Intermittent and Volatile: Renewable Energy Challenges Grid Stability
As climate change continues without signs of diverting its path toward warmer temperatures and more frequent extreme weather events, electricity demand will increase – and the supply of solar and wind energy may become more volatile.
As temperatures surge and weather patterns evolve, the supply and demand for electricity is expected to grow. Areas once characterized by moderate climates grapple with escalating cooling loads, but weather patterns change the stability of renewable energy generation.
Rising temperatures. Image used courtesy of Adobe Stock
At this intersection of challenges, researchers are looking for solutions to better manage the global energy supply.
Increasing Cooling Loads
Over the past two summers, Europe, typically known for its moderate summer temperatures that seldom exceed 80°F in certain regions, has encountered scorching heat waves.
This summer in Italy, a distressing heatwave of up to 118°F shattered local heat records and contributed to the outbreak of numerous wildfires.
While homes in the U.S. have had air conditioning (AC) units since the 1850s, it is rare to find AC units in European homes. However, an International Energy Agency (IEA) report projects the number of AC units in Europe could more than double from 110 million units in 2019 to 275 million units by 2050.
This is the perfect example of how cooling loads are expected to surge in the coming years as GHG emissions continue on their current trajectory.
Europe is just the first of many regions likely to turn to AC as elevated temperatures continue. The IEA has issued a cautionary note regarding a possible "cool crunch," an impending scenario where the global demand for air conditioning surpasses the capacity of electrical grids and available energy resources.
Expected changes to supply and demand of wind and solar energy systems. Image used courtesy of Nature
Weather Pattern Disruptions
Regarding supply, most wind and solar energy systems rely heavily on weather conditions, making them susceptible to unexpected meteorological events that can negatively affect their energy generation capabilities.
For example, alterations in cloud patterns traversing over solar panels can trigger sudden declines (ramp-downs) or surges (ramp-ups), leading to voltage oscillations and even grid failures. Using more variable renewable sources like solar energy can impact the electricity grid's stability, given their intermittent power supply during occurrences like cloud passages.
A study by researchers from Peking University, Brown University, and other institutions indicates that by the close of this century, energy systems characterized by differing reliance on wind and solar energy might confront substantial decreases in the alignment between supply and demand, owing to the influence of climate change.
The diminished or more erratic availability of renewable energy sources could notably impact this supply-demand harmony, particularly in regions spanning middle to high latitudes.
These findings prompt the need for solutions that maintain grid stability as weather patterns become less predictable, particularly considering the ongoing global trend toward renewable energy as a predominant power source.
Where Do Engineers Come In?
The risk of increased cooling loads without stable renewable-generated electricity to meet demand creates many challenges.
The unmitigated strain on the grid can increase the chance of energy shortages during peak periods or blackouts. Without dependable renewable energy, supply will continue to come from fossil fuel sources, keeping us on track for “business as usual.” Increased AC use can contribute to the urban heat island effect, compounding ambient temperatures.
But if researchers suggest wind and solar energy supply may soon struggle to keep up with demand because of changing weather patterns, how do we reliably increase the use of renewable energy on the grid? Batteries and variety.
According to researchers from Australia, who carried out research similar to that from Peking and Brown Universities, mitigating the oscillations caused by solar ramp events can be addressed through leveraging mass storage technology and diversifying the mix of renewable energy sources within the grid.
Net renewable electricity capacity additions by technology, 2017-2024. Image used courtesy of IEA
Renewable energy capacity is expected to jump by a third in 2023 alone. Unfortunately, only solar photovoltaics are currently in line with the Net Zero Emissions (NZE) by 2050 Scenario. The acceleration of wind, hydro, geothermal, solar thermal, and ocean energy adoption must occur significantly faster to align with NZE goals and support the expected changes to solar supply.
Diversifying grid supply will be best complemented by the increased capacity of battery storage technologies to store surplus energy and alleviate the pressure on the grid. In projected ramp-down scenarios, the stored energy can be reintegrated into the grid, compensating for reducing solar power output and sustaining grid stability.
All estimates suggest we are still on track for “business as usual” GHG emissions. The world has various options to alter this track, including increasing renewable energy capacity and building supporting infrastructure such as battery technologies. The hope is that this technology growth will keep up.