Small-scale renewables cause power outages: UK study

Strong points :

  • Renewable energy from home generators is unpredictable as it is switched on and off line intermittently, putting the grid at risk.
  • Researchers have found that seasonal household use and daily changing weather conditions also cause the intermittency.

According to a study published in Science Advances, mathematicians from the University of Nottingham found that several small-scale renewable energy sources can cause power outages.

The researchers used data from smart meters in the UK and came to the conclusion that the behavior of the network changed over time and that the resilience of the network changed at different times of the day. They discovered that high consumption of solar panels can cause outages in grid systems.

Domestic renewable installations are highly democratized in the UK and continue to grow with each passing day. There are more than one million small-scale solar PV systems in the country. The net result is that low renewable energy generation and intermittent supply puts grid systems at risk, researchers say.

Renewable energy generation in the UK is highly dependent on household solar PV generation. Under the feed-in tariff system, households are paid to supply their stored electricity upstream to the grid.

Researchers say renewable energy is unpredictable because home generators cycle on and off intermittently. Seasonal household use and daily changing weather conditions also cause intermittency.

Oliver Smith, who led the research at the University of Nottingham, said: “The increasing proliferation of small, intermittent renewable energy sources is causing a rapid change in the structure and composition of the electricity grid. This is because the actual grid structure can change over the course of a day as consumers and small-scale generators connect and disconnect. Using data from smart meters in UK households, we tracked the change in grid composition over time. »

“We then used a dynamic model to assess the impact of these changes on the resilience of power grids to catastrophic outages. We found that resilience varies over the course of a day and that high solar panel usage can make the grid more susceptible to failure,” Smith added.

During the research, the mathematicians changed the size and proportion of solar photovoltaic generators in the grid and found that the grid needed to be more robust for this absorption than taking power from a single source. They found that the grid does not reach optimal levels when too many small-scale renewable energy systems are operating at different times of the day.

They also found that household batteries for renewable energy storage only reduced household electricity costs. These batteries did not reduce the risk of network failure.

“The main problem is the magnitude of the fluctuations in the supply of small-scale renewable energy. A cost-effective way to overcome this problem would be to intelligently schedule the release of stored photovoltaic energy from home batteries at specific times. This would provide much greater control and reduce the risk of system failure,” Smith explained.

Rosemary C. Kearney