https://tudelft.nl
Sustainability
· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
81
GRADE
B
FIX
1
REVIEW
3
PASS
2
INFO
0
Checks
62 PASS 3 REVIEW 1 FIX
DGreen HostingActionUnknownFIX
Green Hosting
ActionUnknown
Unknown
Info::
Hosting provider could not be identified
Without knowing the provider, we cannot determine their energy sourcing. Check with your hosting provider about their renewable energy commitments.
Info::
Green hosting status based on known provider commitments
Green hosting detection uses a curated database of provider renewable energy commitments. This is not a real-time verification. For authoritative checks, visit thegreenwebfoundation.org.
Green HostingUnable to Determine
Hosting Not identified✗CDN Not identified✗
Based on known provider commitments. Verify at thegreenwebfoundation.org
BCO2 Per Page Load0.59g CO2 per viewREVIEW
CO2 Per Page Load
0.59g CO2 per view
0.59g CO2 per view
Info::
0.59g CO2 per page view
This page transfers 2.1 MB, producing an estimated 0.59g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.11g, network 0.10g, end-user device 0.38g.
Got: 0.59g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 70.6 kg CO2/year
With 10,000 page views per month, this page would generate approximately 70.6 kg of CO2 annually — equivalent to charging 8828 smartphones.
0.59g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 52% of websites
Sustainable Web Design model v4 · Page size: 2.1 MB
Your site
0.59g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.11g
Network
0.10g
End-user device
0.38g
At 10,000 monthly views: Monthly: 5.9 kg · Annual: 70.6 kg · ≈ 8828 smartphone charges
BCarbon Budget48th percentileREVIEW
Carbon Budget
48th percentile
48th percentile
Info::
0.59g CO2 — below the median website (0.60g)
Better than an estimated 52% of websites, but above the sustainability target of 0.50g. Reducing page weight would help reach the target.
Info::
Estimated 48th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
0.59g
48th percentile
Cleaner than 52% of websites
✗ Above the median website
vs Median 2% cleaner ✓
vs Target 18% more
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
ActionWhether the site is served from green-energy infrastructure
Green Hosting
No green hosting detected
A+Repeat Visit Weight98% cachedPASS
Repeat Visit Weight
98% cached
98% cached
Info::
98% reduction on repeat visits
Returning visitors download only 34 KB (vs 2128 KB first visit). 55 of 57 resources are served from browser cache, saving 0.58g CO2 per repeat visit.
Info::
Repeat visit: 0.01g CO2 (first visit: 0.59g)
First visit
2128 KB
Repeat visit
34 KB
98% reduction on repeat visits
Saving 0.58g CO2 per returning visitor
55 resources served from cache · 2 resources re-downloaded
A+Transfer Efficiency96% efficientPASS
Transfer Efficiency
96% efficient
96% efficient
Info::
Transfer efficiency: 96%
Only 75 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 75 KB (4% of page weight)
Unused JS 75 KB
0.02g unnecessary CO2 per visit
Actual transfer 2128 KB
Theoretical minimum 2052 KB
Potential savings 75 KB (0.02g CO2)
See Deep Analysis sections above for specific optimizations.
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.