Combination of wind and solar can contribute to baseload power

The initial results reveal two significant findings:

• Electricity generated from wind and solar resources closely follows the nation's electricity demand profile, meaning they generate power at the time of day it is most needed; and
  
• when wind and solar generation are combined, the net effect is a significant contribution to baseload power.

"This initial analysis strongly underpins the South African government's commitment to renewable energy; not only are wind and solar power cheaper than new fossil fuel generation here in South Africa but when combined, they can also make a very significant contribution to baseload power at the time of day it is most needed," said Mainstream's chief executive, Dr Eddie O'Connor.

Competitive advantage

"The analysis also shows something which gives South Africa significant competitive advantage in that the combined wind and solar resources match the average demand profile for electricity. This is significant because the wind blows and the sun shines when electricity is most needed, and this is not something that occurs with such regularity in other global markets," he said.

Mainstream analysed measured wind and solar resource data from 2013 for eighteen wind and solar sites across South Africa. The sites analysed represent a combined generation capacity of 42,000 megawatts (30,000MW wind and 12,000MW solar). The analysis set out to predict how much electricity the eighteen sites could generate and at what times of the day. Mainstream then examined Eskom's electricity demand data (for 2008) to understand the impact the 42GW of wind and solar generation could have in relation to meeting the country's electricity needs.

The preliminary results show that:

• the electricity generated from the eighteen wind and solar facilities closely follows the country's summer, winter and peak day demand profiles for electricity (see graphic below); and
  
• the predicted electricity generation from the eighteen sites, which have a combined potential capacity of 42,000 megawatts, results in a significant contribution towards firm, baseload power.

Wind and solar portfolio hourly generation profile and 2008 national demand hourly profiles

O'Connor said that it is also interesting to note that the cost of electricity offered by the most recent renewable energy projects is now well below that predicted from the state energy utility Eskom's future coal plants.

Analysts have indicated that in their analysis of the average bid price for wind projects in the REIPPPP:

• round one bids were accepted at 115c/kWh;
  
• round two came in at 100c/kWh;
  
• round three at 74c/kWh;
  
• and by the time round four was reached in August 2014, the bid price had dropped to 62c/kWh;
  
• the same process caused solar power to be bid down from 275c/kWh in round one to 79c/kWh in round four.

This should be compared to the predicted cost of 128c/kWh for electricity from Medupi, which is designed to supply 4,764MW of new capacity.
Tina Joemat-Pettersson, the South African Minister of Energy said in a recent speech that the country has already added a total of 4,322MW of renewable energy capacity in less than four years.

"Wind and solar power are quietly been piling on capacity in South Africa. The fact that these projects have almost surpassed the output of such a station in about half the time of its still-unfinished construction is hard to ignore," concluded O'Connor.