Even though we've heard less talk about Green IT since the last financial crisis weighed down on the industrial world four years ago, the idea is still with us; and today it's more important than ever for CIOs to get on the bandwagon. But before you jump out of your seat to get started, let's go over the history of this trend in information technology to get some perspective. [See also: Green IT, renewable energy and sustainability - Greenpeace IT chief puts pressure on AWS]

The story of Green IT began in the early 1990s, when both the number and size of data centres began to soar. This rise in computing, and the consequent rise in cooling and ventilation equipment to keep computers from overheating, led to greater energy consumption.

But energy consumption and CO2 emissions were not the only concerns. Computers and monitors contain hazardous materials, such as lead, cadmium, and mercury. Getting rid of this so-called e-waste was another big issue.

In industrialised nations, new standards and regulations were written to reduce green house emissions, to control the amounts of hazardous wastes used in computing equipment, and to address the ways organisations and people disposed of electronic components.

Over the years, Green IT has been known by different names. It has been called green computing, green technology, ICT sustainability, and probably a few other names that no longer spring to mind. Even the term Green IT is used less frequently these days, as it is now seen as part of Corporate Social Responsibility (CSR), and CSR falls under the responsibility of a dedicated corporate officer, who rarely doubles as CIO.

Green IT has heated up again in the last few years, as the number and size of data centres has shot up to three or four orders of magnitude above what we saw in the 1990s. YouTube now serves up over 6 billion hours of video per month, Facebook provides 20 billion minutes of usage per day, and Twitter chirps as many as 140,000 tweets per second. That's an awful lot of processing, and it requires thousands of servers, made with hazardous materials, and consuming astounding amounts of energy.

Most IT departments aren't directly affected, as very few companies need anything near the computing power of the new generation of tech giants. However, all are feeling the fall out. Increased public awareness and new expectations from governments, stockholders, and customers place pressure squarely on the shoulders of IT decision makers.

But some industry watchers think IT directors still aren't yet doing as much as they should. According to Gartner, "CIOs' involvement in enterprise sustainability programmes is usually reactive and tactical".

Most of the time IT directors remain in reactive mode, it's because they're under the mistaken assumption that going green is a selfless course of action companies or individuals take to help clean up the environment. Every company that has gone in with this benevolent attitude has run out of steam at the first sign of economic slowdown.

Fortunately for our grandchildren, there are two good selfish reasons organisations take an interest in cleaning up: first, to save money, and secondly to get good PR. Every IT director should proceed with Green IT in pursuit of these two goals.

Saving money and getting good PR

Andrew Donoghue of 451 Research says: "The good news is that because energy use in the data centre is so profligate, and because it is expensive, there is great scope for savings. A recent survey conducted by Uptime Institute showed that in areas where Energy is expensive – Asia, and Europe – there is obviously a lot of interest in improving energy efficiency.

"Shale gas, and generally lower energy prices, means this is less of a priority in the US but that may change over time. For example, if you are a 1 megawatt facility and you make 10% energy savings, you'll save around $90,000 a year. If you are 2 megawatt and you save 30%, that's half a million every year.

"Furthermore, this is just the operating savings from reducing energy bills: the Uptime Institute has carried out compelling research that shows that capital equipment cost savings can also be significant. In fact, for every kilowatt of energy saved, you could save $15,000 to $25,000 in capital costs.

"That means that if at design or refit stage, you shave just 10% off your 1 megawatt peak energy requirement, you could save $2 million in equipment. Any existing data centre that hasn't yet addressed its energy consumption can save at least 20% of its energy costs through fairly basic actions."

Companies, like Google, with humungous data centres, have to take more dramatic steps. They save money by moving the data centres to colder places, like Finland, and where they can benefit from cheaper energy that is also replenishable. The cold climate means less air conditioning is necessary to cool servers.

Organisations can also reduce consumption by moving some of the big applications to the cloud. In a study partially funded by Google, Lawrence Berkeley National Laboratory found that companies can reduce the carbon footprint by as much as 87% if they offload email, productivity software, and CRM.

CIOs can also look for ways of applying technology to help the overall organisation cut down on energy use. Gartner advises CIOs: "Engage facilities managers to collaborate on the use of information, analytics and automation to substantially increase the energy efficiency of the heating, ventilation and air conditioning (HVAC), and the lighting and distributed IT load."

CIOs may even go so far as to implement Internet of Things (IoT) solutions to reduce energy consumption in buildings. Tesco is taking a lead in this area by installing sensors across their stores to reduce heating and lighting costs.

There are also some very simple ways for IT departments to help their organisations reduce consumption. For example, IT directors can encourage people to power off personal computers when they aren't being used. According to Waldemar Siedlok, president and founder of EnviProt: "In Europe, failure to power off costs between €15 and €25 per PC per year. An added benefit of turning off unused computers is that computers cannot be attacked by hackers when they are shut down."

More than just encouraging people to power off, IT can buy software that does the job automatically. There are solutions on the market that shut down equipment at pre-configured times, or upon certain events.

The other thing organisations need to do in the way of Green IT is to address the problem of e-waste, which has increased dramatically in the last few years - mostly due to the proliferation of mobile devices. The e-waste problem is particularly acute in the UK, which has the dubious distinction of leading the EU with 1.4 million tons of e-waste per year.

IT directors should lead the charge towards recycling electronic components. Recycling is not only good for removing hazardous waste. The process of recycling also creates new jobs. What's more, according to the United Nations, recycling saves energy, requiring only a fraction of the energy needed to mine new metals.

Some companies are able to reduce costs by getting smart about e-waste. For example, Google takes old servers and repurposes them in-house. For most organisations, though, managing e-waste in more responsible ways costs more money than it saves. The good news is, you can use your e-waste programme as a way of getting good PR.

Companies like Google, Facebook, Apple, HP, and IBM know how to get good press from their Green IT efforts. Each of these companies has a section of their web site dedicated to publicising their efforts to reduce energy consumption and act responsibility towards e-waste.

Google is so good at PR, that in November, 2013, Greenpeace publicly congratulated Google for their efforts. A little pat on the back can go a long way. According to Waldemar Siedlok, "Green messages influence stock values by up to 33% and profits by up to 9% - and it's increasing."

Five things UK CIOs can do now

Each organisation has its own needs - after all, no UK company consumes as much energy on IT as Google. But while each case should be treated differently, there are five areas in which every IT director should have an action plan:

1. Look for ways of reducing energy consumption in data centres. If you can offload processing to the cloud, pick a provider known for green IT.

2. Look at solutions that automatically power off desktops, laptops, and tablets when they aren't being used. You can't count on users to remember to do this every night. Let software do the work for you.

3. Look at ways of helping operations control the temperature of your warehouses or any other corporate buildings with Internet of Things (IoT) solutions that can monitor systems to make adjustments and even predict energy needs. Follow the lead of Tesco, who are already doing just that.

4. Dispose of old hardware carefully. Give working equipment to a worthy cause. Repurpose the hardware if you can. In any case, don't just bin it like you would any other rubbish.

5. Make the public aware that you are taking steps to reduce energy consumption. Call in the press to make sure the world knows about the positive things you're doing. Put up a section on your public web site expressing your commitment to Green IT and listing what you're doing for the environment.

Above all, be selfish. As long as you approach Green IT with your own interests in mind, you're going to stay in it for the long haul.

Who knows? Maybe one year, Greenpeace will congratulate your company.