Security of energy supplies

Increasing demand for peak-load energy.

There is a steady rise in the demand for peak-load energy. Electricity consumption continues to rise year-on-year. Another important reason is the intensive expansion of the electricity which is generated from wind energy in the coastal regions of the European Union. This leads to an increase in base-load energy. This is dependent on wind conditions and cannot be planned. If the electricity from wind energy is generated at off-peak times, the surplus in pumped storage plants can be used to pump water back into the reservoir. If there is a lack of wind during the day, the pumped storage plants can make up the energy shortfall. The opening-up of the energy market has also contributed towards the rising demand for peak-load energy. Since consumers can buy electricity from any source in the free market, the electricity network operators have to employ system services to ensure a reliable supply.

Axpo AG invests in safeguarding its supply

Maintaining a reliable energy supply places great demands on the operators of an electricity grid and on the power stations. The most important criteria for ensuring a high degree of supply reliability are:

• The power stations must produce sufficient electricity.
• The power stations must have sufficient capacity to cope with peaks in consumption.
• The power plant fleet must be equipped to enable electricity production to be adapted to short-term fluctuations (system services).
• There must be sufficient reserves available to bridge any system failures (system services).
• The idle power required to maintain the voltage supply (system services) must be available on standby.
• The supply network must have adequate capacity for the transport and distribution of the electricity.

The peak-load energy from storage power plants and pumped storage plants, as well as the system services, play a key role in ensuring the reliability of the supply. They deliver as much power as is required at any given time and ensure flexible power production. Pumped storage plants can store energy in the form of water in the reservoirs. Thus, rising demand for peak-load energy can be ensured with pumped storage plants.

Axpo AG plans to expand and overhaul its hydro power stations over the next ten years at a cost of around three billion francs. The addition of a pumped storage plant to the Linth-Limmern power stations is an important project being undertaken in this regard.

Energy and power

Energy is the capacity to perform work. For example, it takes a certain volume of energy to heat water, to generate light with a light bulb or to drive a motor. Electrical energy is measured in kilowatt hours (kWh),
megawatt hours (MWh = 1,000 kWh) or
gigawatt hours (GWh = 1,000,000 kWh).

The power is the amount of energy which is converted in a given unit of time (hour). Power is measured in kilowatts (kW),
megawatts (MW = 1,000 kW) or
gigawatts (GW = 1,000,000 kW).