Why are solar and wind intermittent energy sources?

Solar and wind energy industry are rapidly expanding on global level but there are still some major issues these industries will have to solve prior to becoming top energy sources in the world. One of these issues is no doubt the intermittency of solar and wind energy.

Why do solar and wind belong to intermittent energy sources? Wind energy and solar energy are both called intermittent energy sources because these sources may be uncontrollably variable or more intermittent in normal operational conditions compared to traditional fossil fuels (oil, natural gas and coal). It is a well known fact that wind does not blow constantly all the time, and also we all know that our sun doesn’t shine at night. What this means is that these two sources cannot guarantee reliability of delivery 24-7 without the adequate energy storage solution.

Let us deal with few well known facts to get a better picture here. For starters, wind speeds are usually (quite) higher in the night than during daytime, and you probably also know that winds tend to blow much faster in the winter compared to the summer. To continue the story, sun as we all know does not shine at night, and sunlight is also much stronger in summer than in the winter. What can be concluded from these facts? The right conclusion would be that using wind power and solar power as combo could ensure reliability in delivery, as these two renewable energy sources can complement each other very well, and thus their combination could help reduce the intermittency issue to the minimum.

Even if we do not combine these two energy sources together we can still significantly reduce intermittency issue by for instance dispersing either wind turbines or solar panels across the very large area. There are many energy experts who say that a well planed “dispersion system” can dramatically decrease the intermittency effect, and ensure so much needed reliability in delivering electricity by drawing power from different areas and thus result in reducing variations in electricity generation.

There has been plenty of talk about „renewable energy storage solutions“ but sadly science and technology still haven’t come up with the solutions that would be both very efficient and in the same time commercially viable. However, there has been a decent number of very promising studies and with the big money being invested by many countries around the globe the further research is bound to make future renewable energy storage methods more cost-effective. The U.S. alone has already announced to award more than $200 million in grants for utility-scale energy storage projects.

The future technological solutions will likely be able to solve the intermittency issue of wind and solar energy. Once intermittency issue comes out of the way this should open the door for much improved cost-effectiveness of solar and wind, paving the way to a future clean energy society.

Solar and wind energy industries are growing rapidly in many countries all across the globe. These two fast growing industries, despite all the growth, are still in search of adequate energy storage solution that would solve intermittency issue of these two renewable energy sources.

There are many ongoing researches working on various solutions to save excess solar and wind energy for times when the sun is down and the wind isn’t blowing. The perfect storage solution still hasn’t been found, and batteries are usually the most talked about as the most promising solution.

There have been many proposed solutions, and one that is currently most often used is pumped hydroelectric storage. According to the Electric Power Research Institute (EPRI) pumped hydroelectric storage accounts for more than 99% of bulk production capacity worldwide.

In 2022, there are over 170 GW of pumped storage capacity in operation worldwide. U.S. is the home to the largest operational pumped-storage plant in the world, the Bath County Pumped Storage Station.

Another potential approach for new energy storage solution is using sugar alcohols in mix with carbon nanotubes as reported in ACS’ Journal of Physical Chemistry C. Sugar alcohol is a readily available waste product of the food industry.

Scientists want to store energy as heat and have been exploring sugar alcohols as a possible material for making thermal storage work. There are still plenty of limitations in this technology, but also a big potential that should open the door for further research.

Turning waste into any useful form of energy and doing it cost-effectively would certainly revolutionize our entire energy industry.