Human interaction with the Rock Cycle

Fossils fuels that account for nearly 40% of our primary energy demand are formed from decayed animal and plant remains in anaerobic conditions, most often in marine environments. Over millions of years and due to great heat and pressure, bacteria break down the organic materials into natural gas depots. The natural gas is then squeezed out and travels upwards through permeable rocks before eventually meeting a tap, eg, an anticline with impermeable rock on top.

Human interaction

  1. Geologists first locate anticlines that potentially have gas beneath them

  2. Small explosions are set off, vibrating the ground

  3. These shake the gas, allowing for three dimensional mapping of the field

  4. If gas is present, tests are carried out to determine the exact size and extent of the gas

Gas production in Ireland

  1. There are two main sources of gas in Ireland; both found offshore (undersea) 

  2. The first is the Kinsale Head gas field; discovered in 1971, with production beginning in 1978/ Its main platform was located in 100m of water, with the gas flowing from 1km below the sea bed. This gas was pumped offshore to Cork Harbour via an underwater pipeline. Two additional gas deposits were later found nearby in the Seven Heads area; which were then quickly connected to the main gas terminal. However, they were not as fruitful as had been hoped and quickly became exhausted. Decommissioning began in 2020, with the second gas field expected to be closed by 2023.

  3. The second is the Corrib gas field (Mayo). It is located approximately 70km off the coast and 300m in depth. The gas field itself is more than 3,500km under the sea bed. It is estimated to have about 18 years worth of supply. It’s terminal is located 9km inland and this has caused great conflict between the Shell gas company and the locals in the area. It had been hoped that production would start in 2006 but unfortunately issues between both parties halted that until December 2015. 

Gas use in Ireland

Bord Gais Energy, a state body, is responsible for the natural gas pipelines in Ireland with most of Ireland connected to the gas network. In fact, we have even been connected overseas; one subsea pipeline links Dublin with Scotland, while another links us with Scotland via Northern Ireland. In recent years, our market has become more competitive, with a variety of gas providers now offering cheaper rates, eg, Electricty Ireland and Airtricity. We are now also able to generate electricity using gas. 

Natural gas has been a major benefit to our economy, generating revenue and reducing dependency on imports. This is why the Corrib gas field was so contested, its benefits for the country would be huge. 

Natural gas is also the cleanest of all fossil fuels.