Preface. Clearly fossil fuel plants need to be replaced with energy storage — batteries, pumped hydro, or compressed air. Many hours of backup power will be needed since, unfortunately, over two-thirds of total wind power in the U.S. happens outside the 9–5 peak weekdays maximum demand (Baxter 2005).

Peak solar generation is at high noon, which is not the same time of day as peak people demand. For example, in New England the morning demand starts at 5 am and ramps up to 9 am, stays that high until 5 pm, and then reaches an even higher evening peak from 5:30 to 7:30 pm when people come home (EIA 2011).

A much bigger problem is that wind and solar are seasonal, requiring massive storage to solve the “gigawatt-day” problem of days or weeks when renewable generation is insufficient to meet demand, even after all available load flexibility and short-term storage resources have been deployed (CEC 2011; CCST 2012).

Imagine a future in which wind and solar supply up to 100 % of U.S. electricity. You would need to store hundreds of hours of power (Houseman 2014). Winds are highly variable. Seasonal wind—March comes in like a lion, goes out like a lamb— might require 200 hours of storage, which could clearly be done only with very inexpensive storage media, such as water or air (Cavallo et al. 1995).

Grid operators are ringmasters. They have had to cope with the mismatch between demand and supply, and over decades have learned what the patterns are, and how to turn power plants up and down, on and off, accordingly. But wind goes from a whisper to a roar when storms arrive (Halper 2015), a bucking bronco that gets increasingly hard to manage and control the more wind and solar penetrate as a percentage of overall power (IEA 2013).

So far, wind and solar power penetration is so small that operators can balance it with natural gas peaker plants, dispersing excess generation across a larger region, more frequent scheduling (15 min or less), (pumped) hydropower, or curtailment.

But that is starting to change as renewables penetrate more. I’ll add more blackout stories as I see them in the news below.

Renewables caused or almost caused blackouts in the news:

2021-1-10 Europe narrowly escaped blackout: electricity suppliers warn – Austria

2020-8-20 Poor Planning Left California Short of Electricity in a Heat Wave. Scores of power plants were down or operating below their capacity just as hot weather drove up demand.

As you probably know, the supply and demand of electricity must match within a very small range. There’s yet another quality of electricity called VARs that I’ve read about but never understood. Renewables do not generate Volt-Ampere Reactives (VARs), but wind and solar farms can be expensively altered to generate them, and if they don’t, utilities will curtail their power. Alternating current has electromagnetic properties that have to be kept in balance. It’s a lot like riding a bicycle: The energy you put into the pedals will move the bike forward, but you also have to put some energy into maintaining your balance, or you’ll fall over and won’t be able to move forward at all. If you are a good bicyclist on a smooth road, the “maintaining your balance energy” will be small. If you are a poor bicyclist who swerves around a lot, or if you’re on a bad road, the “maintaining your balance” energy will be larger. In either case, the “maintaining your balance” energy is necessary. That energy is also a parasitical drain on your energy effort: it doesn’t move the bike forward. A well-run grid is like a good bicyclist on a smooth road.  Rotating electric machinery puts VARs on the grid, and if the entire grid was thermal (nuclear, gas, coal) and hydro units with rotating electric machinery.  But wind turbines and solar make direct current that needs to be changed into alternating current, and that process does not put VARs on the grid in the same fashion, which can mess up the grid (Angwin M (2020) Shorting the Grid. The Hidden Fragility of Our Electric Grid)

Alice Friedemann   www.energyskeptic.com  author of “Life After Fossil Fuels: A Reality Check on Alternative Energy”, 2021, Springer; “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer, Barriers to Making Algal Biofuels, and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Collapse Chronicles, Derrick Jensen, Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report

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Starn J (2021) The Day Europe’s Power Grid Came Close to a Massive Blackout. Bloomberg.

A fault occurred at a substation in Croatia and caused an overload in parts of the grid, which in a domino effect spread beyond the country’s borders as far as France and Italy. Although not directly caused by intermittent sources such as wind or solar in this case , it’s only a matter of time before too many renewables and too few balancing fossil fuel plants lead to more blackouts. Similar outages have happened in California, Australia and Germany as well.

The reason is that transmission grids need to stay at a frequency of 50 hertz to operate smoothly and any deviations can damage equipment that’s connected. Had the frequency swings not been reduced within minutes, it could have caused damage across the entire European high voltage network, potentially causing blackouts for millions.

Spinning turbines of thermal plants powered by coal or natural gas connected to the grid create kinetic energy called inertia which helps keep the network at the right frequency. This spinning can’t be created by wind turbines or solar panels. The main solution being proposed for energy storage to replace fossil generation are batteries, but they cannot create inertia either. Batteries to store just one day of U.S. electricity will cost $40 trillion or more and last only 5 to 15 years, depending on battery type (Friedemann 2016). No other kind of energy storage will do the trick, not pumped hydro, compressed air energy storage (there are few sites to put more than the single one that exists in Alabama), or concentrated solar power. Or a national super grid.

Currently, too many renewables are being added while fossil fuel plants are shut down too quickly.

So Germany, despite it’s plan to ditch fossil fuels continues to generate more energy from coal than from wind, because the wind does not blow permanently. It is also generating zero energy from solar at the moment because it’s winter.  And in 2018, the UK went for nine days with zero power generations from wind farms because of  a wind draught.  

We might see an unwelcome repeat of what many Soviet bloc countries experienced in the 1980s—timed blackouts lasting months and even years.

References

Baxter, R. 2005. Energy storage: a nontechnical guide. Tulsa: PennWell.

Cavallo, A., et al. 1995. Cost effective seasonal storage of wind energy, 119–125. TX: Houston, CRC Press.

CCST. 2012. California’s energy future: electricity from renewable energy and fossil fuels with carbon capture and sequestration. California: California Council on Science and Technology.

CEC. 2011. 2020 Strategic analysis of energy storage in California. California: California Energy Commission.

EIA. 2011. Demand for electricity changes through the day. U.S. Energy Information Administration. http://www.eia.gov/todayinenergy/detail.cfm?id=830.

Friedemann AJ (2016) When Trucks Stop Running: Energy and the Future of Transportation. Springer.