There is always a big argument over whether “thin” environments are more energy efficient than traditional ‘rich client’ environments. There is lots of research and speculation out there, but having designed and consulted on thin solutions, I think there is more to the discussion than just client power usage.

Thin clients use less energy?

There is quite a lot of debate over whether thin clients use less energy. And if you believe they do, then you would be right – according to Forrester (2008), thin clients use about 25% less power than a traditional desktop.

However if you are in the market for a thin solution, be careful of claims higher than 25%. Last week one ISV/hardware company was quoted as saying their thin client solution delivered a “75% energy saving over the average PC”. Cool – that’s nice but what they didn’t say is that they aren’t comparing what we in Oz call "apples for apples". As far as I can gather their study only compares direct rich (aka fat) client to thin client. Not what energy the SERVER expends to compensate for thin client computing. Remember that when you change to a thin client model, the SERVER takes over the client processing role. Hence the majority of the energy is spent at the server, not the client.  And once you place servers in a data centre, you need to add cooling into the mix. For a fair comparison then, you need to include server energy expenditure AND cooling costs associated with the server farm in the data centre. The aforementioned Forrester study, at a 25% energy (and subsequent carbon) saving, includes the compensation for the server energy and cooling requirements.

Keep flexibility at the top of the requirements list in a desktop client strategy!

This whole Green IT push originally comes from Corporate Social Responsibility (CSR), which has been around for more than 20 years. CSR is not about giving away your entire business profits to green initiatives. It’s about BALANCE. Balance is achieved between three core areas:

• Economic
• Environmental
• Social

The value of each to your business can be determined by some basic analysis.  One of these analysis types is called a multi-criteria analysis using a qualitative index, similar to the below example.  This is pretty simple, and fairly subjective, but effective for a baseline.  Essentially you apply a weighting to each element (economic, environmental and social) adding up to 100.  Then for everything except most of the economic metrics (which are calculated by hard financial figures like Net Present Value (NPV)), you assign a rating based on considerations for your specific business:

• "--" = 0
• "-" = 0.25
• "0" = 0.5
• "+" = 0.75 (and so on)

As I said, the assignment of ratings is fairly subjective so if you want statistically real results, be objective. Preferably gather multiple opinions and knowledge across your business.  When you assign the rating write good notes on why you have given each rating.  Biased ratings don't do anyone favours in the long term.

Then on top of this type of business analysis, consider what is best practice from an IT architecture perspective.  There is a tonne of material out there on best practice in a Microsoft world - check out the TechNet Library for per-product information: http://technet.microsoft.com/en-au/library/default.aspx.

When comparing rich and thin client strategies, this means considering desktop flexibility. I have seen too many companies commit to a particular long term desktop strategy, only to find their business model changes (e.g. through acquisition) and subsequently the defined desktop strategy is no longer viable.

Before you decide that thin client is the saviour to all your problems, one key question to ask is: What is your business user profile?

To provide two common examples:

1. If you have lots of CAD or GIS users, then thin client is not generally suitable for them. Graphic intensive applications, even after years of thin technology improvement, typically still don’t do well on thin environments.  The exception to this rule, in the future, may be Microsoft's recent purchase of Calista (http://www.microsoft.com/Presspass/press/2008/jan08/01-21VirtualizationAdoptionPR.mspx) which provides presentation virtualisation (terminal services) for graphic intensive apps.
2. If you have employees that are frequently disconnected from the network, then thin is not suitable.  In Microsoft I look after NSW Government agencies who frequently need to operate in an emergency situation, e.g.a flood-ravaged area where there may be no network connectivity for days to weeks on end.  Instead look at technologies like Microsoft Application Virtualisation (aka SoftGrid - http://www.microsoft.com/windows/products/windowsvista/enterprise/features/tools.mspx).  MAV can provide offline application virtualisation (at the same time solving a bevy of application compatibility & packaging issues) while still providing a good measure of centralised application deployment and control.  This can be achieved through MAV natively, or System Centre Configuration Manager (SCCM) 2007 to promote a consistent management infrastructure internally.

So if we look at the three CSR factors (economic, environment & social) combined with IT best practice when developing an environmentally sustainable IT strategy, the best recommendation I could make is to consider a balance between each element, suitable for your specific business type.