A recent study on hybrid power plants reveals that incorporating solar or wind energy storage can exacerbate grid congestion since they only relieve it in regions with significant concentrations of variable renewable energy sources.1
Research from the Lawrence Berkeley National Laboratory indicates that a hybrid power plant’s impact on congestion depends on its location.
It also noted that it depends on how limits on battery cycling constrain a plant’s operation.
In the report, they noted that the ability to charge the battery from the grid is an important factor in determining the ability of a hybrid plant to reduce grid congestion.
The report said that the development of new wind and solar plants has outpaced the development of new transmission. Transmission is important because it allows load centers to access electricity from low-cost resources in other areas.
Congestion occurs when transmission limits are reached, which may prevent low-cost wind and solar resources from fully utilizing, limiting their market value.
Energy storage can minimize transmission congestion by altering generation and load across time. In places with many wind or solar power plants, hybrid solar+battery, and wind+battery power plants are becoming more frequent.
This is partly motivated by the desire to avoid selling energy during peak hours when prices are low.2
According to the report, modern hybrids that can cycle their batteries and charge from the grid alleviate congestion in areas with ample solar and wind energy, nonetheless, the influence is minor.
New hybrids in various combinations increase congestion, these resources, however, produce less congestion than establishing a solo solar or wind plant.
Researchers said that adding batteries to an existing stand-alone wind or solar plant “will almost always reduce congestion.”
The study concentrated on 23 U.S. bulk electricity system locations now experiencing substantial congestion and featured a stand-alone solar or wind plant.
Places were chosen to provide instances of circumstances that could arise in systems with a high VRE penetration.
- Kemp, Julie Mulvaney, et al. ‘Interactions between hybrid power plant development and local transmission in congested regions’, Advances in Applied Energy, https://emp.lbl.gov/publications/interactions-between-hybrid-power
- Smart Energy International. ‘Hybrid power plants not the silver bullet for grid congestion’, Smart Energy International, https://www.smart-energy.com/renewable-energy/hybrid-renewable-power-plants-not-the-silver-bullet-for-grid-congestion-study/