Concentrated Solar Power

Mostly if you mention solar power, people think of solar PV.

However there is another, less widespread method of converting energy from the sun into electricity. Whereas PV converts the sun’s light to electricity, CSP collects heat from the sun, focusing¬†it by means of mirrors. With sufficient focusing (concentration) of this heat, temperatures can be achieved that are high enough to flash water to steam (for example) and drive a conventional thermal power generating cycle. It’s a bit like focusing the sun using a magnifying glass and being able to burn holes in things.

There are various ways in which the focusing system can be arranged, the most common two being a) to use long parabolic mirrors (troughs) or b) flat mirrors arranged to focus onto a high point (tower).

Some potential advantages of CSP over PV include: less rapidly fluctuating power output, the ability to store heat and convert to power later on (e.g. after dark) and applications in direct industrial heat.

Some downsides include: high costs (both capex and opex) compared to PV, the need for cooling (in the power cycle) and the need for direct sunlight (in order to focus).