Solar panels and lithium-ion batteries have dramatically reduced in price in recent years, thanks to a number of innovative advancements. However, these cost savings could be making recycling harder, removing expensive components and killing off the value proposition for recycling. As the number of end-of-life solar panels and batteries continues to grow, is our green technology about to become a dirty problem?

The cost of solar panels has fallen dramatically over the last decade, dropping by 89% since 2009. This is in part because of technological advancements making them cheaper to produce.

For example, advancements have led to the amount of silver needed as a conductive paste for the front and back of most photovoltaic (PV) cells, the most expensive component within a panel, being dramatically reduced. This is a trend that will continue as the technology advances, with a recent report by CRU Consulting, ‘The Role of Silver in the Green Revolution’, predicting that the average amount of silver will fall from 130mg per cell in 2016 to approximately 65mg by 2028.

A PV panel uses a very small amount of silver, but this accounts for as much as 47% of its total cost. In the past, it has also been the most valuable part of solar panel recycling, offering an economic incentive to recyclers.

Similarly, lithium-ion batteries have advanced considerably in recent years, making them cheaper and more accessible. And yet this could have a knock on effect on their value to recyclers.

A report produced by CSIRO titled ‘Lithium battery recycling in Australia’ found that just 2% of the 3,300 tonnes of li-ion created annually in Australia is recycled. This statistic is largely mirrored around the world.

Solar PV and li-ion batteries offer clean energy alternatives to communities and individuals, but without effective recycling facilities and pathways, can they really be considered green technologies?

Stripping the silver from solar

Globally, the uptake of solar panels and li-ion batteries has increased dramatically in recent years. In 2017, for example, 98.9GW of new solar capacity was added across the world.

However, the life expectancy of a solar PV panel is only 30 years. As uptake continues to grow, the number of end-of-life solar panels will mount as we head into 2030 and beyond.

“The deposit of end-of-life photovoltaic panels will lead to an explosion of tonnages to be treated in the next 30 years: several tens of millions of tons by 2050 in the world (China, USA, Japan, India, Germany),” says Veolia corporate communication and institutional relations manager, Camille Maire. “In France, the deposit is already growing by 30% to 40% per year. 53,000 tonnes were placed on the market in 2016 and 84,000 tonnes in 2017.”

As such, there’s an enormous quantity of waste on the horizon that could reach 60 billion tonnes by 2050.

The increases in solar panel demand led, for a time, to an increase in the demand for silver, with PV panels accounting for 8% of overall silver consumption. This hit its peak in 2016, when 83.3 million tonnes of silver was used for solar, up by more than a million since 2002.

Its high cost has since sent companies in search of alternative production methods. Silver is being combined with cheaper metals such as nickel, thanks to inkjet and screen printing technologies, lowering the cost of the technology without reducing the efficiency of the panels.

Less cobalt, lower costs

Li-ion batteries are following similar trends. As they grow in number, buoyed by the boom in electric vehicles (EVs), so too has the price of one of their key components, cobalt. The price of the metal, which is used as a cathode material, increased from $32,500 per tonne at the beginning of 2017 to $81,000 per tonne in March 2018.

It is unsurprising therefore, that makers are seeking alternative materials for the construction of li-ion batteries. Tesla founder Elon Musk told attendees at a conference earlier this year, “We think we can get cobalt to almost nothing”, when asked about reducing the price of the company’s famous li-ion battery technologies.

But without valuable components, the economic incentive to recycle li-ion batteries dwindles. Currently, less than 5% of li-ion batteries in the US are recycled. Traditional lead-acid batteries are 98% recycled, as the prevalence of their use necessitates legislation in most countries, as well as their components offering an opportunity to recycling companies. Such systems aren’t currently in place for their newer counterparts.

Already, li-ion batteries are creating huge volumes of waste, and this will continue to grow along with the increase in the number of EVs, among other technologies. In Australia, for example, the amount of waste is expected to grow by around 20% annually, reaching over 100,000 tonnes a year by 2036.

Solutions for solar

Technological advancements can help provide solutions, working alongside legislature. Recycling of solar panels in Europe is managed by the Waste Electrical and Electronic Equipment (WEEE) Directive, which dictates that they must be recycled.

However, the effectiveness of recycling PVs has been called into question, as they were simply recycled alongside other glass products. Europe’s first dedicated solar panel recycling facility, which is owned and built by Veolia, has now opened in Rousset, southern France. The plant uses robotics to ensure that PV panels can be recycled efficiently and economically.

“This is a first: a unit entirely dedicated to the treatment of photovoltaic panels at the end of life of the ‘crystalline silicon’ type (95% of the deposit),” says Maire. “Before, for lack of sufficient quantities, they were recycled with other flows, especially among glass recyclers. It was often recovered and mixed with other types of glass. However, glass is very specific in a photovoltaic panel. It therefore seems better to isolate and treat it differently. In addition, certain fractions such as plastic and silicon were not separated and were sent for energy recovery in cement plants.”

The Veolia plant is a big step for Europe, providing an option as solar technology ages and the number of panels reaching the end of their life increases.

“The goal for 2018 is the recovery of 1,300 tonnes of solar cells – practically all solar cells that have reached their end of life in France this year,” says Maire. “By 2020, the annual volume of production is to rise to 4,000 tonnes.”

Elsewhere the story is less positive, with little incentive for recycling panels in many parts of Asia and the US. The cost of recycling a PV panel varies, but has been estimated at around $10-$20 per module, a cost that must be footed by the owner. In many state in the US, this means that it is simply cheaper to send a solar panel to landfill than it is to recycle it.

The state of Washington has realised that this is a mounting problem. Its Department of Ecology is currently drafting legislation that would require solar panel manufacturers to provide recycling options for all panels sold.

Li-ion can live on

In theory, when effectively recycled, 95% of a li-ion battery can be turned into new batteries or used in other industries. However, improved regulations and processes are necessary for this to become the reality.

Advancements are being made by companies like Battery Resourcers, an end-of-life company born out of research conducted at Worcester Polytechnic Institute. It is working to develop a process that will be able to recycle all types of cathode, regardless of size and make-up. One of the current issues is that cathodes vary so much, making them harder to sort and process, but they hold 70% of the value of the battery.

“Our advantage is that we can recycle lithium–ion batteries and recover the cathode material from a mixture of lithium-ion batteries, regardless of size, shape or chemistry,” said Battery Resources CEO Eric Gratz. “And that would account for more than 90% of our revenue stream.”

On average, li-ion batteries have a lifecycle of about eight to ten years. The EV market really took off around 2010, so we are just about to see the first proper waves of li-ion batteries that require recycling.

In New Zealand, the Battery Leaders Group, led by energy company Vector, was established in October 2018 to quantify the waste on the horizon, examine the potential market and develop strategies for recycling.

“The numbers of electric vehicles on our roads is growing and with a battery life of around 5-15 years this could become a significant new waste stream for New Zealand to deal with,” saidVector group chief executive, Simon Mackenzie.

“That’s why we’ve formed this Leaders Group to tackle the issue head on. It will be good for the country if we succeed in reducing waste to landfill, and group members will benefit through pre-competitive collaboration to unlock new parts of the battery value chain.”

These examples highlight how work is beginning in developing recycling schemes for li-ion batteries that can deal with the rapidly growing end-of-life market. But without the economic incentive of cobalt, this development is long overdue.