Using less energy is the most important way of reducing carbon emissions, accounting for around a half of the reduction in emissions targeted by 2050. Efficiency is critical in every aspect of how we obtain, generate and use energy and for all three of the “trilemma” parameters: decarbonisation, security of supply and affordability.
The case for energy efficiency – why does it matter?
Using less energy is the most important way of reducing carbon emissions, accounting for around a half of the reduction in emissions targeted by 2050 (DECC, 2011i). Efficiency is critical in every aspect of how we obtain, generate and use energy and for all three of the "trilemma" parameters: decarbonisation, security of supply and affordability.
There are many energy efficiency measures such as improving insulation or making travel choices that are quick and cheap to implement. It is easier for most people and most businesses to reduce demand than to reduce carbon emissions by other means; that we have not done more to date is arguably because many of these measures are dependent on changes in human choices and behaviours.
What is energy efficiency?
Energy efficiency has been defined as "on a technical level...the relationship between the energy consumed and the output produced by that energy...for example the number of miles travelled for a gallon of fuel" (DECC, 2012i). The concept applies in every aspect of energy extraction, generation, transmission and use.
In this briefing, that definition is explicitly extended to include the elimination of unnecessary use of energy in every sector, process, activity and product (whether concrete, steel or goods in shops, including packaging); it also includes reductions through human choice and behaviour as well as by technological development.
Eliminating waste and reducing inefficient use of resources
Eliminating unnecessary use of resources is prevention of waste. It is the best way to achieve the objectives of decarbonisation, security of supply and affordability of energy, not to mention a strong economy, and has the best possible ratio of impact to cost. See Figure 1: The Waste Hierarchy.
In 2012, the UK Government's Secretary of State for Energy and Climate Change said: "I want Britain to get as close as possible to using only the energy we really need" (DECC, 2012ii).
Elimination of waste often depends on consumer choices. For example, how we choose to travel has a significant impact on carbon emissions. Figure 2 presents one comparison of the carbon emissions from various modes of travel (though there are many different comparisons).
Success in this area will depend on behaviour change, which has been addressed by DECC (DECC, 2011ii).
When thinking about efficient use of resources, we must consider the whole of the life cycle of the product, service or activity. For example, bio-fuels require water, land, transportation, processing and storage. Abstraction and distribution for irrigation may use energy; energy output may be low (in W/m2); transportation, processing and storage will use energy; and there may be other environmental effects. For further information on whole-life cycle energy, see our Embodied Energy and Carbon briefing paper.
Exploding a myth, the impact of switching off power supplies and chargers for "gadgets" is insignificant (MacKay, 2009). Perhaps its main benefit is in drawing attention to the need to reduce waste.
The Present Status: World (2014)
Figure 3 shows that worldwide energy intensity (a measure of energy use per GDP) decreased by about 25% between 1990–2013, with some notable variations between regions (only some of which are shown here for clarity). However, this progress is overwhelmed by worldwide use of fossil fuels, which increased by about 54% in the same period (Figure 4). Carbon emissions also increased by about 52% over this period.
Source: Enerdata, 2014
Source: Enerdata, 2014
* koe = kilo of oil equivalent, $2005p = 2005 US$ exchange, price and purchasing power. ** Mtoe = million tons of oil equivalent.
The Present Status: UK (2014)
In the UK, the energy intensity ratio (energy used divided by GDP) more than halved between 1970–2013 – primary energy consumption remains about the same as in 1970 but GDP has more than doubled. From 1990–2013, greenhouse gas emissions diminished by about 30% (see Figures 5 & 6). However, some of the improvement is attributable to the switch from coal and oil to gas in electricity generation and heating, to a shift from UK manufacturing to the import of goods made abroad, and more recently to the impact of recession.
Source: DECC 2014ii
Source: DECC 2014ii
UK energy intensity by sector
Figure 7 illustrates some significant differences between energy used in different sectors. Transport has stayed broadly level since 1970, and the domestic sector (i.e. housing) has started to improve within the last decade. The services and industry sectors have made much better progress, with a noticeable levelling out of progress in industry in the last decade.
Note that the figure shows energy intensity – the total use of energy actually diminished by 2.4% and energy for transport increased by almost 90% in the period shown. Further, this presentation of reduction in energy emissions is potentially misleading in respect of industry; one report states that emissions embedded in imports are estimated to have increased by 40% between 1993–2010, more than offsetting reductions in product emissions (Committee on Climate Change, 2013).
What is being done?
The Kyoto Protocol1 and subsequent summits and conferences have expressed varying degrees of intent and commitment to reduce carbon emissions. The next major international conference is the UN COP21 which will be held in Paris in December 2015. The objective is for all nations to agree a binding treaty covering mitigation, adaptation, finance, technology and capacity-building with the aim of keeping global warming below 2°C or 1.5°C (see UN website and news story).
1 Committed industrialised nations to reduce carbon emissions by 5.2% from 2008–12.
In the UK, the Government has set ambitious targets through the Climate Change Act 20082 , subsequently detailed in The Carbon Plan (DECC, 2011i). Energy efficiency underlies many of the measures, including four carbon budgets covering 2008–27 in five-year periods, sector by sector. The UK Government further committed to energy efficiency in The Energy Efficiency Strategy (DECC 2012ii).
Many efficiency improvements, in all sectors, are driven or incentivised by Government policies such as building regulations, the Green Deal and Electricity Market Reform (EMR). Many efficiency measures are simple, quick and cheap to implement, with immediate or short payback periods.
The simplest include choices such as turning down the central heating thermostat, travelling by bus or train rather than car or plane, or using communications technologies to avoid travelling at all. Low cost measures such as improving insulation of buildings can be very effective and have short payback periods. The Green Deal provides financial support for various home energy efficiency improvements for which "annual repayments shouldn't be more than the savings you might make on your energy bills".
In The Carbon Plan's exploration of plausible scenarios for 2050, DECC anticipates that everybody in the UK would use around a third to a half as much energy in 2050 as they do in 2007 , by adoption of more energy efficient technologies such as heat pumps, district heating, battery electric and fuel cell vehicles. In a study with expert analysis by McKinsey, DECC gives considerable detail on how electricity demand could be reduced (DECC 2012iii). Opportunities for achieving reductions in emissions are presented in a different way, using a "carbon balance", by Professor MacKay (MacKay 2009).
There are many sources of information, initiatives and bodies promoting energy efficiency worldwide. For the UK, the DECC website is recommended as the first port of call. Others include:
- The International Partnership for Energy Efficiency Cooperation (IPEEC), which seeks to provide global leadership on energy efficiency
- The Committee on Climate Change
- The 2050 Pathways calculator which can be used to test and compare a wide range of scenarios
A summary of further information relevant to sources of supply and each sector of demand is set out in the table at the end of this paper.
Benefits
Figure 8 summarises the benefits of improving the efficiency of energy consumption. Obvious ones are reduced cost, reduced carbon emissions, improved health and comfort and improved security of supply of our energy. Others include reduced operating and maintenance costs and extended asset life.
Three examples of the numerous other sources of information on benefits are:
- Technology corporation ABB claims to have achieved substantial efficiency improvements in a wide range of plant in power generation, buildings, industry and ships (ABB, 2010).
- Urban Catalyst Associates, Michigan, include reference to health benefits for building occupants. (Urban Catalyst Associates, 2005)
- Cambridge Econometrics claims that backing energy efficiency would create jobs, stimulate growth and provide warmer homes (Cambridge Econometrics, 2012).
The challenge
Targets and projections for reductions in carbon emissions are set against the continuing growth in world population and GDP and many uncertainties about how we can achieve targets. But whatever the uncertainties, reduction of demand for energy by elimination of waste and adoption of efficiency measures will play a large and important part. We need to get on with implementing a wide range of these measures now, yielding a range of benefits, many in a very short time. The challenge for us, as individuals, communities, businesses and nations, is to start doing it.
References
- ABB (2010) The benefits of energy efficiency: Doing more while lowering costs and emissions. Zurich, Switzerland.
- Cambridge Econometrics (2012) Jobs, growth and warmer homes: Evaluating the Economic Stimulus of Investing in Energy Efficiency Measures in Fuel Poor Homes. Cambridge, UK.
- Committee on Climate Change (2013) Reducing the UK's carbon footprint and managing competitive risks. London, UK.
- DECC (Department of Energy & Climate Change) (2011i) The Carbon Plan: Delivering Our Low Carbon Future. London, UK.
- DECC (Department of Energy & Climate Change) (2011ii) Behaviour Change and Energy Use. London, UK.
- >DECC (Department of Energy & Climate Change) (2012i) Energy Efficiency Statistical Summary. London, UK.
- DECC (Department of Energy & Climate Change) (2012ii) The Energy Efficiency Strategy: The Energy Efficiency Opportunity in the UK. London, UK.
- DECC (Department of Energy & Climate Change) (2012iii) Capturing the full electricity efficiency potential of the UK. London, UK.
- DECC (Department of Energy & Climate Change) (2014i) Energy Consumption in the UK (2014). London, UK.
- DECC (Department of Energy & Climate Change) (2014ii) Energy: chapter 1, Digest of United Kingdom energy statistics (DUKES). London, UK.
- DECC (Department of Energy & Climate Change) (2015i) Final UK greenhouse gas emissions national statistics: 1990-2013. London, UK.
- Enerdata (2014) Global Energy Statistical Yearbook
- ICE (Institution of Civil Engineers) (2013) Energy Briefing Sheet: Embodied Energy and Carbon.
- IEA (International Energy Agency) (2012) Spreading the net, the multiple benefits of energy efficiency improvements. Paris, France.
- Mackay DJC (2009) Sustainable Energy – without the hot air. Chapter 11.
- Urban Catalyst Associates (2005) Building Green for the Future - Case Studies of Sustainable Development in Michigan. University of Michigan, Ann Arbor, Michigan, USA.
