“What is the difference between solar energy and geothermal energy?”

It’s not the most common question however I do get it thrown at me every once in a while and on that basis I thought it’s time to clarify for the views.

 

Solar Energy:

Of all of the solar technologies, solar thermal systems are by far the most straightforward and the best developed. Architectural Designs are being developed to conserve solar energy by taking advantage of the site and building materials which in turn transform a building into a solar collector. There are many mechanical moving parts within an active solar thermal system.

The makeup of Solar Energy Systems and how solar panels work is best described as follows:

The solar collector (basic unit) is a panel generally made from aluminium, glass, plastic and copper. These panels when fixed to a roof absorb direct sunlight and transfer heat to a fluid that passes through the collector or basic unit. This fluid then flows through pipes into the building where it then heats water or warms the rooms.

Sunlight is converted into electricity by Photovoltaics (solar cells). These solar cells produce an electromotive force in a material as a result of its absorbing ionizing radiation.

In the case of semi-conductors, significant conversion efficiencies have been achieved however in theory this effect is also apparent in solids, liquids and gases. The most commonly used component of the solar semi-conductors is Silicon.

There are a range of different solar power systems currently available. These are

  • Grid connect solar
  • Stand-alone or off-grid solar systems
  • Hybrid solar systems
  • Portable solar power systems
  • Solar batteries

More information can be found about these types of systems here.

The usefulness of these Solar Cells in the Space Exploration Program has already been proven in India as well as other countries in the world. The Bhabha Atomic Research Centre in Bombay, have successfully developed Solar Cells which have been tested in the satellite Bhaskara and which also meet part of the power requirement abroad (Gupta, 1981). The likeliness for large-scale power generation to meet energy requirements on earth is even bigger.

Geothermal Energy:

Geothermal Energy is a clean and sustainable power source that comes from heat in the centre of the earth.

Hot molten rock called magma deep inside the earth’s surface has in some places pushed up towards the earth’s crust, resulting in the range of geothermal energy resources to be expanded.

Geysers are produced when water flows over these hot rocks causing steam to rise through crevices in the earth’s crust, which can then be converted into electricity.

There are three types of geothermal energy technologies:

Geothermal Electricity Production: using the earth’s heat to generate electricity.

Geothermal Direct Use: using hot water within the earth to produce heat directly.

Geothermal Heat Pumps: heating and cooling buildings using the shallow ground.

It has only recently become evident that Australia has potential for geothermal energy production, because of the perception that the resources were only found in locations that have active volcanism (which Australia doesn’t have).

However, it has been uncovered that Australia is home to suitable hot sedimentary aquifer and hot rock resources.Two projects are under development in Australia to utilise these resources, and they are hot sedimentary aquifers (HSA), and enhanced geothermal systems (EGS or hot rocks).