Local solar supply and installation specialist Sinetech has been appointed as the sole supplier of a hybrid energy management system that can be installed as an additional source of energy to reduce the fuel consumption of diesel generators and, therefore, their operating costs.
The D:Hybrid photovoltaic (PV) system is manufactured by Germany-based solar energy specialist Donauer, which uses its own PV/hybrid plant to run its business, near Munich, benefiting from many years of experience and representative real-time measurements.
Sinetech GM Herbert Teubner reports that the system can save up to 30% of diesel consumed and does not use battery energy storage.
“With rising energy costs, systems like the D:Hybrid are now becoming viable, con- sidering that many mining operations, shopping centres and island operations have no access to [State-owned power utility] Eskom’s power and are relying on generators,” says Teubner.
Diesel generators are often used to secure the basic energy supply in countries where the public grids do not provide a reliable source of energy. However, despite comparatively low investment costs for buying the machines, the operating costs for maintenance and fuel are high.
“The current development of the crude oil price on the global market, in particular, is leading to a drastic rise in costs,” says Teubner.
He adds that, in 2004, a barrel of oil cost about $43 and more than doubled to over $100 in 2012. Transporting diesel also poses a logistical challenge, which greatly influences the overall costs, particularly if the fuel has to be transported to remote areas.
The favourable price trend of PV systems, however, provides for a short amortisation period.
“The challenge lies in technically con- ceiving and implementing the diesel/PV hybrid system without using energy storage systems, which are costly. Further, the temperature sensitivity and limited life span of energy storage systems are a limiting factor for the entire system,” explains Teubner.
Teubner reports that, in 2010, about 38 GW in new diesel generators were sold worldwide. In 2011, this figure rose to more than 47 GW.
“These figures show how high the world’s energy requirements are outside the public grids and highlights the potential for new hybrid solutions using PVs,” he says, adding that the diesel price plays a decisive role in economic considerations and that the past few years have clearly shown which direction crude oil market prices are going.
“The resulting rising operating costs of energy supplied by diesel generators contrasts with the constantly falling costs of PV systems,” Teubner says, also pointing out that the cost of PV power has more than halved since 2004, when an average of €5 was earmarked for every watt of energy sold.
“To measure the price of energy produced by PV systems, one needs to take into account the cost of maintenance, return rates and life span, as well as the investment costs,” he explains.
Depending on plant efficiency and the level of irradiation at the installation site, this leads to a measurable price of €/kWh, which can be set against the energy price of conventional diesel generators.
Further, it costs significantly less to produce PV-generated energy in regions with high irradiation, including many African regions, than it does to generate this energy in Germany.
Teubner reports that the cost per kilowatt-hour of PV energy produced in Germany – which has an irradiation level of about 1 040 kWh/m2 a year – is about €0.22.
If the same amount of energy were to be produced by a diesel generator, this would cost as much as €0.47/kWh. The cost comparison clearly shows how big the economic advantage could be in today’s conditions – and this potential exists in many countries worldwide, he notes.
“Therefore, the higher the solar irradiation and the cost of diesel, the greater the economic benefits will be.”
The required investment in grid-connected PV systems is comparatively low, since batteries are not needed. However, a high level of technical expertise in operating and systems management is needed.
With the Donauer D:Hybrid energy management system, Sinetech aims to provide a stable, economical and sustainable supply of energy.
“The D:Hybrid ensures that operation takes place during the diesel generator’s optimal operating point, therefore, providing efficient fuel consumption,” says Teubner.
“With a low consumption load and a high PV feed-in, the D:Hybrid secures grid stability and a reliable energy supply. Further, through its manufacturer-independent control concept, it can be easily integrated into energy supply structures with existing diesel generators.”
Teubner adds that Sinetech’s aim is always to reduce operating costs, while guaranteeing a reliable supply of energy. Its services range from small hybrid systems to large-scale industrial plants.
“Sinetech tries to find the ideal solution for individual needs from an economic perspective, while taking into account all project-specific framework conditions, such as the existing supply structures, the user-specific load profile and the solar irradiation level,” he says.