The biggest challenge for solar energy? This duck

Time for alternatives

With the rapid advancement of affordable, sustainable forms of energy such as wind and solar, the energy playing field is changing drastically. Previously, energy was only generated at a number of central points in the country. The coal-fired power stations were built at a remote location where they cause little inconvenience; the power generated is transported from there by thick cables to households and businesses further afield. Simple, efficient and less burdensome for society.

But these coal-fired power stations have one disadvantage: they are extremely polluting. Coal contains toxic substances such as nitrogen dioxide, sulphur dioxide and mercury. When coal is burned, these substances end up in our air and in our drinking water. Resulting in lung problems, cardiovascular diseases, brain damage and eventually premature death. Also, the working conditions in coal mines are often hidden from the public eye and the greenhouse gas emissions of coal-fired power stations have a devastating impact on the climate.

It is time for energy alternatives, which are often cheaper nowadays. These alternatives, such as solar and wind energy, are already widely used worldwide, but are very different from coal-fired power stations as a source of energy. The most emphatic difference is that these energy sources depend on natural conditions, such as the amount of sunlight and wind.

Quack

Let’s zoom in on solar energy. Anyone who comes outside or looks outside will recognize it: the sun rises in the morning, peaks in the afternoon and quietly disappears behind the horizon in the evening. For solar panels, the more sunlight they receive, the more energy they generate. So as we install more solar panels worldwide, the amount of energy we all generate during the day increases significantly. In addition, the demand for electricity is increasing, because we drive, cook and heat more and more electrically.

The biggest challenge for solar energy is called the ‘Duck Curve’. For a few years now it has been flying around the ears of managers of national electricity grids on a regular basis. The Duck Curve owes its name – not entirely surprising – to its resemblance to the side profile of a duck. The orange line stands for the amount of energy that coal-fired power stations and other central energy sources have to deliver per day. You can see that every year the line drops a little at noon, and rises a little in the evening. This change is due to the increased amount of solar panels on roofs of companies and households. Those who generate their own energy during the day – when the sun shines – do not take energy from the electricity grid.

A second development in electricity consumption is the head of the duck. During the evening we use more electricity to charge our electric cars, cook on induction and heat the house with an electric heat pump. Conclusion: the valley is getting deeper and the peak is getting steeper.

Why is this a problem?

For power plants and grid operators it is important that the amount of energy needed in a country is stable and predictable. An increasing amount of solar panels is interrupting this. Does the weatherman predict sunny weather? If so, the coal-fired power stations lower energy production. Is it cloudy after all? Then they will quickly reignite. In regions with many large solar parks, the amount of energy generated is so high on sunny days that the cables of the electricity grid are not strong enough to transport all the solar energy.

In some cases, they opt for ‘curtailment’: ensuring that the solar panels deliver (much) less energy than they can. In other cases, a newly completed solar park is not connected to the electricity grid at all.

This way, we are not going to achieve our targets for more sustainable energy. Anyone who hears that the electricity grid is too weak will think that the solution is simple: strengthen the electricity grid. But that’s how we feed the duck. Moreover, strengthening the grid takes years and is extremely expensive.

How do we beat this duck?

Let’s look at the core of the problem. We generate electricity in places where we don’t use it, after which it has to be transported via long cables. In addition, we generate the least power at moments when we need it the most, and vice versa. This can be done differently.

One of the biggest advantages of solar panels is that we can install them where the energy is consumed. Meaning, on the roofs of households and businesses. Part of the solar energy that is generated is directly used during the day. The part that remains is stored in batteries. In this way, stored power is always available, even when the sun is not shining.

Another big additional advantage: with stored energy from a battery, a household, company, school or hospital can operate independently from the energy grid for a few hours. This is especially important in countries where blackouts due to weather conditions or gnawing squirrels are the norm.

In a world where everyone generates and stores their own energy, we can easily distribute it. For example, not all households have a suitable roof for solar panels because it’s in the shade of tall trees. Those households can now easily use energy that is generated on the roof of a school nearby, for example. This creates so-called ‘micro-grids’ mini versions of the national electricity grid where energy is generated, used and distributed among themselves. Large energy suppliers and polluting coal-fired power stations will be a thing of the past when households and companies become power plants themselves. By using a decentralized energy supply on existing roofs, we do not need to strengthen the energy network as we did when building a new solar park. That way we save money, but above all we save a lot of time. Time that we need to use to make our energy supply more sustainable at record speed.

The rapid rise of solar energy and the increase in our electricity consumption are shaking up the energy world. Grid managers are struggling with a major challenge: the Duck Curve. This is the phenomenon that occurs as solar panels overload the electricity grid during the day and the peaks in our consumption increase. We solve this by generating solar energy in the places where it is used and storing it in batteries. This stored energy is used when no solar energy is generated or shared with households that do not own their own solar panels.