6.3 Sustainable Energy Sources

Sustainable energy production, whether that be renewable or low-carbon sources, is one of the pillars of sustainability, with the goal of reducing emissions and ensuring energy security in the long-term as resources are depleted. This lesson will explore some of the technologies that can be used.

Large Scale Solar Power

Large-scale solar power can be of a similar size to a conventional power station, in the region of 100 MW to 1 GW. Many assume that solar power is only suitable for locations which receive large amounts of sunshine, but the sun’s energy can still be converted into electricity in cloudy conditions, the capacity would simply be reduced.

The parabolic dish system, shown in Figure 1, focuses sunlight onto a central receiver, where a stirling engineEngine that operates on the principle of cyclic expansion and contraction of gases, such as air, to drive pistons, converting heat energy to mechanical energy. absorbs the concentrated heat to convert this into electricity.

Heating of water can also be achieved in a parabolic trough, shown in Figure 3, where the sun is reflected onto the central pipe, reaching temperatures of up to 400 ^oC, heating water to steam in the process. This is then followed by a steam cycle much like a regular power plant, where the steam is used to propel a turbine which, in turn, generates electricity. This is often cheaper than a parabolic dish system, and can run at night if sufficient heat is generated during the day.

Example

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The largest solar power parabolic trough, as of 2023, is the Mohammed bin Rashid Al Maktoum Solar Park located in Dubai, which is used to generate electricity and has a capacity of 700MW, sufficient to power up to 132,000 homes.

Both systems are used throughout the day, where the dish or trough rotates to track the movement of the sun, maximising the utilisation of solar energy.