Overton Blog

An update on Overton's carbon footprint

Doing good is part of our ethos, here at Overton. We want to make public policy better, more representative and more fair. As such, we know it's important to live those values and embed them into all our organisational behaviours. We do our best to be a good corporate citizen, and climate consciousness is at the centre of that. 

We think it’s essential for businesses to assess and address their environmental impact, and Overton is no different! A few years ago we set out to calculate our carbon footprint and shared this with you as part of our ethos of transparency. 

Two years down the line we want to share an update, as we’ve grown considerably in that time. As before, we used the GHG Protocol to calculate our emissions. This protocol requires companies to report on scope 1 and scope 2, while 3 is optional (though we’ve given it a go):

  • Scope 1 = direct emissions caused by any process or activity by the company that causes greenhouse gas emission, eg burning fuels onsite or using company car;
  • Scope 2 = indirect emissions caused by your company purchasing energy (from sources you do not own or control). This is usually in the form of electricity, heat, or steam;
  • Scope 3 = all the indirect emissions that occur because of your business activity. For example: waste (decomposing waste emits greenhouse gases), emissions related to any goods or services purchased (for example any fuel emitted transporting them), employees commuting to and from work.

Here’s the latest figures, as of Spring 2024.


Scope 1: Direct emissions =0 tonnes of CO2 per year

We don’t produce any Scope 1 emissions as we don’t have any manufacturing operations, company vehicles etc. 


Scope 2: Indirect emissions from electricity we have purchased =0 tonnes of CO2 per year

Our only Scope 2 (indirect) emissions would be from energy used to heat and power our workspace but as we have a shared office building and staff working remotely, we do not purchase electricity directly – therefore this is discussed under Scope 3.


Scope 3: Indirect emissions that occur as a result of our business operations


Servers: Although we don’t have a physical product and therefore we have no manufacturing or post-use recycling to consider, our platform is online so our server use is a significant contributor to our carbon footprint. 

Like many other web businesses we rent servers belonging to server hosting companies, which physically sit in very well-connected data centres (most of the ones we use are in northern France) designed specifically for running large numbers of computers. Usually we’re the only company using a particular server, but sometimes we’re sharing them with other businesses.

Calculating the carbon footprint of a server is complicated, and even the server hosting companies themselves struggle to accurately measure it. It depends on how much renewable energy powers the national grid in the server’s home country, the climate of the surrounding area (warmer locations need more cooling), the efficiency of the data centre and server technology, among other things. We have used the UK Energy Research Centres estimate of energy usage per server, which they say is between 500 and 1000 watts an hour depending on its specification. 

Then there’s the challenge of mapping that onto the usage of an individual company such as Overton. Individual servers use more power under heavy load, and less power when they’re idling, and there is no reliable way – at least at a distance – to know exactly how much you’re using in a given period. 

So we have collected all the information we could find, but there are inevitably some unknowns.

We use two different server providers so we calculated our footprint separately for each. 

OVH servers

We have 30 dedicated (i.e. they’re not shared) mid-sized servers with OVH. OVH runs its own data centres and therefore has visibility and control over its environmental impact. They publish their global renewable energy share (79%) and their average carbon emissions (0.18T CO2e / MWh) and have publicly committed to ambitious sustainability goals

All of our OVH servers are located in France. Being in a French data centre makes a very big difference in our carbon emissions because the French national grid has a much lower carbon output of 0.054T / MWh (compare that to 0.309T / MWh if we had UK-based servers – if our servers were in London we’d potentially be responsible for 5-6x more CO2).

To calculate the MWh used by Overton’s OVH servers each year:

30 servers 800 Wh used by each server (using UKERC’s mid-range estimate) 8760 hours in 1 year

1,000,000 to convert Wh to MWh


210.24 MWh per year


Then to calculate the resulting carbon emissions per year:

210.24 MWh per year 0.054T CO2e / MWh (from the French national grid estimate, as of 2019)


11.35 tonnes of CO2 per year

Linode servers

Overton also uses 40 1GB “virtual” (i.e. shared) servers provided by Linode. Linode has given an estimate of their server energy consumption as 64 Wh for a 4GB virtual server, which equates to 16 Wh for the 1GB servers we use. As Linode use data centres run by third-parties around the world their ability to report on the % of renewable energy used is limited so we’ve had to make do with the UK government estimate of 0.309kg CO2e / KWh (or 0.309T CO2e / MWh), despite different countries producing different proportions of renewable energy. 

To calculate the MWh of energy used by Overton’s Linode servers each year:

40 servers x 16 Wh used by each 1GB server (using Linode’s estimate) 8760 hours in 1 year

1,000,000 to convert Wh to MWh


5.61 MWh per year


Then to calculate the resulting carbon emissions per year:

5.61 MWh per year x 0.309T CO2e/MWh (from the UK government)


1.73 tonnes of CO2 per year

Laptop usage

Similarly, we’re reliant on our laptops for almost every aspect of our work so we wanted to include this too. We have 16 staff FTE, a typical laptop uses 0.05 KWh (or 0.00005 MWh), according to Smarter Business, and the UK government carbon emission estimate is 0.309T CO2e / MWh. To calculate the footprint of our laptop usage:

16 full time staff x 8 hours per day x 256 working days per year x 0.00005 MWh used by a typical laptop (from Smarter Business) 0.309T CO2e / MWh  (from the UK government)


0.52 tonnes of CO2 per year

Office space = Unknown but likely small

As we currently have a serviced office in a shared office building, we don’t have access to any of the energy bills to figure out the building’s energy usage or the proportion which is renewable. In addition, the number of people who share the space changes on a daily basis, so we can’t estimate our proportion of the building’s energy usage with any reliability. As it stands our impact is likely to be pretty small as we only have around 6-7 people working from the office 2-3 days per week.


Home working

Although we don’t have access to exact figures for our team’s household energy consumption, we can make an estimate of how much energy may be used by staff to heat and light their homes during work hours. Not all of this will be directly attributable to work – for example if other people share the house, if energy is used for cooking or laundry or if other rooms are being heated/lit – and we have already included laptop usage above – so we’ve assumed a quarter of average household hourly energy use could be attributed to work.

Roughly two thirds of our staff time is spent working from home, which equates to 11 FTE staff. According to Ofgem, the average household in the UK uses 2,900 KWh of electricity and 12,000 KWh of gas, totalling 14,900 KWh per year. This equates to 1.7 KWh used per hour (14,900 KWh / 8760 hours per year). We used the UK government carbon emission estimate of 0.309T CO2e / MWh.

To calculate the energy used by Overton per year:

11 FTE staff x 8 hours per day 256 working days in a year x 1.7 KWh average energy used per hour in a UK household (from Ofgem)


4 (to remove non-work energy usage and laptop power) 


1000 to convert KWh to MWh

9.57 MWh per year


Then to calculate the carbon emissions from this energy:

9.57 MWh per year x 0.309T CO2e / MWh


3 tonnes CO2 per year

Staff travel

All our office-based staff travel to work by public transport – the impact of this is very hard to estimate but likely to be very small so we’re leaving it out for now. We try to keep business travel to a minimum but there are some events that we need to attend in person. Our 3 non-UK staff attend a company meeting in London 4 times per year from mainland Europe and one US-based employee comes to London once per year. We also attend around 8 sector conferences per year which can’t be attended remotely. Therefore we estimate that the team makes 18 short-haul flights (London-Rome 234 kg CO2 per passenger) and 3 long-haul flights (London-New York 986kg of CO2 per passenger) per year.

((18 x 234kg for short-haul flights) + (3 x 986kg for long-haul flights))


1000 to convert kg to tonnes


7.17 tonnes of CO2 per year

Waste = 0 tonnes CO2 per year

Our product is virtual, we are virtually paperless in our operations and our office space doesn’t use single use cups so we don’t send any waste to landfill.


Other suppliers = unknown but likely very small

The vast majority of our supply spend is with our server providers and coworking space, which have been explored above. We use a few subscription tools like Hubspot, Slack and Google suite, but calculating our footprint for these is very difficult as we don’t have the environmental impact figures from these providers and we don’t know our proportion of the supplier company’s overall impact.


Totalling our carbon footprint

As we’ve mentioned above there are limitations to the available data on Scope 3 emissions; where this is the case, we’ve over-estimated a bit, and we’ve also added an extra 2 tonnes, just to be on the safe side.

Scope 1 = 0 tonnes

Scope 2 = 0 tonnes

Scope 3 = 25.77 tonnes

  • 11.35 tonnes - OVH servers
  • 1.73 tonnes - Linode servers
  • 0.52 tonnes - laptop use
  • unknown - office space
  • 3.00 tonnes - home working
  • 7.17 tonnes - staff travel
  • 0.00 tonnes - waste
  • unknown - other suppliers
  • 2.00 - to account for unknowns (eg office space, other suppliers)

TOTAL = 25.77 tonnes of CO2 per year


Minimising our impact

Obviously the best option would be to eliminate the carbon emissions we produce altogether. We have scrutinised all areas to see where we can reduce our impact. Our server usage and staff travel are the main areas of impact. Our OVH servers account for a large part of our footprint but they are ahead of the competition in terms of improving energy efficiency and increasing their use of renewable energy, so we’re satisfied that our aim to reduce our carbon footprint is best served by continuing with them. Although we tried to find alternate modes of transport and attend meetings/events virtually where possible, where we do use flights there is no feasible alternative. We will continue to review our relationships with our server suppliers and scrutinise each travel decision to see if there are low-carbon alternatives. The other areas cannot reasonably be reduced any further either.

Given that we have reduced our footprint as far as we can, the next best option is to offset our emissions. We know this can be controversial as many companies use it instead of genuinely trying to cut their own emissions and to ‘greenwash’ their brand, and because many players in the carbon offsetting market have been fraudulent or unscrupulous. So we will commit to only using offsetting as a genuine last resort where we cannot reduce our emissions, prioritising suppliers who have a good environmental record and offsetting using a reputable provider.

In order to achieve carbon neutrality, we chose to buy carbon offset credits with Gold Standard as it was founded by WWF and other environmental NGOs and tracks the credits linked to the projects supported so they cannot be re-sold elsewhere. We chose to support two projects: ​​Mozambique Safe Water Project and 50 MW Wind Power Project in Madhya Pradesh, India.

Carbon neutral and net zero status

Under the definition outlined by the Carbon Trust, we have achieved carbon neutral status as our Scope 1 and 2 emissions are zero. The definition of Net Zero is more stringent – it requires us to have reduced our Scope 1, 2 and 3 emissions as far as we reasonably can (which we have) and to offset the rest (which we have). So we also meet the definition of Net Zero.

We will continue to monitor our environmental impact and strive to maintain our Net Zero status as we grow.

Read more about the standards we hold ourselves to at Overton:

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