Padmashree Prof. Dr. P. K. Jena
(Former Director General, Council of Scientific & Industrial Research, India)
Institute of Advance Technology & Environmental Studies (IATES),
80A – 81A, Lewis Road, Bhubaneswar – 751 002,
Email: [email protected]
Energy is the most essential resource for our industrial and socio economic developments. Since the dawn of civilization, man has been using renewable energy resources like sun and wind in various ways in his day to day life. In due course with development of science and technology, he discovered more attractive and readily available large reserves of non renewable energy resources like coal, oil and natural gas and started mining and using these extensively by generating energy for mining of minerals, producing various items in industries, transporting men and materials and for other commercial and domestic purposes. At present, nearly 90% of total energy consumed by human society on this planet, is being derived from fossil fuels. Due to extensive mining and utilization of these non renewable fossil fuels with limited reserve, it is apprehended that, by end of the century most of these will be consumed. Besides this, release of large amounts of green house gases like carbon dioxide and oxides of nitrogen and sulphur along with fine particulate matters to the atmosphere during combustion of these fossil fuels, has resulted in global warming and climate change causing sufferings to all living beings on the planet.
In view of the abundant energy available from sun and wind, the scientists and technologists in different parts of the world are engaged in developing better technology to harness clean energy from these for meeting the growing needs of human society. Harnessing renewable energy resources while enhancing our total energy resources, will also help in various ways like mitigating the adverse effect of climate change, improving our health conditions and maintaining sustainable development for all time to come. At the United Nation Climate Change Conference which took place in Paris in the latter part of 2015, all nations have committed to replace at a fast rate the fossil fuels by green renewable energy. At present, extensive research and development programmes have been taken up all over the world for using renewable energy in major areas like mining, industries and transport sectors besides their application in domestic sector for supplying electricity.
It has been estimated that, approximately 10% of world energy consumption take place in mining and processing of mineral resources. It has been found that, the energy cost in mining sector is nearly 20% of the total operating cost and is second biggest cost factor after the labour cost.
Most of the time, mining companies have to deal with high electricity cost due to their remote locations. In addition to that, sometimes because of interruption in supply of electricity the mining activities are greatly hampered. It is felt that, replacement of fossil fuels like diesel, by renewable energy for generating power, is a wise move; for example, solar energy is a good substitute of fossil fuel because it is clean and large in quantity. The soaring price of diesel and difficulty in availing its required amount at mine site very often result in increase of the cost of minerals. In mining sector, application of solar energy will be very appropriate because of its abundance, clean in nature and availability of developed technology for harnessing it in large scale. It is suggested that, solar power can add value to mining for grid connected mines as well as off grid mines thus by allowing mining of minerals all day and night.
Solar Power and Wind Power for Grid Connected Mines
Mining companies in a number of countries even though most of these are connected with the grid, prefer to have additionally renewable energy resource like solar and wind energy because of high electric prices or unstable supply from the grid. This situation prevails in most of the countries. Some of the mining companies because of availability of sun shine or wind for a number of days in the year, prefer to have their own source of solar or wind energy or long term Power Purchase Agreement (PPA) for solar or wind energy with some other companies. This investment in renewable energy helps the mining industries to continue mining activities throughout the year without any interruption for want of grid connected power. This helps in cutting down the ultimate price of minerals.
Solar and Wind Power for Off-Grid Connected Mines
There are many mines in different parts of the world where electricity is not available and it would be very costly for developing infrastructure to get electricity from distant places. At the same time, in those remote areas producing electricity from diesel set to run mining activities, from the cost point of view, is not wise. In such cases it is felt that, it would be cost effective to produce electricity from solar and wind energy. It is reported that, in some areas in the world, solar energy is found to be about 50% less expensive than diesel based electricity, particularly where diesel is more costly along with higher expenses incurred towards its transportation. In such cases, it would be always preferable to use solar power.
Where solar power is interrupted because of cloudy weather or at night, the solar – diesel hybrid system is found to be more advantageous. In this case the stored solar energy can be utilized and consumption of diesel for producing electricity can be reduced to a large extent. However, it has not been economized so far to use solar stored energy. At present, there are many companies in the world who are producing renewable energy and willing to offer long term PPA for off-grid mines. In the off-grid mine areas the independent power producers are willing to invest if there are a large number of mines in the locality so that they are assured of utilization of the power they generate. The mined out areas can be used for generating wind and solar energy and supply the renewable energy to the nearby active mines.
The use of renewable energy in mining sector with or without fossil fuel powered energy, seems to be more attractive in near future particularly due to technological advancement in harnessing clean energy from sun and wind economically. The opportunities and some barriers in using renewable energy are summarized below:
- Renewable energy can make mining operation more efficient as the price of diesel as well as its transportation expenses are getting more expensive.
- In remote areas where there is no fossil fuel based electricity, the renewable energy can play a major role in regular functioning of the mine.
- With development of better technology, it is likely that renewable energy as such or in combination with conventional energy source can be economically more attractive. For example, it is reported that, solar photovoltaic (PV) system integrated into diesel fired energy generation with a capital cost of 2.2 million dollar per mega watt and diesel with a price of one dollar per litre, it would be financially beneficial to use the energy thus produced for mining minerals in a mine even with a life of only 7 years.
- Very often in remote areas, there is disruption of electric supply more frequently causing a lot of problems in mining operation. In such cases, a standby renewable energy system will come to the rescue.
- One of the most important factors is that by using renewable energy there is a drastic reduction in carbon emission from fossil fuel based energy system and it would be a less polluting mine atmosphere.
- The use of renewable energy would be more profitable in case of mines having longer life and makes the project more viable.
- The renewable energy can be utilized to supply power to the local communities and improve the local economy.
- Renewable energy if produced by the company at the site, besides the scope for utilizing this energy, the company can create jobs for the region and the community.
- If the life of mine is short, heavy investment in production of renewable energy has to be made by the company or if it is supplied by another party the agreement can be more complex.
- In many cases, renewable energy requires a long payback period as well as investment in adopting better technology or power purchase agreement.
- Areas where mining projects have access to sufficient conventional energy resources, the adoption of renewable energy may be more challenging.
- Renewable energy Power Purchase Agreement (PPA) may cause long term liability or conflict with the existing arrangement with power station operators or fuel supplier.
- Seasonal adverse weather condition may cause interruption in renewable power generation and causes problems for supply of energy for mine operation.
All over the world in recent years serious efforts are being made to utilize solar and wind energy in mining sector particularly in remote off grid areas as the oil price is soaring and the solar and wind energy is becoming economically attractive particularly with the application of advanced technology. In many cases solar – diesel hybrid has been found to be more attractive as it is possible to run mining operation throughout the day and night without interruption.
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