Limits to Wind and Solar on the Grid: A Discussion

By Robert Bradley Jr. -- June 14, 2023

“While solar and wind receive huge subsidies, the end user pays for the party.”

“The dream of a solar and wind grid is collapsing very quickly as they are only profitable in a low penetration context.”

The following LinkedIN discussion is notable for its insight and reader reaction–and timely with summer concerns about grid reliability, given the wind/solar penetration at the expense of reliables.

Oscar L. Martin teed things off with this post:

Early adopters of solar and wind such as Texas or California are starting to see alarming signs of saturation even when the total energy production of intermittent sources barely reaches 24% of the total in those areas. Basically the dream of solar and wind is collapsing very quickly as they are only profitable in a low penetration context.

The image below shows the curtailed percentage of annual production curtailed from solar and wind farms in Texas in the last 12 months, ranging from 10 to 30 percent of the total production, and growing year over year.

Another example is the exponential growth of the curtailed percentage in California, an underdeveloped grid that needs to import almost 1/3 of its energy. In this state, the curtailed renewable energy was 0.75% in 2015, 1.1% in 2018, 3.1% in 2021, and skyrocketing to 4.5% in 2022. In the past 12 months, 2.6 TWh were curtailed in California, equivalent to the energy consumed by 300,000 homes in a year. When the amount of curtailed energy grows faster than the installed capacity the signs of saturation are starting to be relevant, showing that the cost of additional solar and wind will be more and more expensive as they won’t be as productive as before and will increase even more the total cost of energy for the end user.

How is this possible in a region such as California with a deficit in energy production? Solar and wind are notorious for failing to generate when they are most needed, and flooding the grid when they are not. For instance, electric car charging peaks at night, when solar energy is absent. And the wind speed drops significantly in summer and winter when electricity demand is highest. The consequence is a daily excess of discarded energy that worsens during the spring and fall seasons. The more renewables, the more curtailment, and lower returns for renewable farm owners but the same high fixed cost for the end user.

While solar and wind receive huge subsidies, the end user pays for the party. Is there any other alternative? Of course, instead of using clean intermittent sources that are destabilizing the grid and making it more expensive for the end user, the use of clean but dispatchable energy sources such as nuclear, geothermal, or hydroelectric have demonstrated they result in lower overall energy cost, lower emissions, lower rate of blackouts, lower waste, and lower impact on the environment.

The dream of a solar and wind grid is collapsing very quickly as they are only profitable in a low penetration context.

One Brian Wark angrily responded:

Oscar has real hate on for wind, solar, and storage. Every week posting misinformation. Who is really paying for your nice suits Oscar? You can’t just hate a new technology can you? Missing the point that closing or limiting use of a Gas or Coal plant leaves capacity on its transmission lines. Or we can stick battery storage either on site in your home or factory. Or nearby to power the entire neighbourhood. Lots of unused transmission lines at a site near you, San Onofre nuclear plant now closed.

Oscar Martin responded:

Brian, it is not hate. I only think we have way better options. It is not a feeling, but a rational deduction based on the poor performance of these technologies in those regions with higher grid penetration such as California, Texas, or Germany. I see two main problems:

– Intermittency is something that could be solved with affordable and massive energy storage, something that so far doesn’t exist. So, they require a backup of 100 percent of the peak demand.

– Extensive material and energy requirements, make them very invasive to the environment, with massive mining and waste generation. This is way more complicated as recycling is not required in most places and the toxic waste goes to landfills.

So, neither solar nor wind are ready for prime-time. I like nuclear because it is the most efficient, with the lowest emissions, waste, and land requirements. Geothermal and hydroelectric are not as efficient but they are great clean and reliable options where available.

Regarding San Onofre, I would like to see a refurbishment program like the Canadians successfully did in 2005, updating and bringing back online reactors that were shut down in 1990 and 1995.

Steve M commented:  Texas uses all of the Wind and Solar that it can transmit. The lines get saturated and need either A) bigger lines or B) Energy Storage or C) Both. Oscar L. Martin can you show any point in time where Texas’ demand was less than its Wind and Solar supply?

Oscar Martin responded: … You can’t deploy solar and wind as a replacement for dispatchable sources already installed, so any new solar or wind farm is installed on top of the dispatchable backbone. In a solar/wind grid, that would be considered the backup capacity. Something that costs money even when they are not producing. So any additional wind or solar farm requires new power lines. Without them, the grid gets saturated quickly and makes all those solar and wind fields completely useless. We know ERCOT has been struggling with this, and it is not an easy solution as new powerlines take 10-15 years to be deployed due to the similar environmental requirements compared to nuclear.

By using geothermal, nuclear, or hydroelectric, you can effectively replace fossil fuel generation with another reliable but clean power source, without requiring additional power lines in the case of nuclear, as they can directly replace fossil fuels.

Final Comment: Yes, wind and solar as grid electricity are cancers for reliability. But Martin’s clean-for-clean energies’ swap neglects 1) hydropower as unreliable (bad water years) 2) geothermal as unproven at scale and 3) nuclear as capacity limited. Natural gas generation technologies–more efficient and cleaner than ever before–are the solution.