It was enriching meeting Arijit Ghosh at his residence, A2/206 Silver Estate, Tower 5. His scope of work is in geothermal space. India has huge potential in generating eco-friendly and cost-effective geothermal power – an urgent need of the hour. What he shared on this topic is as follows.
Buildings do end up consuming 40% of World’s energy, and similar carbon emission – 20 % component lights and 70% component the HVAC and 10% Plugs. Buildings are run with electricity (Primary Energy) and this energy comes from the Grid. 73 % of the grid electricity is produced from Coal. Grid electricity has a lot of carbon. At the point of burning coal to get the electricity, its 824 Gms per unit of electricity generated. But the renewable electricity produced through Solar, Hydel and wind contributes to 12% of the grid capacity at the National level. This brings down grid carbon by 12%, still 724 gms per unit of Electricity that we use. When we burn our diesel generators every litre burnt emits 2769 gms of carbon.
To reduce carbon and leave the world in a better shape for our next generations, that’s the definition of sustainability. The bigger challenge is how we cool our living places. Cooling is a necessary evil. It forms 5 sustainable development goals out of 17.
When we use window, split and VRF air conditioners, we use a lot of electricity. The electricity produced from coal is another evil. Each of these types of air conditioners consumes 1 unit of electricity and produces 2.75 units of cooling. That’s a lot of energy consumption.
It happens for a lot of reasons though and the primary one our homes are not insulated. The heat comes in and then we are forced to cool the house down by air conditioners.
So how do we decarbonize the cooling?
When we use AC machines, we collect the heat from the house and throw it back in the environment. We cool the house and heat the environment. So slowly the machines start operating in hotter and hotter environment. This increases the energy consumption and requires more electrical energy and unfortunately more coal watts to be produced at the grid level.
So is there any other way?
There is a novel way. Suppose we send the heat collected from the building to the soil, deep inside, a level not affected by the temperature above, to stable temperature that remains the same in summer and winter. This is earth’s thermal energy stored in the soil, making soil the biggest thermal battery.
This is called Geothermal Energy.
It consumes 1 unit of electricity to produce 5 units of thermal energy (cooling /heating and hot water).
In summer we need to push the heat into the soil and in winter and when we need hot water, we need to pull the heat out and recycle in the house.
The benefit is the exchange temperature is less than half of what is available outside. So very little (only 50 % of the conventional systems energy required, no gas to fill every year and biggest benefit is since the energy is in the form of heat, there is no carbon in it. And come to think, if it was run by Solar that is off grid there is almost no carbon in the system.
But not everything is so sweet! It’s expensive and almost impossible unless planned from the beginning for residential apartments. But it’s extremely beneficial in a lone house or bungalow with some land.
True it’s expensive to set up, but almost free energy and no carbon emission.
