By Aditya Chhatre
The first ever paper on the variations of atmospheric carbon dioxide contributing to long term climate changes was written in the year 1896 by a Swedish physicist Svante Arrhenius. For the analysis in this work, he uses the term ‘carbon acid’ to describe fossil fuels as a source of carbon emissions. The paper mentions fossil fuels to be a potential source for the carbon dioxide. Although later in his works, he articulates fossil fuels being the major contributor to global warming. As the electrical industry is highly based on fossil fuels, the concept of energy transition has carved its way in seeming as the unavoidable solution to most of the climate problems. Parallelly, research and development in solar and wind energy technologies had its advancements which created a sense of optimism. These renewable technologies with their high costs and having generation inconsistencies, were quite a dream to become reality in 1950s. But the urge to achieve energy transition has been only growing. Eventually, the price of electricity from renewable energy technologies dropped lower than electricity from conventional fossil fuel resources. Countries started to aim for targets of 70-100% share of renewables in their energy mix as fast as possible. Fossil fuel-based electricity is one of the largest contributors to carbon emissions. Also, various sectors such as transport, agriculture ought to increase the electricity consumption. Given these circumstances, energy modelling has been useful for forecasts future scenarios and requirements. We can call this century as the century for ‘Energy Transition’. Few countries have achieved and many are deploying solar and wind farms with their maximum capacity to achieve the transition. The global urgency is such that 2050 is set as the year to achieve carbon neutrality by most of the countries.
In these times where humans are trying to realign their carbon dependency, the focus has majorly been on energy resources such as solar PV, wind and batteries. Let’s look into the case of plastics – a light, durable and cheap product which turned out to be a game changer in our everyday life. Visiting grocery stores in 1950s, it was hard to find something which can keep the products more durable, increasing their shelf lives. 70 years later, it is really hard to find any product without plastic rapped around it in a grocery store. Immoderate amount of plastics made it difficult to handle turning the situation undesirable. Moreover, various types of plastics, made it worse for organized recollection. Recycling plastics has caught the eye of several start-ups but as the material is a composition of complex elements it makes it hard for the recyclers to separate the plastic which could be recycled in one facility. Countries such as US, Kenya, EU have banned the use of single use plastics. On the other hand, countries such as UK have tried introduction of tax on plastics bags with fines for breaking rules. It is a big task to get such a useful product out of the supply chain. There are lessons to be learnt for our energy transition. Renewable energy technologies are surely beneficial than the high carbon generation technologies. Concern here is to avoid the energy transition being the same story of starting a revolution with optimism and in 2050 finding a clueless heap of materials to deal with. This rapid change has vulnerabilities which are easy to miss out and it is better to assess and act on them. One of such weakness in the renewable industry is lack of circularity.
To have an estimate of the amount of recycling capacity needed, we have to look at the material requirements for individual energy resources. The material required for the different sources of energy are shown in Figure 1. Solar and wind power plants have the highest material use per Tera watt hours (TWh) of electricity production. Even though these power plants are not carbon intensive, they need a lot more material than conventional sources per TWh. After the designed life of a panel or a wind turbine, the challenge is recollection and then creating a business model which use the recycled material back in the economic chain. Renewables have a characteristic challenge when it comes to recollection of panels or turbine blades. Solar and wind power plants need much more space for the same amount of electricity generation than the conventional thermal power plants. The non-concentrated designs, increases costs and scheduling time to transport the waste to the recycling centres. Another thing which needs to be taken care is that the life of these resources is 20-25 years compared to the conventional plant of 40-50 years. Because of these reasons it is very likely that the solar panels, wind turbines and batteries have higher chances of being mishandled and landing up in the landfills without proper processing. It now becomes a need to increase the recycling capacities, ideally targeting recycling capacity to be consistent with the installed capacity. It is important for designers, policy makers and entrepreneurs to already align recycling techniques, predict the expected timeline and deploy the recycling facilities at necessary geographical locations.
Solar & Wind
Solar PV and wind power plant’s rising trend is expected to grow even further as the technology progress. As of now 629 GW of solar PV and 742 GW wind has been installed globally. To achieve energy transition, models recommend the growth to be 10-12 times of the current installations till 2050. The average life span of solar panels designed by the manufacturers is for 25 years. Also there have been cases, maintaining panels regularly, increased solar plants life up to least 30 years or even more in some applications. Recently, a study from Harvard reviewed the market PV panel replacement rate. The study shows that the utility and residential customers connected to the grid replace the modules after their mid-life period (15-20 years) which makes an economically beneficial decision considering the current technology improvements, panel prices and electricity prices. In 2021, we can expect that the panels from 1990-2000s have already started to be decommissioned and replaced. Similarly, the wind turbine blades which have a life of 15 years. Working on the yearly installation rate, Figure 2 shows the cumulative million tonnes of panels which are expected to be out of service till the year 2046. The graph gives a clear picture of the expected timeline and the quantity of the renewable waste. Solar panel and wind turbine blade waste is calculated according to the installations and assuming average weights. Also, wind technology saw an earlier installation phase even before the solar technology deployment started extensively. Therefore, we can expect a higher quantity of turbine blades as waste before high number of solar panels are decommissioned. But eventually, as solar plants have higher material to electricity densities than wind farms, solar PV waste would cross over wind waste around 2040. If renewable recycling processes are not in place, the waste would be 50 and 30 million tonnes till 2046 for solar panels and turbines blades respectively. To have a comparison, these quantities are way more than Australia’s one-year solid waste of 13 million tonnes. We can expect a boost from the year 2030 where we need to be prepared with the recycling sectors supply chain which can handle this amount of the renewable wastes.
Photovoltaic panels have glass, aluminum and silicon as dominant materials. Project owners usually take the easy way to send the panel to a glass recycler who uses the glass and scraps the rest. Globally, photovoltaic panels are broadly of 2 types, Silicon based and Thin-film based. As silicon based solar panels are common, the processes are developed for its recycling and is comparatively less energy intensive than recycling thin film based solar panels. After removal of the glass the solar cells are retreated with thermal processes and the silicon is reused in the form of modules and other applications. Laws for collection of solar panels are inconsistent even in developed countries. Such as in US there exists a state wise plan which is not consistently stringent nation-wide . In 2012, EU WEEE included solar panels in their electronic waste category. According to this regulation, it is mandatory for the manufacturers and companies in EU to collect the panels after their use and put them back in the recycle chain. The companies are also allowed to charge extra for the post product life activities. This framework has helped the EU solar industry to recycle 80% of their panels. This is a great way to make the authorities responsible for handling the waste and making the recycling market profitable. Similar regulations are been drafted in various countries and would soon be implemented to make solar industry more circular.
Wind turbine blades are made up of composite materials which are highly durable and light. Apart from wind turbines, composites are also used extensively in sectors such as constructions, transport, aeronautics and electrical components. So, a viable solution for recycling composites will have a positive impact on all these sectors in the terms of circularity. There are composites recycling options such as solvolysis and pyrolysis. But particularly in the wind sector it is not possible to shred the blades on site because of size and feasibility of the cutting processes. This is the reason for high costs for transporting back the blades to the recycling centers. Freight costs being high, this makes recycling an economically non-viable leading to the convenient decision to dispose the blade in a nearby landfill. Currently unlike solar panels, there has been absence of recycling regulations and laws for wind turbine blades. Even countries within EU like Germany and France are still in the research stage to implement wind blades recycling policies mainly due to the site shredding blades and transport issue. However, a project, ‘zero waste blade research’ (ZEBRA), is a 24 months project launched in September 2020 for 100% recycled wind turbine blade. This project is been regarded as an opportunity to have a full-scale opportunity for achieving technical, economic and environmental solution necessary for recycling wind turbines and reducing the blades waste.
The stagnant lead acid batteries market, have seen a steep rise with the advancement of lithium-ion technology in this decade. The demand of portable device and electric vehicles (EV) have bolstered the additional investment in the development of the technology. Along with it, the current trends of compatibility of batteries and renewable energy power plants for residential and grid applications has put pressure on its manufacturing capabilities. There are also questions to be answered about the end-of-life of such huge number of batteries. To consider the EV industry there are studies claiming the batteries after their life in an electric vehicle still have 70-80% capacity. These secondary applications of batteries are particularly used at charging stations or connected to the grid for ancillary applications. This improves life of EV batteries by at least 7-10 years. After a certain threshold there has be recycling tie-ups of battery manufactures for their specific battery type. The lithium-ion technology all together is a broad concept with different anode and cathode chemistries involved. Each battery application employs a different technology, which raises serious concerns over type of material used, its availability and recycling these new used batteries. Battery technology is still undergoing huge transformations; hence the topic of its recycling is still of secondary priority, but is nevertheless important.
We need a conceptual change where products need to have more recycled material percentage and use lesser raw material at the design stage focusing on energy efficiency and recyclability. This is a sectoral challenge where not only recyclers but manufacturers and customers have to play an active role together. Bad handling would weaken the advantages of using renewable technologies. For project owners and users, recycling can be a demanding extra step, which is also currently non-economical. We need to act pro-actively by taking steps such as not scrapping the panels, batteries and wind turbines blades to a convenient local with no expertise of recycling, but contact recycling authorities/companies and make this energy transition truly effective. There are scenarios wherein countries within EU have better recycling rate for batteries and solar panels compared to other developed nations. Hence, recycling rates are variable and eventually they would be less dependent on the technology rather more on the geographical location.
The volume of renewable waste is expected to increase exponentially and even go over the board from 2030 if recycling facilities are not in place till then. A business model should include the amount of renewable waste streamed back into the economy and in due course should make recycling profitable. Whether be it a company or a country the task is to have a 100% close loop system reusing and recycling materials. National and governmental policies are key to incentivize this market. It is crucial for governments and regulators to introduce and fund organizations working in this field to strengthen them to be efficient by the end of this decade. The recycling industry is that the sector will have a swooping growth as an effect of the market demand at the point when recycling of these products gets cheaper than mining the needed raw materials. This could be the point where market needs and the environmental needs meet.