Bringing the light at the lowest cost

Wind and Solar: always better together

XANT has delivered wind turbines for all kind of mini-grids across the globe: from a wind-diesel system in a fishermen village in Alaska, to a large multi-MW system in the Pacific to an experimental system on a demonstrator. If systems are being configured without considering wind power, this might lead to non-optimized systems and thus higher-than-necessary electricity costs.

Often mini-grids nowadays are still combined with a “dispatchable” power generation technology, however, with the sharp decline in storage technologies the path is paved for 100%-renewable systems.  What would such a system look like? To simplify things let’s only consider the two renewable-energy sources that are available on every location on this earth: solar and wind power.

Resource maps guide the way

The Energy Sector Management Assistance Program (ESMAP) of the World Bank has done a great job in mapping the global wind and solar resource data and making them publicly available in interactive maps.

At first sight the two resources seem to complement each other quite well: wind is abundant at higher latitudes while the irradiance levels increase towards the equator. Also, the sun shines the brightest at higher altitudes while the wind blows the hardest near the coast lines.

ESMAP Solar Resource map (http://globalsolaratlas.info/)

ESMAP Global Wind Resource Map (https://globalwindatlas.info/)

It’s the COE, stupid!

To dig deeper we ran a bunch of HOMER simulations with the same system configuration providing power to a typical village load (250kW peak, 2MWh/day electricity demand).

Investment costs of solar, wind and storage are deemed to be representative of today’s total installed cost at remote locations (respectively 1.2$/W, 2.5$/W and 500$/kWh) but are obviously not considering the large local variations that may exist due to temporary market shifts and/or incentive schemes. Also, these costs are not for MW-scale power plants but for wind turbines and solar arrays in the tens to hundreds of kW’s.

The HOMER Optimizer then does the job of finding the lowest-cost system comparing all the feasible system configurations. In Chilean Patagonia the lowest-cost-of-electricity system (COE) would consist of 135kWp PV, 300kW wind and a 1.3MWh battery and deliver electricity at 25cents/kWh.  While in eastern Ethiopia, an LCOE of 22cents/kWh is obtained with 420kWp PV, 100kW wind and a 1.3MWh battery.

The graph below shows the reduction in LCOE obtained when adding wind power to the mini-grid system.

Levelized Cost of Electricity reduction by adding wind power to the mini-grid system

Conclusion

Adding wind to the mix can bring the LCOE down significantly: a 10% reduction is already achieved at wind speeds of 6m/s, and up to 25% can be achieved at higher wind speeds. So, what had been proven in larger interconnected systems[1], also holds for mini-grids: wind and solar are better together.

Thanks to their complimentary in diurnal and season patterns, wind and solar together can always match the load better than alone and the necessary amount of storage can be reduced.

So, include wind in system-sizing calculations, otherwise you’ll never know what COE you could have got!

About XANT:

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 ETR (Extended Temperature Range) versions are available.

www.XANT.com

[1] www.scientificamerican.com/article/wind-and-solar-are-better-together/