If a third of all South African households implemented renewable-energy power solutions, such as photovoltaic (PV) panels and wind turbines, State-owned power utility Eskom’s current capacity issues could be alleviated, says Port Elizabeth-based alternative power solutions company Kestrel Renewable Energy.

The company’s power solutions include solar- and wind-powered solutions, which can be used individually or incorporated into hybrid systems, says Kestrel sales and marketing manager Leon Gouws. He points out that the hybrid systems can supplement Eskom’s electricity feed, which would drastically lower power consumption from the national grid, cutting costs and reducing carbon dioxide emissions.

He tells Engineering News that the most popular of Kestrel’s power products since they were launched onto the local market in 1999 are its off-grid systems, which are especially popular in rural areas. Off-grid power solutions offer electricity derived only from renewable energies and do not facilitate a connection to the national power grid.

Gouws says the high amount of rural sales may also be attributed to a lack of infrastructure in some remote rural locations.

“The payoff of off-grid systems is immediate, while grid-connected systems typically see a return on investment in 7 to 14 years,” Gouws says.

A major benefit of power solutions that rely fully on renewable energies is that they provide free electricity once the initial purchase and installation fee is paid, says Gouws, who further explains that off-grid systems comprise three elements.

The first element involves power generation through an Eveready Kestrel wind turbine, which can be combined with a solar PV panel in hybrid systems.

The second element is a battery bank, which is used to store electricity when power generation is low, such as during dark, overcast or low-wind days.

Lastly, a power management system is incorporated into an off-grid system to protect and manage electrical devices while providing stable electricity as required by the consumer.

Wind turbines available from Kestrel’s electricity production range include
600 W, 800 W, 1 kW and 3.5 kW systems.

Grid-Connected Benefits
Kestrel also offers grid-connected power solutions for consumers with existing electrical connections to the national power grid.

These systems offer consumers the opportunity to reduce their electricity dependence on the national grid, as buying less electricity from Eskom will entail a significant cost reduction.

Grid-connected systems first exploit power generated from solar and wind power-generating devices until the generating capacity of the wind turbines or solar PV panels is depleted. At this point, electricity is drawn into the system from the national grid to meet the increased demand, which ensures that electricity consumption from the national grid is minimal as less will be required owing to the energy produced by the wind turbine and solar panels.

Kestrel’s grid-connected power solutions comprise various components, including a grid-tie inverter, which is used to synchronise the varying voltages produced by wind turbines and solar PV panels to ensure a stable and predetermined supply. Sophisticated algorithms then ensure that the renewable energy generated is used optimally and that the grid-tie inverter secures network safety if the grid fails or becomes unstable.

A significant benefit of the grid-connected system is its ability to feed excess electricity back into the national grid. However, Eskom does not yet have the infrastructure for this, notes Gouws.

Further, the grid-connected system can also be connected to a backup uninterruptible power supply if the grid fails.

Gouws notes, however, that grid-connected systems have had poor market acceptance, owing to their higher cost, compared to off-grid systems. “The grid-connected systems have also proved difficult to market, as they offer no customer incentives. Off-grid systems, therefore, make more financial sense, as their return on investment is faster. We have also found that they are easier to sell,” says Gouws.

He adds that, “if and when” Eskom’s power generation capacity issues worsen, the sales of Kestrel’s products will increase. However, Gouws does not predict significant sales growth this year, as pricing still remains a key hindrance when it comes to residential market acceptance.

Kestrel offers various turnkey hybrid off-grid and grid-connected renewable-power solutions, as well as installation and after-sales services of all its products.

Renewable-energy exploitation and alleviating Eskom’s capacity issues will be a key focus point at the 2015 Africa Energy Indaba, which will take place at the Sandton Convention Centre, in Johannesburg, from February 17 to 18.