Wind Energy & Solar Panel: Challenge of Using Renewable Energy for a Sustainable Future
KAKALI DAS

The 15th of January 2023 was an unusual day for Germany. Strong winds swept across the north, causing thousands of wind turbines on land and at sea to spin at maximum capacity.
At certain moments, there was theoretically enough wind energy to power the entire country.
However, in practice, the energy couldn’t be delivered to where it was needed.
As a result, the wind turbines had to be slowed down, leading to the unfortunate wastage of cheap and clean electricity.

Meanwhile, in the South, residents were urged to conserve energy, neighbouring countries were called upon to provide backup capacity, and coal power plants were reactivated to meet the demand.
While one half of the country was overflowing with electricity, the other was taking measures to avoid running out. What happened here underscores one of the most overlooked challenges of transitioning to renewable energy, not just in Germany, but everywhere.
Constructing wind parks and solar farms is one thing; ensuring electricity reaches where and when it’s needed is another. So, what exactly must be done, and why?
When was the last time you plugged in your phone and it didn’t charge? Depending on where you live, this may never have happened. Kelly Sanders, an engineer who studies the evolution of energy systems, explains, “What’s happening behind the scenes is actually quite complex.”
The electricity you consume is generated in real time as you use it and travels to you through a complex network of wires, cables, and transformers known as the grid.
The grid consists of generators that produce electricity, such as gas plants, nuclear power plants, or wind turbines. It also includes transmission lines that carry electricity to substations, where it is transformed to a lower voltage, and distribution lines that deliver it to homes and businesses. For the system to function, everything must remain in perfect balance at all times.

The supply, or generation, must precisely match the demand, or load. Too much power can cause a surge that damages infrastructure, while too little can lead to a blackout. To prevent this, there is a skilled operator overseeing the system.
“Think of it as the conductor coordinating all the power plants and loads, ensuring everything works together seamlessly,” Kelly said.
This has become much more challenging recently. To extend the metaphor, some new musicians—solar panels and wind turbines—have joined the orchestra, but they operate on their own terms. As a result, we can’t control them as easily as the dispatchable generators we’ve relied on in the past, according to Kelly Sanders.
“Dispatchable” refers to electricity sources that are available almost on demand, such as coal or gas power plants. They can be turned up or down based on the desired operation.
Solar and wind power are the opposite—they are “nondispatchable.” We rely on the sun to shine and the wind to blow for them to generate electricity. This unpredictability has changed the way our grids are managed.
“I wouldn’t say it’s necessarily a problem, but it presents a different challenge compared to 20 or 30 years ago,” said Tim Meyerjürgens, COO of one of Germany’s four major operators.

In Germany, over 40% of electricity is generated from renewable sources, with a target of reaching 80% by 2030. So, what challenges arise from having such a high share of wind and solar energy?
For one, they make us dependent on the weather. “It’s more difficult to accurately forecast what we can expect the next day,” said Tim.
Fortunately, we’ve gotten much better at this, but even the most accurate forecasts can’t change the weather. The German term “Dunkelflaute,” or “dark doldrums,” describes periods with little sun and minimal wind—a nightmare for grid operators.
Even on days with plenty of both, the energy may not be available exactly when it’s needed. During the day, when the sun is up, it meets a significant portion of the total demand. However, as evening approaches and the sun begins to set, solar generation drops quickly, widening the gap between supply and demand.
“Somebody has to be ready with a generation resource to turn on quickly. Unfortunately, in California, that often means natural gas. So, you end up with these small combustion turbines, which are quite polluting,” Kelly explained.

Remember that story from Germany, where the North had to waste electricity while the South was running short? In countries like Germany, renewable energy is not always available where it’s needed most.
Germany generates most of its wind energy in the North and most of its solar energy in the South. Currently, there is no efficient way to transport large amounts of wind energy to the South, where industrial demand is high, nor to move solar energy to the North.
A similar situation exists in the U.S. Most of the wind energy is generated in the central part of the country. However, more than two-thirds of the population lives within a hundred miles of the coast, where the demand is concentrated.
As a result, wind and solar energy are giving grid operators plenty of challenges. But what if the issue isn’t the renewable energy sources themselves, but the grids?
“For the past 100 years, we have been expanding and designing our grid as a centralized system,” said Patricia Hidalgo-Gonzalez, who researches the best ways to integrate more renewables into our energy systems.
Historically, power stations were built close to cities, with fuels like coal, gas, or later uranium brought to them. As a result, electricity didn’t need to travel far. Solar and wind energy, however, must be installed where their resources—sunshine and wind—are most abundant. Additionally, utility companies are no longer the only ones generating power.

“Of course, we have the infrastructure for this centralized grid because it has been cost-effective to maintain such a system. But now, we’re also seeing a significant rise in distributed energy resources,” Patricia explained.
People are installing solar panels on their roofs, for example, turning traditional consumers into electricity generators. While things have evolved since the old days, our grids haven’t kept up. They no longer align with the energy system we are trying to create.
That leaves us with two options. One: abandon renewable energy altogether and stick to traditional coal and gas. However, this would be a questionable choice, especially considering we are in the midst of a climate crisis.
Or, option two: we make our grids more flexible, and there are several ways to achieve that. “We need to transport electricity from where it’s produced to where it’s needed. This requires more energy transport than we’ve had in the past,” Tim explained.
This means we need to improve the connectivity of our grids. That’s why the grid operator TenneT is constructing SuedLink, a 700-kilometer high-voltage transmission line connecting Germany’s North to its South. The idea is that when the sun isn’t shining in the South, it can rely on wind energy from the North.
“Building these large transmission lines is really challenging,” Kelly explained. “You have property rights issues, concerns about endangered species, and environmental impacts. As a result, these projects take a very long time to complete and become quite expensive.”


SuedLink is a prime example. Initially planned as an overhead line in 2012, it faced massive public backlash against the so-called “monster line.” In response, politicians decided in 2015 that it would be built underground instead.
This decision also nearly tripled the cost of the project to €10 billion. Additionally, it continues to face resistance, particularly from farmers and landowners.
By the end of 2022, when SuedLink was originally supposed to be completed, not a single cable had been laid. It is now slated for completion in 2028. Despite these setbacks, building infrastructure to transport renewable energy to where it’s needed is crucial for making the grid more flexible.
Another solution is to incorporate storage into the grid, enabling energy supply when it’s needed. To cover shorter periods, large battery packs are increasingly being deployed.
“You essentially charge the battery when the sun is shining or the wind is blowing, and then discharge it when those solar or wind resources decrease,” Kelly explained.

Some grids also store energy through pumped hydro. Surplus electricity is used to pump water up a hill, and then it is released to flow down through a turbine when needed. However, both of these solutions can only store a few hours’ worth of energy.
For longer periods, such as to cover a Dunkelflaute, we need other solutions like hydrogen. It can be produced from renewable electricity and burned in power plants without generating any CO2 emissions.
“That doesn’t mean we should burn hydrogen all the time, as it’s not a very efficient method. But for certain situations, we will still need it,” Tim explained.
There’s another part of the solution that, until recently, hadn’t been widely discussed. We have the opportunity to increase generation to meet demand, but we can also reduce demand to align more closely with supply.
For example, we could delay doing our laundry or running the dishwasher when the grid is under stress and instead do them when there is plenty of renewable energy available.

Some utilities already offer customers lower rates for doing exactly this. Additionally, we could allow grid operators to access electricity from the solar panels on our roofs or from the batteries in our electric cars.
“With distributed energy resources, we’re moving toward a two-directional flow. It’s no longer just from generators to consumers, but now from consumers—who we would call prosumers—because they are producing electricity and supplying it back to the transmission network when it’s needed most,” Patricia said.
The vision is to create a technology-driven smart grid that provides operators with much more information to flexibly balance supply and demand. If all of this sounds incredibly challenging and costly, that’s because it is.
A study by the Energy Transmission Commission shows that, to meet our net-zero targets, grids worldwide will require an investment of $1.1 trillion every year until 2050. This amount doesn’t even include new solar panels and wind turbines. Overhauling the grid is a monumental task, but it’s one we must address if we’re serious about phasing out fossil fuels.
In the end, our grids are the backbone of the energy transition. If we don’t succeed, the entire energy transition will fail. This is a race we must win; there’s no alternative.

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