Understanding a new idea: will it make alternative energy popular and will it help save electricity?
MIRACLE TILES
Elon Musk has announced the start of taking orders … for solar tiles. This proposal has blown the brains of millions of homeowners around the world and is fraught with a revolution in the construction market. Because now, for the same money, you can either just buy a roof, or you can buy the same roof, but which also generates electricity. Solar tiles cost about the same as standard ceramic tiles. Fantastic calculations are posted on the website of Tesla Motors, Elon Musk's favorite brainchild. For 30 years (as long as the warranty is valid), the solar roof of a standard house can generate electricity for $ 52,900 (see diagram). This is enough to install a super-accumulator PowerWall (you have to store solar kilowatts somewhere) and feel like an absolutely free person! From now on you do not depend on companies,who sell you gas, heat and electricity. You will receive almost all the benefits of civilization for free!
The scheme of a unique solar battery. Photo: DMITRY POLUKHIN / kp.ru
THE ECONOMY WILL BE DEEP
How it works? What kind of know-how did Musk use? With these questions, we turned to Pavel Troshin, a professor at the Skolkovo Institute of Science and Technology (Skoltech).
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- In principle, there is no technological revolution here, - explains Pavel Anatolyevich. - It is based on HIT solar panels, which are manufactured by Panasonic. The idea of using panels as roofing material for private houses is also not new. But such projects did not receive much distribution. The novelty of Musk's approach is that they made solar panels in the form of tiles. It's comfortable. Because the benefits are quite decent: we save both on material and on work. Because in the standard scheme, we first cover the roof with tiles or other standard material, and then we attach solar panels on top, which stand decently and weigh a lot, which makes the whole structure heavier …
Musk says this move will make solar technology popular. After all, now solar panels are more fun for techies or fans of green energy
- Here everything is solved by simple calculation. In most regions, we have 12 hours of daylight hours with an average light output of 50 percent of peak power. If the roof is 20 sq. m of panels (according to statistics, this is the average area that is installed on houses in the USA), we get 2 kilowatts - this is the power of an average kettle or a weak electric heater. We can accumulate about 20 kWh per day. The question is: is it enough or not? If for heating the house, then definitely not enough.
Wait, but 20 meters is a very small roof, and if you pave 100 meters - with tiles?
- Firstly, the roof has a sunny and not sunny side, where it is pointless to install panels. Secondly, if you have a roof of 100 meters, then the area of the house is 200 - 300 meters. Consequently, heating costs increase proportionally. In terms of energy generation, there is no fundamental difference between a flat panel house and a solar tile house (the difference, as we said above, is that you save on materials and labor. - Ed.). In the best case, this is the same efficiency of 20% and the same area. Because Musk was never able to solve the main problem …
Which one?
- This is, of course, energy storage.
What about Musk's super-accumulators?
- The accumulation of electricity in lithium-ion batteries is the most common and still very expensive technology. Lithium warranty
ion batteries do not exceed several years. And the total cost is often more than the price of solar panels. The panels will work for 20 and 30 years, and the drives will have to be replaced in 5 years. The problem with energy conservation leads to the fact that the autonomy of such a house becomes very conditional - you still "hang on the network."
What does it mean?
- Solar panels are actively used and pay off in those countries where solar energy can not be stored, but downloaded into the general power grid. In the daytime, when everyone is at work and no one is at home, we generate energy with solar panels, pump it into the network and get paid for it. In the evening we take it from the network, but pay less money. This so-called preferential green tariff is used in a number of countries to stimulate the development of solar energy. But in Europe, this tariff has been canceled for several years.
For what reason?
- Because, for example, in Germany on a sunny and windy day, alternative energy generates more energy than the country can consume. And more than it can accumulate in existing energy storage systems. It turns out to be an absurd situation - Germany is forced to drain energy outside the country and also pay extra to its neighbors to take this electricity. As I say, the paradox of alternative energy, at least in Europe, is that it ran into the problem of energy storage. Today, the only cheap option for storing energy on an industrial scale is taking a mountain lake and pumping water there when you have an excess of energy. If this energy needs to be taken back, the water from the lake goes down to the turbine, and it generates energy again. But it's clearthat there are not many such places in Germany or anywhere else in Europe.
Are you skeptical about solar energy?
- Not really. For about 100 years of active use, mankind has exhausted more than half of the reserves of fossil hydrocarbons. Why? Just because more than 50% of the world's energy is generated by burning oil and gas, another 30% from coal, nuclear energy accounts for about 7%, and the total contribution of alternative energy sources is unlikely to exceed 2%. If we do not change the rate of resource consumption, then in 100 - 150 years we will burn all hydrocarbon reserves. Therefore, the transition to alternative energy is inevitable. But, from my point of view, local solutions such as solar tiles will not fundamentally change the situation. The future belongs to efficient storage systems for large amounts of energy and large solar power plants. A good example is a power plant that was recently opened in Dubai. It generates electricity at a cost of about 4 to 5 cents per kilowatt. It is cheaper than getting energy from fossil sources.
WHAT IS IN RUSSIA?
Skolkovo invents a "people's" battery
Is a solar sheepskin worth the candle in our latitudes?
Contrary to popular belief that the weather in Russia is too gloomy for such undertakings, the sun actually shines for everyone the same.
“You know that Germany is one of the flagships of alternative energy,” says Professor Troshin. - At the same time, in terms of average insolation, Germany and the middle strip of Russia are quite comparable. But in Russia there are a lot of natural resources and people do not think about what will happen in 100 years. The other side of the coin is that in Russia a significant part of the territory beyond the Urals does not have centralized electrification. Alternative energy provides undeniable advantages for these regions.
In general, the emergence of fundamentally new technologies can change the situation. I don't mean Elon Musk here. There are certain developments related to perovskite (a rare earth mineral discovered in Russia - Ed.) Solar batteries, which are now being actively investigated all over the world, and we are also actively developing them at Skoltech. This know-how will reduce the cost of solar panels several times compared to silicon, while maintaining their efficiency. If this technology does indeed enter the market, then it can compete with traditional fossil energy sources.
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