A typical island : 100% renewables in sight
Matching the load with renewables makes the case for a mix
The location is an island in the Atlantic Ocean and one of the more remote places on this earth. The local utility company has put out an RFP for the installation and operation of renewable power plants on the island grid. Applicants should act as Independent Power Producers (IPP) and propose a Power Purchase Agreement (PPA). The island has raised the bar proclaiming the goal is to be all renewables by 2022, with the addition of first 2MW and finally 5MW of generation capacity. In addition, a price cap has been set on the electricity delivered of 0.154 USD/kWh.
Current generation capacity is mainly diesel-based (7.6MW) with about 1MW of wind (of which about half is reaching its end-of-lifetime), PV capacity is planned to increase to about 0.6MW. The island’s electrical system has a current peak load of about 2MW; total electricity consumption in 2016 was 9.7GWh (for 4,500 inhabitants) mainly for residential and commercial use. The island electricity consumption is poised to increase with the construction of an international-airliner-ready airport and the expansion of tourism: peak load is expected to increase to about 5MW.
The island has very good wind resources, with average wind speed of 6.9m/s, and a global solar irradiance of 5.6kWh/m² per day. Dominant winds are from the SE, and are fairly constant throughout the day.
This case is a very typical example of the energy transition on remote locations: the shift away from fossil fuels and the ambition to eventually have an all-renewable electricity supply. More and more often such “overhauls” of remote electrical systems are done based on PPA’s made with an IPP who takes charge of the assets in a Build-Own-Operate model.
XANT simulated this island case in HOMER Pro1 to assess the challenge of achieving the targeted PPA price and the optimal system configuration. The HOMER Optimizer finds the system configuration with the lowest Net Present Cost (NPC): about 5MW of newly-installed PV capacity, 2MW of wind (6 x XANT L-33) and a 14MWh Li-Ion battery. The table below shows the LCOE and renewable energy fractions of the various system configurations:
The graph below gives an overview of the relative contributions of the solar and wind assets to the total electricity generation. Utility-scale PV can deliver electricity at about 6.18 USD cent/kWh on the island while the XANT L turbines achieve a LCOE of 7.09 USD cent/kWh.
- At current market prices of PV, wind and batteries the system with the lowest Net Present Cost is already an all-renewable system with PV providing 58% of the energy and wind 42%.
- This optimal configuration can deliver electricity at almost half the cost of the existing system (USD 0.202 per kWh vs. USD 0.388/kWh assuming a landed diesel cost of USD 1,28 per l).
- Mixed-technology system perform better than solar-only systems: adding wind to the system reduces the size of the battery, and at the same time enables an all-renewable solution.
Not only in financial terms is a mixed system to be preferred: also other constraints favor adding wind to island electricity systems. The intermittency of PV on cloudy days is easier to mitigate when not solely relying on solar power. And in space-constrained locations, the total footprint of the power generation assets obviously is of importance.
At XANT we manufacture turbines for exactly these locations: the limited craning capacity of the island and difficult road access, make the logistics of large MW-size turbines very costly. The tilt-down towers of the XANT M and XANT L allow for crane-less erection and maintenance done at ground level for all O&M interventions avoiding any crane cost during the complete lifetime of the turbines. The JEEP (Just Enough Essential Parts) design philosophy ensures maximum availability on such remote locations.
XANT is a manufacturer of midsize (50…500kW) turbines for the microgrid and off-grid markets. XANT turbines are designed with microgrid applications in mind and a with a special focus on remote areas and harsh operating conditions. They have Just Enough Essential Parts (JEEP!), fit in 40ft containers and can be erected without a crane. For deployment in typhoon-prone areas the turbines can be lowered to the ground, also facilitating the maintenance. XANT turbines have the capability of active power curtailment and can be equipped with integrated energy storage to allow for a high penetration rates.
The extreme simplicity, easy maintenance, silent operation and low cost of ownership make XANT turbines ideally suited for wind power on remote locations and close to the consumer. The XANT product portfolio consist of the XANT M (100kW) and the XANT L (330kW) – commercially available in 2019- platforms. Both turbine types exist in class Ia (average wind speeds up to 10m/s) and class IIIa (7.5m/s) executions; for extremely cold areas the XANT M ETR (Extended Temperature Range) version is available.