- National Wind Watch: Wind Energy Documents - https://www.wind-watch.org/documents -

# How does intermittent wind power interact with controllable power?

This article considers a typical load supplied by a set of identical controllable units. More and more wind power is then added to the production system, and the simulation shows how the system behaves and how the wind power is used.

The analysis considers only the energy and power balances at system level, using the Load Duration Curve representation of the load. No consideration is given to the network constraints, power prices and other similar topics. It is basically a theoretical exercise that uses simple hypothesis and modelling techniques to simulate the injection of intermittent power into a classical thermal system, and tries to illustrate what intermittent power is, how it works and what are its intrinsic limitations.

When a wind turbine begins to produce power, some running mirror controllable unit must reduce its output: this is backdown power. The amount of reduced power must remain ready to be produced again if the wind stops blowing: this is backup power. The wind turbine is so tightly coupled with its mirror controllable unit that from the point of view of the network operator they cannot be treated separately. Using this approach, it is possible to describe the way the wind power is inserted into the system, and to calculate the expected resulting output of the various units.

The model shows that the intermittent power is not “added” to the controllable power but is rather “merged” with it, partly replacing the controllable power and energy by its own. It explains why installation of wind power could not result in a reduction of installed conventional power. It describes how wind power destroys the power system by forcing controllable units to run in base. It shows the limits on installed wind power, and that these limits are mainly related to the availability of storage capacity. It asserts that the lack of storage capacity becomes critical when the total installed wind power exceeds some identified thresholds. Finally it describes how we could quantify the savings of CO₂ emissions due to wind power – and shows that there are probably no savings at all.

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