Let us now focus on the three examples of energy conservation and energy efficiency for the solar strategy explained in the previous section.
Example 1: Standby power consumption
In Germany, electrical appliances in offices and homes consume some 22 billion kilowatt-hours of electricity each year,25 roughly the amount generated by four nuclear power plants. If this electricity had to be provided by solar panels, more than 200km2 would be needed. In light of the costs and materials required, the effort would be absurd, especially when we realize that this standby consumption could already be reduced by more than 80 per cent today if we replaced our current appliances with newer ones that consume less standby power. The Eco-design Directive for Energyusing Products (2005/32/EC) was adopted in 2005 and came into force in August 2007. It establishes a framework under which manufacturers of energy-using products (EuP) will, at the design stage, be obliged to reduce the energy consumption and other negative environmental impacts that occur during the product’s life cycle. From the beginning of 2010, the ‘off mode’ electricity consumption of all appliances sold in Europe is not allowed to exceed 1W and the stand-by mode is limited to 2W.
And if we switch appliances off completely (i. e., do without standby mode), we can reduce our consumption even further.
Example 2: Space heating
The average German single-family detached house with 120m2 of floor space consumes some 30,000kWh per year for heating and hot water. A large solar hot water system (12m2) can produce some 13 per cent of the energy required for that task. To increase that share considerably, consumption has to be reduced by means of good insulation and efficient windows. Such ‘low-energy buildings’ (see 4.1) make do with around 10,600kWh per year. But a 12 m2 solar thermal array would then cover 28 per cent of peak demand (see Figure 1.8). The greater the efficiency, the greater the share of solar energy.26