Innovators about innovations
Professionals from the KNESS RnD Center: Ukrainian researchers, scientists, and inventors tell about what their colleagues work upon around the world

Development of concentrating solar power technologies
Oleksandr Horchynskii
Head, Product Development Department, KNESS RnD Center
Concentrating solar power (CSP) is a quite promising technology that is already used and continuously improving. The use of concentrated solar radiation and multijunction solar modules significantly reduces requirements for the area necessary for solar generation, while the efficiency of such modules is several times higher than that of conventional single- junction modules. However, this technology has a significant disadvantage – only direct sunlight can be collected. Everyone who has ever tried to start a fire with a magnifying glass knows that – if the sun hides behind a cloud, it will not work out. Diffused light, for instance, in Ukraine, constitutes a significant percentage of the total insolation. Any collectors under diffused lights lose their ability to concentrate, and the system built on this principle will not work. Moreover, the collector optics is extremely sensitive to dirt. While cloudiness is a rare phenomenon in deserts, and concentration could be a good option, however, dust and sand come into play here. In the absence of rain, it should be cleaned up manually, which increases maintenance costs. The outer space is an ideal environment to use multijunction photovoltaic modules: sunlight is not diffused by anything, and a module surface does not get dirty. The world aerospace companies are aware of that, too, that is why such modules are used to power spacecraft.

Therefore, the use of collectors of a particular design is perhaps a niche option that has its advantages and disadvantages. Still, it can hardly be named a breakthrough solution that has a significant impact on the development of the sector.


A combination of generation, accumulators, and software for energy sharing
Bohdan Kozachuk
Head, Department of Process Control System Design, KNESS RnD Center
Imagine a situation when the electricity consumer is not aware of such things as reporting the power meter readings or planning your power consumption to save. Or another situation, when the power producer does not monitor frequency or voltage at the output attachment point of their generation unit. Instead of the consumer and producer with their staff, all of that can be done by certain technologies: smart power meters, a set of special transducer, new analysis and response systems (completely automatic, independent of the human factor). This complex of technologies is called a Smart Grid.

The Smart Grid (smart electricity grids) is a group of technologies constructing a 'new' approach to the organization of the generation-grid-consumer system. Combined in a single platform, these technologies turn each grid node into an active element for the timely and precise correction action for the stable operation of the grid as a whole.
We see the latest trends in the energy sector: a portion of renewables in the general power balance increases. Renewables are characterized by unpredictable and unstable generation. To stabilize their parameters, some measures need to be implemented that increase their technical and economic performance.
The grid
The main grid-related problem is losses during power transmission. Of course, these losses are impossible to avoid, but it is quite a feasible task to reduce them. Lower losses mean less natural resources for production, which, in turn, reduces a negative environmental impact.
The consumer
For instance, we all use, washing machines. It is efficiently and economically practical to use them at night when the general power consumption and the power price are going down. However, we all used to doing that during the day; therefore, it makes sense to set on our washing machines to work at night automatically.
The smart grid construction is dynamically developing in the world. It is still a long way to go to achieve the final results of the ideology. However, the development of the system is necessary because an increase in the overall energy efficiency is one of the main development vectors in the progressive countries of the world. By turning analog power grids into the smart ones, energy companies will be able to manage the whole power grid as a single system, and consumers will be able to regulate their consumption with precision.


Organic photovoltaics and new crest factors and concepts for solar power generation
Maryna Provorova
Research Engineer, Chemical Research Department, KNESS RnD Center
It is necessary to choose a visual aid that is appropriate for the material and audience.
Nowadays, the most widespread solar batteries are those based on polycrystalline and amorphous silicon. A disadvantage of such batteries is the price of their production process. Several new, more affordable technologies of solar energy conversion are coming to replace them. The flexible organic solar batteries are the most interesting of such technologies.

A British company Solivus developed a new pliable solar carbon-based material that can take any shapes and stick together. In the future, the company is planning to introduce new cheap power solutions on its basis. It is a non-polluting and durable product, which plays an essential role in the energy sphere.

The solar organic photovoltaic (OPV) fabric works like a typical solar light absorber for power generation, but a distinctive feature of the material is the possibility to be used on surfaces of any shape and size, as well as the absence of heavy mounting frames in the constructions. The product will be produced by a German company Heliatek that came up with an idea of the OPV fabric.
The fabric weighs 1.8kg per m2 section, which is one- tenth of the weight of traditional solar panels with frames. It does not contain any toxic or rare earth materials and comes with a guarantee for 20 years. The laboratory test results optimize the OPV fabric efficiency at about 13%, which allows generating more kWh than conventional photovoltaic modules. Heliatek has claimed that the fabric can collect a broader spectrum of light, which permits the equipment to continue producing power even during grey days without as much sunlight. They expect that a 10,000 m² roof will be able to provide about 1MW of energy, which is enough to power an entire block of houses.

The product will be available on a large scale in 2021- 2022; the works are planned to start from the large commercial properties and stadiums. This technology will trigger a real breakthrough in the renewable energy sector as it enters the market. It as well may be that the OPV will displace conventional silicon solar batteries in use because the products of this range are manufactured from inexpensive, readily available and environmentally friendly materials.

Solivus is also planning to change the way of energy storage by using chemical-free kinetic batteries. These modules may be used in e-cars.


Highways and bicycle lane powered by solar energy
Valentyn Burdeinii
Product Design Engineer, Power Electronic Department, KNESS RnD Center

China is completing the construction of another highway with built-in solar panels. The generation of power for wireless e-car charging is not the only task of the new 1.9 km-long section of the Jinan highway. With time, it will also provide information support to driverless vehicles.
It has a new three-ply coverage. Transparent concrete with properties close to those of asphalt covers load- resisting solar panels, which are protected from the wet ground underneath. The road is intended for both automobiles and trucks.
The first solar highway in China has already been constructed. A state company called Quilu Transportation Development Group used 660 m2 of solar modules for its construction.
Pioneers of such projects are the Netherlands: a solar bicycle lane was installed there back in 2014. The initiative was taken up by France, which constructed a kilometer of a solar highway. Despite the corruption scandals around the project, the French are going to increase the length of photovoltaic highways up to 1000 km. The USA followed suit, where the State of Idaho has pioneered in solar roads.
Construction of highways with solar panels is an exciting, innovative solution, especially with regard to the use of transparent concrete. Though wireless charging technology is still underdeveloped and inefficient, technologies are making progress, and with the development of electric vehicles, the solar highways have significant prospects. In comparison with regular stations, the solar roads are located very close to the consumers and do not occupy any additional area. The massive use of such roads will enable, for instance, permanent access to electric power for electric cars.


Solar roofing tiles
Oleksiy Kordysh
Research Engineer, Chemical Research Department, KNESS RnD Center
A Swedish company Benders presented a new type of photovoltaic modules (PhMs) for roofs called SunWave. These modules allow preserving an attractive and aesthetic appearance of roofs because they reproduce the shape of roof tiles entirely and can be installed on top of the existing roofing or completely replace it. Research by a Swedish company Vattenfall showed that the installation of PhMs on the roof results in a 14% increase in the average price of the house.

The manufacturer assures that the production of SunWave modules in Sweden is entirely powered by renewable energy and emits only 10% of CO2 as compared to the manufacturing of traditional silicon elements. The modules are cadmium free.

Traditional surface silicon elements are 35 mm thick and installed on roofs with special mountings. Thin- film SunWave panels are based on the CIGS technology and are only 1.3 mm thick. CIGS is a mix of selenides of copper, indium, and gallium with a chemical formula of CuInxGa(1-x)Se2. It is a semiconductor that can be
applied on flexible bases to produce extremely flexible and lightweight solar modules. In comparison with conventional silicon elements, such a production method provides for high performance even on cloudy days.

Another advantage of these elements is their low sensitivity to shadows from trees, chimneys, and so on.
PhMs are installed on the roof tiles. To protect them from blowing-off, the panels are held in place by clasps at the lower edge of the tile. The panels are connected consequentially with supporting cables. Each element covers 5 roof tiles in width. The manufacturer promises a capacity of about 110 W per m2. Each PhM weights
2.3 kg, has an output of 55 W and contains 20 cells. If a cell is located in shadows, the module's output drops by 5%, and though cells are connected consequentially, a failure of one of them does not affect the rest.

The prices vary in the range from 2400 to 2700 euros per kW depending on the total capacity of the plant. The product and technology combine consumer's needs in the energy-efficient building and the aesthetic appearance of the roof.

In comparison to the current mainstream in solar generation, i.e., with silicon panels, the thin-film technology potentially allows applying a photovoltaic layer on any surface, that is why it will be possible to make a product for generation of any shape. Also, thanks to the thin film, the panel's weight is a lot less than the conventional one, which makes it easier to install. However, in comparison to the conventional silicon panels, such technology is more expensive today, and that is why it is not used in the industry. Such panels would not be cost-efficient for higher-capacity. In the nearest 15-20 years this technology will not be able to replace SPPs conventional silicon panels yet as it is used mostly in individual low-capacity cases, for instance, when it comes to an energy-efficient roof in the premium-class houses or the use in electric cars instead of glass or the body coating. However, if the way could be found to make this technology as cheap as silicon panels, it can drive out the latter from the market.


Yulia Ziubrytska
Research Engineer, Chemical Research Department, KNESS RnD Center
To convert solar energy into electric power, most solar power plants use silicon elements. That despite some indisputable advantages, have some critical flaws, in particular, dependence of the operation on the time of the day, high price, difficulties with the disposal of photocells, and – most important – relatively low efficiency at the level of 22%.

One of the ways to improve the performance of solar panels is to use an alternative material, namely, perovskite. Perovskites are hard crystals that were discovered in nature in 1839 and now are easily synthesized with different modifications. The main advantages of perovskites are their ability to absorb light almost at all visible wavelengths, high efficiency of energy conversion, and relative simplicity of production. Notably, the perovskite coating on a solar panel is no more than 2 mm thick. Due to the material's unique properties, a panel color may be adjusted.

Despite its high potential, the perovskite-based technology is still at the early stages of commercialization as compared to other technologies due to some problems. Cheap perovskite solar panels have a short working lifespan. The material also quickly deteriorates in the presence of humidity. Another problem is scaling: high-performance values have been registered with small cells that are suitable for laboratory tests, but too small to be used in a real solar panel.

Nonetheless, perovskite solar panels are, no doubts, a rising star in the photovoltaics. Despite the problems with using such coating, it is thought to be a material of the future. In particular, such company as Hunt Perovskite Technologies focuses on improving this material with an outlook at its commercial use in the future. Besides, in 2015, Saule Technologies concluded an investment contract with a Japanese investment company Hideo Sawada. Saule intends to combine perovskite solar panels with other products available today.


Anti-solar batteries: a photovoltaic cell that works at night
Volodymyr Holodiuk
Head, Power Electronics Department, KNESS RnD Center
An apparent dependence of generation on the level of illumination and solar activity is one of the largest problems in solar energy today. According to Jeremy Munday, a professor in the Department of Electrical and Computer Engineering at UC Davis, a great solution to this problem would be 'solar' panels that could generate electric power not only during the daytime.

In fact, a specially developed photovoltaic cell could generate up to 50 W of power per square meter under ideal conditions at nighttime. This is approximately a quarter of what a regular small photovoltaic panel can generate in daytime, according to a concept paper by Munday and graduate student Tristan Deppe. The article was a post graduate in the January 2020 issue of ACS Photonics.

Munday claims that the process is similar to the way a regular solar panel works but in reverse. An object that is hot compared to its surroundings will radiate heat as infrared light. A conventional photovoltaic panel is cold compared to the sun, so it absorbs light. The Space is very cold indeed, so if you have a warm object and point it at the sky, it will radiate heat towards it. People have been using this phenomenon for nighttime cooling for hundreds of years.

In fact, this phenomenon, known as thermoradiative photovoltaics, remains almost unstudied today. Nonetheless, in case of proper development, it has considerable potential to provide humanity with access to renewable energy 24/7.

The most interesting in this technology is the possibility to make up for the time when the solar generation is absent and this way to reduce the dependence on traditional energy sources in the future – of course, in case of the extensive use of the technology.
Unfortunately, it is a concept yet, and evaluating the technology is not that simple. This is, no doubts, a new, absolutely different type of photovoltaic elements whose 'daytime' properties are not quite clear yet.
In the future, it would be interesting to combine fields of regular PhMs with the 'nighttime' ones.
The article holds that the efficiency of such panels is 4-6 times lower than in the case of conventional photovoltaic modules. However, considering that this technology is used in the nighttime when the power consumption is 20-30% lower, their usage may be very promising.

A potassium-metal battery as a competitor to the lithium-ion technology
Andrii Bondar
Head, Chemical Research Department, KNESS RnD Center
Half of what we use in our lives contains 'batteries.' A cell phone, computer UPS, electric car – all of that contains a means to store and reproduce electric power. The development and spread of renewable energy sources essentially need a cheap and affordable system for its large-scale storage. Today, the dominant technology is that of lithium-ion batteries that combine high electric capacity and convenience in practical implementation.

Researchers from the Rensselaer Polytechnic Institute (the USA) suggest an alternative to Li-ion technology, namely, batteries that rely on potassium, which is a more abundant and cheap material in comparison to lithium. The main point of this technology is to replace a graphite anode with metal potassium. It will simultaneously increase energy density (weight-and-dimensional characteristics) and make the device cheaper.

However, the scientists faced with a problem of dendrite formation during multiple charging cycles of the device. The dendrite accumulation over time is dangerous due to the possibility of device short-circuit, ignition, and explosion. The researchers dealt with this problem by increasing and adjusting the temperature of the battery to boost the diffusion of metal potassium throughout the anode surface. Due to this effect, when not charging or discharging, dendrites self-heal while smoothing the surface, thus preventing the battery separator breakdown.

In order to implement the large-scale project using this technology, more studies of the effect of temperature on the battery self-healing should be conducted. However, this technology and the principle of using the cheap and light metal as the energy carrier is one of the few ways to go away from the Li-ion technology, which is not quite 'clean' due to the destructive extraction of cobalt, and the use of lithium, which is relatively less abundant as compared to potassium.