What is Energy Harvesting?

All manner of technologies are used to sate the thirst for energy among the world’s growing population. Here, carbon-neutrality is the main objective. Energy Harvesting is one of the new ways to combine them. But, what ist Energy Harvesting?

By 2040, global energy requirements are set to rise by around a third according to BP’s “Energy Outlook 2019”. Nonetheless, BP’s CEO Bernard Looney is sure that “Carbon-neutrality can be achieved by 2050. Appropriate CO₂-free energies and technologies already exist. The challenge is really deploying them on a large scale as soon as possible. I remain optimistic that we can make this happen.”

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Energy Outlook 2019. The main statements at a glance:

1. Global energy requirements will increase by around one third by 2040. Driven by a rise in living standards, especially in India, China and throughout Asia.

2. The energy consumed in industry and buildings will account for around 75 per cent of the increased demand. While the growth in the transport sector will be much slower than in the past. Due to the improved efficiency of motorised vehicles.

3. The energy sector will account for around 75 per cent of the rise in primary energy.

4. 85 per cent of the growth in the energy supply will be generated from renewable energy sources and natural gas. And with renewables set to become the largest energy source for power generation worldwide by 2040.

This has already started on a small scale. Energy Harvesting refers to the use of energy that already exists in the environment. Such as body movements, water currents, air flows or temperature differences. “Energy-Harvesting solutions are the key to supplying a multitude of batteryless IoT applications. That will make our lives easier in the future through digital transformation,” Dieter Bauernfeind from Elec-Con technology says confidently. The company is involved in a project to develop an energy-harvesting power supply for logistics applications. That generates electricity from a variety of movements. For example, this means that sensors can be supplied with power before wirelessly relaying the gathered data.

Yet energy-harvesting solutions can do much more than provide energy to IoT devices. They can also generate electricity on a large scale. Professor Zhong Lin Wang from the Georgia Institute of Technology in the USA is sure of that. He has developed triboelectrical nanogenerators that can produce electricity cheaply from slight mechanical motions. The operation of these nanogenerators is based on two material layers that are repeatedly joined and then separated again. In doing so, they build up electrical charges that can be used to generate power. Wang can even imagine using the oceans as a source of renewable energy. “A network of nanogenerators that converts the motion of waves into electrical energy could make a significant contribution,” he says.

Increased efficiency levels in photovoltaics

Nonetheless, traditional sources such as wind or solar energy still dominate the renewables sector. Here, the use of sunlight to generate power with photovoltaic solar modules is leading the charge. The crystalline silicon technology used in such solutions has a share of around 95 per cent in the global photovoltaics market. Nowadays, this technology offers a cell efficiency of up to 22 per cent.

Although new materials will enhance this even further. Organometallic perovskites, a new class of semiconductor, have already been used to achieve an efficiency of 24.3 per cent. What is more, they promise considerably cheaper and simpler manufacturing. Cells made from this material can also be used for direct, solar water-splitting for the purpose of creating hydrogen.

All hopes are pinned on hydrogen

In the future, hydrogen is expected to extensively replace fossil fuels. So, potential areas of application include the industrial sector. Not to mention load balancing and storage of electricity in conjunction with wind farms and solar power stations.

The eFarm project is the largest hydrogen mobility of project of its kind in Germany. There are five of the company H-Tec Systems’ electrolysers. Each with an output of 225 kilowatts, convert electricity from regional community wind farms into hydrogen. This is then supplied to public transport and private vehicles from two nearby filling stations. The waste heat from the electrolysis process is incorporated into the regional heating system. This holistic utilisation of the conversion process enables an optimum efficiency of up to 95 per cent.

“The use of alternative fuels like hydrogen is growing more and more important,” claims Deutz CEO Dr Frank Hiller. Deutz is collaborating with Munich-based company Keyou to build CO₂-free hydrogen engines for on- and off-road applications. Keyou is developing zero-emissions hydrogen engines based on conventional diesel or petrol engines. And featuring components specially adapted to hydrogen. Such as the ignition system or engine control unit.

What is Keyou?

Keyou’s approach yielded a technology that has already received multiple honours, most recently the SET100 Award. Every year, this honour is given to the 100 most trail-blazing and innovative start-ups worldwide. That can “revolutionise the world” with their technologies, solutions and ideas, as set out in the official jury statement of the SET100 initiative.

The technology is much more cost-effective than that found in electric and fuel-cell vehicles. And hydrogen engines have no need of rare raw materials. “Manufacturers’ interest in hydrogen engines is extraordinarily high. We have even received enquiries from the rail and maritime sectors,” says Thomas Korn, CEO and co-founder of Keyou.

The sun is a shining example

Hydrogen also plays an essential role in a technology that promises to bring the biggest revolution to power supplies everywhere: fusion. A global population approaching ten billion will constantly require enormous amounts of energy. Such energy cannot be provided solely by fluctuating wind and solar power, nor with the associated storage technology.

In the fusion process, hydrogen atoms are fused to form helium at a temperature of over 100 million degrees Celsius. The energy given off by this can be used to generate electricity. Currently under construction in France as the result of a global collaboration is the international experimental reactor (ITER). Whose 500 megawatts of fusion power will demonstrate the feasibility of this concept.