The growing cities of the world need energy, and a lot of it.
According to the United Nations, cities consume an outsized portion of the world’s energy. Close to 75 per cent of global primary energy consumption comes from cites. This results in emissions between 50 and 60 per cent of the world’s total greenhouse gases.
“Large populations are moving from rural areas to urban areas,” says Jatin Nathwani, executive director of the Waterloo Institute for Sustainable Energy. “As cities become denser, these hubs of our modern global economy will need more clean, sustainable, efficiently delivered and affordable energy,” Nathwani says.
The information and telecommunications technologies of today can help, he adds. “It sets in motion a whole set of considerations as to what types of technologies and solutions can be put in place to address the needs of these intense developments.”
Waterloo researchers are working on solutions
Dayan Ban, a Waterloo electrical and computer engineering professor, for example, is developing nanogenerators that would allow devices to power themselves, just by converting ambient mechanical energy, such as the vibrations from movement or sound vibrations, into electrical energy.
Such devices will be needed in the increasingly connected internet of things cities of the future, Ban says.
Already, the internet of things is all around us. We see it in everything from modern connected refrigerators, toasters and robotic vacuum cleaners, to Apple’s Siri or the Google assistant, smart TVs and home or office security cameras.
But the number of connected devices is set to grow tremendously as self-driving cars with multiple sensors make their way along smart highways and as cities embed more devices into their infrastructure. The connected devices will help cities be more efficient in delivering services for transport, industrial and commercial activity and even water and food distribution.
But the conundrum is that these devices also consume power as they connect to telecommunications networks. “There could be billions more sensors. But how do you power them?” Ban asks. That’s where nanogenerators can help.
Ban’s research team has already developed several nanogenerator prototypes, made with materials deliberately designed, using nanotechnology, to have properties that will enhance their ability to harvest mechanical energy.
His team designs the nanomaterials and grows the incredibly tiny “nanowires” in the Giga-to-Nanoelectronics (G2N) Centre at Waterloo.
One prototype utilizes the piezoelectric effect, which causes certain types of materials to generate an electric charge when squeezed or pressed. Another prototype takes advantage of the triboelectric effect, something people encounter in the form of everyday static electricity.
The lab’s researchers have also developed a hybrid nanogenerator prototype making use of both these effects to allow for more energy to be harvested across a broader range of frequencies.
It’s a young field, pioneered 10 years ago by professor Zhong Lin Wang from Georgia Tech. Ban has been working on these devices at Waterloo for the past seven years. But already, the technology has advanced enormously and Ban is getting good results from his prototypes.
The energy generated by his prototypes “would be good enough for some practical applications,” he says. His team is working on improving the efficiency and the reliability of the devices.
Managing services in growing cities will also require the flow of clean energy on “smart grids” that involve using information technology to ensure that clean power flows efficiently to where and when it is needed.
Nathwani says this will be necessary if there is to be any hope of mitigating global warming. “The climate change question cannot be avoided any longer,” Nathwani says.
About 85 per cent of energy used globally comes from fossil fuels and scientists say if the world does not limit global warming to well below 2°C, the consequences will be dire. Using up all the fossil fuels would take us well beyond that limit, Nathwani says. “I don’t think there is anyone willing to accept a future along those lines.”
Democratizing clean energy
Researchers at Waterloo are also working to get more people involved in producing green energy and being able to market it. Waterloo computer science professor Srinivasan Keshav, for example, is helping to “democratize” the clean energy market by speeding up blockchain.
Blockchain is a digital ledger distributed on a network, providing an independent, transparent and trustworthy history of transactions. One can imagine it as being like a digital spreadsheet recording changes in contracts or financial transactions. The spreadsheet gets updated when the transfers happen and are verified. It is trustworthy because everybody can see the history of the ledger, even though the identity of the users is hidden behind powerful cryptography.
People may have heard of blockchain in connection to cryptocurrency such as Bitcoin, but it can be used for just about anything that people might want to exchange or buy or sell, including green energy certificates or credits, Keshav says.
Keshav imagines a future in which an individual can buy solar panels at the hardware store, install them, along with a device like a tamper-proof meter that can verify how much energy is being produced, and convert those units of power into renewable energy certificates that can be sold to large energy users, such as corporations wanting to offset their carbon footprint.
Globally, these renewable energy certificates are already being purchased by large companies. A good example is Budweiser Canada recently announcing that it is partnering with Direct Energy to buy renewable energy certificates that will be equivalent to the electricity used to brew Budweiser.
But currently, to produce renewable energy certificates and sell them on the market, there is a costly auditing and certification process. Only the very large power producers — such as companies that might own solar farms on hundreds of acres of land and install over a million solar panels — can afford to do that.
Keshav says if the average city dweller could produce green energy and get renewable energy certificates, then people in an entire urban neighbourhood might invest in solar panels on their rooftops and sell the green energy credits that a big power user, such as a local university, might be interested in buying.
Blockchain changes the game because it can verify the transactions between players in the energy market without the costly certification process. It will also allow people to gain income from their green energy investments without being as dependent on government pricing and policies for energy sold to the hydro grid.
Keshav says some startup companies, such as Power Ledger in Australia and LO3 Energy in Brooklyn, are already using blockchain to store green energy generation certificates created by tamper-proof meters attached to solar rooftops.
But the problem is that blockchain is slow, which means it’s difficult to bring thousands of new green energy producers on board. The system of rules to verify each transaction, and make sure that no one is selling a green energy certificate for the same block of energy twice, for example, slows everything down.
Keshav has been working on solving this blockchain scalability problem, with some remarkable success. He and his colleagues have recently been improving an open source blockchain system called hyperledger and the IBM version of that, called Hyperledger Fabric. They increased the transaction throughput for Hyperledger Fabric from 3,000 to 20,000 transactions per second.
“That is something that IBM is super-excited about,” Keshav says. “They are keen to implement our ideas so our code could be part of every single hyperledger installation in the world.”
He and his colleagues are also developing a new solution called Canopus, that dramatically speeds up the part of blockchain that orders the transactions, something that becomes extremely complex. With the Canopus solution, Keshav envisions blockchain that could handle a million transactions a second.
By making blockchain fast, Keshav believes more people will be able to get into the renewable energy certificate market and will start producing green energy. “If you made it more affordable, allowing people to make additional revenue by investing in it, that will really accelerate the use of solar,” he says.
Nathwani of the Waterloo Institute for Sustainable Energy says policy changes coupled with new technologies could lead to a cleaner, more affordable energy future for the cities of the future.
“This will result in the integration of cleaner technology into our lives at price points and value points that will be far different from the old, wasteful, way of doing things,” Nathwani says.
Photo of Hong Kong by Andrew Wulf
