3.2. Energy efficiency and energy saving

The first way to mitigate climate change is to use energy sources that least damage the environment and the climate, as discussed in the previous section.

The second way is to reduce our overall energy consumption. In this chapter we will look at two similar, but different concepts: energy efficiency and energy saving.

A device is energy efficient if it uses less energy than other similar devices to do the job it was designed for. For example, two lamps may give an equal amount of light in your room but may consume different amounts of electricity. The lamp that consumes less energy will be more energy efficient. We can save a lot of energy by turning off lights when they are not needed, keeping windows, light, and lamps clean, and installing bulbs that are more energy efficient. Instead of taking a car, we can walk and use bicycles, where possible.

Figure 3.2.1 Comparison of the energy efficiency of different lamp bulbs

ENERGY EFFICIENCY is the ratio between the amount of energy consumed and the useful result that is obtained from its consumption, such as lighting or energy for cooking. In recognition of the importance of energy efficiency, it is sometimes called ‘the first fuel.’ ENERGY SAVING are all measures taken to reduce the amount of energy consumed.

So, most of the time, there is no need to invent anything to save energy. We simply need to change our habits, so that we stop wasting it.

Electricity for lighting accounts for 15-20% of global power consumption. In the EU, lighting represents around 10% of electricity consumption in residential buildings and is the third consumer after electricity for heating and cold appliances. In office buildings, lighting can use even more energy – 30–40%. But it is possible to reduce the energy used for lighting in both commercial and residential buildings without making rooms darker, while significantly cutting electricity bills by choosing appropriate light bulbs based on light emitting diodes (Fig. 3.2.1).

For example, we all brush our teeth in the morning. Do we need to leave the tap running while we do? No, we only need the tap on when we rinse our mouth. But watch yourself and your family: do they all clean their teeth with the tap off? A lot of energy is used to make water come out of our taps, from operations at the water treatment plant to the pumping system, not to mention the water itself.

When you turn off the TV (and some other electronic devices), you leave it on standby. What a lot of people don’t know is that the TV goes on using energy when it is

on standby, though not so much as when it is working, and that pushes up the family’s electricity bill by a few cents every month. It may not seem worth bothering about, but think how much energy is being wasted, if you count in terms of a whole neighbourhood, a whole city, or a whole country! So, in countries where energy saving is taken seriously, people are advised not to leave appliances on standby, but to switch them off.

Charging a mobile phone emits about 0.3 kg of CO₂ a year. If a mobile phone charger is plugged in all the time (without being used), 2.4 kg of CO₂ are emitted. CO₂ emissions from the use of mobile phones

Two minutes’ use per day produces 47 kg of CO₂ per year
One hour’s use per day produces 1,250 kg per year
One minute’s use produces about 57 g
One text message produces 014 g
One Google search produces 2 g (total annual emissions from the use of Google are 1.3 million tonnes)

The demand for digital services is growing rapidly. The IEA estimated that since 2010, the number of internet users worldwide has more than doubled, while global internet traffic has expanded 25 times. Rapid improvements in energy efficiency have, however, helped moderate growth in energy demand from data centres and data transmission networks, each of which accounts for 1–1.5% of global electricity use. Overall, the IT industry is responsible for about 2–2.8% of global carbon dioxide emissions, with some scientists putting the figure at around 3.8%, including emissions from the use of personal computers.

You may have heard of ‘green hosting’, a kind of internet hosting service that uses green technologies to reduce negative impacts on the climate and the environment. Green hosting works by compensating for the carbon dioxide emissions caused by its hosting service. It does this by using renewable energy sources (solar, wind, water, geothermal), planting trees and other plants, and through other actions that save energy. Some experts point to cloud technologies as a promising form of green hosting. Cloud technologies that became widespread enable much more efficient use of computing power, mainly by reducing power consumption.

Human invention makes new progress every day. But only a small part of it is used. Before new technology can replace an old one, people must change their habits.

Cloud technologies It is not only the real world that is changing, but also the virtual world. Internet users have recently been given a new tool, called ‘cloud computing’, which is already used by Facebook, Twitter, and the ‘engines’ that drive services such as Google Docs, Gmail, and the like. Most websites and server applications run on specific computers or servers. The cloud is a network of computers, constituting a system that lets people use certain applications or store data. You could call it a global, virtual computer where applications run independently of each individual computer with its specific configuration. As broadband Internet develops, it becomes less and less important to have an application installed on your computer. Because all ‘clouds’ are configured to work together, the total power of these computers is available to the applications as if the application was running on just one individual computer. An increasing share of today’s software is based on web technologies, and ‘clouds’ are just lifting the advantages of web applications to a new level.

Changing habits means first finding the time to get acquainted with the invention.

Second, you need to spend money and effort to replace the old machine with a new one and teach people how to use it. This effort and money will pay off, but not straightaway, and not everyone wants to go to this trouble for future gain.

Third, people who earn money by selling the old technology do not want to lose their business, particularly if it brought in more money than the new technology. They might even do whatever they can to obstruct the invention, preventing it being widely used, persuading people that it is harmful, or even threatening the inventor.

A summary of all energy-efficient technologies would require a thick volume. Whatever you do in the future, it will be important to have a good knowledge of the equipment you use, and to support efforts to make it better. And you should remember that the way forward is not always by making machines more efficient – a lot also depends on how people’s work is organized.

Energy efficiency and energy saving are very important. For families they mean savings on gas and electricity bills. For electricity companies, they mean reduction of fuel costs and supplying consumers with cheaper electricity. For the country, they mean spending less on resources, and making industry more productive and competitive. For the climate, they mean a reduction of greenhouse gas emissions into the atmosphere.

Reducing electricity consumption in different countries will lead to different amounts of saved emissions as it depends on the mix of fuels used for electricity generation. The ratio of CO₂ emissions per kW hour produced or saved is known as the grid emission factor. Countries with a hydro-based power system, such as Bhutan, have a zero-grid emission factor. UNFCCC provides a harmonized set of grid emission factors for more than 200 countries (see https:// unfccc.int/documents/198197).

For example, each person in Russia consumes about two kWh each day on average. An economical citizen manages with one kWh, while a more wasteful energy user might be consuming three kWh per day. Fig. 3.2.2. shows how the average Russian in an apartment uses energy for various purposes over a year. On average, the generation of one kWh of power results in 800g of CO₂ emissions. Emissions from power generation in the European part of Russia are twice lower, because a large part of energy needs in that part of the country are met by power plants using natural gas, hydroelectric and nuclear-powered generation, while coal is hardly ever used. CO₂ emissions from natural gas combustion are much less than from coal combustion, and newer combined heat and power plants emit less CO₂ than older plants.

In Russia’s northern and far eastern regions, where coal is much used for power generation and fuel must be carried over large distances, reducing electricity use by one kWh yields a reduction of emissions of about three kilogrammes of CO₂. So, the annual CO₂ savings of three people who change from being ‘average’ to being ‘economical’ consumers would be three tonnes.