Flexibility assessments

To support Member Countries’ transition from a fossil-fuelled energy system towards one dominated by renewables, IRENA provides modelling for the long-term expansion and short-term operation of power systems. Transforming the electricity grid comes with challenges, as a high renewable share increases the system’s requirements when balancing supply and demand. One particular need is to move on from traditional protocols where power systems are backed by system services purely from conventional resources, such as hydropower and thermal plants. In the new era, several flexibility sources need to be planned ahead of time and exploited to integrate solar and wind effectively on a large scale.

Flexibility is the power system’s ability to cope with the variability and uncertainty that renewable generation introduces into the system at different time scales, from the very short term to the long term, avoiding the curtailment of renewables and reliably supplying all the demanded energy to customers.

Flexibility has to be harnessed in all sectors of the energy system, from an adapted power generation sector to more robust transmission and distribution systems, the addition of storage (both electrical and thermal) and more flexible demand (demand-side management and sector coupling). The production of heat and synthetic gas (e. g. hydrogen) from renewable electricity is also key for energy system decarbonisation in the long term.

Solutions of varying complexity, timescale and cost have been implemented successfully.They have facilitated the integration of high shares of variable renewables in large interconnected systems (as in the case of Denmark), in gigawatt-scale isolated power systems (as in Ireland) and in small-island systems (such as King Island in Australia). The flexibility assessments performed by IRENA help countries find their own pathway, using an approach to planning for flexibility in power systems with the expectation of achieving high solar and wind shares.

Power system modelling is helpful to:

• Assess system expansion, operation and costs.
• Evaluate the most cost-effective mix of power system assets at a point in the future.
• Identify indicators that may highlight a lack of power system flexibility (e.g. loss of load, energy curtailment, transmission congestion, negative power prices) and evaluate cost-effective measures to overcome them.
• Quantify annual greenhouse gas emissions.
• Compare and contrast different efficiency options.