Drying for a greener future

We're all keen to live better, more sustainable lives, whether it is the car we drive, the house we live in or the place we work at. But making that “right” choice is not always as straightforward as it may seem.

We may feel good about buying an electric car, for example, but what about the energy consumed in its manufacturing process? And what about the battery? 

Read more: Life-cycle GHG emissions associated with EVs compared to ICEVs

Moisture is, in many ways, an invisible threat that can have huge consequences if not controlled properly. If too much moisture gets into battery housings or wind turbines, the net positive effect of this “green energy” can be greatly diminished.

As an independent, family-owned Danish company, Cotes has a long, successful track record in the fields of wind energy production and Li-ion batteries, among others, thanks to a high level of competence and numerous patents to meet growing demand from a rapidly accelerating green energy transition.

Cotes’ technology and dry-air solutions essentially get rid of moisture and humidity (control humidity better) in all types of environments.

In the case of offshore environments, humidity is mixed with airborne salt. It causes expensive electrical faults and critical component failures in wind turbines and substations, so removing excessive levels of humidity is combined with filtering out airborne salts. Simply put, the less salt and moisture there is inside a wind turbine, the more productive it is with fewer electrical faults or other expensive critical component failures. Failures and unscheduled maintenance mean downtime for sustainable energy production, expensive repairs, and a reduced operational lifetime - bad news for the green energy transition.

In the case of Li-ion battery manufacturing, battery dry room environments need dew points as low as -70°C, because of the sensitive chemistry involved in making batteries. Maintaining such extremely dry conditions requires a lot of energy, so if your dry-air solution is not an energy-efficient solution, you increase the embedded carbon footprint of the battery cells long before it even has a chance to power your favourite electric car down the road.

Read more: The world's most energy-efficient battery dry rooms

HOW DO COTES DEHUMIDIFIERS WORK?

In simple terms, Cotes’ dehumidifiers work by capturing the humid air that comes into the unit in a rotor, which acts as a filter. This rotor has a honeycomb surface coated with silica gel, which attracts water molecules and keeps them “trapped”. The air, now almost free of moisture, is then vented out as dry air.

THE ANSWER IS BLOWING THE WIND

The wind power industry provides a perfect example of how effective the technology can be, and how great the threat is if humidity is not adequately dealt with.

Thomas Rønnow, Owner and Business Development Manager at Cotes who steered the' move into the wind sector, reflects that the offshore wind industry has seen a lot of growth because it operates in more favourable conditions for wind energy production that tend to be more steady and predictable than on land.

“It will be a hot topic in the coming years, because a lot of green energy will be produced in offshore wind turbines, but if they are not protected, their lifetime will be reduced, they will have more faults and you will see more and more expensive breakdowns,” says Rønnow.

“With offshore turbines, the threat is caused mainly by droplets of seawater,” he explains. “When you have waves breaking, you get seawater in the air. The big drops just fall down, but small droplets become airborne, so out to sea, you have a lot of airborne droplets. This combination of salt, water and high humidity can potentially be harmful to turbines, both in the tower and in the nacelle – a bit like how there is a high risk of corrosion in your car during winter from the salt that is collected,” he adds.

And that can be costly. It is estimated that as much as 25% of all breakdowns in offshore wind turbines are caused directly or indirectly by moisture. When they do break down, it is an expensive business, not just in terms of the lost energy production but also the cost of spare parts and transporting staff and equipment out to sea.

Read more: High ROI for installing a dehumidifier in a wind turbine

The solution developed and patented by Cotes is, in simple terms, a moisture and salt filter.

“We mix the incoming air with dry air and evaporate the water from the seawater droplets,” explains Rønnow. “You are left with just the salt, which will then crystallise. Then we have dry air without salt that we can push into the tower, which will go all the way up the tower to the cell, and that protects the whole turbine.”

Onshore turbines face similar issues, although in a less aggressive way. “Power converters can frequently break down due to humidity inside the turbine, so we have invented another solution again, by adding dry air. Offshore the problem is more about salt, whereas onshore, it is more about dust and sand in the air, and also a lot of dirt in the air when farmers are harvesting, for example,” Rønnow adds.

CHARGING TOWARD THE FUTURE

Nevertheless, the prospects for Cotes’ future look bright. “Wind power is seen as one of the major sources of green energy in the future, and high growth in the industry is expected in the coming years so we see ourselves playing a big role in that development,” says Rønnow.

His optimism is well placed. For customers, Cotes’ dehumidifiers represent the most cost-effective and environmentally responsible way to tackle many practical problems across a raft of industries. Having control over issues such as condensation, rust and corrosion, mould and rot, electrical faults, and spoilt materials means lower energy costs, reduced expenditure on service and maintenance, longer service life for equipment, better ROI and a much-decreased environmental impact.

Meanwhile, beyond wind power, Cotes has recently made a big push into the Li-ion manufacturing industry, which has boomed in the past two years, particularly due to the demand for batteries and the acceleration of the energy transition.

Here again, the need (and potential) for dehumidifying products is clear. Some 43% of the energy demand for lithium battery cell production comes from running dry room dehumidifiers. Extremely dry air (with a dew point of below -40°C) is necessary to avoid batteries being exposed to humidity during the manufacturing process. This is important to avoid moisture being trapped inside the battery, which in the worst case, can lead to a risk of explosion during charging and discharging.

In response, Cotes has patented a technology (Exergic Technology ™) that enables a reduction of the net energy consumption of running the dry room by up to 92%.

Learn more about Cotes dehumidifiers: Download Cotes Ultradry Dehumidifiers Datasheet

THE RIGHT WAY FORWARD

Another cause for optimism is the increased interest in a safe, well-functioning industry. As interest in the battery sector grows, so too does the regulation around it. The EU is creating a new sustainable regulatory framework for the battery industry in Europe which is pushing for more ambitious sustainability goals for EU battery manufacturers. Read more about the New EU Battery Law. There will be tougher consequences for those who do not comply with sustainability and energy standards, meaning ultimately that the more forward-thinking operators – like Cotes – look set to be in even more demand than ever before.