By: Jim McDowall, Saft business development manager
From remote islands to the frigid Arctic, residents of isolated communities across the globe rely on diesel-dependent microgrids to support their power needs. The high cost of diesel in these remote areas combined with potential challenges in fuel delivery logistics are driving operators to consider renewable energy integration. Combining diesel gensets with lithium-ion (Li-ion) energy storage systems (ESS), provides the capability for high levels of renewable penetration. The combination significantly reduces the hefty costs of diesel generation including transportation, handling and maintenance, along with reductions in greenhouse gas emissions.
Li-ion paving the way for renewable integration in remote regions
Li-ion batteries offer numerous benefits to operators, particularly providing high energy density in a compact and lightweight package enabling simple installation, as well as maintaining stability despite renewables’ variability. Requiring little maintenance, Li-ion can provide more than ten years of highly efficient operation at a competitive price. Saft’s Intensium Max® is an example of a megawatt scale Li-ion containerized energy storage system with a low total cost of ownership in complex applications, simple integration despite challenges presented by isolated locations and remote supervision capabilities.
Coupling solar PV and Li-ion for valuable power
PV can provide up to 25% of power generally produced by the diesel genset with no issues and up to 50% when special controls are used. At higher levels of PV penetration, energy storage is needed to maintain stability, and when PV power exceeds 100%, diesel-off is enabled, resulting in significant fuel savings. Shutting down the diesels requires that the ESS be grid-forming, generating the voltage and frequency to which the PV inverters can synchronize.
Utilizing an ESS with PV also eliminates inefficient genset operation. Operating and maintenance costs are greatly reduced when a genset operates at maximum efficiency and no longer has to deal with constant ramping to accommodate varying demand. The optimum combination of ESS and PV ratings can generate fuel savings of 50 to 75%, depending on the location. Higher levels of fuel savings are possible by increasing the ESS energy rating to allow shifting of PV energy to other times of the day, but the additional capital expenditure involved typically results in a lower return on investment.
Benefits of modeling a Li-ion battery before installation
Every site will have different challenges associated with integrating renewables and energy storage. The variables include the environmental conditions, cost of fuel delivery, nature of the load, load profile and renewable generation profile. With the multitude of factors contributing to a successful application that maximizes fuel savings, detailed modeling of the dispatch model is necessary. For example, Saft’s Matlab-Simulink models allow operators to understand the electrical and thermal aspects of the Li-ion battery system and its interaction with the PV and gensets. Such modeling accurately simulates the behavior of the microgrid, providing an in-depth look at the battery’s power and aging with dynamic charge and discharge operation.
Powering the Arctic Circle
Colville Lake is a remote off-grid community north of the Arctic Circle in Canada’s Northwest Territories. The community’s access to electricity and heat depended primarily on diesel – expensive and challenging to transport on ice roads. The power utility company sought out to achieve less expensive, more reliable and environmentally-friendly power via renewable integration – the community is now powered by solar panels coupled with new diesel generators and a Li-ion battery ESS.
This unique project required a customized cold temperature package ESS that would maintain the battery temperature and thus its charge and discharge rates. The package developed by Saft contains a hydronic heating coil and layers of high-tech insulation to endure harsh temperatures as cold as -50˚C. Saft provided an Intensium Max 20M ESS and leveraged advanced modeling help determine the ideal size of the ESS and solar array. The hybrid system is saving more than 80,000 liters of fuel annually.
Optimizing power in the rainforest
Down south below the equator, Cobija Bolivia is in the midst of the rainforest and houses the world’s largest hybrid PV-diesel microgrid with an ESS that contains a Saft Intensium Max battery. This remote location presented exceptional challenges, particularly to transport all the equipment to the site – it required shipping containers to be sent across rivers and driven by truck over the Andes to reach the town. Reducing the community’s reliance on diesel gensets, PV panels and the ESS have expanded the reach of the microgrid and helped the operator eliminate usage of two gensets, which saves two million liters of fuel annually.
Wind turbines and energy storage work together
North of the Arctic Circle, Kotzebue is a remote Alaskan community that installed Li-ion energy storage into its microgrid. This distinctive hybrid project integrates wind turbines, diesel gensets and a Li-ion ESS. Built with Saft’s Intensium Max technology and cold weather package, the hybrid solution enables the Kotzebue Electric Association to boost its use of wind power while decreasing reliance on diesel generators. In 2015 alone, the endeavor saved 250,000 gallons of fuel, equating to $900,000.
Li-ion technologies prove to be a valuable asset to hybrid microgrids in remote locations, delivering the energy and power required to successfully integrate renewable energy and relieve significant reliance on diesel gensets. From the Arctic Circle to south of the Equator, remote communities are now capable of delivering significant fuel and maintenance savings, along with positively reducing greenhouse gas emissions.