User acceptance of ancillary service markets

In any electrical power system, there must always be a balance between generation and load of electricity. Any imbalance will instantaneously be compensated by a change in kinetic energy of rotating generators and motors. Therefore, any imbalance results in a frequency deviation from the nominal frequency. To ensure a reliable supply of electricity, frequency deviations must always be within limits. The balance between generation and load is maintained using control and reserve capacity that can be activated within a specified amount of time. Usually units with low marginal costs are used for base load production, while units with high marginal costs and flexible loads are used for control and reserve purposes. To ensure the balance of generation and load, the European Network of Transmission System Operators for Electricity (ENTSO-E) has set up a number of policies that describe what the individual control areas should do in case of any frequency deviation. In these policies, different control mechanisms are mentioned that should act in different time frames. These mechanisms are primary, secondary, tertiary and time control as well as scheduling and accounting. Besides the policies on ENTSO-E level, there is also regulation on a national level. In the Netherlands, balance keeping is based on a system of balance responsibility. A balance responsible party represents one or more producers or consumers and is responsible for delivering or consuming an exact amount of energy per time frame as stated beforehand. Any deviation from this will be penalised and balancing power for balance settlement is traded on a single sided market with the transmission system operator (TSO). The opinions of involved stakeholders on the existing regulatory framework, ensuring the provision of enough balancing capacity for primary and secondary control, are gathered and discussed. Future power systems are considered to contain much more distributed and renewable generation. This will inevitably lead to higher numbers of intermittent generators. This results in a higher complexity to match generation and load because of less predictability and larger variations in time. Different organisational structures have been mentioned in literature to cope with the higher complexity of future power systems. One of these ideas is based on autonomous networks which can be considered as aggregations of producers and consumers on both a physical and a business level. Agents, representing the autonomous networks, are able to trade both energy as well as ancillary services for balance management