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An energy model

An energy model

A CO²-neutral energy supply for the major industrialised countries, and even for the entire global energy industry, would not be an insurmountable problem. What is mainly missing is the will.

The main argument against a rapid expansion of sustainable energy sources is the allegedly too high cost of green energy. All energy produced, worldwide, whether electricity, petrol or other forms of energy, cost an amount of US$ 9.1 trillion in 2015. The recorded global gross domestic product was about US$75 trillion for the same period, according to some statistics. In reality, the actual total global economic output is probably much higher. So we can roughly say that in every product, every service, every performance there is an average cost factor for energy of 10 %. Let’s assume that in order to prevent a climate catastrophe, we would have to switch to energies that are CO²-neutral but 50% more expensive. This would mean that all prices, whether for a product, a service or a service, would increase by 5% in price. Would this really be completely impossible?

A second argument against green energy is that renewable energies are not constant enough to ensure an uninterrupted power supply. On closer inspection, this argument does not seem tenable either.

The team and the group of companies around Niveau élevé are trying to create an energy supply for the international urban project Auroville, i.e. ultimately for a micro-society with 50,000 people, that is based entirely on renewable energies, without the aid of conventional energy sources and without using the storage capacity of an electricity grid. The aim is to show that it is possible to convert an entire society to green energy and still remain comfortable and competitive in all areas.
The first phase of this effort is, or was, to ensure that the current electricity needs of the emerging town (currently approx. 2400 inhabitants) are covered entirely by wind energy. For example, the group of companies associated with Niveau élevé has had six wind turbines built by Aditi Diamonds, Gold-in-Glas and Varuna, which produce a total of about 8,000,000 KWh of electricity per year. The total annual consumption of electricity in Auroville, at its current stage, is about 3,500,000 KWh. In India, it is possible to feed the electricity from wind generators into the grid at the location of the plant and then to take it out of the grid again at the location of self-consumption and consume it, paying a fee. With the help of this scheme, Auroville is currently supplied with electricity from wind energy. In any case, you produce twice as much green electricity as you currently consume in Auroville. The surplus energy is sold and the money invested in new plants. Of the six turbines, each with a capacity of 0.8 megawatts, four are located in wind farms in the central southern tip of India, near the city of Coimbattore, and two in the state of Karnataka.

Supplying a nascent city like Auroville with carbon-free electricity with the help of a few wind generators is a good step, but not really of a dimension that could make any essential difference in the race against climate collapse. The crucial element would be if the city’s power supply could be maintained without the Tamil Nadu state power grid. But this is currently not possible with wind energy for two reasons: Firstly, there is too little wind in Auroville itself to operate wind turbines sensibly, which is why the turbines are located about 500 km away from Auroville. Secondly, the plants produce most of their electricity within the “wind season” from May to September. The state of Tamil Nadu has set up a so-called “banking” for wind power operators who consume their own electricity. This means that you produce your electricity independently of your consumption and put surplus kilowatt hours into your “energy bank account” from which you can “withdraw” them again if your consumption is higher than your production. Only with the help of this system can the wind turbines with their irregular production meet Auroville’s continuous electricity demand. So in the end we do use conventionally generated electricity to buffer our asymmetric supply-demand situation.

However, this first phase has shown at least one thing: Wind energy is cheaper than coal-fired power in Tamil Nadu. Each of the six turbines has cost about 700,000 €. The lifetime of the turbines is at least 20 years and the annual electricity production is between one and two million KWh. Let’s assume a deep average production of 1,300,000 KWh per year per plant and assume a linear depreciation of 5 % per year. With an average “maintenance” fee, i.e. the costs for repairs, insurance, etc., of 15,000 € per year, we would then have annual costs of about 50,000 €. With a production of 1.3 million KWh, this results in a cost price of 3.8 euro cents per KWh. However, the electricity we get in Tamil Nadu through a normal electricity bill from the only supplier, the state electricity company, costs 0.10 euro cents per KWh. By producing our own green electricity, a KWh now costs us only 3.8 cents. That is less than half of what we used to pay for the state coal-fired electricity.

In order to build an energy system for Auroville that is self-sustaining and independent of all external factors, which is truly self-sufficient and can continuously supply the city with green electricity, we are planning solar plants within the city area that are dimensioned to produce at least 20 % more electricity than is consumed within the city’s own electricity distribution network. In addition, a pumped storage plant is planned, which will use the surplus energy to pump water into an artificial lake at the highest point of the area. We have linked the laying of the pipeline to another project, the construction of a seawater desalination plant (see Chapter 20), so that we are putting two huge pressure pipelines into the ground at the same time. One for transporting the drinking water from the desalination plant to the highest point in Auroville, from where the drinking water can be distributed, and a second for the pumped storage plant. At night and on cloudy days, the water will then flow through a pressure pipe to a reservoir about 45 m below on the seashore and release the stored energy again via a turbine.

Such a pumped storage plant traditionally works with an efficiency of about 70 %. This means that if we have to spend 100,000 KWh to pump the water from the reservoir at the sea into the reservoir on the hill, we get 70,000 KWh back via the turbine at the end of the pressure line. Recently, however, there are already systems that have an efficiency of 90 %.

Ultimately, the following needs to be done in Auroville for a self-sufficient, CO²-free energy supply:

  1. Its own electricity distribution network, which does not belong to the state-owned energy company
  2. A maximum of solar panels on the roofs of Auroville
  3. Additional, relatively large solar installations in the city’s industrial sector
  4. An upper reservoir with approx. 100,000 m² of water surface and an average depth of 8 m
  5. A lower reservoir of the same capacity
  6. A pressure line from the upper to the lower reservoir
  7. A turbine house with turbine and transformer station. The turbine can be used to generate electricity when the water flows from the upper into the lower reservoir and is used as a pump when the water from the lower reservoir is pumped back into the upper reservoir over the midday hours.

With these seven elements, we can convert the city, which ultimately has 50,000 inhabitants, to 100 % CO²-free green electricity. With its own electricity production, the city would thus be completely independent of the Indian power grid and could possibly even decouple itself from it altogether. The electricity from the already existing wind generators will then probably be sold and the proceeds used to maintain and expand the solar plants.

What remains is the traffic. But here, too, efforts are already underway to move away from normal petrol traffic. Electric motorbikes are already being produced in Auroville. In Auroville, 90 % of inner-city traffic is by motorbike; cars are rare. Since the electricity for charging is available free of charge everywhere in the city, since the electric motorbikes run almost noiselessly and since they are relatively cheap from local production, one has to assume that quite soon the majority of Aurovilleans will ride such e-motorbikes. Perhaps later, all petrol and diesel vehicles will be banned from the city by referendum. There are plenty of nice alternatives in India, such as small and cheap electric cars.

Niveau élevé thus hopes that one day it will be possible to present a micro-society with about 50,000 inhabitants that covers 100 % of its energy needs from ecological electricity and whose traffic is supplied with energy via the electricity grid and not via petrol stations. Until then, however, there is still a lot of work to be done.