44.2% less
Average monthly data transfer
Birmingham.ac.uk: Website sustainability progress
Over the past year, we have made targeted improvements to reduce the environmental impact of our website. By optimising images, streamlining font delivery, and minimising unnecessary data requests, we have reduced website data usage by over 40%. These changes are making pages faster to load, reducing energy consumption, and improving accessibility for users on slower connections or mobile devices.
These changes make our site faster, more efficient, and more sustainable - benefiting all users while supporting our environmental goals. To ensure transparency and ongoing progress, we will provide updates on these sustainability measures a couple of times each year. This commitment helps us track our impact and share our achievements as we continue to improve.
Our impact so far
- 43.1% less
Data transferred per session
- 55.2% less
Data transferred per user
June 2026 findings
This initial report compares website performance before and after the completion of our recent optimisation work:
- Baseline period: May to December 2025
- Post-implementation period: April to May 2026
Data from January to March 2026 has been excluded because infrastructure testing during this period materially affected the results.
| Metric | Baseline: May-Dec 2025 | Post-implementation: April–May 2026 | Reduction |
|---|---|---|---|
| Average monthly data transfer | 17.2 TB | 9.6 TB | 44.2% |
| Data per session | 14.84 MB | 8.44 MB | 43.1% |
| Data per user | 28.63 MB | 12.84 MB | 55.2% |
Year-on-year comparison: May 2025 to May 2026
Comparing the same month across years provides a like-for-like view of our progress:
- Origin data transfer reduced by 40.7% (from 16.2 TB to 9.6TB)
- Data per session reduced by 52.3% (from 17.32MB to 8.27MB)
- Data per user reduced by 64.5% (from 35.42MB to 12.58MB)
This equates to a saving of approximately 6.8TB per month compared to May 2025. Importantly these changes have been achieved despite relatively consistent user and session numbers.
About our sustainability reporting
Methodology
Methodology
Data is sourced from our CMS provider and from Google Analytics. "Data transfer" refers to the total data served from our origin infrastructure.
The baseline period (May-December 2025) represents performance before targeted optimisation measures were fully implemented.
The post-implementation period (April-May 2026) represents steady-state performance following completion of all measures.
Sustainable website hosting
Sustainable website hosting
Our Content Management System (CMS) supplier
Sustainability measurement is something Zengenti actively supports across all of their clients. Based on 40 kWh p/a average per environment (which is a value they have calculated based on the number of environments we run and our total kWh usage per year):
Based on Renewable Energy Claims
Market-based emissions: 0 kg CO2 per year
Rationale: If the data centre exclusively runs on, or procures, 100% certified renewable energy (like wind or solar), the emissions assigned to the electricity consumed are treated as zero.
Based on Standard UK Grid
Location-based emissions: 5.4kg CO2
Rationale: UK grid intensity averages about 130 - 135g CO2kWh. ===> 40kWh x 135g/kWh => 5.4kg CO2
Notes
Notes
The data centres use 100% renewable energy eliminating the operational footprint, making this a highly sustainable hosting environment.
This calculation reflects only the energy consumed by the servers. It does not factor in "grey energy" (the embedded emissions from manufacturing the server hardware) or the energy used by visitors' devices (such as laptops and smartphones) to load the website.
Last updated: June 2026