Thin clients: a sustainable alternative to PCs

The IT industry’s share of global CO₂ emissions is estimated to be around 2%, according to market analysts at Gartner. While there has been a focus on making data centres more energy efficient, computer workstations frequently go unexamined despite producing one quarter of these emissions. Thin clients are designed to provide a smaller, cheaper and more energy-efficient desktop computing alternative to traditional PCs.

A thin client is basically a small form-factor, solid-state computer optimised for connecting to a data centre or cloud service provider, and is managed centrally by a manufacturer’s operating software. With no user-accessible storage on board, thin clients can be cheaper than most PCs. Removing the user-accessible storage from a device also means that there are no moving parts, since there is no need for a fan to cool things down. They therefore run cooler, use less energy and have fewer breakdowns.

Centralised infrastructures

Nowadays, virtualised applications and desktops centrally provisioned from in-house data centres or outsourced cloud services are replacing locally based programs. Increasingly in Australian companies, applications and desktops are being centrally managed and delivered over an internal network. The benefits can include increased efficiency, data security and cost transparency.

Conventional PCs, often called ‘fat clients’ since they contain extensive local hardware, don‘t fit very well into such lean scenarios because, compared to thin clients, they are excessive for these purposes and can tie up too much capital.

In terms of the environment, PCs are also far behind thin clients, according to a study by the Fraunhofer Institute for Environmental, Safety and Energy Technology in Germany titled ‘Thin Clients 2011 - Ecological and Economical Aspects of Virtual Desktops’.

In the study, two live thin-client infrastructures were analysed and compared to PC-based infrastructures used in an equivalent manner. In the first application scenario, the combination of IGEL thin clients and virtual desktops based on VMware View proved to have 47% less of an environmental impact than a similar, PC-based environment. This investigation covers the entire lifecycle of the product - from production through a five-year lifecycle then all the way to its ultimate disposal.

In the second thin-client installation employing the application/desktop virtualisation solutions Citrix XenApp and Citrix XenDesktop, the global-warming potential (GWP) calculated over the entire service lifecycle of three years was 30-63% lower than that of the PC-based control scenario, depending on the type of user involved. The GWP is measured in kilograms of CO₂e and covers a total of six gases harmful to the environment. A conventional workstation PC for a medium-level user has a GWP of 417 kg CO₂e. For a thin client, including its share of central server usage and cooling, the GWP ranges from 156 to 277 kg CO₂e.

Operational phase

The climate-relevant advantages of thin-client/VDI solutions are primarily due to lower power consumption in their operational phase. Depending on the application scenario and the type of user, the energy requirements for a thin client, and thus its power costs (including its share of server power and cooling), are 61-77% less than those of a modern, energy-efficient PC. If a thin client is used solely for web browsing as part of a cloud computing solution, these savings can be as high as 88%.

The level of CO₂ emissions is highest during the operational phase. The actual extent depends on two factors: the power consumption of the device and the method used to produce its power. Since the Fraunhofer study was conducted in Germany, the calculations are based on the currently produced German power mix, which releases 575 g of CO₂ per kWh (as of 2010). Based on these figures, a thin client can reduce the emission of greenhouse gases by up to 148 kg each year compared to a PC. According to the International Energy Agency, Australia’s CO₂ per kWh is 841 g, so subsequent savings would be even higher.

Production, transport and disposal

Manufacturing a thin client requires fewer components than a PC. This not only means less material in general, but also less energy, fewer raw materials, fewer manufacturing supplies and less water pollution.

A thin client generally weighs 2.70 to 2.80 kg depending on the actual user scenario, after its server share has been added. In contrast, a typical workstation PC has a total weight of about 12.75 kg. Since a thin client weighs approximately 78% less and requires 70 to 81% less packaging volume than a PC, it also comes out way ahead during shipment and distribution, especially given the vast geographical size and widely dispersed state capitals of Australia. A standard overseas shipping container can hold far more thin clients than PCs, and ground transport requires far fewer truckloads. This, in turn, further reduces greenhouse gas emissions.

When both types of end-user devices are ultimately disposed of, the lower amount of materials in thin clients also becomes evident. During recycling, a thin client yields only one third of the electronic scrap (e-waste) left by a PC. In addition, it also yields comparatively small amounts of non-recyclable materials. In research conducted by the TUV Rheinland group in 2006, 76% of the materials used in making thin clients could be recycled. These days, estimates from recyclers themselves indicate that the level of recyclable material has reached 98%.

Thin client management

A contributing factor to their lower power consumption is that thin clients can be remotely managed. At many locations, PCs are left running continuously (overnight and over the weekend), while thin clients are automatically set into sleep mode over the network during these periods. In energy-saving mode, they only use about 1 W of power. Centralised management of the servers for thin clients also offers potential for automation, another significant environmental saving. For instance, virtual desktops can be dynamically created and deleted as needed, depending on the presence or absence of employees. In this way, centralised IT resources can be made available on an as-needed basis. During periods of low demand, they are automatically switched off.

Thin clients can also be switched off and then back on again as needed, by means of management software that transmits Wake-on-LAN commands. The management software used in the Fraunhofer Institute testing comes standard with all IGEL Universal Desktop devices, allowing smooth, universal remote management of thin clients in a network. This means that expensive, time-consuming service calls for maintenance and support are no longer necessary. If a thin client happens to fail, a replacement unit can be shipped to the location concerned. Upon its arrival, employees can easily hook up the new device themselves. During the interim period, the employee can move to another thin client workstation from which they can still access the data centre and their personalised workstation environments, with no loss of business continuity.

IGEL’s Universal Device Management software allows legacy devices such as PCs and laptops to operate as a thin client on the same virtualised platform. This gives companies the ability to integrate a deployment of thin clients in stages and minimise the upfront cost.

The sustainability of IT environments greatly depends on their service life. The longer IT devices remain in service, the less e-waste will accumulate and the greater the environmental and economic benefits will be. In general, PCs are usually due for replacement after three or four years, thus requiring relatively frequent investments in new equipment. Thin clients have service lives of six years and even longer, as their hardware has fewer moving parts and is inherently less prone to failure. In addition, thin clients also receive free firmware updates that keep them constantly up to date. With thin clients, investments in new equipment primarily occur in centralised data centres where, due to the nature of IT consolidation and efficiency, they have less of a financial impact.

In conclusion, the evidence is very much in favour of a virtualised environment running thin clients, which offers organisations in Australia lower upfront costs, fewer overheads and a smaller environmental footprint