LOW←TECH MAGAZINE English

Rebuilding a Solar Powered Website

Tue, 13 Jun 2023 00:00:00 +0000

A screenshot of the markdown file for this page.

During the last months we have been working on switching the solar powered website from one static site generator (Pelican) to another (Hugo). Many readers will not notice the changes right away, as we have not made any major adjustments to the design. Nevertheless, the new platform has allowed us to address some issues based on the feedback we received over the years.

The new solar website was designed by Marie Otsuka and Roel Roscam Abbing, the same people who were behind the first solar design. Marie Verdeil assisted throughout the process and coordinated the migration of the website.

Switching Platforms

The original solar website, launched in 2018, ran on a static site generator called Pelican. While this remains a good choice for a relatively small website, the solar-powered version of Low-tech Magazine has grown significantly over time. Initially it featured only a selection of the English language website, but has expanded over time to contain not only more English language articles, but translations in five other languages as well. Organizing articles and publishing changes on such a large website became a cumbersome process. For example, it took more than an hour to regenerate the site on changes – even if we only added one comment.

Hugo is a static site generator written in a faster programming language. In Pelican, much of the functionality we needed for the website such as support for multiple languages and image compression came as plugins of varying quality. This lead to limitations over time. In Hugo, these features are better supported from the start as they are core to the project. As a consequence of switching to Hugo we managed to reduce the generation time on the server from over an hour to approximately twelve minutes. On a modern laptop the difference is between several minutes and several seconds of generation.¹ This difference in time also means a difference in energy use on the server.

Aside from faster website builds, Hugo allows for a better organisation of content and is more flexible in defining categories for displaying that content. This allowed us, for example, to create dedicated pages highlighting the different contributors and translators to the magazine. However, despite both projects using posts written in Markdown, migrating all content from Pelican to Hugo was a time-consuming task. Both because of subtle differences in the post metadata format and because our Hugo setup requires its own shortcodes to allow the display of images, captions, and links. We converted the majority of articles from one platform to another using a custom script, but it still took another two months to iron out and manually repair inconsistencies in the content.

Design changes

Battery meter

The new platform allowed us to address two design issues that regularly came up in the feedback over the last years. The first concerns the battery meter, which reflects the battery status of our off-the-grid website configuration. Some people found that it interfered with the reading process, especially when it’s halfway the page. The battery meter remains an elementary part of our design, revealing the material infrastructure that supports the website. However, it now remains at the top of the document, and no longer moves along as one scrolls down an article to interfere with the text.

Images

The second and major design improvement concerns the images. Dithered image compression works great for many images, and even makes black and white images more attractive. However, some images become unclear. This is especially so for graphs, which can become unreadable if they are not designed with dithering in mind. For some other images, the colors convey information that is lost in the dithering process.

The new design allows the visitor to turn off the dithering compression for individual images, revealing the original photo or illustration. The original images we show are compressed in a conventional way and are slightly heavier than the dithered images. Revealing them thus increases the load on our server. It remains to be seen how this will influence the energy use and uptime of the solar website.

Furthermore, the images are no longer full screen, which is especially advantageous when the website is viewed on a large computer screen.

Source Code

As was the case with the original Pelican theme, we release the Hugo theme as open source software. The original solar web theme and plugins remain available, but are no longer updated nor maintained.

Running Low-tech Magazine on 1 website

This major redesign is the penultimate step towards running Low-tech Magazine on just one (solar-powered) website. Ever since the launch of the solar powered website in 2018, the old (English language) website has remained online and up-to-date. This is troublesome, for several reasons.

First, running two similar websites is not consistent with our aim to lower the ecological footprint of the publication. The more so because the original website – a dynamic website hosted on blogging platform TypePad – is not lightweight. A second website running on grid power also defeats the purpose of going offline when the weather is bad – the old website remains online no matter the weather. Second, the need to update two websites involves a lot of extra work that would better be dedicated to writing and researching. The layout for every article has to be made twice, on different platforms. Comments and changes to the articles also have to be updated on two platforms.

The higher quality of the images was one of the main reasons to keep the old website up-to-date. Now that the original images can be viewed on the solar powered website, we will no longer update the old website. From now on, new content (including comments on older articles) only appears on the solar powered website. The TypePad website will remain online until summer, when we plan to move the part of the archive that has still not been converted to the static web format. It concerns mostly articles and pages from the early days.

For most other languages, the switch to the solar powered website has been completed already and the original websites have been shut down. The only exception is the original Dutch language website, which is no longer updated but remains online (also hosted at TypePad) to keep the older articles accessible. Due to the high number of original articles on that website, it will be the last original website to disappear, if ever. It still has the original design from 2007.

User-friendliness

The new solar design brings nothing but advantages to the readers of Low-tech Magazine. However, on the publishing side, the balance is less positive. A greater usability for the visitors has gone (partly) at the expense of a lower usability for the author. The shortcodes used by Hugo are much clunkier than the syntax used by Pelican, and that adds to the time that it takes to make the layout for an article. This partly negates the time that is won by no longer having to update the second website.

Static websites are much more energy efficient than dynamic websites. However, static site generators still have a long way to go in terms of usability before they can become more mainstream and compete with tools such as WordPress. In the five years between our initial release and this one, to our surprise, no robust and user-friendly application for static site generators has appeared that could replace our current workflow. Several projects exist, but these are all dependent on proprietary cloud services. A usable graphical interface for static site generators is still where key contributions to this field can be made. In the upcoming months, we will try to improve things on the publishing side, and as always, we welcome your feedback and suggestions. Please also share bugs or inconsistencies that we have missed in the migration. Thanks to everyone who has supported this project over the years.

To understand the difference, we ran both the Hugo and the Pelican site generators in an experiment. The Pelican build is based on the solar theme and plugins. The Hugo build is based on the solar_v2 theme and dithering and file size calculation scripts as defined in the build script. Both sites have 447 articles across various languages and more than 1500 images. The results of the experiment are visible in the table below. The first two rows show how long it takes to build the site on first run. During the first run, all assets need to be generated and images need to be compressed, which takes longer than subsequent runs where the assets are cached. The last two rows show generation times when assets are already cached. The times displayed are the average time of three runs on both the solar server (an A20 processor with two 1 GHz cores and 1 GB of RAM) and a modern laptop (an Intel i7-8650U Processor with four cores at 1.9 GHz and 32 GB of RAM). Generating the Hugo site on the solar server without cached assets is not possible to do in one go because the process either runs out of memory or exceeds the timeout limit of Hugo. In that case, the command has to be run several times in a row. While it seems as if Hugo is slower than Pelican on the laptop, that is likely explained by the Hugo site running both a dithering logic and another compression logic for the images. In Pelican, images are only dithered and originals not recompressed.

	Hugo	Pelican
Solar Server (first run)	-	100 minutes, 47 seconds
Modern Laptop (first run)	13 minutes, 31 seconds	12 minutes, 53 seconds
Solar Server (cached)	11 minutes, 57 seconds	68 minutes, 47 seconds
Modern Laptop (cached)	46 seconds	04 minutes, 57 seconds

↩︎

How Sustainable is a Solar Powered Website?

Tue, 28 Jan 2020 00:00:00 +0000

Illustration: [Diego Marmolejo](https://www.instagram.com/ddidak/).

Our self-hosted, solar-powered, off-grid website has been running for 15 months now. In this article, we present its energy and uptime data, and calculate the embodied energy of our configuration. Based on these results, we consider the optimal balance between sustainability and server uptime, and outline possible improvements.

Uptime, electricity use, system efficiency

What’s the optimal balance between uptime and sustainability?

Uptime and battery size

Uptime and solar panel size

Embodied energy of different sizes of solar panels and batteries

CO2-emissions: how sustainable is a solar powered website?

Possible improvements

Let’s scale things up!

Energy use of our website throughout the internet

Introduction

In September 2018, Low-tech Magazine launched a new website that aimed to radically reduce the energy use and carbon emissions associated with accessing its content. Internet energy use is growing quickly on account of both increasing bit rates (online content gets “heavier”) and increased time spent online (especially since the arrival of mobile computing and wireless internet).

The solar powered website bucks against these trends. To drop energy use far below that of the average website, we opted for a back-to-basics web design, using a static website instead of a database driven content management system. To reduce the energy use associated with the production of the solar panel and the battery, we chose a minimal set-up and accepted that the website goes off-line when the weather is bad.

Uptime, Electricity Use & System Efficiency

Uptime

The solar powered website goes off-line when the weather is bad – but how often does that happen? For a period of about one year (351 days, from 12 December 2018 to 28 November 2019), we achieved an uptime of 95.26%. This means that we were off-line due to bad weather for 399 hours.

If we ignore the last two months, our uptime was 98.2%, with a downtime of only 152 hours. Uptime plummeted to 80% during the last two months, when a software upgrade increased the energy use of the server. This knocked the website off-line for at least a few hours every night.

Electricity Use and System Efficiency

Let’s have a look at the electricity used by our web server (the “operational” energy use). We have measurements from the server and from the solar charge controller. Comparing both values reveals the inefficiencies in the system. Over a period of roughly one year (from 3 December 2018 to 24 November 2019), the electricity use of our server was 9.53 kilowatt-hours (kWh).

We measured significant losses in the solar PV system due to voltage conversions and charge/discharge losses in the battery. The solar charge controller showed a yearly electricity use of 18.10 kWh, meaning that system efficiency was roughly 50%.

Energy Use per Unique Visitor

During the period under study, the solar powered website received 865,000 unique visitors. Including all energy losses in the solar set-up, electricity use per unique visitor is then 0.021 watt-hour.

One kilowatt-hour of solar generated electricity can thus serve almost 50,000 unique visitors, and one watt-hour of electricity can serve roughly 50 unique visitors. This is all renewable energy and as such there are no direct associated carbon emissions.

One kilowatt-hour of solar generated electricity can serve almost 50,000 unique visitors

Embodied Energy Use & Uptime

The story often ends here when renewable energy is presented as a solution for the growing energy use of the internet. When researchers examine the energy use of data centers, which host the content that is accessible on the internet, they never take into account the energy that is required to build and maintain the infrastructure that powers those data centers.

There is no such omission with a self-hosted website powered by an off-the-grid solar PV installation. The solar panel, the battery, and the solar charge controller are equally essential parts of the installation as the server itself. Consequently, energy use for the mining of the resources and the manufacture of these components – the “embodied energy” – must also be taken into account.

A simple representation of our system. The voltage conversion (between the 12V charge controller and the 5V server) and the battery meter (between the server and the battery) are missing. Unfortunately, most of this energy comes from fossil fuels, either in the form of diesel (mining the raw materials and transporting the components) or in the form of electricity generated mainly by fossil fuel power plants (most manufacturing processes).

The sizing of battery and solar panel is a compromise between uptime and sustainability

The embodied energy of our configuration is mainly determined by the size of the battery and the solar panel. At the same time, the size of battery and solar panel determine how often the website will be online (the “uptime”). Consequently, the sizing of battery and solar panel is a compromise between uptime and sustainability.

To find the optimal balance, we have run (and keep running) our system with different combinations of solar panels and batteries. Uptime and embodied energy are also determined by the local weather conditions, so the results we present here are only valid for our location (the balcony of the author’s home near Barcelona, Spain).

Illustration: [Diego Marmolejo](https://www.instagram.com/ddidak/)

Uptime and Battery size

Battery storage capacity determines how long the website can run without a supply of solar power. A minimum of energy storage is required to get through the night, while additional storage can compensate for a certain period of low (or no) solar power production during the day. Batteries deteriorate with age, so it’s best to start with more capacity than is actually needed, otherwise the battery needs to be replaced rather quickly.

> 90% Uptime

First, let’s calculate the minimum energy storage needed to keep the website online during the night, provided that the weather is good, the battery is new, and the solar panel is large enough to charge the battery completely. The average power use of our web server during the first year, including all energy losses in the solar installation, was 1.97 watts. During the shortest night of the year (8h50, June 21), we need 17.40 watt-hour of storage capacity, and during the longest night of the year (14h49, December 21), we need 29.19 Wh.

Minimum energy storage required to keep the website online during the night*

Month	Daylight	Night	Storage
21 Sep 2018	12h13min	11h47min	23.21 Wh
21 Oct 2018	10h52min	13h8min	25.87 Wh
21 Nov 2018	9h41min	14h19min	28.2 Wh
21 Dec 2018	9h11min	14h49min	29.1 Wh
21 Jan 2019	9h41min	14h19min	28.2 Wh
21 Feb 2019	10h53min	13h7min	25.84 Wh
21 Mar 2019	12h13min	11h47min	23.22 Wh
21 Apr 2019	13h34min	10h26min	20.55 Wh
21 May 2019	14h41min	9h19min	18.35 Wh
21 Jun 2019	15h10min	8h50min	17.4 Wh
21 Jul 2019	14h43min	9h17min	18.29 Wh
21 Aug 2019	13h36min	10h24min	20.49 Wh

Location: Barcelona
Provided that the weather is sunny
Wh = Watt-hours

Because lead-acid batteries should not be discharged below half of their capacity, the solar powered server requires a 60 Wh lead-acid battery to get through the shortest nights when solar conditions are optimal (2 x 29.19Wh). For most of the year we ran the system with a slightly larger energy storage (up to 86.4 Wh) and a 50W solar panel, and achieved the above mentioned uptime of 95-98%.¹

100% Uptime

A larger battery would keep the website running even during longer periods of bad weather, again provided that the solar panel is large enough to charge the battery completely. To compensate for each day of very bad weather (no significant power production), we need 47.28 watt-hour (24h x 1.97 watts) of storage capacity.

From 1 December 2019 to 12 January 2020, we combined the 50 W solar panel with a 168 watt-hour battery, which has a practical storage capacity of 84 watt-hour. This is enough storage to keep the website running for two nights and a day. Even though we tested this configuration during the darkest period of the year, we had relatively nice weather and achieved an uptime of 100%.

However, to assure an uptime of 100% over a period of years would require more energy storage. To keep the website online during four days of low or no power production, we would need a 440 watt-hour lead-acid battery – the size of a car battery. We include this configuration to represent the conventional approach to off-grid solar power.

< 90% Uptime

We also made calculations for batteries that aren’t large enough to get the website through the shortest night of the year: 48 Wh, 24 Wh, and 15.6 Wh (with practical storage capacities of 24 Wh, 12 Wh, and 7.8 Wh, respectively). The latter is the smallest lead-acid battery commercially available.

A website that goes off-line in evening could be an interesting option for a local online publication with low anticipated traffic after midnight.

If the weather is good, the 48 Wh lead-acid battery will keep the server running during the night from March to September. The 24 Wh lead acid-battery can keep the website online for a maximum of 6 hours, meaning that the server will go off-line each night of the year, although at different hours depending on the season.

Finally, the 15.6 Wh battery keeps the website online for only four hours when there’s no solar power. Even if the weather is good, the server will stop working around 1 am in summer and around 9 pm in winter. The maximum uptime for the smallest battery would be around 50%, and in practice it will be lower due to clouds and rain.

A website that goes off-line in evening could be an interesting option for a local online publication with low anticipated traffic after midnight. However, since Low-tech Magazine’s readership is almost equally divided between Europe and the USA this is not an attractive option. If the website goes down every night, our American readers could only access it during the morning.

Expected uptimes by battery type on a full charge.

Battery	Uptime
440Wh	Website gets through 4 days of bad weather
168Wh	Website gets through 1 day of bad weather
86.4Wh	Website gets through the night if the weather is good
48Wh	Website goes offline many nights of the year
24Wh	Website goes offline every night
15.6Wh	Website goes offline every night

Uptime and Solar Panel Size

The uptime of the solar powered website is not only determined by the battery, but also by the solar panel, especially in relation to bad weather. The larger the solar panel, the quicker it will charge the battery and fewer hours of sun will be needed to get the website through the night. For example, with the 50 W solar panel, one to two hours of full sun are sufficient to completely charge most of the batteries.

Replace the 50 W solar panel by a 10 W solar panel, however, and the system needs at least 5.5 hours to charge the 86.4 Wh battery in optimal conditions (2 W to operate the server, 8 W to charge the battery). If the 10W solar panel is combined with a larger, 168 Wh lead-acid battery, it needs 10.5 hours of full sun to charge the battery completely, which is only possible from February to November.

Clouds

A larger solar panel is equally advantageous during cloudy weather. Clouds can lower solar energy production to anywhere between 0 and 90% of maximum capacity, depending on the thickness of cloud cover. If a 50 watt solar panel produces just 10% of its maximum capacity (5W), that’s still enough to run the server (2W) and charge the battery (3W).

However, if a 10 W solar panel only produces 10% of its capacity, that’s just enough to power the server, and the battery won’t be charged. We ran the website on a 10 W panel from 12 to 21 January 2020, and it quickly went down when the weather was not optimal. We are now powering the website with a 30W solar panel (and a 168 Wh battery).

A larger solar panel increases the chances that the website remains online even when weather conditions are not optimal.

A 5 W solar panel – the smallest 12V solar panel commercially available – is the absolute minimum required to run a solar powered website. However, only under optimal conditions will it be able to power the server (2W) and charge the battery (3W), and it could only keep the website running through the night if the day is long enough. Because solar panels rarely generate their maximum power capacity, this would result in a website that is online only while the sun shines.

Even though the combination of a small solar panel and large battery can have the same embodied energy as the combination of a large solar panel and a small battery, the system each creates will have very different characteristics. In general, it’s best to opt for a larger solar panel and a smaller battery, because this combination increases the life expectancy of the battery – lead-acid batteries need to be fully charged from time to time or they lose storage capacity.

Embodied Energy for Different Sizes of Batteries and Solar Panels

It takes 1.03 megajoule (MJ) to produce 1 watt-hour of lead-acid battery capacity², and 3,514 MJ of energy to produce one m2 of solar panel.³ In the table below, we present the embodied energy for different sizes of batteries and solar panels and then calculate the embodied energy per year, based on a life expectancy of 5 years for batteries and 25 years for solar panels. The values are converted to kilowatt-hours per year and refer to primary energy, not electricity.

A solar powered website also needs a charge controller and of course a web server. The embodied energy for these components remains the same no matter the size of solar panel or battery. The embodied energy per year is based on a life expectancy of 10 years. ⁴⁵

Embodied Energy of Different Components (per year of operation)

Battery*	Embodied Energy
440Wh battery	25.17 kWh/year
168Wh battery	9.60 kWh/year
86.4Wh battery	3.91 kWh/year
48Wh battery	2.75 kWh/year
24Wh battery	1.27 kWh/year
15.6Wh battery	0.89 kWh/year

Calculated on a life expectancy of 5 years
kWh/year = primary energy

Solar Panel*	Embodied Energy
50W solar panel	16.96 kWh/year
30W solar panel	10.20 kWh/year
10W solar panel	3.40 kWh/year
5W solar panel	1.70 kWh/year

Calculated on a life expectancy of 25 years
kWh/year = primary energy

Other Components*	Embodied Energy
Solar charge controller	3.33 kWh/year
Server	5.00 kWh/year

Calculated on a life expectancy of 10 years
kWh/year = primary energy

We now have all data to calculate the total embodied energy for each combination of solar panels and batteries. The results are presented in the table below. The embodied energy varies by a factor of five depending on the configuration: from 10.92 kWh primary energy per year for the combination of the smallest solar panel (5W) with the smallest battery (15.6 Wh) to 50.46 kWh primary energy per year for the combination of the largest solar panel (50 W) with the largest battery (440Wh).

Embodied energy per year for different solar set-ups*

Battery	50W	30W	10W	5W
	Solar Panel
440Wh	50.46 kWh	43.70 kWh	n/a	n/a
168Wh	34.89 kWh	28.13 kWh	21.33 kWh	n/a
86.4Wh	29.20 kWh	22.36 kWh	15.64 kWh	13.94 kWh
48Wh	28.04 kWh	21.28 kWh	14.18 kWh	12.78 kWh
24Wh	26.29 kWh	19.80 kWh	13.00 kWh	11.30 kWh
15.6Wh	26.18 kWh	19.42 kWh	12.62 kWh	10.92 kWh

Includes embodied energy of the server and charge controller
kWh/year = primary energy
n/a = solar panel cannot charge the battery completely, no matter the season.

If we divide these results by the number of unique visitors per year (865,000), we obtain the embodied energy use per unique visitor to our website. For our original configuration with 95-98% uptime (50W solar panel, 86.4Wh battery), primary energy use per unique visitor is 0.03 Wh. This result would be pretty similar for the other configurations with a lower uptime, because although the embodied energy is lower, so is the number of unique visitors.

Carbon Emissions: How Sustainable is the Solar Powered Website?

Carbon Emissions of the Solar Powered Website

Now that we have calculated the embodied energy of different configurations, we can calculate the carbon emissions. We can’t compare the environmental footprint of the solar powered website with that of the old website, because it is hosted elsewhere and we can’t measure its energy use. What we can compare is the solar powered website with a similar self-hosted configuration that is run on grid power. This allows us to assess the (un)sustainability of running the website on solar power.

Life cycle analyses of solar panels are not very useful for working out the CO2-emissions of our components because they work on the assumption that all energy produced by the panels is used. This is not necessarily true in our case: the larger solar panels waste a lot of solar power in optimal weather conditions.

Hosting the solar powered Low-tech Magazine for a year has produced as much emissions as an average car driving a distance of 50 km.

We therefore take another approach: we convert the embodied energy of our components to litres of oil (1 litre of oil is 10 kWh of primary energy) and calculate the result based on the CO2-emissions of oil (1 litre of oil produces 3 kg of greenhouse gasses, including mining and refining it). This takes into account that most solar panels and batteries are now produced in China – where the power grid is three times as carbon-intensive and 50% less energy efficient than in Europe. ⁶

This means that fossil fuel use associated with hosting the solar powered Low-tech Magazine during the first year (50W panel, 86.4 Wh battery) corresponds to 3 litres of oil and 9 kg of carbon emissions – as much as an average European car driving a distance of 50 km. Below are the results for the other configurations:

Embodied energy in oil equivalents (L / year) and carbon emissions (kg / year) for different solar setups*

	50W	30W	10W	5W
440Wh	5.05 L 15.14 kg	4.37 L 13.11 kg	n/a	n/a
168Wh	3.49 L 10.47 kg	2.81 L 8.44 kg	2.13 L 6.40 kg	n/a
86.4Wh	2.92 L 8.76 kg	2.24 L 6.71 kg	1.56 L 4.69 kg	1.39 L 4.18 kg
48Wh	2.80 L 8.41 kg	2.13 L 6.38 kg	1.45 L 4.34 kg	1.28 L 3.83 kg
24Wh	2.63 L 7.89 kg	1.98 L 5.94 kg	1.3 L 3.90 kg	1.13 L 3.39 kg
15.6Wh	2.62 L 7.85 kg	1.94 L 5.83 kg	1.26 L 3.79 kg	1.09 L 3.28 kg

Includes embodied energy of the server and charge controller
n/a = solar panel cannot charge the battery completely, no matter the season.

Comparison with Carbon Intensity of Spanish Power Grid

Now let’s calculate the hypothetical CO2-emissions from running our self-hosted web server on grid power instead of solar power. CO2-emissions in this case depend on the Spanish power grid, which happens to be one of the least carbon intensive in Europe due to its high share of renewable and nuclear energy (respectively 36.8% and 22% in 2019).

Last year, the carbon intensity of the Spanish power grid decreased to 162g of CO2 per kWh of electricity. For comparison, the average carbon intensity in Europe is around 300g per kWh of electricity, while the carbon intensity of the US and Chinese power grid are respectively above 400g and 900g of CO2 per kWh of electricity.

If we just look at the operational energy use of our server, which was 9.53 kWh of electricity during the first year, running it on the Spanish power grid would have produced 1.54 kg of CO2-emissions, compared to 3 - 10 kg in our tested configurations. This seems to indicate that our solar powered server is a bad idea, because even the smallest solar panel with the smallest battery generates more carbon emissions than grid power.

When the carbon intensity of the power grid is measured, the embodied energy of the renewable power infrastructure is taken to be zero.

However, we’re comparing apples to oranges. We have calculated our emissions based on the embodied energy of our installation. When the carbon intensity of the Spanish power grid is measured, the embodied energy of the renewable power infrastructure is taken to be zero. If we calculated our carbon intensity in the same way, of course it would be zero, too.

Ignoring the embodied carbon emissions of the power infrastructure is reasonable when the grid is powered by fossil fuel power plants, because the carbon emissions to build that infrastructure are very small compared to the carbon emissions of the fuel that is burned. However, the reverse is true of renewable power sources, where operational carbon emissions are almost zero but carbon is emitted during the production of the power plants themselves.

To make a fair comparison with our solar powered server, the calculation of the carbon intensity of the Spanish power grid should take into account the emissions from the building and maintaining of the power plants, the transmission lines, and – should fossil fuel power plants eventually disappear – the energy storage. Of course, ultimately, the embodied energy of all these components would depend on the chosen uptime.

The 50W and 30W solar PV panels on the balcony. One is powering the website, the other is powering the lights in the living room. Image by Marie Verdeil.

Possible Improvements

There are many ways in which the sustainability of our solar powered website could be improved while maintaining our present uptime. Producing solar panels and batteries using electricity from the Spanish grid would have the largest impact in terms of carbon emissions, because the carbon footprint of our configuration would be roughly 5 times lower than it is now.

What we can do ourselves is lower the operational energy use of the server and improve the system efficiency of the solar PV installation. Both would allow us to run the server with a smaller battery and solar panel, thereby reducing embodied energy. We could also switch to another type of energy storage or even another type of energy source.

Server

We already made some changes that have resulted in a lower operational energy use of the server. For example, we discovered that more than half of total data traffic on our server (6.63 of 11.16 TB) was caused by a single broken RSS implementation that pulled our feed every couple of minutes.

A difference in power use of 0.19 watts adds up to 4.56 watt-hour over the course of 24 hours, which means that the website can stay online for more than 2.5 hours longer.

Fixing this as well as some other changes lowered the power use of the server (excluding energy losses) from 1.14 watts to about 0.95 watts. The gain may seem small, but a difference in power use of 0.19 watts adds up to 4.56 watt-hour over the course of 24 hours, which means that the website can stay online for more than 2.5 hours longer.

The solar powered server in its new housing, screwed against the wall in the living room. The battery is in front. The solar charge controller below the laptop powers the lights in the room. Image by Marie Verdeil.

System Efficiency

System efficiency was only 50% during the first year. Energy losses were experienced during charging and discharging of the battery (22%), as well as in the voltage conversion from 12V (solar PV system) to 5V (USB connection), where the losses add up to 28%. The initial voltage converter we built was pretty suboptimum (our solar charge controller doesn’t have a built-in USB-connection), so we could build a better one, or switch to a 5V solar PV set-up.

Energy Storage

To increase the efficiency of the energy storage, we could replace the lead-acid batteries with more expensive lithium-ion batteries, which have lower charge/discharge losses (<10%) and lower embodied energy. More likely is that we eventually switch to a more poetic small-scale compressed air energy storage system (CAES). Although low pressure CAES systems have similar efficiency to lead-acid batteries, they have much lower embodied energy due to their long life expectancy (decades instead of years).

Energy Source

Another way to lower the embodied energy is to switch renewable energy source. Solar PV power has high embodied energy compared to alternatives such as wind, water, or human power. These power sources could be harvested with little more than a generator and a voltage regulator – as the rest of the power plant could be built out of wood. Furthermore, a water-powered website wouldn’t require high-tech energy storage. If you’re in a cold climate, you could even operate a website on the heat of a wood stove, using a thermo-electric generator.

Solar Tracker

People who have a good supply of wind or water power could build a system with lower embodied energy than ours. However, unless the author starts powering his website by hand or foot, we’re pretty much stuck with solar power. The biggest improvement we could make is to add a solar tracker that makes the panel follow the sun, which could increase electricity generation by as much as 30%, and allow us to obtain a better uptime with a smaller panel.

Let’s Scale Things Up !

A final way to improve the sustainability of our system would be to scale it up: run more websites on a server, and run more (and larger) servers on a solar PV system. This set-up would have much lower embodied energy than an oversized system for each website alone.

Illustration: [Diego Marmolejo](https://www.instagram.com/ddidak/).

Solar Webhosting Company

If we were to fill the author’s balcony with solar panels and start a solar powered webhosting company, the embodied energy per unique visitor would decrease significantly. We would need only one server for multiple websites, and only one solar charge controller for multiple solar panels. Voltage conversion would be more energy efficient, and both solar and battery power could be shared by all websites, which brings economies of scale.

Of course, this is the very concept of the data center, and although we have no ambition to start such a business, others could take this idea forward: towards a data center that is run just as efficiently as any other data center today, but which is powered by renewables and goes off-line when the weather is bad.

Add More Websites

We found that the capacity of our server is large enough to host more websites, so we already took a small step towards economies of scale by moving the Spanish and French versions of Low-tech Magazine to the solar powered server (as well as some other translations).

Although this move will increase our operational energy use and potentially also our embodied energy use, we also eliminate other websites that were hosted elsewhere. We also have to keep in mind that the number of unique visitors to Low-tech Magazine may grow in the future, so we need to become more energy efficient just to maintain our environmental footprint.

Combine Server and Lighting

Another way to achieve economies of scale would give a whole new twist to the idea. The solar powered server is part of the author’s household, which is also partly powered by off-grid solar energy. We could test different sizes of batteries and solar panels – simply swapping components between solar installations.

When we were running the server on the 50 W panel, the author was running the lights in the living room on a 10W panel – and was often left sitting in the dark. When we were running the server on the 10 W panel, it was the other way around: there was more light in the household, at the expense of a lower server uptime.

If the weather gets bad, the author could decide not to use the lights and keep the server online – or the other way around

Let’s say we run both the lights and the server on one solar PV system. It would lower the embodied energy if both systems are considered, because only one solar charge controller would be needed. Furthermore, it could result in a much smaller battery and solar panel (compared to two separate systems), because if the weather gets bad, the author could decide not to use the lights and keep the server online – or the other way around. This flexibility is not available now, because the server is the only load and its power use cannot be easily manipulated.

Energy Use in the Network

As far as we know, ours is the first life cycle analysis of a website that runs entirely on renewable energy and includes the embodied energy of its power and energy storage infrastructure. However, this is not, of course, the total energy use associated with this website.

There’s also the operational and embodied energy of the network infrastructure (which includes our router, the internet backbone, and the mobile phone network), and the operational and embodied energy of the devices that our visitors use to access our website: smartphones, tablets, laptops, desktops. Some of these have low operational energy use, but they all have very limited lifespans and thus high embodied energy.

Energy use in the network is directly related to the bit rate of the data traffic that runs through it, so our lightweight website is just as efficient in the communication network as it is on our server. However, we have very little influence over which devices people use to access our website, and the direct advantage of our design is much smaller here than in the network. For example, our website has the potential to increase the life expectancy of computers, because it’s light enough to be accessed with very old machines. Unfortunately, our website alone will not make people use their computers for longer.

Both the network infrastructure and the end-use devices could be re-imagined along the lines of the solar powered website.

That said, both the network infrastructure and the end-use devices could be re-imagined along the lines of the solar powered website – downscaled and powered by renewable energy sources with limited energy storage. Parts of the network infrastructure could go off-line if the local weather is bad, and your e-mail may be temporarily stored in a rainstorm 3.000 km away. This type of network infrastructure actually exists in some countries.

Because the total energy use of the internet is usually measured to be roughly equally distributed over servers, network, and end-use devices (all including the manufacturing of the devices), we can make a rough estimate of the total energy use of this website throughout a re-imagined internet. For our original set-up with 95.2% uptime, this would be 87.6 kWh of primary energy, which corresponds to 9 litres of oil and 27 kg of CO2 per year. The improvements we outlined earlier could bring these numbers further down, because in this calculation the whole internet is powered by oversized solar PV systems on balconies.

Thanks to Kathy Vanhout, Adriana Parra and Gauthier Roussilhe.

The storage capacity for our original set-up is an estimation. In reality, during this period we have run the solar powered server on a 24 Wh (3.7V, 6.6A) LiPo-battery, and placed a very old 84.4 watt-hour lead-acid battery in between the LiPo and the solar charge controller to make both systems compatible. The cut-off voltage of the lead-acid battery was set very high in summer (meaning that the system was running only on the LiPo) but lower in winter (so that part of the lead-acid battery provided a share of the energy storage). This complicated set-up was entirely due to the fact that we could only measure the storage capacity of the LiPo battery, which we needed to display our online battery meter. In November 2019 we developed our own lead-acid battery meter, which made it possible to eliminate the LiPo from our configuration. ↩︎
“Energy Analysis of Batteries in Photovoltaic systems. Part one (Performance and energy requirements)” (PDF) and “Part two (Energy Return Factors and Overall Battery Efficiencies)” (PDF). Energy Conversion and Management 46, 2005 ↩︎
Zhong, Shan, Pratiksha Rakhe, and Joshua M. Pearce. “Energy payback time of a solar photovoltaic powered waste plastic recyclebot system.” Recycling 2.2 (2017): 10. ↩︎
There is little useful research into the embodied energy of solar charge controllers. Most studies focus on large solar PV systems, in which the charge controller’s embodied energy is negligible. The most useful result we found was a value of 1 MJ/W, estimated over the size of the controller: Kim, Bunthern, et al. “Life cycle assessment for a solar energy system based on reuse components for developing countries.” Journal of cleaner production 208 (2019): 1459-1468. For a capacity of 120W, this comes down to 120 MJ or 33.33 kWh. For the life expectancy, we found values of 7 years and 12.5 years: same reference, and Kim, Bunthern, et al. “Second life of power supply unit as charge controller in PV system and environmental benefit assessment.” IECON 2016-42nd Annual Conference of the IEEE Industrial Electronics Society. IEEE, 2016. We decided to make the calculation based on a life expectancy of 10 years. ↩︎
There is no research about the embodied energy of our server. We calculated the embodied energy on the basis of a life cycle analysis of a smartphone: Ercan, Mine & Malmodin, Jens & Bergmark, Pernilla & Kimfalk, Emma & Nilsson, Ellinor. (2016). Life Cycle Assessment of a Smartphone. 10.2991/ict4s-16.2016.15. We have no idea of the expected lifetime of the server, but since our Olimex is aimed at industrial use (unlike the Raspberry Pi), we assume a life expectancy of 10 years, just like the charge controller. ↩︎
De Decker, Kris. “How sustainable is solar PV power?”, Low-tech Magazine, May 2015. ↩︎

How to Build a Low-tech Website?

Mon, 24 Sep 2018 00:00:00 +0000

First prototype of the solar powered server that runs the new website. The solar charge controller (on the right) is powering the server (on the left) through a USB-cable.

Low-tech Magazine was born in 2007 and has seen minimal changes ever since. Because a website redesign was long overdue — and because we try to practice what we preach — we decided to build a low-tech, self-hosted, and solar-powered version of Low-tech Magazine. The new blog is designed to radically reduce the energy use associated with accessing our content.

Why a Low-tech Website?

We were told that the Internet would “dematerialise” society and decrease energy use. Contrary to this projection, it has become a large and rapidly growing consumer of energy itself.

In order to offset the negative consequences associated with high energy consumption, renewable energy has been proposed as a means to lower emissions from powering data centers. For example, Greenpeace’s yearly ClickClean report ranks major Internet companies based on their use of renewable power sources.

However, running data centers on renewable power sources is not enough to address the growing energy use of the Internet. To start with, the Internet already uses three times more energy than all wind and solar power sources worldwide can provide. Furthermore, manufacturing, and regularly replacing, renewable power plants also requires energy, meaning that if data traffic keeps growing, so will the use of fossil fuels.

Running data centers on renewable power sources is not enough to address the growing energy use of the Internet.

Finally, solar and wind power are not always available, which means that an Internet running on renewable power sources would require infrastructure for energy storage and/or transmission that is also dependent on fossil fuels for its manufacture and replacement. Powering websites with renewable energy is not a bad idea, however the trend towards growing energy use must also be addressed.

To start with, content is becoming increasingly resource-intensive. This has a lot to do with the growing importance of video, but a similar trend can be observed among websites. The size of the average web page (defined as the average page size of the 500,000 most popular domains) increased from 0.45 megabytes (MB) in 2010 to 1.7 megabytes in June 2018. For mobile websites, the average “page weight” rose tenfold from 0.15 MB in 2011 to 1.6 MB in 2018. Using different measurement methods, other sources report average page sizes of up to 2.9 MB in 2018.

The growth in data traffic surpasses the advances in energy efficiency (the energy required to transfer 1 megabyte of data over the Internet), resulting in more and more energy use. “Heavier” or “larger” websites not only increase energy use in the network infrastructure, but they also shorten the lifetime of computers — larger websites require more powerful computers to access them. This means that more computers need to be manufactured, which is a very energy-intensive process.

Being always online doesn’t combine well with renewable energy sources such as wind and solar power, which are not always available.

A second reason for growing Internet energy consumption is that we spend more and more time on-line. Before the arrival of portable computing devices and wireless network access, we were only connected to the network when we had access to a desktop computer in the office, at home, or in the library. We now live in a world in which no matter where we are, we are always on-line, including, at times, via more than one device simultaneously.

“Always-on” Internet access is accompanied by a cloud computing model – allowing more energy efficient user devices at the expense of increased energy use in data centers. Increasingly, activities that could perfectly happen off-line – such as writing a document, filling in a spreadsheet, or storing data – are now requiring continuous network access. This does not combine well with renewable energy sources such as wind and solar power, which are not always available.

Low-tech Web Design

Our new web design addresses both these issues. Thanks to a low-tech web design, we managed to decrease the average page size of the blog by a factor of five compared to the old design – all while making the website visually more attractive (and mobile-friendly). Secondly, our new website runs 100% on solar power, not just in words, but in reality: it has its own energy storage and will go off-line during longer periods of cloudy weather.

The Internet is not an autonomous being. Its growing energy use is the consequence of actual decisions made by software developers, web designers, marketing departments, publishers and internet users. With a lightweight, off-the-grid solar-powered website, we want to show that other decisions can be made.

With 36 of roughly 100 articles now online, the average page weight on the solar powered website is roughly five times below that of the previous design.

To start with, the new website design reverses the trend towards increasingly larger page sizes. With 36 of roughly 100 articles now online, the average page weight on the solar powered website is 0.77 MB — roughly five times below that of the previous design, and less than half the average page size of the 500,000 most popular blogs in June 2018.

A web page speed test from the old and the new Low-tech Magazine. Page size has decreased more than sixfold, number of requests has decreased fivefold, and download speed has increased tenfold. Note that we did not design the website for speed, but for low energy use. It would be faster still if the server would be placed in a data center and/or in a more central location in the Internet infrastructure. Source: Pingdom.

Below are some of the design decisions we made to reduce energy use. We have published a separate document that focuses on the front-end efforts, and one that focuses on the back-end. We have also released the source code for our website design.

Static Site

One of the fundamental choices we made was to build a static website. Most of today’s websites use server side programming languages that generate the website on the fly by querying a database. This means that every time someone visits a web page, it is generated on demand.

On the other hand, a static website is generated once and exists as a simple set of documents on the server’s hard disk. It’s always there – not just when someone visits the page. Static websites are thus based on file storage whereas dynamic websites depend on recurrent computation. Static websites consequently require less processing power and thus less energy.

The choice for a static site enables the possibility of serving the site in an economic manner from our home office in Barcelona. Doing the same with a database-driven website would be nearly impossible, because it would require too much energy. It would also be a big security risk. Although a web server with a static site can be hacked, there are significantly less attack routes and the damage is more easily repaired.

Dithered Images

The main challenge was to reduce page size without making the website less attractive. Because images take up most of the bandwidth, it would be easy to obtain very small page sizes and lower energy use by eliminating images, reducing their number, or making them much smaller. However, visuals are an important part of Low-tech Magazine’s appeal, and the website would not be the same without them.

By dithering, we can make images ten times less resource-intensive, even though they are displayed much larger than on the old website.

Instead, we chose to apply an obsolete image compression technique called “dithering”. The number of colours in an image, combined with its file format and resolution, contributes to the size of an image. Thus, instead of using full-colour high-resolution images, we chose to convert all images to black and white, with four levels of grey in-between.

A dithered image of our server.

These black-and-white images are then coloured according to the pertaining content category via the browser’s native image manipulation capacities. Compressed through this dithering plugin, images featured in the articles add much less load to the content: compared to the old website, the images are roughly ten times less resource-intensive.

Default typeface / No logo

All resources loaded, including typefaces and logos, are an additional request to the server, requiring storage space and energy use. Therefore, our new website does not load a custom typeface and removes the font-family declaration, meaning that visitors will see the default typeface of their browser.

We use a similar approach for the logo. In fact, Low-tech Magazine never had a real logo, just a banner image of a spear held as a low-tech weapon against prevailing high-tech claims.

Instead of a designed logotype, which would require the production and distribution of custom typefaces and imagery, Low-tech Magazine’s new identity consists of a single typographic move: to use the left-facing arrow in place of the hypen in the blog’s name: LOW←TECH MAGAZINE.

No Third-Party Tracking, No Advertising Services, No Cookies

Web analysis software such as Google Analytics records what happens on a website — which pages are most viewed, where visitors come from, and so on. These services are popular because few people host their own website. However, exchanging these data between the server and the computer of the webmaster generates extra data traffic and thus energy use.

With a self-hosted server, we can make and view these measurements on the same machine: every web server generates logs of what happens on the computer. These (anonymous) logs are only viewed by us and are not used to profile visitors.

With a self-hosted server, there’s no need for third-party tracking and cookies.

Low-tech Magazine has been running Google Adsense advertisements since the beginning in 2007. Although these are an important financial resource to maintain the blog, they have two important downsides. The first is energy use: advertising services raise data traffic and thus energy use.

Secondly, Google collects information from the blog’s visitors, which forces us to craft extensive privacy statements and cookie warnings — which also consume data, and annoy visitors. Therefore, we replace Adsense by other financing options (read more below). We use no cookies at all.

How often will the website be off-line?

Quite a few web hosting companies claim that their servers are running on renewable energy. However, even when they actually generate solar power on-site, and do not merely “offset” fossil fuel power use by planting trees or the like, their websites are always on-line.

This means that either they have a giant battery storage system on-site (which makes their power system unsustainable), or that they are relying on grid power when there is a shortage of solar power (which means that they do not really run on 100% solar power).

The 50W solar PV panel. On top of it is a 10W panel powering a lighting system.

In contrast, this website runs on an off-the-grid solar power system with its own energy storage, and will go off-line during longer periods of cloudy weather. Less than 100% reliability is essential for the sustainability of an off-the-grid solar system, because above a certain threshold the fossil fuel energy used for producing and replacing the batteries is higher than the fossil fuel energy saved by the solar panels.

How often the website will be off-line remains to be seen. The web server is now powered by a new 50 Wp solar panel and a two year old 12V 7Ah lead-acid battery. Because the solar panel is shaded during the morning, it receives direct sunlight for only 4 to 6 hours per day. Under optimal conditions, the solar panel thus generates 6 hours x 50 watt = 300 Wh of electricity.

The web server uses between 1 and 2.5 watts of power (depending on the number of visitors), meaning that it requires between 24 Wh and 60 Wh of electricity per day. Under optimal conditions, we should thus have sufficient energy to keep the web server running for 24 hours per day. Excess energy production can be used for household applications.

We expect to keep the website on-line during one or two days of bad weather, after which it will go off-line.

However, during cloudy days, especially in winter, daily energy production could be as low as 4 hours x 10 watts = 40 watt-hours per day, while the server requires beteen 24 and 60 Wh per day. The battery storage is roughly 40 Wh, taking into account 30% of charging and 33% depth-or-discharge (the solar charge controller shuts the system down when battery voltage drops to 12V).

Consequently, the solar powered server will remain on-line during one or two days of bad weather, but not for longer. However, these are estimations, and we may add a second 7 Ah battery in autumn if this is necessary. We aim for an “uptime” of 90%, meaning that the website will be off-line for an average of 35 days per year.

First prototype with lead-acid battery (12V 7Ah) on the left, and Li-Po UPS battery (3,7V 6600mA) on the right. The lead-acid battery provides the bulk of the energy storage, while the Li-Po battery allows the server to shut down without damaging the hardware (it will be replaced by a much smaller Li-Po battery).

When is the best time to visit?

The accessibility of this website depends on the weather in Barcelona, Spain, where the solar-powered web server is located. To help visitors “plan” their visits to Low-tech Magazine, we provide them with several clues.

To help visitors “plan” their visits to Low-tech Magazine, we provide them with several clues.

A battery meter provides crucial information because it may tell the visitor that the blog is about to go down – or that it’s “safe” to read it. The design features a background colour that indicates the capacity of the solar-charged battery that powers the website server. A decreasing height indicates that night has fallen or that the weather is bad.

In addition to the battery level, other information about the website server is visible with a statistics dashboard. This includes contextual information of the server’s location: time, current sky conditions, upcoming forecast, and the duration since the server last shut down due to insufficient power.

To access Low-tech Magazine no matter the weather, we have several offline reading options available.

Hardware and Software

We wrote two extra articles with more in-depth technical information: How to build a low-tech website: software and hardware, which focuses on the back-end, and How to Build a Low-tech Website: Design Techniques and Process, which focuses on the front-end.

SERVER: This website runs on an Olimex A20 computer. It has 2 Ghz of processing power, 1 GB of RAM, and 16 GB of storage. The server draws 1 - 2.5 watts of power.

SERVER SOFTWARE: The webserver runs Armbian Stretch, a Debian based operating system built around the SUNXI kernel. We wrote technical documentation for configuring the webserver.

DESIGN SOFTWARE: The website is built with Pelican, a static site generator. We have released the source code for ‘solar’, the Pelican theme we developed here.

INTERNET CONNECTION. The server is connected to a 100 MBps fibre internet connection. Here’s how we configured the router. For now, the router is powered by grid electricity and requires 10 watts of power. We are investigating how to replace the energy-hungry router with a more efficient one that can be solar-powered, too.

SOLAR PV SYSTEM. The server runs on a 50 Wp solar panel and one 12V 7Ah lead-acid battery. However, are still downsizing the system and are experimenting with different setups. The PV installation is managed by a 20A solar charge controller.

What happens to the old website?

The solar powered Low-tech Magazine is a work in progress. For now, the grid-powered Low-tech Magazine remains on-line. Readers will be encouraged to visit the solar powered website if it is available. What happens later, is not yet clear. There are several possibilities, but much will depend on the experience with the solar powered server.

Until we decide how to integrate the old and the new website, making and reading comments will only be possible on the grid-powered Low-tech Magazine, which is still hosted at TypePad. If you want to send a comment related to the solar powered web server itself, you can do so by sending an e-mail to solar (at) lowtechmagazine (dot) com. Your comment will be published at the bottom of this page.

Financing

We’re hoping for people to support this project with a financial contribution. Advertising services, which have maintained Low-tech Magazine since its start in 2007, are not compatible with our lightweight web design. Therefore, we are searching for other ways to finance the website:

We offer print-on-demand copies of the blog. These publications allow you to read Low-tech Magazine on paper, on the beach, in the sun, or whenever and where ever you want.

You can support us through through PayPal, Patreon and LiberaPay.

The solar powered website was made by Kris De Decker, Roel Roscam Abbing, and Marie Otsuka. The printed website is made by Lauren Campbell.