https://web.gencat.cat
Sustainability
· 8 checks — CO2 emissions, green hosting, repeat-visit weight, carbon budget, and transfer efficiency rolled into one auditable list.SCORE
67
GRADE
D
FIX
2
REVIEW
2
PASS
3
INFO
1
Checks
83 PASS 2 REVIEW 2 FIX
FCO2 Per Page LoadAction4.88g CO2 per viewFIX
CO2 Per Page Load
Action4.88g CO2 per view
4.88g CO2 per view
Critical::
4.88g CO2 per page view
This page transfers 20.6 MB, producing an estimated 4.88g of CO2 per visit using the Sustainable Web Design model (v4). Breakdown: data center 0.12g, network 1.01g, end-user device 3.75g.
Got: 4.88g CO2 Expected: < 0.50g (sustainability target)
Info::
At 10,000 monthly views: 586.1 kg CO2/year
With 10,000 page views per month, this page would generate approximately 586.1 kg of CO2 annually — equivalent to charging 73265 smartphones.
Info::
Green hosting reduces data center emissions
4.88g
Carbon Footprint per page view
✗ Above sustainability target (0.50g)
Cleaner than 5% of websites
Sustainable Web Design model v4 · Page size: 20.6 MB
Your site
4.88g
Top 10%
0.20g
Target
0.50g
Median website
0.60g
Energy Breakdown
Data center
0.12g
Network
1.01g
End-user device
3.75g
At 10,000 monthly views: Monthly: 48.8 kg · Annual: 586.1 kg · ≈ 73265 smartphone charges
FCarbon BudgetAction95th percentileFIX
Carbon Budget
Action95th percentile
95th percentile
Warning::
4.88g CO2 — above the median website (0.60g)
Heavier than an estimated 5% of websites. Reducing page weight, optimizing images, and removing unused JavaScript would lower the carbon footprint. See the Performance tab.
Info::
Estimated 95th percentile
Compared to: top 10% = 0.20g, target = 0.50g, median = 0.60g per page view.
Top 10%
Target
Median website
4.88g
95th percentile
Cleaner than 5% of websites
✗ Above the median website
vs Median 714% more
vs Target 877% more
BWeb Font Weight VariantsNo detectable Google Fonts weightsREVIEW
Web Font Weight Variants
No detectable Google Fonts weights
No detectable Google Fonts weights
Info::
No detectable Google Fonts weights
The analyzer detects font weights via Google Fonts URL parameters (~70% of font-using sites). Self-hosted fonts and non-Google CDN fonts aren't visible to URL-based detection. If you self-host fonts, manually audit how many @font-face weights you ship -- 2-3 weights per family is typically enough; 5+ is usually unused payload.
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
AGreen HostingGreen (cdn)PASS
Green Hosting
Green (cdn)
Green (cdn)
Info::
Fastly CDN uses renewable energy
Since most traffic is served through the CDN, the majority of data transfer energy is renewable.
Info::
Fastly: 100% renewable energy for edge network
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 Hosting✓ Green Hosted
Hosting Not identified✗CDN Fastly✓
Fastly: 100% renewable energy for edge network
Based on known provider commitments. Verify at thegreenwebfoundation.org
A+Repeat Visit Weight100% cachedPASS
Repeat Visit Weight
100% cached
100% cached
Info::
100% reduction on repeat visits
Returning visitors download only 19 KB (vs 21131 KB first visit). 93 of 94 resources are served from browser cache, saving 4.88g CO2 per repeat visit.
Info::
Repeat visit: 0.00g CO2 (first visit: 4.88g)
First visit
21131 KB
Repeat visit
19 KB
100% reduction on repeat visits
Saving 4.88g CO2 per returning visitor
93 resources served from cache · 1 resources re-downloaded
A+Transfer Efficiency98% efficientPASS
Transfer Efficiency
98% efficient
98% efficient
Info::
Transfer efficiency: 98%
Only 389 KB of potential savings identified. Your page is well-optimized for size.
Total waste: 389 KB (2% of page weight)
Unused JS 389 KB
0.09g unnecessary CO2 per visit
Actual transfer 21131 KB
Theoretical minimum 20741 KB
Potential savings 389 KB (0.09g CO2)
See Deep Analysis sections above for specific optimizations.
Image Optimization49 images, 22696 KB total, 19 KB wastedINFO
Image Optimization
49 images, 22696 KB total, 19 KB wasted
Image Optimization Audit
Total Images
49
Total Size
22696 KB
Oversized
1
Wasted
19 KB
48 missing dimensions 45 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.