It’s astonishing, but clean energy from the sun, solar energy, has become the cheapest way to generate electricity. It’s even cheaper than coal. And yet it produces only three percent of the world’s electricity.
One can’t help but wonder: Why aren’t we using way more of it?
First, let’s take a look at how much the price for solar has fallen. In 2005, you would pay about $4 a watt for a solar panel and today, you would pay about $0.20 for that same watt. And that is just the last 15 years. If you look further back, the price drop is even more impressive. In 1980s, the price was $100 for the same watt.
How did this happen?
Basically, no one country did it. It was an exchange of one country building on another one. The United States created the technology.
The modern-day solar cell made from silicon was invented in the United States in 1954. Back then it mainly got used in the space industry and was still super expensive. But as the technology progressed, prices started to fall.
In 2000, Germany passed a law to boost renewable energy development. This was big because it put a fixed price on energy generated from sources like wind or solar. That gave people and companies a reason to set up solar panels. And for them to do that, someone needed to build these solar panels.
Once the German law had come into force, China really started to pump out those solar cells. China was almost a non-existent player 20 years ago. And today, they are the biggest producer of solar panels, about 70% of the world’s production.
So this is how we ended up where we are now – with clean energy that also makes business sense. But the question arises: If solar is so great, why don’t we rely on it much more and just switch off all these dirty power plants?
Well, solar has always had this one big problem. It only really works when the sun is shining. When it’s cloudy or – even worse – dark, even the best solar cells are pretty useless. And that’s a real shame because that’s when we would need them the most.
To understand further, let’s take a look at how we use energy.
In the morning, when most people get up and get ready, we need energy. The so-called Duck Curve charts our demand for power from non-renewable sources like coal and gas throughout the day – first, in places without much solar.
After the morning spike, it stays pretty level. When people come home in the evening, it goes up again and then drops at night. At this point, you might get an idea why they call it the Duck Curve.
Anyways, in places with lots of solar, for example like California in the United States, this curve changes. The mornings are pretty much the same. Then the sun rises and solar energy production kicks in. This lets demand for non-renewable energy drop. Until the sun sets, that is. That is when conventional demand shoots up again, way steeper than the first curve.
There are two problems with this. One: Traditional power plants are not good at ramping up this quickly. That means you have to keep them running at a certain output all day, even though there’s a lot of solar. And that means you can end up with actually more power produced in the middle of the day than is used.
That leads to the second problem: There are limits to how much energy you can put into the grid. Too much solar could overpower it, so it needs to be thrown away. This has always made it super difficult to add lots of solar to power systems. But, there is now a solution to this problem. And chances are you have part of it in front of you right now, a lithium-ion battery.
What has been quite good over the last few years is that batteries have got a lot cheaper as well. And we are now seeing solar projects built with a couple of hours of storage in the battery so that they could shift some generation from the middle of the day to the evening – where there’s often a peak in electricity demand.
In the United States for example, the state of New Mexico decided to shut down a coal plant earlier this year – and instead build new solar farms that store large amounts of the energy they produce in batteries. Lithium-ion batteries have become a lot better and a lot cheaper than expected in the last few years.
They are now a viable option for storing and shifting at least a few hours worth of solar energy as needed. So, the storage problem that solar always had is actually not that much of a problem anymore.
Sometimes, though, we might want longer-term storage in places without much sunshine, for example. And that’s why companies are offering other solutions. Let’s just run through a few.
Another type of battery, called a flow battery, separates the charge outside a cell. That has two advantages: it can store more energy – and for longer. The problem is: They are still relatively expensive.
Then there’s pumped hydro storage, which is already used quite a bit. You need two lakes and one of them needs to be on a hill. During the day, you use solar energy to pump water from the lower lake up to the higher lake.
When you need energy at night, you can just let it run down through a turbine. But for that you need to find lakes and, well, a hill.
Another solution using gravity comes from a Swiss company. It’s working on a tower that raises building blocks with solar energy, and then releases the energy by lowering them again. But for this too, you need space. In addition, there is also the option of using solar to produce hydrogen.
With that hydrogen you could then do a number of things, like fuel cars or even make steel. But the whole process is still pretty costly.
There are alternatives, it’s just that lithium-ion batteries are becoming so flexible and so inexpensive that it will be hard for these alternatives to compete. But they do have other attributes, like they hold a charge longer, which could turn out to play a pretty important role in some applications.
So solar has become cheap and has petty much fixed its biggest problem. What’s next, you may ask?
Well experts believes that it is going to be big and everywhere. Even with no further policy, solar would supply about 23% of global electricity by 2050. It won’t be surprising that if by 2030, we are talking about solar supplying a large part of the world’s electricity.
Solar has come a long way. But now that the technology is in place, it really looks like it’s time to shine.