The transition towards green energy and the use of renewable resources has been on the global agenda for several years now. This issue became particularly pertinent after Russia's invasion of Ukraine. Finding itself next to such an aggressive neighbor, it is crucial for Latvia to realize and understand how to generate green energy, and a safe and sustainable energy supply system. Latvian scientists from all over the globe will discuss this in greater detail at the 5th World Congress of Latvian Scientists, before sitting down at the round table they outlined ideas for the green transition.

 

According to RTU Faculty of Electrical and Environmental Engineering Professor Gatis Bažbauers, "Resources and energy are the key to green transition. In using fossil resources, we were worried that they would run out. Right now, we are probably more perturbed by the pollution resulting from the use of these resources, including CO₂ emissions into the atmosphere. A fossil depleting resource is stock. The alternative is renewable resources, which are flow. If we are clever enough to adapt our energy consumption, we can utilize this flow indefinitely. It is vital that we take action now, while we still have enough resources, time and knowledge. If we don't take action, we could find ourselves under tremendous pressure in a situation where we are out of time and resources." Professor Bažbauers stresses that transformation is one of the key words in the context of the green transition, "This means that we must radically change the way in which we use our energy resources, operate our economy and how we live as a society."

 

Too complicated for the ordinary user

But life demonstrates that changes are not easy. According to Professor Andra Blumberga of the Institute of Energy Systems and Environment of the Faculty of Electrical and Environmental Engineering of Riga Technical University (RTU), nowhere in the world is saving energy a priority for people. She explains that, "There are several reasons for this. The more complicated the problem to be solved, the more challenging it is for people to understand it. Accordingly, the greater the number of obstacles, the lower the likelihood that people will take action. Everything concerning and related to energy conservation and renewables is complicated. Especially in the absence of corresponding education. Consequently, people decide not to tackle such complicated problems. As a result, with the help of politics, we must try to reduce these obstacles." This is one of Professor Blumberg's research directions – what sort of interventions are needed to stimulate changes the way people think? "Technology is available. In many and varied forms. But people don't use them. And technology are not that useful if you don't put them to good us. This is not just a problem in Latvia alone. For example, Europe has a building renovation strategy. In reality, over the course of a year, measures are being taken in only about two percent of the existing amount of buildings – either insulation is being installed or other energy saving measures are being implemented. This is way too little," says Professor Blumberga.

 

But why is it so vital for buildings to be energy efficient? The primary reason is that buildings consume energy, which in the majority of cases is produced from fossil fuels. Burning it generates CO₂ emissions, which increase the risk of global warming. Accordingly, we must reduce our consumption of fossil fuels. "Renewable energy resources in the form of the sun, wind, and water can definitely help Latvia. Invariably, there is the counter-argument that the sun only shines when it shines; the wind blows when it blows; water is available when it is available. So what are we to do the rest of the time? The answer is accumulation. Accumulation technologies are now developing fast all over the world," says Blumberga.

 

 

There's plenty of sun

Despite the fact that the sun does not shine all the time, it is an efficient means of generating energy, which is underlined by the huge demand for solar panels. "The volume of solar panel production has risen by 30% annually over the past decade," says physicist Professor Pauls Stradiņš, who is currently working in the USA and has been involved in developing solar panel technology. "At the end of 2022, we reached the point where the total installed capacity of solar panels is over one TW. Globally, an average of 2.8 TW of electricity is generated continually. One TW equals 1000 GW. In turn, one GW is the volume that Latvia continually generates and consumes on average. More precisely – 0.8 GW. One large power plant can generate one GW of energy. If we divide up the aforementioned amount per capita, then one person in Latvia consumes about 400 W of power in continuous mode. This is just a little more than the world average. So, if the total amount of energy generated is 2.8 TW on average, once concludes that a third of it is already provided by solar energy. However, this is not the whole story. This is the maximum output when the sun shines directly onto the panels. If we want to get the average, then we need to divide the volume by approximately five. Or in Latvia's case – by seven or eight."

 

At present, production of solar panels is dominated by silicon, which is used in 95% of all panels manufactured. "There is no prospect of it being replaced by any other technology it in the near future, because no others have yet been developed to the point where they could occupy a niche market. Over the past decade, silicon technology has developed very quickly. Previously, the efficiency of silicon cells in solar panels was about 18%. Five years ago, the technology was replaced by an improved version. Now we have cells that are up to 24% efficient. The next technology, which is now gaining momentum massively, and which I was involved in researching a decade ago, is based on even more efficient silicon layers. In this case, we're already talking about 26% efficiency." However, Professor Stradiņš points out that the development of this technology cannot go on forever, because there is a fundamental limit that dictates that the maximum efficiency of a single-level cell is 30%. The solution is to develop multi-level cells. "These are already 47% efficient (in focused or concentrated sunlight). In normal sunlight, they are up to 39.5% efficient. In comparison to silicon, the efficiency limit under normal sunlight is about 30%. However, multistage cells are also extremely costly. They are currently used in space in satellites, where extremely high efficiency is needed. It is anticipated that in future these highly efficient cells could be utilized, for example, to cover electric cars. Japanese car manufacturers are already experimenting with this. Yes, it is costly, but they assert that by utilizing these 35% efficient multi-stage cells, one can drive up to 50 km per day without recharging," explains Professor Stradiņš, adding that existing technologies will be useful for another decade.

 

Global electrification awaits us

The aforementioned example of electric cars, for which there is already considerable demand, indicates a trend. The world is going to have to devote an increasing degree of thought to how to continually generate more electricity. "The green transition involves moving away from fossil fuels. The alternative is to turn everything into electricity, which is a much more efficient form of energy and far more efficient than fossil fuels. For example, the efficiency factor of an electric car is 85-91%, whereas the efficiency of an internal combustion engine is just 24%. The difference is huge. It is a similar story with heating buildings. Of course, if we simply connect power and use it to get heat from radiators, it is costly. However, if we manufacture a heat pump instead of radiators, then instead of converting electricity into heat, we use it to pump heat from outside and inside our building. In doing so, we use three times less energy to generate the same heat than we would if we used radiators. If we were to massively electrify the whole global economy, then we would have to at least double, if not triple, electricity production," believes Professor Stradiņš.

 

In order for Latvia to feel secure in such conditions, the professor stress that that it would need to produce about another GW of energy, which is a feasible objective. "A coordinated approach is required. Including at the level of the human mind – we need to accept this and install the system ourselves. Or merely support its installation. We cannot build more hydroelectric power plants. Ideally, we would even get rid of them at some stage. This would leave us with the sun and the wind. Wind is a very good resource. Especially in the Baltic Sea. It is a cheap form of energy. Of course, there is another option in the form of nuclear energy, which is very controversial. In principle, it is not considered to be renewable. Its only advantage is no CO₂ emissions, but we have limited resources with which to obtain nuclear fuel. And then there is the problem of waste and safety. The principal advantages of solar and wind energy are that they are dispersed or decentralized. In other words, in the event of a disaster, this infrastructure would be very difficult to destroy. If there is only one power plant and it is destroyed, everything comes to a halt. However, if every small town and village has solar power, then it's a highly decentralized network that is almost impossible to raze or damage. Moreover, if something breaks down, you can get a replacement from somewhere else," says Professor Stradiņš, illustrating the situation.

 

Nuclear energy has its supporters

Although nuclear power generation is definitely the most controversial form of power generation, it too has its supporters. For example, Andris Šternbergs, who will propose that the role of nuclear energy in Latvia's energy supply should be discussed at the World Congress of Latvian Scientists believes that, "We must consider the energy generation menu as a whole. It is vital for each country to ensure this. Thus, the existence of nuclear power is no bad thing. It is the kind of energy that we can obtain anywhere on Earth, regardless of the sun and wind. It is green and sustainable." However, he adds that it would be unfeasibly expensive for Latvia to go it alone in building a nuclear reactor. The solution is to create one at Baltic level, which is an idea that has been discussed before. It was initiated by the Estonians. "This would be a massive project, preparations for which should start now. Infrastructure has to be built and waste storage has to be considered. If we could our act together and secure the funding, the nuclear reactor could be ready by about 2045," believes Šternbergs.

 

The article was written within ERDF project No. 1.1.1.5/17/I/002 "Integrated national measures to strengthen the representation of Latvian R&D interests in the European Research Area"