A Free-Market Energy Blog

The Problem of Renewable Energy and Intermittency

By Cornelis van Kooten -- May 14, 2019

“Open-cycle (peak) gas plants are the most common asset used to backstop wind and solar intermittency. However, as the wind and solar capacity increases, the incentive for a private company to invest in such assets declines to the point where the operator of the electric system must provide a subsidy to the construction of gas plants capable of providing electricity on very short notice.”

A number of utilities are trying to become 100% carbon free in their production of electricity by relying on renewable sources of energy.

I am not at all certain what this means. Often the only sources of renewable electricity are wind turbines and solar photovoltaic (PV) panels, and, to a much lesser extent, geothermal. (Iceland is the only country relying on geothermal.)

Both wind and solar energy suffer from what is known as intermittency, because winds have a nasty habit of suddenly dying or springing up, while the sun will disappear behind clouds and provides no power at night. During these periods, sometimes only short bursts of several seconds, there may be too much, too little, or no electricity whatsoever entering the grid.

Three Backup Choices

During those times, it is necessary to have backup resources that are capable of responding almost instantaneously to changes in the availability of electricity from wind and/or solar assets.

There are only three practicable sources of such backup power. The first two are back-up energy-generating devices: open-cycle natural gas (or diesel) turbines and hydroelectric units (hydraulic power). These operate essentially like an automobile: by pushing the gas pedal down, the turbines provide more electricity; by releasing the pedal, less power enters the grid.

The third option is a back-up energy storage device, best thought of as a battery. (There are many other types of backup, such as flywheels and compressed gas, but these are either too small to be employed at a grid level or require special geological formations.)

Gas-fired Infrastructure at Risk

Open-cycle (peak) gas plants are the most common asset used to backstop wind and solar intermittency. However, as the wind and solar capacity increases, the incentive for a private company to invest in such assets declines to the point where the operator of the electric system must provide a subsidy to the construction of gas plants capable of providing electricity on very short notice.

This subsidy is a cost that should be—but usually isn’t—attributed to the intermittent renewable source. Certainly, the ratepayer will eventually have to cover this cost in the form of higher electricity prices.

Of course, it is easy to demonstrate that wind and solar power reduce the wholesale price since the cost of subsidizing backup capacity is a fixed cost that does not show up in price at that level. But it certainly does show up in the long run as capacity subsidies to peak gas need to be covered. Those subsidies are over and above the subsidies governments have paid to wind and solar, which also fall into the lap of ratepayers.

Where Coal is Still King

With the exception of biomass, renewable solar and wind energy are incapable of providing low-cost baseload power. The least costly baseload power comes from coal in important areas of the world, which is why China and India are aggressively expanding their coal-fired generating capacity.

Yes, these countries are leaders in the provision of wind and solar energy, much of which has been funded by western countries through Kyoto’s Clean Development Mechanism (whereby rich countries have been able to claim carbon offset credits for meeting Kyoto Protocol targets). But wind and solar are unreliable, while coal is not.

The biggest problems facing China, for example, are ensuring continued economic growth, which requires low-cost, reliable power, and environmental improvement, particularly in air quality. Such improvement comes from more efficient, cleaner-burning coal plants that have ‘scrubbers’ in their smokestacks that can remove almost all of the pollutants but two: water vapour and CO2, neither of which has a negative effect on air quality.

Given that a grid operator, whether in China or the U.S., must have a source of reliable, baseload power, it has to have one of the following in its system: coal, combined-cycle natural gas turbines (where heat lost through the stack in a peak gas plant is used to heat a boiler much as in a coal plant), large hydroelectric dams and reservoirs, or nuclear power.

Otherwise the operator must import electricity from another grid. Society now eschews all these sources of power: Coal and gas are out of favor because they emit CO2. Hydro reservoirs are opposed by environmentalists. And, of course, nuclear energy is the greatest taboo!


It would appear that biomass burning is the only environmentally friendly alternative to the traditional sources of power. It is considered carbon neutral, at least according to many countries’ legislation, but my graduate students and I have shown that biomass is worse than even coal. It simply takes too long to recover the CO2 debt that biomass creates relative to the fossil fuel.

If climate change is an urgent matter, environmentalists need to redo their math.

The Battery Option

Finally, there is the battery. Excess wind and solar energy can be stored in a battery to be used when required as a backstop to renewable intermittency.

Our research indicates that the size of battery required to function in this capacity has to be humongous. Tesla installed a battery to backstop wind energy in Australia. It has a rated capacity of 100 MW of power (what can be delivered at any given time) and 129 MW of energy (total energy stored).

That is, for a grid that might have a baseload of, say, 8000 MW, the Australian battery would be able to supply only 1.25 percent of the needed power, and for only about 78 minutes. This ‘huge’ battery (as it was described) would be incapable of preventing a blackout if the system had no fossil fuel generators, large hydro, or nuclear capacity that exceeded 8000 MW.


It is true that the cost of building wind and solar capacity has gone down and that it is competitive with that of coal and gas, and much more competitive than nuclear power is in the West. The cost of nuclear power in China, for example, is much lower because engineers there are taking advantage of learning economies of scale as more plants are built, and because costs are not inflated by environmental regulations based on unrealistic fears about safety.

As to low reported costs of renewables, these ignore the indirect cost that solar and wind impose upon other, more reliable assets in the system. One only needs to look at what has happened in Germany and other countries that rely on increasing amounts of solar and wind power (while abandoning nuclear energy and building new coal capacity) to determine the futility of trying to become 100% carbon neutral.

Studies find that the cost of electricity increases as the penetration of wind and solar into the system increase. And there is often little benefit in terms of reduced CO2 emissions. The latest data on the German grid indicate that total power produced by German power plants exceeds what is consumed domestically by what is approximately produced by solar and wind.

That difference often has to be exported at low prices, thereby further increasing the cost to the entire system. One can only conclude that electricity costs will rise as the electric system operator seeks to rely more on renewable energy from wind and solar.


G. Cornelis van Kooten, Ph.D., is Professor of Economics and Research Chair in Environmental Studies and Climate at the University of Victoria, BC, Canada, author of Climate Change, Climate Science and Economics: Prospects for an Alternative Energy Future, and a Senior Fellow of The Cornwall Alliance for the Stewardship of Creation and of the Fraser Institute.


  1. Kathy  

    Compounding the unreliability/intermittency problem with ‘renewables’ like wind, solar and small waterpower (often dries up during late/hot summers when air conditioners increase electricity demand) are FIT-type power purchase contracts – hello Ontario! – that give them first-to-the-grid-access (above reliable, cheaper ‘baseload’ electricity generation that could have otherwise benefited consumers). Too often this additional problem with ‘renewables’ evades the public attention deserved, IMO.


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  4. JoseDispatcher  

    I would recommend reading the article:

    “Electricity storage as a matching tool between variable renewable energy and load”,

    proposed for publication. Link below:


  5. John Droz  

    I thought that this was a fine article that made several good points.

    I must strenuously disagree with one sentence, saying that wind energy is “competitive with that of coal and gas.” That is simply not so if ALL the taxpayer and Grid-related costs attributable to wind energy are fully assigned to wind energy. At that point onshore wind energy would be about four times the cost of our conventional electrical energy sources.


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  9. Adrienne McGuire  

    Thank you for this educational article. It’s always helpful to read about different perspectives regarding alternative energy!


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  15. AAfigg  

    That was why our ancestors are stop using Sun and Wind… and economy grew fast after we shift to coal.

    Why do the alarmists always talk about model predictions which we all know very unreliable…

    Why don’t they educate us on How the CO2 will affect the climate? I tried to learn this… but all explanation is … “What 97% of the scientist believes or faith or has learned from other scientist”…(who cares any way).. Or “CO2 is like a blanket…”


  16. Douglas Smith  

    I agree that an intermittent source of electricity should should have an inherently lower value than a steady source electricity, and this value should be reflected in the cost of electricity to the grid.

    If the grid is allowed to pay less for intermittent sources, this would motivate solar and wind providers to develop their own sources of backup power, which could be anything they want, including battery backup, gravity backup, thermoelectric storage, etc.

    I also argue that a carbon-light source of electricity should have inherently higher value than a carbon-heavy source of electricity. The cost of responding to global warming is expensive. The cost of preventing global warming is much lower.

    As a society, we need more carbon-light sources of electricity. Some form of carbon tax or carbon credit system is required to disincentivize production of electricity from natural gas, petroleum, or Coal.


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  18. Envision Digital  

    Renewable energy is now cost competitive with fossil fuels, and booming technology will continue decrease its cost. The world could leverage the opportunity of smart and clean energy transformation to achieve both economic and environmental sustainability.

    We should see that, before 2050, wind power and solar power will become the new coal for generating power, batteries and hydrogen fuels will be the new oil, and AI and IOT will turn into the new power network. Humankind by then will step into a beautiful era of clean energy.


    • rbradley  

      If this is true, Envision Digital, then Biden’s $2 trillion energy plan is unnecessary, right? In fact, the ‘soft energy path’ is anti-green on close inspection.


  19. Hannah N  

    Just read an interesting article that took into account potential additional battery capacity of all the future electric cars that will be plugged in at any given point. What an exciting time to be alive, we have a great problem to solve but we can do it! Renewables are getting cheaper by the day and some much needed innovation and efficiencies are only increasing in this field. We will need to get creative for sure but as one commenter mentioned- we either pay now or pay in multiples in the not so distant future in disaster recovery, economic loss, etc due to climate change.


  20. Flux  

    Actually, I don’t want to show skepticism about renewable energy sources and the transition to green energy in general. Oil is finite, the cost of its production is constantly growing, and gas and coal alone cannot improve the environmental situation. Until mankind subjugates controlled thermonuclear fusion, the most active developments in the field of “green” energy will have to be carried out. This is a very thorny path, consisting of solving the most complex problems: economic, technological and even social.


  21. Michael Smith  

    Experts from the Finnish University of Technology Lappeenranta and the Energy Watch Group are confident that the planet can fully transfer its energy balance to renewable resources by 2050. We are talking about the generation of electricity and heat, transport and water desalination. Together, they painted a more than 300-page roadmap for this process, where they described in detail the possible consequences of such a step for humanity and specific regions. In their opinion, the new energy system will be more economical and more efficient than the current one. But how it all will be conduct from a business point of view? Are there any software to lead these processes? I have only heard about https://fluix.io/industry-renewable-energy, are there more?


  22. John Courtney  

    Indeed, we are having some difficulties using renewable energies. Currently Solar panels do not work at night, and wind turbines are not working without wind. But technology is moving at faster rate and scientists and engineers are finding ways to make more sensitive panels and turbines.


    • rbradley  

      Yes, always the case. But all technologies are improving. Think gas-fired combined cycle. And mineral energies have storage embedded and are more dense and reliable–and can be transported. It’s a fossil-fuel world for as far as the eye can see.


  23. Rafe Champion  

    Australia, Europe and quite likely the US experience frequent periods of “wind droughts” lasting up to 30 hours or more. When the sun is off duty during wind droughts there is next to zero RE in the grid, unless you count hydro and biomass.
    RE can never replace conventional power until storage is available to replace all the power in the grid for 30 hours or more.
    Battery capacity is not following Moore’s Law *doubling every couple of years) like data storage.
    Pumped hydro is a joke.
    Replace old coal plants with HELI and nuclear power.


  24. Chris Kapsambelis  

    I recently downloaded about two year’s worth of output from a local 1.5 MW wind turbine. Using the trial and error method, I was able to calculate just how much battery storage will be needed to ensure a fraction if power without failure over the two year period. I was alarmed to discover, that just this one wind turbine, will need some 500 megawatt-hours of battery storage to provide about a quarter of its rated power on a continuous basis.


    The fact, that it take some 4 to 5 times the size of the largest battery in the world to provide a firm power output from just one wind turbine, is proof that the whole idea of 100% carbon free power system is a myth.


  25. Chris Pederson  

    Thanks for sharing how sometimes you need a backup resource that can respond immediately. No one wants to be left without power. Back up power is great for keeping your home safe and secure.


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