The expenses associated with connecting renewable-energy sources to the national energy grid are often underestimated and should be factored into the cost-benefit analysis of all renewable-energy projects prior to their implementation, Paris-based energy utility Électricité de France business development manager Olatunde Kolade has asserted.

“People sometimes think that there is no cost to bring sources of renewable energy online, [but] it doesn’t work like that. The [supply of energy offered] by these sources is often intermittent, so they are difficult to use in standalone operation and, therefore, need to be integrated into the larger system, requiring conventional power plants to increase their participation in the load… to ensure sustainable [supply].

“[In addition], the cost of developing transmission lines and connection [points] to often geographically isolated renewable-energy projects, such as wind farms, is high. You’re the one forcing the grid to do what it doesn’t want to do, so you should bear the cost,” he told an energy forum breakfast organised by the French-South Africa Chamber of Commerce on Tuesday.

According to Kolade, once renewable-energy sources started to generate electricity, their running costs reduced to “nearly zero”, and traditional energy sources – which were required to provide back-up power – became unable to compete economically, as they were required to buy costly fuel for generation.

As such, renewable-energy project developers may be required to pay so-called “capacity payments” to ensure that energy was available to the grid when renewables were unable to generate power.

Kolade, whose company had previously been tasked by the European Commission to investigate the opportunities and constraints associated with the introduction of renewable-energy sources “on a large scale”, added that it was, thus, critical that such energy sources be introduced in such as way and at a cost that they did not negatively affect the overarching power system.

The first step towards developing a “useful and competitive” analysis of the introduction of renewable energy into a power system was the identification of the location, type of technology and potential energy yield.

“The location and amount of power [produced] will provide information about how and where renewable energy has to be placed and connected to the grid,” Kolade said.

Moreover, the resources’ variability and availability would define the requirements of the grid extension and power reinforcements, as well as the most suitable conventional units required to provide back-up generation.

This would allow the cost of developing the energy source, as well as the cost of connecting it to the national grid, to be calculated.

“The power system’s capability of incorporating sources of renewable energy without additional costs is limited, because some of them only supply intermittent energy, especially wind, photovoltaic and run-of-river projects.

“This also increases the uncertainty of planning activities and reduces the overall stability of the system,” Kolade remarked.

He added that, while the maximum level of renewable-energy penetration by a national grid was calculated on a case-by-case basis, there would “never” be a system that was able to supply energy exclusively from renewable sources.