An energy model

Providing a CO2-neutral energy supply for major industrial countries, or even for the entire global energy economy, is not an insurmountable problem. The main thing that is missing is the will to do this.
The main argument against a rapid expansion of sustainable energy sources is the supposedly excessive cost of green energy. The cost of all the energy produced worldwide (electricity, petrol and other forms of energy) in 2015 amounted to 9.1 billion US dollars. Statistics show that the global gross domestic product recorded for the same period was approximately 75 billion US dollars. In reality, the actual global overall economic output may have been a little higher. So, roughly speaking, every product and every service has a hidden average cost factor for energy of 10%. Let us assume that, in order to prevent a climate disaster, we will need to convert to energies that are CO2-neutral, but 50% more expensive. This would then mean that all prices, whether for products or services, would rise by 5%. Would this really be totally impossible?
A second argument against green energy is that renewables are not reliable enough to ensure an uninterrupted power supply. But if we examine it more deeply, we find that this argument isn’t sustainable either.
The team and group of companies associated with Niveau élevé has been attempting to establish a power supply for the Auroville international city project, and so ultimately for a micro-society with 50,000 people. This power supply should be based entirely on renewable energies, without the aid of conventional energy sources and without relying on the storage capacity of an electricity network. The aim is to demonstrate that it is entirely possible to convert an entire society to green energy and still remain comfortable and competitive in all areas.
The first phase of this endeavour consists or consisted of covering the current power requirement of the emerging town (which has around 2400 inhabitants) entirely from wind energy. So the group of companies associated with Niveau élevé, made up of Aditi Diamonds, Gold-in-Glass and Varuna, built six wind turbines which produce around 8,000,000 kWh of power in total every year. The annual total power consumption in Auroville, at that stage of development, was around 3,500,000 kWh. In India it is possible to feed the electricity generated by wind turbines into the grid at the wind farm location. On payment of a charge, it can then be drawn back from the grid and used at the place of consumption. This rule means that Auroville is currently supplied with electricity from wind power. In any case, the amount of green electricity produced is currently twice as much as Auroville consumes. The surplus power is sold and the money is invested in new equipment. 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, in the vicinity of the city of Coimbattore. The other two are in the state of Karnataka.
Supplying an emerging town such as Auroville with CO2-free electricity with the aid of a few wind turbines is certainly a good step, but it is not really a large enough step to bring about something essential in the race against climate collapse. The decisive element would be to be able to maintain the power supply to the city without relying on the electricity grid of the state of Tamil Nadu. But this is not currently possible with wind power for two reasons. First there is actually not enough wind in Auroville to meaningfully drive wind turbines, which is why the wind farms are located some 500 km from Auroville. Second, the turbines produce most of their electricity during the “windy season” from May to September. The state of Tamil Nadu has set up a “banking” system for people who use their own generated electricity. This means that they produce their power separately from their consumption and move any surplus kilowatt hours to their “energy bank account” from which they can “make withdrawals” when their consumption exceeds their production. The wind turbines with their irregular generation rate need this system in order to cover Auroville’s ongoing electricity requirements. In the end, we therefore use conventionally generated power to cushion our asymmetrical supply and demand situation.
But this initial phase has revealed at least one thing: in Tamil Nadu, wind power is cheaper than coal-generated electricity. Each of the six turbines cost around € 700,000. The turbines will last for at least 20 years and they will generate between one and two million kWh electricity every year. Let us assume a rounded-down average production of 1,300,000 kWh per year per turbine and calculate a linear amortisation of 5% per year. With an average maintenance charge, i.e. the cost of repairs, insurance, etc., of € 15,000 annually, this gives annual costs of around € 50,000. With production of 1.3 million KWh, the cost is thus 3.8 euro cents per KWh. The electricity that we purchase in Tamil Nadu under normal purchase conditions from the only supplier – the state-owned electricity company – costs 0.10 euros per kWh, however. Because we produce our own green electricity, one kWh now costs us just 3.8 cents. This is less than half of what we previously paid for the nationalised coal-generated electricity.
In order to construct an energy system for Auroville which is self-supporting and independent of all external factors, is really autonomous and can supply the city with green electricity continuously, we are planning to incorporate photovoltaic systems within the city area which are large enough to produce at least 20% more electricity than is consumed within our own electricity distribution network. A pumped-storage plant is also planned. This will use the surplus energy to pump water up to an artificial lake at the highest point in the area. We have combined the cabling work with another project – construction of a seawater desalination plant (see chapter 20) – so that we can bury the two massive pressure lines in the ground at the same time. One will be used to transport drinking water from the desalination plant to the highest point in Auroville from where it can be distributed. The second is for the pumped-storage system. At night and on cloudy days, the water will then flow through a pressure line to a reservoir on the seashore and its stored energy will be given up again via a turbine.
This type of pumped-storage plant traditionally works with 70% efficiency. This means that, if we need to use 100,000 kWh to pump the water from the reservoir by the sea to the reservoir on the hill, we will get 70,000 kWh back via the turbine at the end of the pressure line. However there are now system that are 90% efficient.
Ultimately the following will need to be provided to ensure an autonomous, CO2-free power supply in Auroville:
a) A dedicated power distribution network that does not belong to the state-owned electricity company
b) The maximum possible number of PV systems on the roofs of Auroville
c) Additional, relatively large PV systems in the city’s industrial quarter
d) An upper reservoir with approx. 100.000 m2 water area and average depth of 8 m
e) A lower reservoir with the same capacity
f) A pressure line from the upper to the lower reservoir
g) A turbine house with turbine and transformer substation. The turbine can be used for power generation when the water flows from the upper to the lower reservoir and as a pump when the water is pumped from the lower reservoir back to the upper reservoir during the midday hours.
One day, these seven elements will allow us to convert a population of up to 50,000 people to 100% CO2-free green electricity. By generating its own electricity, the city would then be totally independent of the Indian power network and might even be able to go off-grid altogether. The power from the existing wind turbines will then be sold and the proceeds used to maintain and extend the PV systems.
This now leaves us with the issue of transport. Here, as well, we are already in the process of moving away from normal petrol-driven transport. There are already electric motorbikes in production at Auroville. 90% of its inner-city traffic is by motorcycle. Cars are rarely seen. The electricity needed to charge the electric motorcycles is available free of charge in the city, they are almost noiseless in operation, they are produced in the city and are relatively cheap, so it can be assumed that it will not be long before the majority of Auroville inhabitants ride these E-motorbikes. Perhaps all petrol and diesel vehicles will eventually be banned from the city by referendum. Indeed there are already enough suitable alternatives in India, such as small and low-cost electric cars.
Niveau élevé therefore hopes that, at some point, there will be a micro-society with around 50,000 inhabitants that covers 100% of its energy requirements from green electricity and where traffic is powered via the electricity network and not at petrol stations. But there is still quite a lot of work to be done before we reach that point.
Niveau élevé