Some researchers estimate that in 2000, two thirds of the world's population will live in cities, so they will see together with some engineering companies to generate renewable energy coming from the city furniture surrounding us. Is it realistic?
If we consider new materials, inventions and devices that are being developed, nobody can say that this is an unattainable goal.
Another very different thing is if they are feasible from an economic point of view and if they really are an alternative to the existing energy producers.
These are five revolutionary inventions that have already demonstrated their effectiveness,
1. Energy element
Cement blends made with waste from power plants can serve to build for example buildings that act as batteries.
This Concrete compound of potassiumgeopolimétrico (KGP) is cheaper than usual cement and can store electricity.
According to the researchers, a six meter high light pole made with KGP and equipped with a small solar panel can contain enough energy to feed all night.
"We have shown that KGP cement mixtures can be used to store and release power without having to add anything that is expensive or dangerous," said Lancaster University Professor Mohamed Saafi, Head of Research.
Buildings made with KGP can be used in cities to meet their electrical requirements.
2. Windows made of solar panels
The new materials also help to make the solar panels cheaper and more profitable.
Solar energy is the most common source of renewable energy in cities, because the cost has fallen from US $ 4 per watt, it costs a decade ago to US $ 0.50 worth it now.
In the United Kingdom, more than one out of three companies already produce some of their own electricity, which usually uses solar panels on roofs.
But the production of solar panels based on silicon is a high energy consumption because it requires temperatures above 1400ºC or higher and silicon must be 99.9999% pure.
Now, materials like perovskit have come up that can make the panels much thinner, cheaper and work at much lower temperatures, "said Nitin Padture, professor of engineering at Brown University in the United States.
be partially transparent, they can also be used for windows.
The downside is that most contain lead, a very toxic metal, but an option suggested by Professor Padture and his team is Replace lead with titanium.
"Titan is quite common, but nobody had thought about using it to replace lead in solar panels. perovskitehe says.
"We do not want to replace the silicon technology currently available, but to improve it."
3. Urban wind power plant
When talking about wind, the most common source of renewable energy, Conventional turbines do not work well in areas with many buildings because the wind direction varies greatly.
But scientists Nicolas Orellana and Yaseen Noorani have created one spherical wind turbine to finish the problem. Its o-wind turbine, which has won the 2018 James Dyson Prize in Britain, is a spherical device that turns when the wind hits him from any direction.
Another solution is provided by the Turkish company Devici Tech. It's about using vertical wind turbines along the roads that can use the energy generated by the cars when it circulates.
The company claims that its Enlil turbines, which have already been tested in Istanbul, can meet the energy requirements of up to two houses and that they can also include solar panels and seismic sensors.
But there are some inventions that despite the work proved not to be profitable at all.
4. Photovoltaic roads
For example, in France, engineering company Colas was a pioneer in the construction of photovoltaic roads. He installed several throughout the country as well as in some parts of Japan and the United States.
The first construction was on a 1 kilometer single lane road in Normandy, in the northeastern part of the country.
There are doubts as to whether solar panels are sunny for solar cells because they are in a horizontal position instead of leaning against the sun, they can do not get as many rays of sunshine. In addition, heavy traffic, snow or clay block them.
In 2014, a small 70 meter long bike route in Amsterdam was built for $ 3 million. It produced 3,000 kilowatt per hour (kWh) of electricity in the first year, but for that money, 65 million kWh of electricity could have been purchased in the open market.
5. Energy to movement
Another technique that tries to rely commercially is piezo. It is a type of energy like when some materials are squeezed, such as quartz, it flows through them.
Therefore, cars and trucks traveling along special road surfaces equipped with piezoelectric devices can generate energy. Pedestrians can do this on special sidewalks.
In 2009, the Israeli company Innowattech experimented with energy-intensive roads, and now a US company Pyro-E wants to test similar technology on a small road in Fresno, California.
But even though these projects are technically viable, they are currently expensives.
Some estimate that in the United States, one kilometer of a two-way street would require 13,000 piezoelectric devices, which would increase USD 400,000 to construction costs.
Even if you do not consider the costs of manufacturing or installation, it takes about 12 years to recover this amount.
The company in the United Kingdom of Pavegen has developed electricity producing sidewalks which can produce two to four joules of energy with each step given over them.
Its sidewalks, which cost around US $ 2,700 per square meter, have been installed in 200 locations around the world.
The figure can be quite high, but also expensive solar panels when they entered the market for the first time.
"We believe that people, not just technology, will be those who will improve our cities," said Laurence Kemball-Cook, founder and CEO of Pavegen.
The idea they hope is that people can help create sustainable cities with renewable energy.
The technology is now it's cheaper to lower costs.