After reading about the environmental impact of server farms I wonder what are the alternatives for someone who needs to host a website.
Is there a sustainable choice when it comes to hosting a domain?
Is hosting a website at home on a computer powered by green energy the best green option?
Is there another green alternative to the server farms?
I feel like the term 'sustainable choice' is pretty open here - sustainability is mostly a case of what we as a civilization want to devote limited resources to. In general, server farms are going to be a more efficient use of electricity than everyone hosting a site locally (even if that were technically feasible). And, for context, while server farms consume a lot of electricity on an absolute basis, the whole internet uses about 2% of the nationwide total, a very good deal considering the services provided (and clearly room to improve). Having pages hosted at home would require a lot of personal computers to be on all the time, rather than shared servers. So, assuming we want to have a digitally connected civilization, server farms are probably a good choice to get economies of scale.
To the second question: Primarily, what you want to look for is where they get their electricity, ideally whether they pay attention to energy efficiency, and, if possible, whether they are decent to their employees. There are several companies out there that buy renewable energy directly, or buy renewable energy credits (RECs) equal to or greater than their demand. It's probably preferable to go with one that buys direct, but either way will help incentivize more green power. Statements of corporate responsibility - sponsorship, values, etc. - might help with the other metrics. As with anything, there are a lot of different impacts that could be considered, but since electricity is responsible for the bulk of the global warming impacts from the internet (as well as some respiratory-related ones), that's a straightforward decision tool.
The most sustainable hosting choice would use:
You could consider hosting yourself at home and use electricity generated by your own solar panels. The solar.lowtechmagazine.com website does that for example. The advantage is that you are sure where the electricity is coming from, have control over what servers are used and how they are disposed eventually. However if you rely on solar panels only, your site may go down when it's clouded (which does happen occasionally to the lowtechmagazin.com site mentioned above) unless you invest a lot in batteries. Also at home you can't be as energy-efficient as a professional hosting company. They use shared servers or virtualization to host many sites on a single server. Some data centers even transfer their waste heat to near-by houses, greenhouses or swimming pools for even better efficiency.
There are a large number of hosting companies that claim they are using 100% renewable energy. Unfortunately data on how they recycle their hardware is very rarely provided. Also it is hard to check if a hosting company is telling the truth about their sources of electricity or are only green-washing.
Luckily there is a not-for-profit organization called The Green Web Foundation (GWF) that checks hosting companies and publishes a list of companies that use 100% renewable energy. At the time of writing their directory contains 533 green hosting companies in 63 countries. Another interesting source is the blog on sustainable.dev about 'How to find a green hosting provider'.
You could ask the service providers for the PUE (Power Usage Effectiveness) score of the Data Centre the services run out of. Although it's not a perfect measurement it widespread enough that the information should be readily available and could be useful in determining a providers commitment to driving down their use of on-grid electricity.
I would not recommended RECS (Renewable Energy certificates). Even though they are endorsed by the USEPA and several other NGOS, it's been empirically proven to have no impact on the additionality of renewable energy investment or the dispatching of renewable energy generators. For more information I would read studies from Michael Gillenwater and the GHGinstitute. Having the servers powered directly from a renewable energy source (renewable energy generators physically connected to the electricity transmitted to the servers) is the best way to ensure your using renewable energy. However this may not be the easiest or most inexpensive method. Renewable generation is also variable generation which I would assume may be an issue for servers that need to run 24/7.
To elaborate further, Renewable Energy Credits are commodity instruments used to represent the ownership of an environmental attribute for 1 MWH of renewable energy generated. I don't want to go too deep into it, because I'm basically say that I would not recommend it as a metric for determining how sustainable a company or organization is (in this case a hosting service). Many organizations endorse RECS, but if you would like to further understand why they do not impact renewable energy generation, please check out the links below.
http://ghginstitute.org/2014/03/12/is-your-green-power-really-just-green-washing/ http://ghginstitute.org/2015/01/26/have-you-fallen-for-the-green-power-accounting-shell-game/
Brander, M. 2014. “The Enron of carbon accounting?” Isonomia Blog Post, March 7th, 2014. Gillenwater, M., Lu, X. & Fischlein, M., 2014. “Additionality of wind energy investments in the U.S. voluntary green power market.” Renewable Energy, 63, pp.452–457. Gillenwater, M., 2013. “Probabilistic decision model of wind power investment and influence of green power market.” Energy Policy, 63, pp.1111–1125. Gillenwater, M. 2013. “Redefining RECS: Additionality in the Voluntary Renewable Energy Certificate Market“, Doctoral dissertation, Princeton University. Offset Quality Initiative, 2009. “Maintaining Carbon Market Integrity: Why Renewable Energy Certificates Are Not Offsets”, June. Gillenwater, M., 2008a. “Taking green power into account,” Environmental Finance, October. Gillenwater, M., 2008b. “Redefining RECs (Part 1): Untangling attributes and offsets,” Energy Policy, Volume 36, Issue 6, Pages 2109-2119. Gillenwater, M., 2008c. “Redefining RECs (Part 2): Untangling certificates and emission markets,” Energy Policy, Volume 36, Issue 6, June 2008, Pages 2120-2129.
Is hosting a website at home on a computer powered by green energy the best green option?
No.
A home computer uses perhaps 100 watts of electricity. You can't reasonably host any other domain on your home computer because nobody else is willing to put their domain under your control / your unreliable electricity supply.
A high-end server computer uses perhaps 1000 watts of electricity and can host 3000 domains (assuming it has 3000 gigabytes of memory and one domain requires 1 gigabyte of memory). Ok, there are auxiliary power uses such as cooling and uninterruptible power supply. But even with them taken into account, power use won't exceed 1500 watts.
So you're looking at 100 watts of electricity for your domain or 0.5 watts of electricity used for your domain. This is 200x difference.
I'd say even if you have 100% solar electricity in your home, it makes sense to host your domain in a data center powered by dirty coal. Reasoning being, one domain hosted in a data center requires so little of its resources. 0.5 watts of coal is arguably better than 100 watts of solar, taking fully into account the electricity costs of manufacturing the said solar panels.
The key here is, use the least amount of resources you need from a cloud provider. Host your name servers e.g. on Amazon AWS Route 53. Host your servers e.g. on Amazon AWS EC2.
For example, Amazon AWS EC2 nano instance has 0.5 gigabytes of memory. If that's enough for you, you can halve the estimate I had about needing 1 gigabyte of memory, so your domain would use only 0.25 watts of electricity then.
In contrast, some heavier instance such as m5.metal instance would probably run on dedicated hardware, meaning all of its power consumption is attributable to you and you only.
