Commercial solar power systems are among the best building upgrades available for companies in Australia, capable of achieving a payback period below three years while having a service life of over two decades. In addition, companies can deploy photovoltaic systems through the Power Purchase Agreement (PPA) business model: the provider owns, finances and services the photovoltaic array, while the client only pays a monthly fee based on the electricity supplied. The kWh price in a PPA can be up to 50% lower than the retail kWh price, which results in immediate savings for the client.
Utility-scale solar is already breaking records globally, achieving some of the lowest kWh prices ever reported. Recent projects in Saudi Arabia, Mexico and USA offer electricity costs below 20 USD/MWh. Wind power is the only other electricity source that achieves these low prices in new installations.
When a country develops a mix of solar, wind and hydroelectric power, the results are better than if only one resource is developed. Solar panels and wind turbines both rely on variable energy inputs, but variation tends to become less drastic when both resources are deployed together. A solar array becomes unproductive at night or during cloudy days, while a wind turbine suffers when there is no wind, but a combined project only stops generating electricity if both conditions are present at the same time.
If hydroelectricity is added to the mix, the outlook is even better. The strengths of hydroelectricity cover the main relevant weak spots of solar and wind power:
Hydroelectric power plants with water reservoirs can be considered a form of energy storage. As long as the reservoir holds enough water, it can be used to produce electricity at any time. Of course, the added capabilities of hydropower plants do not come for free; they normally have a higher cost per kilowatt-hour compared with solar and wind farms.
The outlook for renewable energy sources becomes even better when batteries are added to the power mix, and this has been demonstrated by the 100-MW Tesla battery in New South Wales. The unit saved around $35 million in frequency control and ancillary services (FCAS) in its first four months of operation, which is great for a system that cost around $50 million.
Although solar, wind and hydro power complement each other in utility-scale applications, solar power is the clear winner in residential or business settings. Wind turbines and hydroelectric turbines do not have scale flexibility – their cost per kilowatt of capacity increases dramatically when you deploy them in small-scale systems. On the other hand, solar power can adapt to any system size thanks to the modular design of photovoltaic panels.