Johannesburg - Technology that pairs renewable energy with a traditional power source, such as diesel, offers a compelling way for local companies to protect themselves from blackouts.
A chromium ore mine in Limpopo was the first in South Africa to adopt the hybrid technology manufactured by German company First Solar.
First Solar has pitched the concept to mining houses and large industrial users of conventional fuel, and is working on a number of projects.
A hybrid back-up system can be used to power mining operations when the Eskom grid becomes unreliable, while off-grid solar technology can substitute for the use of diesel on irrigation schemes during the day.
Some companies use the hybrid system to generate revenue or offset what they would normally buy from utilities.
First Solar manufactures advanced thin film solar photovoltaic (PV) modules.
“On an industrial application of PV hybrid, we would look at installing a plant on the roof of a large manufacturing facility or adjacent to it, if it has land, so that it can help provide a back-up solution to an unstable grid,” John Eccles, the director of fuel replacement solutions at First Solar, said.
The company had found that mining and manufacturing facilities used back-up diesel power sources in countries where the grid was unreliable, Eccles said.
If those facilities installed a PV plant, the power generated would reduce the amount of diesel used when the grid went down. When the grid was fully functional, “you just export the [PV-generated power] and make some revenue from that”.
In November 2012 the Cronimet mine in Thabazimbi became the first in South Africa to adopt the PV hybrid technology. The 1 megawatt PV-diesel hybrid electric plant at Cronimet supplies 60 percent of the mine’s full load energy requirement of 1.6MW.
Hybrid power systems mean that renewable energy can be integrated with other technology and conventional energy sources, such as coal and diesel.
The market for the PV hybrid system is still fairly new because the cost of PV only became competitive with thermal power less than two years ago.
The PV-diesel hybrid is the most common form because diesel power generation is the most expensive method at present and replacing it significantly reduces costs for intensive users.
“If we have an assumption where a load is sufficiently large so the PV displaced diesel entirely, we would hope that we can achieve up to 30 percent overall reduction in [energy] costs,” Eccles said.
The solar industry is abuzz with exploring the PV hybrid system as a reliable source of energy for industrial operations that cannot switch off completely from diesel or electricity but struggle to keep down the costs of these.
PV is not the only hybrid option. Wind, hydro or biogas generators can also be used in hybrid systems.