Solar Energy in the fight against climate change.
A great technological solution for climate change is Solar energy. Demand for solar energy has been on the rise for the last 10 years and this has been because of the staggering reduction of solar prices around 90% (0.35$/kWh in 2009 and now 0.035$/kWh). This reduction in prices has been driven mostly through heavy investment subsidies happening in Europe that pushed the technology through the technology chasm to the mainstream.
Solar energy has great potential in Cyprus we all have understood that however injecting too much solar in the electricity grid has its drawbacks and one of these drawbacks is the "duck curve". The "duck curve" can be seen below in the graph and is the shape taken by the load curve (load curve is the average load in one day) when too much solar is injected in the electricity system, which creates a duck-shaped curve. The graphical representation below shows different levels of solar capacity injected into the electricity system of Cyprus and how this changes the average load of the country. The numbers used in the graph are based on how much solar is expected by the government of Cyprus to be into the electricity grid by 2030 based on the National energy and climate plan they have created.
The problem that it is created by the "duck curve" is the net load of Cyprus being pushed down at very low levels for 10 am - 1pm due to the solar generation being pushed into the grid.. These phenomena cause flexibility problems (ramping up problems) in the system and usually high levels of curtailment (excess energy).
ramping up problem: Conventional power plants such as coal power plants or steam turbines power plants (that exist in Cyprus) require time to power up from 0 to 100% power output due to heating up times, so ramping up really fast is difficult thing to do without causing issues to your power plants.
The "duck curve" is a common issue faced in sunny places like California, this effect does reduce the energy needed in any given day, however, due to the fact that peaks in demand occur at around 6 pm, this creates a huge ramping up requirement. This ramping up effort will be needed to compensate for the steady reduction of output from the solar generation at that point to the meeting of energy demand at peak hours.
In the graph above the ramping up in the initial years until the first 300MW of solar in Cyprus will not greatly impact the Load and will not create these so-called flexibility issues, however with further integration of solar generation we can observe that ramping up changes dramatically. With 500MW of solar the ramp from 4 to 6 pm reaches 100MW/hour and with 750MW of solar the ramp reaches 140MW/hour. These are huge ramp rates that Cyprus has not yet seen in current Load curves that will affect negatively the grid. The negative effect that will be seen by the grid with these issues most probably increases in the cost of electricity, in the long run, sometimes they can even bring power outages in extreme cases.
This is an issue currently faced by other sunny electricity grids but not in Cyprus, however, it is an issue that needs to be taken into account moving forward with our evolving grid in Cyprus and this is an issue projected to be a problem after 2029. Solutions to this problem exist with the introduction of Energy storage technology, demand response, and any other technology that increases grid flexibility and these solutions will be studied in other articles.
By Sotiris Kyprianou
Sotiris is an energy analyst that dedicated his career to the energy sector with degrees in engineering and management in the sector with specialization in renewable energies, energy storage, and energy modeling.