From 332bea74bf22d85d13c48a5cba5fbc5d6df609b7 Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 10:58:19 +0100 Subject: [PATCH 1/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...n-emissions-of-end-user-devices-part-one-swd-method.markdown | 2 ++ 1 file changed, 2 insertions(+) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index 10c9607a6a..12aa99d752 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -11,6 +11,8 @@ summary: This is the first of a series of blog posts that examine the various me author: drees --- + + # Introduction This series of blog posts discusses the methods of estimating carbon emissions of end-user devices. Specifically, this looks at web user interfaces, such as websites and web applications, and the devices we use to access them. After intending to write a single blog post, the research journey prompted me to reconsider how to present this to an audience. So, this is the first of a series of blog posts that broach this subject and look at the various methods, concluding with a comparison of the techniques. From cf4f02e331c34e32c6e3066e3c1207b74a8ca5a1 Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:10:00 +0100 Subject: [PATCH 2/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...-emissions-of-end-user-devices-part-one-swd-method.markdown | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index 12aa99d752..d217551030 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -11,7 +11,8 @@ summary: This is the first of a series of blog posts that examine the various me author: drees --- - + + # Introduction From 13f808078247a5cecef7f59eb200ce55a50bdd86 Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:20:40 +0100 Subject: [PATCH 3/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...-emissions-of-end-user-devices-part-one-swd-method.markdown | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index d217551030..12aa99d752 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -11,8 +11,7 @@ summary: This is the first of a series of blog posts that examine the various me author: drees --- - - + # Introduction From 17b7e55469413750f852b749565cfdb58cf57e4f Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:26:08 +0100 Subject: [PATCH 4/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...-emissions-of-end-user-devices-part-one-swd-method.markdown | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index 12aa99d752..d217551030 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -11,7 +11,8 @@ summary: This is the first of a series of blog posts that examine the various me author: drees --- - + + # Introduction From 771197f61b63b3b24696a4cbd6d1e3e76c452825 Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:31:22 +0100 Subject: [PATCH 5/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...ns-of-end-user-devices-part-one-swd-method.markdown | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index d217551030..83b9d04a8e 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -62,9 +62,9 @@ However, the energy grid is typically served by a mixture of these sources, and So, the product of the estimated energy use and the carbon intensity of that energy gives us an estimated carbon emission. -\$$ +$$ C = E \\times C_i -\$$ +$$ Where: @@ -80,9 +80,9 @@ Again, it is a simple formula for a complex problem. The example use of the SWD method is a little more complicated, but it demonstrates how it can be used to get more accurate results. It applies some assumptions: that 75% of visits to a web page are from new visitors or, more precisely, uncached visits. For the 25% returning visitors, the data transferred will only be 2% of the uncached data transfer, meaning a significant reduction of data transfer due to cached files. -\$$ -E_v = (D_v \\times 0.81 \\times 0.75) \+ (D_v \\times 0.81 \\times 0.25 \\times 0.02) -\$$ +$$ +E_v = (D_v \times 0.81 \times 0.75) + (D_v \times 0.81 \times 0.25 \times 0.02) +$$ where: From 460d64fa6bee25764de9a8e02f2b6b88772748c4 Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:36:05 +0100 Subject: [PATCH 6/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...ns-of-end-user-devices-part-one-swd-method.markdown | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index 83b9d04a8e..44ed87475a 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -38,17 +38,17 @@ The method has two parts: calculating the energy use and then applying the grid The key metric is a simple calculation. The estimated annual global energy use for the internet (1,988 TWh) is divided by the estimated global yearly data transferred (2,444 exabytes (EB)): -\$$ +$$ 1988TWh / 2444EB = 0.81kWh/GB -\$$ +$$ This straightforward equation proportionally marries energy use to data transferred. So, to estimate the energy used (kWh), multiply the data transferred in gigabytes (GB) by 0.81. -\$$ -E = D_t \\times 0.81 -\$$ +$$ +E = D_t \times 0.81 +$$ That’s too easy, right? From f25b6c0dce36e6cf3e4aff0ff3cd3d4a455ef97b Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:43:45 +0100 Subject: [PATCH 7/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...s-of-end-user-devices-part-one-swd-method.markdown | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index 44ed87475a..92672dc817 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -11,8 +11,17 @@ summary: This is the first of a series of blog posts that examine the various me author: drees --- + - + # Introduction From e47ebc6df06633b2865c32a104f1a5802690ec81 Mon Sep 17 00:00:00 2001 From: "drees@scottlogic.com" Date: Fri, 5 Apr 2024 11:52:31 +0100 Subject: [PATCH 8/8] Updated Carbon Emissions Of End User Devices Part One Swd Method --- ...-user-devices-part-one-swd-method.markdown | 44 +++++++++---------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown index 92672dc817..d3bbd3b353 100644 --- a/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown +++ b/_drafts/carbon-emissions-of-end-user-devices-part-one-swd-method.markdown @@ -13,14 +13,14 @@ author: drees # Introduction @@ -72,7 +72,7 @@ However, the energy grid is typically served by a mixture of these sources, and So, the product of the estimated energy use and the carbon intensity of that energy gives us an estimated carbon emission. $$ -C = E \\times C_i +C = E \times C_i $$ Where: @@ -103,9 +103,9 @@ Of course, if you have actual metrics, you can easily replace these assumptions After calculating the energy per visit, we can apply the carbon intensity. We can use the global carbon intensity value (490gCO2e/kWh) for a generalised worldwide perspective or if we assume a global distribution and audience. -\$$ -C_v = E_v \\times 490 -\$$ +$$ +C_v = E_v \times 490 +$$ If we’re confident about where our web page and data are stored and where our users are accessing the web page, we can use a more specific carbon intensity. @@ -145,9 +145,9 @@ Using [websitecarbon.com](http://websitecarbon.com) (which implements the SWD me With this data, we can use the SWD method to calculate the estimated carbon emissions of the blog page as follows: -\$$ -E_v = (E_t \\times D_n \\times V_n) \+ (E_t \\times D_r \\times V_r) -\$$ +$$ +E_v = (E_t \times D_n \times V_n) + (E_t \times D_r \times V_r) +$$ Where: @@ -163,29 +163,29 @@ Where: * $V_r$ is the percentage of returning visits (25%) -\$$ -E_v = (0.81 \\times 0.0043 \\times 0.75) \+ (0.81 \\times 0.0000106 \\times 0.25) = 0.0026kWh -\$$ +$$ +E_v = (0.81 \times 0.0043 \times 0.75) + (0.81 \times 0.0000106 \times 0.25) = 0.0026kWh +$$ Using the system boundaries, we can break down that energy use as follows: -* User device energy: $0.0026 \\times 0.52 = 0.001352kWh$ +* User device energy: $0.0026 \times 0.52 = 0.001352kWh$ -* Network energy: $0.0026 \\times 0.14 = 0.000364kWh$ +* Network energy: $0.0026 \times 0.14 = 0.000364kWh$ -* Data centre energy: $0.0026 \\times 0.15 = 0.00039kWh$ +* Data centre energy: $0.0026 \times 0.15 = 0.00039kWh$ -* Hardware production energy: $0.0026 \\times 0.19 = 0.000494kWh$ +* Hardware production energy: $0.0026 \times 0.19 = 0.000494kWh$ While we have a known energy carbon intensity for the user device, the network, and the data centre where the blog is hosted, we will assume the hardware production energy using the global carbon intensity of 490gCO2e/kWh (given the lack of specific evidence otherwise). With this, we can calculate the estimated CO2 emissions per visit per system: -* User device carbon emissions: $0.001352 \\times 238 = 0.322gCO2e$ +* User device carbon emissions: $0.001352 \times 238 = 0.322gCO2e$ -* Network carbon emissions: $0.000364 \\times 238 = 0.087gCO2e$ +* Network carbon emissions: $0.000364 \times 238 = 0.087gCO2e$ -* Data centre carbon emissions: $0.00039 \\times 50 = 0.019gCO2e$ +* Data centre carbon emissions: $0.00039 \times 50 = 0.019gCO2e$ -* Hardware production carbon emissions: $0.000494 \\times 490 = 0.242gCO2e$ +* Hardware production carbon emissions: $0.000494 \times 490 = 0.242gCO2e$ Giving a total estimated carbon emissions per visit of 0.67gCO2e.