Renewable Energy Systems.
The Indian Scenario. As India goes big on innovative technologies, renewable and Sustainable Energy situation look up.
The concept of renewable energy systems has come a long way since its origin.
It is widely believed that renewable energy technologies have the potential to provide long lasting solutions to the energy problems being faced by India.
Although renewable energy concepts have been well proven both on paper and on ground, it is still at various stages of evolution. There is enough scope for improving the work efficiency and reducing overall costs. In particular, solar and wind have shown several encouraging trends for tropical countries where there is no dearth of sunshine.
A renewable energy system design is all about man’s ability to optimally use locally available resources – sun, wind, earth, and even wastes – renewably. The most familiar such sources are:
– wind energy,
– solar energy,
– geothermal energy,
– ocean energy,
– biomass energy and
– fuel cell technology.
The factors which determine the correct choice are mainly the locally available resources, demographic conditions, the terrain, and the nature of usage.
Sources of energy are well known. Means to harness those are varied. It is the adaptation of the combination of such sources and the choice of the working substance which hold the key to run the renewable energy system efficiently.
Critics point out that the solar panels, wind turbines or the storage batteries used in a renewable energy system depend upon coal because the material used therein are fabricated by using energy from coal. Their transportation is carried out by burning fossil fuel. That is, the initial investments in renewables are made on materials – steel, concrete, glass, PV panels, mountings, transmission lines, copper, aluminium, etc. All such materials are produced after consuming huge amounts of coal and oil like resources and electrical power. A 3 MW wind turbine, for example, will need almost 200 MT of steel, a few kilograms of aluminium, copper and composites which are actually produced by burning coal and coke!
However, there have been instances where even coal mines have to resort to solar power to operate the mining equipment, especially in remote places where grid connection is practically ruled out.
Despite such arguments, it can be safely assumed that man has been reasonably successful in his attempt to substitute coal to a great extent. The energy delivered from those panels and turbines do contribute positively in bringing about a net green effect.
Other than electric power
Renewable energy systems do not necessarily give electric power only. They are capable of operating other utilities like:
– heating, ventilating, and air conditioning (HVAC) systems
– water and waste management
without involving electricity!
Also Read: One Concept How to integrate renewables with a high-rise building.
Under a typical Indian urban condition, the user will opt for a combination of solar, wind, bio-mass, and geo-thermal energies to meet all its energy needs. In a hilly terrain, the user may add hydel in its scheme of renewables.
The solar power system, one of the components of a renewable energy system, also has to encounter criticisms like: ‘the sun disappears at night, the system has to see cloudy days; in such a scenario how can one use solar power systems to provide uninterrupted reliable electric power 24x7x365 ?’
One normal solution is: Store it. Storage batteries are indeed the most popular form of storage. Unfortunately, storage of electric power comes at a price. Battery technology has immensely improved; its costs too have reduced; though the change is not similar with that of mobile call rates. Storage of electricity invariably involves conversion processes – AC to DC, then to chemical, then to DC, and then again to AC. Every successive stage of conversion is naturally accompanied by less than 100% efficiency.
Storage of Power
The success of a renewable energy system largely depends upon the ‘storage of power.’ Herein lies the significance of the choice of energy source and the nature of energy usage. Since a source of energy is intermittent – both in terms of quality and quantity as per the time of the day & season of the year – it calls for a stable form of ‘energy storage’ system in the design. That is, capture of energy produced at one time, and use of the same at a later time. The various energies so obtained be collected and stored. And then it be made available for distribution and consumption in a regulated way that will finally become the rated capacity of the system. Compressed air energy storage (CAES) and pumped-storage hydroelectricity (PSH) are very popular. Batteries are losing out.
A smart renewable energy system design will surely have adequate power storage capacity and minimum number of conversions between production and consumption.
For instance, in case of an HVAC application, geo-thermal energy provides most of the power storage solutions; water is pumped to higher heads with little or no use of electric power.
Stand-alone power generation
Renewable energy system has found its way into a wide range of large and small stand-alone power generation applications. This versatile range of applications is what makes renewable energy systems special. It becomes very advantageous as compared to the traditional electrical energy technologies which need an existing power infrastructure.
Being largely centralized the traditional electrical energy technologies have to depend unavoidably upon a network of long transmission lines to deliver power to end users. As a result, they have to tolerate issues like line stability, efficiency losses typically associated with transmission lines.
Decentralized Power Systems
Renewable energy systems, in contrast, are inherently decentralized. That is, the
generation and consumption of electric power take place in relatively close proximity. Long transmission lines along with the associated equipment are not needed. Having electrical power sources near the point of consumption eliminates transmission losses and thereby enhances the net efficiency of the whole system. In case of remote areas, this seems to be the only alternative.
In addition, a decentralized power facility gives the end users a fair degree of control over the production and usage of their own power supply.
Further, a decentralized power generation system competes fairly favourably against retail electricity sale through the grid.
Features like environment friendly, decentralized nature of production and consumption, storage ability, and low operating costs make renewables more lucrative than coal or oil. Investing in renewables thus makes a prudent business sense.
As the number of such decentralized renewable energy systems increase, the load on the grid and the need to install more coal based power plants progressively reduce. With such a long term perception, India is presently engaged in setting new highs in renewable energy installations, and is well prepared to permanently discard coal for electricity generation.
In India, during the last 25 years or so, there has been a strong quest of actions relating to a range of renewable energy technologies. India is progressively more accommodating environment friendly renewable energy techniques. Today, renewable energy systems account for nearly 33% of India’s primary energy consumptions. The info released by the Ministry of New and Renewable Energy (MNRE) in June 2018 reveals:
– Renewable power installed capacity has already reached over 70 GW and over 40 GW of renewable capacity is under construction or has been tendered.
– Solar energy capacity increased by 8 times from 2.63 GW in 2014 to 22 GW.
– Wind energy capacity increased by 1.6 times from 21 GW in 2014 to 34 GW.
– $42 billion investment attracted over the past four years in green energy projects
– 10 million man-days of employment per annum created
– Globally, India stands 4th in wind power, and 6th in solar power installed capacity
– Globally, India stands 5th in renewable power
– India is well on track to achieving 175 GW target of installed renewable energy capacity
The chief achievement listed by the MNRE is the reduction in solar and wind power tariffs to historic lows through transparent tariff based competitive bidding. Solar tariffs have touched Rs 2.44 per unit, the lowest they have ever reached, in the latest 2000 MW auction conducted by Solar Corporation of India (SECI).
Prof Hiranmay Saha, Green Energy Center, IIEST insists, “You must have a combination of sources, integration of different and dependable sources.”
To give a real shot in the arm to India’s renewable energy mission, the government policy makers and industry stakeholders must collaborate with each other. It is to overcome the barriers, to come up with rational decisions and to enhance the deployment of renewables for the future.
Then only India would be able to attain its ultimate objective. That is, ‘To get rid of coal and fossil fuel for electricity generation.’
With the right policies and relentless focus on quality, costs and consumer & producer interests, this appears to be possible.