What is the potential contribution of energy efficiency to our energy future?

The systematic implementation of energy efficiency measures could make a crucial contribution to Switzerland’s energy transition; it would enable us to reduce our energy consumption by 50% without affecting our comfort level, while reducing our CO₂ emissions and energy dependence on foreign countries, provided that the rebound effect can be avoided.

The term “energy efficiency” refers to all technologies that make it possible to reduce energy losses. Energy efficiency means that, for the same service rendered, less energy is consumed: a more efficient engine, a better-insulated building, a ventilation system with heat recovery, etc.

No piece of energy-efficient equipment is 100% efficient. Energy production, distribution and use processes always involve losses, usually in the form of heat. Here are four examples:

• A conventional car engine converts only 15 to 30% of the energy contained in petrol into traction power; the rest is lost as heat (the engine heats up) [→ Q33].
• The fact that a lamp (for example, halogen) heats up indicates that it does not convert all the electricity received into light, but that it dissipates a large part of it into heat. The LED, which heats up less, is therefore more efficient [→ Q41].
• Not all of the heat produced by combustion in a boiler can be fully recovered, since some of the heat goes with the flue gas.
• The steam that escapes from the cooling towers of a nuclear, gas, or coal-fired power plant discharges in the form of heat any energy from the fuel that could not be converted into electricity.

At constant population and gross domestic product (GDP), efficiency is the only way to reduce our energy consumption without affecting our demand; that is, without compromising our comfort level. In other words, we can continue to use our equipment in the same way (no reduction in demand), but it will simply consume less for the same quality of service.

If we were to systematically implement all the energy efficiency measures at our disposal, Switzerland could reduce its consumption by around 108 TWh per year, i.e. almost half the current consumption of around 225 TWh. The greatest potential contribution to energy efficiency comes from buildings (55%), followed by industry (30%), transport (10%) and services (5%) [→ Q30], [→ Q39], and [→ Q34].

In addition, of the 108 TWh of potential savings, 16 TWh could be saved in the form of electricity, which represents 2/3 of the annual production of our nuclear power plants. In theory, energy efficiency alone could therefore replace the nuclear reactors at Beznau I, Beznau II, Mühleberg and Gösgen, which will be the first four to be shut down!

Energy-efficiency technologies are not environmentally controversial. The sooner we implement energy-efficiency measures, the smaller, if not zero, will be the electricity deficit resulting from the abandonment of nuclear power! And the less we will have to resort to other sources of supply, most of which are controversial (imports, wind power, gas power plants, etc.). Unfortunately, the large-scale implementation of energy efficiency faces several obstacles [→ Q44], and may lead to a rebound effect [→ Q94].