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https://uva.nl

Sustainability

· 6 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.
SCORE
68
GRADE
D
FIX
2
REVIEW
3
PASS
1
INFO
0
Device:
Mobile Desktop
Checks
6
1 PASS 3 REVIEW 2 FIX
D
Green Hosting
Action
Not green
FIX
Not green
Info::
No confirmed renewable energy commitment detected
Consider providers like Cloudflare, Google Cloud, or Vercel that match 100% of their energy use with renewables.
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 HostingNot Green Hosted
Hosting Amazon Web Services✗CDN Not identified✗

Based on known provider commitments. Verify at thegreenwebfoundation.org

D
Carbon Budget
Action
52th percentile
FIX
52th percentile
Warning::
0.69g CO2 — above the median website (0.60g)
Heavier than an estimated 48% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 52th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website

0.69g

52nd percentile

Cleaner than 48% of websites

✗ Above the median website

vs Median 16% more
vs Target 39% more
B
CO2 Per Page Load
0.69g CO2 per view
REVIEW
0.69g CO2 per view
Info::
0.69g CO2 per page view
This page transfers 2.5 MB, producing an estimated 0.69g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.13g, network 0.12g, end-user device 0.45g.
Got: 0.69g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 83.4 kg CO2/year
With 10,000 page views per month, this page would generate approximately 83.4 kg of CO2 annually — equivalent to charging 10419 smartphones.

0.69g

Carbon Footprint per page view

✗ Above sustainability target (0.50g)

Cleaner than 48% of websites

Sustainable Web Design model v4 · Page size: 2.5 MB

Your site
0.69g
Top 10%
0.20g
Target
0.50g
Median website
0.60g

Energy Breakdown

Data center
0.13g
Network
0.12g
End-user device
0.45g
At 10,000 monthly views: Monthly: 6.9 kg · Annual: 83.4 kg · ≈ 10419 smartphone charges
B
Transfer Efficiency
78% efficient
REVIEW
78% efficient
Info::
Transfer efficiency: 78%
An estimated 564 KB (22%) could be eliminated: 0 KB via better compression, 0 KB via modern image formats, 564 KB of unused JavaScript. This wasted data produces 0.16g of unnecessary CO2 per page view.
78% efficient

Total waste: 564 KB (22% of page weight)

Unused JS 564 KB

0.16g unnecessary CO2 per visit

Actual transfer 2511 KB
Theoretical minimum 1947 KB
Potential savings 564 KB (0.16g CO2)

See Deep Analysis sections above for specific optimizations.

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Repeat Visit Weight
93% cached
PASS
93% cached
Info::
93% reduction on repeat visits
Returning visitors download only 164 KB (vs 2511 KB first visit). 39 of 40 resources are served from browser cache, saving 0.65g CO2 per repeat visit.
Info::
Repeat visit: 0.05g CO2 (first visit: 0.69g)
First visit
2511 KB
Repeat visit
164 KB

93% reduction on repeat visits

Saving 0.65g CO2 per returning visitor

39 resources served from cache · 1 resources re-downloaded

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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