Energy is crucial for our country’s growth as it powers all sectors of the economy, from industrial production and agriculture to transportation and households, leading to improved living standards, job creation, and access to essential services.
Nature provides us with abundant, constantly replenishing energy sources like solar from the Sun, wind from moving air, hydropower and ocean energy from water movement, geothermal from Earth’s heat, and biomass from organic matter in addition to non-renewable fossil fuels and radioactive minerals from Mother Earth. But we are in a Catch-22 situation! On one hand, the former energy sources, though constantly available, are subjected to nature’s phenomena and its vagaries and thus, are less dependable. On the other hand, the non-renewable fossil fuels, though dependable, pollute our planet Earth and threaten our very existence with greenhouse gas emissions, and the atomic energy, though non-polluting, has its own challenges of nuclear safety and waste disposal. Additionally, both of these are subjected to geopolitical influence. Hence, we need to strategize our energy needs and explore with an intelligent mix of all these options, however, minuscule it might be. We need to innovate and think out of the box. This article is an attempt in this direction.
I recall my college days when we were taught the concept of phase rule in physical chemistry with the example of water that exists in three different phases of solid, liquid and gas at 00C temperature and releases its latent heat energy during phase change. Latent heat is the energy absorbed or released by a substance during a phase change at a constant temperature. The question is can we harness this latent heat energy?
Realising the potential of latent heat energy, there is ongoing research in material science on developing Phase Change Materials (PCMs) that can have wide-ranging applications. Akin to batteries that store energy in the form of chemical potential and convert into electrical energy on demand, these PCMs can store latent heat energy from green sources like solar, wind or biowaste, for later use when no active energy is available. This is what we call Passive technology, which involves systems and devices that perform their function with minimal or no energy input or where the user’s interaction is limited and non-interactive.
But the biggest challenge in developing this passive technology is to overcome issues like low thermal conductivity of materials, improving durability, and finding sustainable synthesis methods, often by incorporating PCMs into composites or utilizing waste materials. Increasing use of passive technology of PCMs may give a boost to conserving energy in the wake of fast-depleting fossil fuels.
A PCM works in a two-step process: i) Through phase transition, when a PCM reaches its melting point, it absorbs heat and changes from solid to liquid, storing energy. Conversely, when it cools and solidifies, it releases the stored heat and ii) Thermal regulation that allows a PCM to maintain temperature stability in various applications, reducing the need for active heating or cooling systems.
A few examples of PCMs application that comes to my mind could be: i) In building materials where it can be integrated into walls, ceilings, and floors to regulate indoor temperatures, improving energy efficiency and comfort, ii) In thermal energy storage where excess solar energy is stored as heat for later use, enhancing the efficiency of solar power systems, iii) In cold chain logistics where these can be utilized in packaging for temperature-sensitive goods, such as pharmaceuticals and food, to maintain required temperatures during transportation and iv) In textiles where some clothing and bedding products are designed with PCMs to provide temperature regulation for comfort.
A few of the PCMs other than water which acts as coolant in cars or for heating purposes by circulating hot water in especially designed tubes that are still in use in Russia and many of the eastern European countries are: i) Paraffin Wax that is commonly used in building materials and thermal storage systems due to its relatively high latent heat and stable properties, ii) Salt hydrates such as sodium sulphate decahydrate, which have high thermal storage capacity and are used in various applications, including thermal energy storage systems, iii) Fatty acids that can be used in textile applications for their ability to absorb and release heat, providing comfort in clothing and bedding and iv) Biodegradable material like certain natural waxes or plant-based oils that are being developed for eco-friendly applications.
India can take the lead in this new emerging field that can contribute to efficiency and sustainability efforts in the energy sector. To foster innovative applications across various industries that contribute to energy security, the government needs to allocate generous funding for R&D and entrepreneurship, support incubators and startups, implement strong intellectual property protection, and encourage collaborations between academia and industry, both at the national and international levels. The time is right with the proactive and positive political leadership in the country.
I know it is difficult to replace today’s energy dependence on oil and gas, which is widely available and easily transportable. But the tariff blackmail of the USA in recent times has provided us with an opportunity to innovate. Indian scientists have always come out in flying colours when either the technology or the resources are denied. As Rabindranath Tagore said, “You can’t cross the sea merely by standing and staring at the water”. So, let us take a dip in the ocean of innovation and emerge as a winner.
