptor – this guidance is based on personal opinion, readers should use their own judgement as to what is appropriate for their business


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