Towards a sustainable photovoltaic industry
Currently and for the years to come, photovoltaic technology (PV) is – and will stay – based on silicon (Si). Second most abundant element in the Earth crust, this material needs to be severely purified in order to create the photovoltaic effect. This purification requires very energy-intensive processes and a highly capital-intensive manufacturing base. The cost for photovoltaic-grade silicon accounts for up to 20% of the total cost for a PV module. And the investment related to this material accounts for 45% of the capital requirements for the whole value chain of PV modules production. Although the silicon atom is abundant on Earth, photovoltaic-grade silicon is a critical raw material.
Furthermore, the production of photovoltaic-grade silicon consumes a significant amount of energy and releases massive quantities of greenhouse gases. The energy requirement for producing 1 kg of silicon is on average 80 kWh. It is higher than the energy requirements for the production of steel or aluminum and on the same order of magnitude as the production of magnesium or titanium. For every kilogram of photovoltaic-grade silicon, 50 kg of CO₂ are released in the atmosphere – the highest value among these metallurgic industries. In other words, for every MW of PV modules produced, the CO₂ emissions related to silicon reach 200 tons.
Given the photovoltaic installation targets for the years to come, it is urgent and essential to use reliable technologies that allow to reduce the greenhouse gas emissions related to PV modules production.