Perspective: Wind-Hydro hybrid power plants to overcome the demerits of stand-alone wind farms

Introduction:

Wind and Hydro, both renewable forms of energy, both economical and best alternatives to thermal (coal based) energy and avoid harm to nature. But they too come with their baggage of demerits. Wind does not blow when there is a peak demand for energy (i.e. during afternoons) but is at full action in the night generating electricity when we need the least. There are no viable ways to store energy in the scale of mega-watt’s either. On the other hand, hydro, the cheapest source of electrical energy production, has geographical limitations such as elevations which are not significant enough or the insufficient water flow rate to set-up a hydro power plant.

Opportunity:

There are significant water bodies across India acting as reservoirs used for irrigation purposes, but no power generation is done as the elevations are not enough. Often, if not always, wind turbines are co-located around water reservoirs like the one shown in this picture.

So there lies an opportunity to utilize the energy generated from wind-turbines which cannot be stored to pump up the water from reservoir to a tank in upper hill to provide the required elevation needed to set-up a hydro power plant. While this method of storing energy is many centuries old but the benefits of adopting are huge now as Wind turbines these days generate power in the scale of mega-watts and are capable of pumping up great amount of water. The energy that can be recovered could be as high as 80%. Such a hybrid system can turn out to be a cost effective power plant due to higher utilization factor enabling power supply according to the varying demands across the clock.

Financial viability

For such system to be financially viable, capital costs required to set-up a hydro power plant have to be recovered from energy produced from it and there has to be a subsequent increase in the bottom line (profits) of the hybrid power plants. Let us work out a scenario with approximate costs to see if it makes sense or not.

We may consider a pool of wind turbines with a combined capacity of 100 MW, operating 12 hours a day, so generating 1200 MW hours of energy a day. Since there is always a case of production-demand mismatch and with absence of an energy storage system, we may consider an under utilization of capacity, assumed at 30% or 360 MW hours a day. If we consider 80% of energy recovery from a hydro power plant which is being set up which can produce 288 MW hours of energy on daily basis. If thus produced energy is sold at a rate of Rs. 4 per unit, it can create a revenue stream of Rs. 11.5 lakh a day. If we expect that this plant is operational 300 days in a year, it can contribute Rs. 34 crores of additional revenue every year and around Rs. 690 crores in its expected life span of 20 years. If the capital costs for setting up of this hydro power plant with a peak load capacity of 30 MW are around Rs. 100 crores, it would generate 7x returns in its life time or around 30% simple rate of return a year.

Maintenance costs are not considered here as they are minimal and an electrical distribution grid is considered to be already present with wind-power plant is being operational. All these financial figures are for illustration purposes only and the actual figures vary from project to project.

Policy and Regulations

Since the Governments promote production of renewable energy with many incentives, combination of Wind-Hydro power plant would not find any resistance from regulatory bodies even though additional approvals may be needed. Since the water being drawn from the reservoir is being returned to it, it may not invoke any objections from stakeholders of the reservoirs, the farmers.

Adoption and Scalability

While water bodies may not always be present in the vicinity of wind farms, other alternatives such as compressed air or thermal energy storage can be explored (on case to case basis) even though they may not offer the similar benefits of wind-hydro combination.

But if one takes a look at the geographical chart of India, each state on an average has at least 10 locations where wind farms and water bodies are co-located. There lies an opportunity to harness the infrastructure deployed to provide energy for growing India.

This system can be scaled and extended for projects such as linking of water reservoirs to bring a balance in the water availability across geography instead of wasting the enormous power generated by wind turbines when there is no load.

References:

1.     Wind Generates Electricity When We Need It Least  (Institute for Energy and Research) http://www.instituteforenergyresearch.org/2012/10/24/study-wind-subsidies-disproportionately-produce-electricity-when-we-need-it-least/

2.      Calculating the amount of available hydro power

 where,

P is power in watts; η is the dimensionless efficiency of the turbine; ρ is the density of water in kilograms per cubic metre; Q is the flow in cubic metres per second; g is the acceleration due to gravity; h is the height difference between inlet and outlet (Source: Wikipedia)

3.      Picture shown is taken at Vanivilas Sagar in Karnataka

4.      Scientific American magazine, March 2012, page 50, reports energy recovery from pumped up hydro power plants can be 80%

Book Review: Young Tagore

This book is about Tagore in the making. It is a careful reconstruction of days of Tagore during his childhood and youth. It has liberal references to Tagore’s memoirs ‘My Reminiscences’ and ‘My Boyhood Days’ and his other works to create a psycho biography of young Tagore, the inner world within him shaping the genius.

Rabindranath’s creativity and literary interests were evident when he translated Shakespeare’s works when he was 13. His ability to write poems brought him praise from his school teachers but won him no friends instead he was bullied by schoolmates for being feminine. He lost his mother when he was 14. While making efforts to overcome the feeling of abandonment, he became emotionally closure to his sister in law, Kadambari (his elder brother’s wife) who nurtured the creative abilities of Tagore. And a travel to England for a year, when he was 17, expanded the universe of Tagore making him more expressive and liberal in thoughts. On his coming back, his literary works flowed uninterrupted and brought him name and fame. But his marriage against his liking proved an emotional drain and the suicide of Kadambari puts Tagore into depression which was expressed in his works produced during that time, more evidently in Ghare Baire (The Home and the World).

While the world knows of Tagore as a poet, novelist, story writer, painter, and philosopher (and so on), this book shows he was a private person and a series of untimely deaths in his family made him more sensual and gave him an ability to create stories from his own life.

--0--

After reading this book, I thought of checking with Sudhir on the question I had and he replied. Here is the e-mail conversation.

Dear Sudhir,

Reading your ‘Young Tagore’ helped me understand the sensual young Tagore but a question raised in myself, that, if Rabindra was not born in a rich family, or if he was forced to earn for his daily bread, was his sensual creativity still remained high?

I thought many are born with creative abilities but that does not see nurturing or the person cannot spend much time in creative expressions in the form of writing, painting, theater etc. as their daily chores of life forces them to earn from some other routine jobs to feed themselves and their family. For young Rabindra, there were no such financial worries or denying access to resources he wanted. Did this help him to spend time in what he was good at and what he liked to do and flourish?

Thanks,

Anand

----------------

Dear Anand,

You are right that creative ability need facilitating circumstances, social and financial, to express itself.

Regards

Sudhir Kakar

Book Review: Ecstasy

This is the story of a village boy Gopal (symbolic representation of Ramakrishna Paramahamsa), coming in contact with sadhus residing in the rest house of his village, developing an interest in mysticism and reaching spiritual heights, quite unconventionally and rapidly. Another story of Vivek (representation of Swami Vivekananda) runs parallel who becomes disciple of spiritually enlightened Gopal, known as Ram Das Baba. While Gopal takes up his destined path of becoming a Yogi with a little resistance from his mother, Vivek had no idea of taking up spiritual path until his father’s death even though his horoscopes suggested that is his destiny.

This would have been a fictional biography of Ramakrishna Paramahamsa, but author had made changes by setting up the story in a different time, so the protagonist characters become symbolic representations of the spiritual legends.

Book Review: Mandra (Kannada)

Art is divine but need not be the artists. This contradiction is the plot of this novel. It is the story of a classical singer Mohan Lal and his women. On his way to mastery of the Hindustani music, he scores over many females. Two failed marriages and other relationships does not deter him from his path to popularity and fame, rather they fuel it. Like all things come to an end, his musical career too tops out coinciding with his failure in indulging in bodily pleasures resulting in calling off of his relationships. He attempts to review some of the facts from his past, the responsibilities he ran away from, but with no great success. His break-down in the musical performance prepares the ground for the rise of a new artist, one of his pupils and a past associate.

Music is more than producing sounds for expression of an emotion. It could be the life spirit. The author shows how the subject of an art gets finer with knowledge and skills being passed on from the master to his pupils, but the art within the master dies when the life spirit gets destructed. A complex web of musical world is reveled in precise details.

Book Review: Argumentative Indian

This book brings together sixteen essays under a single title. Here Amratya Sen reasons how India found its identity during different times. He takes multiple references of Bhagavdgita and the influence ancient writings such as Vedas and Upanishads had on the culture and lives of the people. He argues how the Mauryan king Ashoka and the Moghul ruler Akbar had similar outlooks and were tolerant of different religions. He narrates how Gandhi and Tagore disagreed on many aspects. He explores how much of the grand vision of Nehru as delivered in his speech ‘Tryst with Destiny’ is realized.

This books has no bounds as it travels across different time horizons and subjects. If you are an Argumentative Indian, you should have this book on your study table.