“Engineering the energy transition is a key consideration that ought to be discussed at high level events and other fora, otherwise we will keep pushing for a transition without putting in place the mechanisms to achieve a successful transition”
Engineering the energy transition which speaks to the ‘how’ is not always appreciated in discussions surrounding the energy transition as stated by Francois Pienaar (a renowned Electricity distribution utility specialist). In his words ‘We need to start ancillary services, grid response services, battery storage, system changes, operational changes in utilities, changing organisations, new business models, etc’. I completely align with Francois position because without the ‘how’, we would be embarking on a journey in circles. Nevertheless, various factors need to be considered in the ‘how’ discussions including:
There is a need to balance security of supply with sustainability/decarbonisation objectives in integrating variable renewable energy (VRE) although VRE has the lowest variable cost of power generation.
VRE curtailment however is a costly measure that contradicts the transformation towards an efficient and low carbon power system. Low levels of VRE curtailment are a good indicator of successful VRE integration, while growing curtailment rates indicate inflexibility in the power system.
Flexibility options are crucial; for successful power system transformation ranging from grid management and infrastructure, energy storage, demand-side integration (demand side management (DSM) and demand side response (DSR), dispatchable generation, etc.
Levers must be taken into account in achieving the smooth deployment of VRE which includes- optimal location of new VRE capacity, appropriateness of the mix of VRE technologies, etc.
Grid and VRE planning are two peas in a pod, therefore it is essential for a grid operator to know the load flow across all its lines ahead of time through accurate short-term forecast of VRE production.
Operating reserve allocation can be efficiently achieved via the use of interconnections linked to adjacent balancing areas and cooperation between balancing areas can significantly reduce operational costs of power systems through mechanisms such as imbalance netting.
Reinforcement of transmission lines and load flow control are critical considerations that can be appropriately managed through various tools and equipment such as High-temperature low sag (HTLS) conductors that are used to reinforce transmission lines and are more reliable than Aluminum conductor steel reinforced conductors (ACSR) which are conventional overhead transmission line conductors, as HTLS conductors made up of the Aluminum conductor composite core (ACCC) allow for more transmission capacity based on the fact that they possess low thermal expansion and thus lower sag that results in higher conductor temperatures and higher currents. On the other hand, load flow control helps with the distribution of load flows and thus results in the efficient utilisation of the transmission grid capacity.
Storage is an important option that can provide flexibility for power systems. Additional flexibility can also be achieved through the shaping of customer load demand popularly known as demand-side integration (DSI).
Thermal power plants depending on their flexibility rates can also provide value to the system depending on the speed and extent to which such plants can adjust their power output. For example, coal-fired plants usually have longer start-up times and lower ramp rates than gas plants although they achieve very low load levels.
For thermal based power systems which are pre-dominant across Africa, a key consideration and food for thought is the ability to balance thermal generation with VRE to align with carbon emission targets. This will require system and network improvements and advancements in technology, institutional capacity build-up, stakeholder cooperation both on an in-country basis and where there is cross-border interconnection particularly from the standpoint of system operation, supporting policy and regulatory framework, etc.