Good vibrations: Developing new tech for energy harvesting

12 Jul 2022

Dr Valeria Nico. Image: Alan Place

University of Limerick’s Dr Valeria Nico is looking to develop vibrational energy harvesting tech that could provide renewable and sustainable energy for IoT sensors.

After receiving a PhD at University of Limerick in 2018, Dr Valeria Nico started working as a postdoctoral researcher. She has focused on the commercialisation of the vibrational energy harvesting technology that she developed during her PhD, demonstrating to potential customers that this tech could be used to power sensor nodes from ambient vibrations.

It is a topic she started working as part of her bachelor’s and master’s degrees at the University of Perugia in Italy. “My group was developing a wireless sensor to measure temperature and acceleration, and I was amazed because it was powered by the vibrations of a car without any battery,” she told

Nico’s experience with electromagnetic devices also led her to develop a novel microfluidic pump based on an oscillatory magnetic shuttle. Last year she was awarded funding from the European Space Agency to integrate the pump and a flow sensor into a two-phase liquid cooling system for satellite applications. The project is almost complete and the tech may be advanced in a follow-up project.

She was also awarded funding from Science Foundation Ireland last year to develop a vibrational energy harvester. She is currently based at the Bernal Institute at the University of Limerick and is also an associate investigator at Connect, the Science Foundation Ireland research centre for future networks.

‘Providing an alternative to batteries for IoT applications seeks to reduce a significant environmental hazard’

Can you tell us about the research you’re currently working on?

My main research interest is vibrational energy harvesting: the conversion of ambient vibrations in electric energy to power small electronic devices such as wireless sensors that form the internet of things (IoT).

These small sensors are generally battery powered, however battery replacement represents a significant cost for the user and an environmental hazard if batteries are not properly discarded and recycled.

There is an abundance of kinetic energy in the form of ambient vibration – for example, the vibrations of a train or an industrial air compressor – in the vicinity of sensors that could be used as power source. My aim is to develop a vibrational energy harvesting technology that could provide renewable and sustainable energy to the billions of sensors that comprise the IoT.

In your opinion, why is your research important?

The aim of vibrational energy harvesting technologies is to provide a renewable source of energy for IoT sensors. Most IoT nodes are battery powered and, according to the WEE Annual Environmental Report 2019, 886 tonnes of portable batteries were collected by WEE in Ireland.

Battery replacement is a significant cost for industries and an environmental hazard if they are not properly discarded and recycled. Battery production also has an environmental impact because the raw materials used, such as lithium, zinc and manganese, are generally mined and metal is released into the surrounding environment during their extraction.

Providing an alternative to batteries for IoT applications seeks to reduce a significant environmental hazard, ultimately helping to reduce soil pollution, chemical and electronic waste, in line with the UN Sustainable Development Goal 12.

What commercial applications do you foresee for your research?

There is a growing need for sustainable, power efficient and durable IoT applications that require little or no maintenance. A salient feature in the growth of harvesting technologies is the replacement, or augmentation, of battery power for low-power electronics.

The major driving factors for this growth are energy savings, government investment in cleaner carbon-neutral energy, and consumer demand to change the way battery-powered electronics operate. By deploying self-powered electronics, the consumer will also incur savings as battery replacement will no longer be necessary.

There is potential for a route to market either via a spin-out enterprise or by licensing the technology for incorporation into products made by Irish companies operating in the IoT space. Companies that provide wireless sensor nodes for IoT applications and IoT national testbeds will benefit from the provision of sustainable, maintenance-free autonomous sensors.

What inspired you to become a researcher?

My mum is a physics teacher and I have always been exposed to science and physics. When I was a kid I was fascinated by stars and planets so, when I was five, she gave me a book on astronomy, with images and explanations of the characteristics of the different planets in the solar system. I just loved it. It is still one of my favourite books.

Growing up we used to do simple physics experiments at home, from building a compass with a metal needle to powering a Casio watch with potatoes. We spent hours in the physics laboratory at my mother’s school doing complex experiments.

Going to college to study physics was an obvious choice. My interests moved from astrophysics and astronomy to applied physics, and I started working on energy harvesting to replace battery usage to power small electronic devices.

What are some of the biggest challenges you face as a researcher in your field?

The generation of enough energy from a small harvester to power an IoT sensor.

To solve this problem, novel approaches are being developed to increase the output power of the harvester, using multiple types of conversion mechanisms or harvesting multiple energy sources, such as solar, thermal, vibrations. Research also is ongoing to minimise the energy consumption of communication protocols and sensors.

Another challenge that researchers face is that the generated power depends on the environment in which the sensor will be placed – for example, it can depend on the type of machinery that is vibrating (for vibrational energy harvesting), if it is placed indoor or outdoor (for solar energy harvesting) or the temperature gradient available (for thermal energy harvesting).

Hence, it is hard to predict the output power and harvesting technologies needed to suit specific applications. This is a barrier at the moment to the widespread adoption of energy harvesters.

Are there any common misconceptions about this area of research?

Two of the most common misconceptions are the myth that energy harvesting technologies are more expensive than batteries and that they are unreliable because there could be periods where the energy generated is not enough to power an IoT sensor.

While a single battery is cheaper than an energy harvester, the cost associated with its periodic replacement is significant – a lithium battery has a lifespan of one year if transmitting data every five minutes. By using energy harvesting technologies as power source, it is possible to realise autonomous sustainable IoT sensors that would result in a cost saving for the end user.

Sensors are placed in environments where multiple sources of energy could be used and where multiple sources could be harvested to generate energy to power IoT sensors. For example, on a railway track it is possible to use a vibrational energy harvester in conjunction with a small solar cell, or in a factory it could be used in conjunction with a thermoelectric generator if near hot or cold pipes.

What are some of the areas of research you’d like to see tackled in the years ahead?

I would love to see more efforts in both research and commercialisation of sustainable materials for energy generation.

In recent years, there has been a large push towards renewable energy such as wind and solar. But even if energy is generated from renewable sources, there is still an environmental hazard because wind turbines and photovoltaic panels have a lifetime of around 20 to 25 years and are made of materials that cannot be recycled and generally are discarded in landfills.

The environmental hazard of energy generation is hence shifted from the source (fossil fuels versus wind or solar energy) to the components of the generator. Research is ongoing to develop sustainable composite materials for turbines blades and alternative materials for solar energy conversion. I would love to install solar panels in my house, knowing that it will be possible to recycle them.

One of the methods used to convert vibrations into electricity uses piezoelectric materials. I am interested in the work to develop efficient lead-free organic piezoelectric materials.

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