Wind is a fickle friend
Nobody likes an unreliable friend. Phrases like ‘A friend in need is a friend indeed’ are cliches for a reason. A friend who does not support you in times of need is not considered a friend. Electricity sources should be similar. A source that cannot deliver when needed is of little value. Wind turbines are possibly the least reliable source of energy that are out there. The world is discovering this fact.
Let us begin with Germany.
The ruling coalition in Germany collapsed a few days ago. Economic crisis in the country underlies this political crisis. Germany’s energy policies are a huge reason why the country is struggling. Germany, in its energy policies, has made all mistakes that can be made. It phased out its nuclear and coal plants. Consequently, it relied more and more on Russian gas. With the curtailment of the Russian gas supplies, Germany’s energy prices shot up. In the midst of this turmoil, wind energy decided to take its periodic break.
A few days ago, Javier Blas, the energy and commodity columnist at Bloomberg, tweeted this
Wind turbines generated only 0.2 GW against their rated capacity of 70GW! The electricity prices have shot up. Wind is not turning up for Germany when it is in trouble.
Dunkelflaute, or dark doldrums, is a time when it is dark and still. A time when neither wind turbines nor solar panels generate electricity. Note that this does not happen just in one turbine but across the country (and even across Europe) at the same time. It means that the country needs to back up these plants — especially wind turbines — with conventional energy plants. This makes electricity more expensive than it otherwise would be. Expensive electricity means manufacturing becomes less competitive.
What does the German experience have to teach us about India? Is wind unreliable in India too?
A recent draft discussion paper by the Central Electricity Authority (CEA) has some answers. According to the paper, the year on year variation in wind can be up to 50%! Within a year, the variation can be much more as this chart from a different CEA publication shows.
In one month, the wind generation varied from 105 (Million Units) MU to 619 MU! The minimum was one sixth of the maximum! This is for all India. The regional variations would be even more severe. The day to day and hour to hour data variation would be even sharper. No wonder the CEA discussion paper makes the powerful yet bland statement,
“The generation of VRE sources in India, particularly wind, is subject to significant fluctuations and cannot be accurately forecasted. (sic)”
The challenge is going to get worse as more Variable Renewable Electricity (VRE), especially wind, gets added to the grid. As the CEA paper says
“…the determination of capacity credit for VRE sources is a challenge for system planners. This becomes a major issue as more and more VRE capacity is added to the portfolio and a reliable supply of power becomes a challenge during RE Disturbances Demand variation etc.”
Some assume that storage would take care of these challenges. They do not realize that it is exponentially more difficult (and expensive) to store electricity for a few days than it is to store it for a few minutes and hours. Lok at the chart for the month of May above. The minimum of 105MU comes after days of very low production of wind electricity. Storage of electricity can be done only if there is surplus and for many days in May there was no surplus of wind energy. That means that the storage for all those days would need to be done by electricity generated by conventional sources a few days in advance. This storage would get quickly depleted and would be incredibly expensive especially if it is used only a few days a year. As the CEA paper says,
“However, due to energy storage limitations, the entire capacity may not be available for a longer period during high-demand hours.”
Modern societies need reliable electricity round the clock. Without electricity, trains cannot run, life giving medical care may be disrupted and even mundane business activities like billing in department stores may stop. Distribution companies tasked with providing this electricity need reliable suppliers. Across the world, they are realizing that wind turbines are not reliable.
Distribution Companies face this reality today. Tomorrow it will be the turn of investors in these technologies. The day after it would be the turn of the whole society to bear the burden.
The fickle friend would not be very popular that day.
Edit: Typo corrected. Thanks Abhijit.
This story is part of a series called ‘Electricity deep dive’. In the coming weeks, we will be diving deep in many of the issues discussed above.
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