Green datasheets: how can you tell how energy efficient a product actually is?

Melvyn Wray, Senior Vice President Marketing EMEA at Allied Telesis, discusses how to separate the facts from the greenwash and tell the real energy efficiency of a product.

These days, networking product manufacturers offer customers such a vast array of features and functions that it can make choosing the ideal solution for the application a daunting and demanding task.

Products will usually be installed with a working life expectancy of three to five years therefore many network administrators must guess which functions will serve them best in the long-term. This has led to a complicated trade-off between a lower cost product that meets today's specifications and an over specified product guaranteed to be future-proof. In reality, this decision is often ultimately left in the hands of finance departments to analyze Return On Investment (ROI).

Green specifications needed

Now, as if this decision-making process wasn't complicated enough, there is another factor that must be taken into consideration - the new environmentally friendly range of networking equipment, developed to meet the needs of a new, more energy conscious marketplace.

The hype surrounding energy efficiency has created a substantial upsurge in the development of green products, with many manufacturers jumping on the bandwagon. This is leaving customers with a bewildering choice. If a network administrator is truly concerned with saving power, the question is: what key functions should they look for when examining a datasheet for 'green' products?

The most obvious way to be 'green' when it comes to networking equipment is to recycle responsibly and to choose a product which has been manufactured using environmentally friendly materials. In fact, the most important issue for the network administrator when choosing 'green' networking solutions is its efficiency whilst in use, as this can also yield cost savings.

Power efficiency

Determining the power efficiency of networking equipment is an essential part of inspecting how 'green' products are. Power supply efficiency indicates how much energy is wasted when powering the electronic components of the networking equipment. Power supplies can vary in efficiency from between 40% and 80%, a considerable variation. Consequently, a highly efficient power supply can halve the total power needed by a switch.

In addition, inefficiency generates heat which in many cases must be extracted from a building or a server room using air conditioning. This further increases both CAPEX and OPEX costs and clearly, is less environmentally friendly. As a result, network administrators must verify power consumption by comparing this on the product's datasheets against other products of its type.

Power saving functions

Environmentally friendly networking equipment should also include power saving functions. 'Green' switches use a variety of mechanisms to save power and these must be scrutinized when picking the 'greenest' product on the market. Such features include the ability to 'power down' ports when they are not in use. This is an important part of the 'green' checklist as in practice it is common for network administrators to use 75% of the total number of ports on a switch, withholding the remaining 25% for future network expansion. If these ports cannot be put into a 'power down' mode or disabled manually, they will consume power even when they are not connected.

The length of the cabling is also a key specification for power saving, and switches such as Allied Telesis' Eco range, detect cable length to drive less power through them. So if the physical configuration doesn't demand cables of 100m, products that support this could yield incremental power savings. Equipment with the ability to switch off LEDs during the course of a 24-hour cycle can also help to reduce power consumption, as in many instances LEDs are not monitored so the ability to switch them off can be an easy way to make power savings.

Efficiency over range of loads

In addition to power consumption and efficiency, 'green' products should also be economical for the wide range of network loads that they have to support. Many power supplies become less efficient at either low loads or full loads. Therefore, the power saving features described here must be able to operate efficiently from no load where there are no cables and there is full power saving functionality, to full loads, where all ports are functional with 100m cables in use and all LEDs switched on. As such, datasheets must also be checked for the power consumption of the product at various load levels. The networking administrator must therefore ensure they have checked the maximum power consumption, which should ideally stand at around 75% loading for normal business use and 5% loading in overnight mode.

Check green specifications carefully

If datasheets are examined carefully, choosing a 'green' networking product can be both effective to use and easy to run. If factors such as loading efficiency, power supply efficiency, materials used and power saving features are examined closely when comparing 'green' networking products, the most suitable solution for the deployment and most importantly, the most efficient, will become clear.

Melvyn Wray, Senior Vice President Marketing EMEA at Allied Telesis. As a major industry developer and manufacturer of networking equipment, the Allied Telesis Group is committed to providing customers with products designed and built to the highest quality, whilst minimising the impact to the environment during both manufacture and product operation.