The End of the Line for Today’s Wind Turbines

By: Dr Athanasios Kolios and María Martínez Luengo

We need to start thinking today about the future of our wind turbines, according to Dr Athanasios Kolios and María Martínez Luengo from Cranfield University.

Since the EU’s 2007 target of generating 20% of its total energy output from renewables by 2020, offshore wind has become the UK’s key renewable source with an increasing number of turbines being deployed every year. But with an average lifespan of 20-25 years, what will become of these in the next 10 years as they approach the end of their lives? (Image courtesy of Shutterstock).

EDF’s recent announcement that they will extend the life of 4 of their 8 UK-based nuclear power plants has focussed analyst’s minds on the pros and cons of extending service life. There are numerous cost and engineering issues at play here. These obviously include balancing the initial investment cost against profits already made and the potential decreasing efficiency alongside the increasing maintenance costs in an aging facility. The issues cut across the whole energy sector, but they aren’t something many of our renewable technologies have yet had to face.

Wind turbines, for example, are currently designed to be efficient and reliable for 25 years with possible extensions beyond that. According to RenewableUK, wind (and particularly offshore wind) is the UK’s most promising renewable source to help meet the targets set by the EU in 2007 of obtaining 20% of total energy from renewable sources by 2020. As a result, vast numbers of turbines have already been installed on and offshore, and many more will be deployed in the next 5-10 years. What, though, will be happening in 20-25 years’ time when today’s turbines are reaching the end of their lives? The question of what we are doing with all of these turbines is already becoming a hot topic.

The benefits of extending the life of our current turbines seem clear cut. With a typical wind turbine costing usually a few millions per unit, extending the service life could result in a substantially greater return on investment. It also increases the overall electricity produced, and can therefore decrease the levelised cost of electricity – the cost per kWh in real terms of building and running the turbine. These are the main reasons operators will look to extend the service life, but we already know that there may be potential barriers.

The main risk is extensive degradation of one or more parts of the turbine. Rotor and blades, for example, can be impacted by lightning strikes, vibrations, corrosion and unsteady air loads. The efficiency of a wind turbine is even decreased by the smooth blade surface becoming roughened by erosion and icing to which the turbine will obviously be exposed. The tower and foundation of the turbine are also obviously critical to operation, as they can’t be easily replaced. Cracks and corrosion are real threats, and while they can be modelled in design stages, exactly how a turbine will be impacted by the natural environment can’t be accurately predicted. Other potential failures may lie in the electronics – responsible for 13% of failures at present – or in other crucial components like the generator, gearbox and pitch control.

Even with these risks, as today’s wind turbines reach their final service life years, it can still be very beneficial to increase their service with some minor refitting. Common spare parts can cost between 5% (rotor hub) and 20% (blades) of the cost of a brand new turbine. At these prices, a ‘make do and mend’ approach makes financial sense.

Just like any consumer good, the better the turbines are cared for, the more likely it is that they will outlast their original purpose. Optimum asset management, including inspections and maintenance activities, will make turbines more efficient for longer. However, the cost of maintenance and inspection can be high – especially at offshore sites where it can cost 5 times as much as onshore. It is a substantial but vital investment. The ideal solution to increase life span is to integrate Structural Health Monitoring and Condition Monitoring Systems. These include the use of remote sensors on the turbine, for example strain gauges or accelerometers, to provide useful data about the condition of the structure and components. This would mean a more cost effective maintenance programme that responds to condition, and allows for carefully planned activities – rather than urgent responses to component sudden failure.

Reaching the end of nominal service life, the options on the table for our turbines won’t only be to extend or not. Repowering – either rebuilding a turbine in the same location replacing some parts or starting from scratch – is also a feasible alternative. And if extension or repowering is not feasible, decommissioning and returning the location to the same state it was in prior to the turbine installation comes with its own challenges and costs.

The options for repowering assume reusing part of the infrastructure from the existing wind farm to reduce the capital cost of the new one. For example, for an offshore site, most of the original subsea cables might be reused, along perhaps with the existing grid connection. The options might be to use the original tower with a new, lower capacity turbine. This may produce less electricity, but also needs less maintenance, and the tower will be less fatigued by the load as it ages. The same tower might also have a new, higher capacity turbine – producing more electricity, but the greater load may make structural integrity an issue. Or, a new tower with a new higher capacity turbine using the same site assets.

The decision on the best solution here would be based on profitability as reliability and performance decreases, the cost-benefit ratio against decommissioning the turbine totally, and the profits expectation for the life extension. However, since wind turbines tend to be in high wind sites, repowering can be lucrative. The first repowering in the UK is happening onshore imminently. RWE npower Renewables are applying it to reduce the number of turbines at the Taff Ely Wind Farm in Wales from 20 installed in 1993 to 7 higher capacity turbines which would double the output from the site each year.

When repowering or extending service life is no longer an option, decommissioning represents the final alternative. The main objective will be to return the landscape or the seabed to the state it was in before the turbines were first installed. However, all the elements of the turbine must be dissembled. Firstly blades, nacelle and the tower will be disassembled and hoisted down by crane; its posterior elements will be disjointed and reduced into smaller pieces suitable for scrap. These all need to be transferred by boat or truck to a recycling location where almost every part of a turbine can be recycled. The scale of the decommissioning operation is comparable to that of the initial commissioning! As such, this is definitely the least preferred option for the industry that should spend without the expectation for future return.

Most wind turbines should last for about 25 years with normal inspection and maintenance. A 2014 study found that the UK’s first wind turbines deployed in the 1990s are still largely profitable as their power production is about 75% of their ideal production. Those first turbines are expected to have about another five years of profitable operation. To best extend the life of our new or more recent turbines, time and money need to be wisely spent on identifying at-risk components and assessing the units’ condition. We believe that the industry will need to put more efforts into planning for the end of life scenarios, especially when it relates not just to single turbines but to whole wind farms. As wind farms get bigger and more ambitious in terms of the unit scale and the number of turbines deployed, the issues get more pressing. At the same time, the technology within the turbines and the technology for monitoring structural health of the turbines will improve. The issues will get increasingly complex, but our understanding of the assets’ condition should improve. Since it is widely accepted that we can rely heavily on wind for our future needs, we need to think about the future today.


Dr Athanasios Kolios is a Senior Lecturer in Risk Management and Reliability Engineering and the  Director of the Energy Doctoral Training Programme at Cranfield University.

Mrs María Martínez luengo is an EngD researcher within the EPSRC Renewable Energy Marine Structures Centre for Doctoral Training (REMS CDT)  at Cranfield University.



This $16 Water Filter Could Save 100,000 Lives a Year

By: Alex Janin

Sixteen dollars. That’s the price of a movie ticket plus tax in Los Angeles—or of a week’s worth of coffee at a trendy java shop. Thanks to an Indian chemist, that amount of cash could also provide clean water for a year to an impoverished family in the developing world.

The AMRIT water purifier, which Pradeep debuted in 2012, is the first filter of its kind in India. Photo credit: Thalappil Pradeep

“If this will be useful for water, it has to be very cheap, have a low carbon footprint, require no electricity and should not contaminate water sources in the process,” Thalappil Pradeep, a chemistry professor at the Indian Institute of Technology, told TakePart.

Pradeep spent 14 years developing a nanoparticle water filter system that can remove contaminants from India’s groundwater as it is being pumped. The AMRIT water purifier, which Pradeep debuted in 2012, is the first filter of its kind in India. The country’s federal government recently decided to implement the pumps across the nation, an expansion that is under way, Pradeep said. He and a team of students formed a company, InnoNano Research Private Ltd., to keep up with the installation, he added.

The device comes in two sizes and at three price points, which include installation costs: The $16 version is for homes. A larger one that can be hooked up to schools or office buildings is about $500 (connecting a whole village costs $1,200). The largest purifier, which stands at nine feet tall and resembles a giant green coconut, produces about 80 gallons of clean water per hour.

Globally, 663 million people do not have access to clean and safe water, according to the United Nations. In a country such as India, with its high poverty rates and underdeveloped rural infrastructure, access to clean water is particularly poor. About 21 percent of illnesses in India are the result of consumption of dirty H2O, according to The Water Project and there are more than 100,000 deaths related to water-borne illnesses each year.

Pradeep estimates that 5 percent of old-school hand pumps, of which there are 2.4 billion in India, spew arsenic-contaminated water. Arsenic is carcinogenic to humans and can have drastic long-term health effects, such as skin lesions, diabetes and cardiovascular disease.

The first of his pumps was installed in West Bengal, a state in eastern India, in 2012. The state government took notice and installed pumps at 330 schools across the region. As a result, about 500,000 people have access to clean water from these pumps, said Pradeep.

AMRIT water purifier for small communities. Photo credit: Thalappil Pradeep

When researching the best way to build the pump, energy efficiency and the use of natural materials were a priority, said Pradeep. As a result, the device uses materials with a low carbon footprint, such as silver ions and requires no heating and no electricity.

As the water flows through, the pump allows the silver ions into a “protected cage” to pick up contaminants. Dirty water goes in, the ions grab arsenic, mercury and other contaminants and clean water goes out, explained Pradeep.

Pradeep said he had long contemplated how to make clean H2O widely accessible. Clean water is a human right, he said, but in developing countries, access to safe, hygienic water sources is far from equal.

“The problem with water is [the] poor suffer; the rich find solutions. In many places in India, people suffer for no fault of their own. They are destined to suffer because arsenic is such a geological problem. People have to be given solutions by the state,” Pradeep said.

Pradeep said this kind of pump could be useful in developed countries with water crises, such as that caused by lead-leaching pipes in Flint, Michigan.

“We don’t want to celebrate another century of arsenic [in India] … Same is the case with Flint. When we implement wrong industrial technologies, new kinds of technologies have to come,” Pradeep said.


Researchers Produce Electricity with Paper, Tape and a Pencil

By: Megan Treacy

Courtesy: EPFL

A team of researchers at Ecole Polytechnique Federale de Lausanne (EPFL) and the University of Tokyo have created a device made with everyday materials that can produce enough electricity to power several diodes, a small LCD screen or other small electronics and could be used in developing countries with low-power medical diagnostic tools.

Using card stock paper, Teflon tape and a pencil, they made the 8-cm2 device that can generate more than 3 Volts of power — the same as two AA batteries or enough to power a remote control.

Essentially, the device produces static electricity. Two pieces of card stock paper are covered with pencil on one side and the carbon from the graphite acts as an electrode. The Teflon tape covers is applied to the other side of one of the cards. The paper and Teflon both act as insulators.

EPFL says:

When brought together, they make a sandwich: two layers of carbon on the outside, then two layers of paper, and one layer of Teflon in the middle. They are then taped together in such a way that cannot touch, giving the system a configuration that makes it electrically neutral.

By pressing down with your finger on the system, the two insulators come into contact. This creates a charge differential: positive for the paper, negative for the Teflon. When you release your finger and the cards separate, the charge passes to the carbon layers, which act as electrodes. A capacitor placed on the circuit absorbs the weak current that is generated.

The researchers were able to boost the electricity output by pressing sandpaper against the cards, giving them a rough surface. This increased the contact area and lead to a six time increase in output.

Tapping the cards 1.5 times per second for a short burst of time releases the same voltage as two AA batteries, which could power small low-power sensors.

The TENG device (triboelectric nanogenerator), could be a natural fit for low-cost sensors made from paper that are already being tested in the medical field in developing countries. These devices could replace conventional batteries in those types of applications and the materials could be composted at the end of their use.

You can see the tiny generator in action below.


This is the Next Generation of Renewable Energy Technologies

Hi-tech football pitches, wave power and nuclear fusion are helping to move Britain away from ‘dirty’ fuels towards sustainable energy

By: Rebecca Burn-Callander

Children playing football in the Morro da Mineira favela in Rio de Janeiro are helping to power their neighbourhood’s street lights by running on an AstroTurf pitch that converts their steps into energy

Scientists all over the globe are working to develop sustainable new energy sources to reduce our dependence on dwindling fossil fuel supplies.

In the UK, just 5pc of the nation’s energy comes from renewables. The Government has set a target of 15pc by 2020, but progress is slow.

Some sustainable energy sources, such as solar energy, are mature marketplaces, with 60 years of research behind them. Others, such as antimatter, are more experimental.

The science of antimatter is still in its infancy but scientists claim that mixing just half a gram of antimatter with half a gram of matter would create the same energy generated by the Hiroshima bomb.

There are several start-ups developing other ground-breaking technologies for generating electricity, some using methods that seem more Star Trek: The Next Generation than National Grid. We meet three entrepreneurs leading the charge into next-generation renewables.

Turning footsteps into electricity

Youngsters playing on a newly-installed football pitch in one of Rio de Janeiro’s most notorious slums are now powering the neighbourhood’s street lights with every step.

Their movements across the AstroTurf are converted from kinetic energy into electricity by 200 hidden energy-capturing tiles built by London-based Pavegen.

The Pavegen tiles took less than a week to install

Founded by Laurence Kemball-Cook in 2009, the company exports its energy-converting tiles to 20 countries across the world. Customers range from infrastructure giants such as Siemens to retail brands Nike and

Uniqlo. “I started this in my bedroom with just a sketch,” Kemball-Cook, 29, tells The Sunday Telegraph. “Now we employ 30 staff in four offices and we’re profitable.”

Pavegen, which converts high footfall areas into pseudo-batteries, and sister company Roadgen, which aims to harvest energy from vehicles on the world’s roads, will help to power Read more »

SolarCity To Deploy Tesla Energy Batteries For 52 MWh Of Evening Electricity Storage On Kaua’i, Hawai’i

By: Glenn Meyers

According to Pacific Business News, Tesla Energy batteries will be used for a SolarCity solar farm and energy storage system which is being developed for Kauai Island Utility Cooperative (KIUC) in Kaua’i, Hawai?i.

The Tesla Energy batteries will supply a 52 MWh utility-scale energy storage system in order to help KIUC meet evening peak demand, which typically occurs between 5:00 pm and 10:00 pm. The storage system will be located at a 12 MW solar farm.

Artist’s impression of Tesla’s utility-scale storage systems. Image via Tesla Motors.

Of its commitment to solar energy, KIUC president and CEO David Bissell has said, “No other utility in the US has a higher percentage of large-scale solar on its grid than KIUC.”

It is hoped the solar farm and storage capacity will help KIUC further reduce fossil fuel use. SolarCity said it would charge the utility 14.5 cents per kilowatt-hour for power from the batteries in a 20-year arrangement. News of the solar storage deal was reported in September 2015.

This project awaits approval from the state’s regulator, the Public Utilities’ Commission. SolarCity and KIUC asked last year for permission to accelerate development, so that it could begin by April this year, when existing ITC (investment tax credit) rates were due to drop.

As much as 95% of daytime demand on Kauai is met by solar at present but KIUC has targeted extending this number into the evening hours. When all is said and done, SolarCity’s grid-connected project will provide the 52 MWh utility-scale battery facility, built to distribute up to 13 MW of solar power.

“That a small co-op on Kaua‘i can become a world and national leader in energy transformation in such a brief time is something all of our members can be proud of and celebrate,” said Bissell.

Expect many others to be tracking the progress of this development.