How Corporations With Access to Land Can Benefit From Single Axis Tracking Solar PPAs
Solar panels convert more sunlight into electricity when they face the sun directly. However, since most solar arrays use fixed racking, this only happens for a few hours each day. The rest of the time solar panels receive sunlight at an angle, and this reduces their power output. This is exactly why solar panels are more productive around noon, but not early in the morning and late in the afternoon.
Solar panels can be equipped with tracking mechanisms to keep them facing the sun, and this increases their electricity output over time. Solar trackers increase the upfront cost of photovoltaic systems, and they also require maintenance. However, the increase in electricity production can surpass the additional costs of solar tracking in many cases.
In general, solar trackers make sense from a business standpoint when there is plenty of land available, and there are few obstacles blocking the sun’s path in the sky. This means they have little use in a city center with plenty of buildings, but they can greatly increase electricity output in an open field with many hours of sunlight per day.
Types of Solar Trackers
The position of solar panels can be adjusted by rotating or tilting them. A single-axis solar tracker is only capable of one movement, while a dual-axis tracker is capable of both. Single-axis trackers have lower ownership costs thanks to their simplicity, but dual-axis trackers can adjust solar panels more effectively, achieving a larger boost in productivity.
Solar trackers increase the weight of a solar array due to the additional components. They also require more spacing between groups of solar panels to avoid shading. These factors limit the usefulness of solar tracking in residential and small commercial installations, where space is limited. However, corporations with plenty of land available can take advantage of tracking mechanisms to increase the productivity of each solar panel.
Single-axis solar trackers that tilt rows of solar panels to the east and west have become very popular thanks to their simplicity. They have lower installation and maintenance costs than more complex tracking devices, and the increase in space requirements is less drastic.
Based on their operating mechanism, solar trackers can also be classified into active and passive. Active solar trackers use light sensors and motors to position solar panels with respect to the sun, while passive trackers have an hydraulic mechanism that responds to heat. Active solar trackers are more accurate, but they consume electricity and are more expensive. On the other hand, passive solar trackers are less accurate, but they consume no electricity and have lower costs. In general, passive trackers offer enough accuracy for solar panels. Active trackers are used in applications that demand more accuracy, such as concentrating solar power.
The US National Renewable Energy Laboratory (NREL) developed the PVWatts Performance Calculator, which can be used for solar power systems around the world. When used to simulate photovoltaic systems in Australia, the following results are obtained:
- Single-axis tracking boosts performance by 19% to 29%.
- Dual-axis tracking boosts performance by 23% to 36%.
Generally, the performance of solar trackers increases in locations close to the equator, since the sun stays in the sky for more hours during the year. However, the local terrain and weather also affect the effectiveness of solar tracking.
Single-axis tracking increases the productivity of solar panels without the higher cost and complexity of a dual-axis tracker. Also, the productivity gain between no tracking and single-axis tracking is significant, while the additional benefit of dual-axis tracking is smaller. For these reasons, single-axis tracking is a more popular option.
Advantages of a Single-Axis Tracking Solar PPA
As discussed in a previous article, a solar PPA is an attractive option for corporations who want to deploy solar panels:
- The upfront cost is assumed by the provider, which means the client can install solar panels without affecting the operating cash flow.
- Operation, maintenance and component replacements are also delegated to the provider. This way, companies can focus on their core business without having to train a solar maintenance staff.
- Solar power components from quality brands are covered by solid warranties. However, when a component fails, someone must file the warranty claim and replace the damaged component. This task is also delegated to the provider in a solar PPA.
When single-axis tracking is used, a solar PPA brings additional advantages. The solar provider also assumes the upfront cost of the tracking mechanism, and also the additional maintenance requirements. In other words, a tracking solar PPA offers more electricity production without increasing the investment risk for the client.
Single-axis tracking increases the space requirements and weight of solar power systems, and the technology is not viable for many rooftop installations. However, corporations with access to large amounts of land can take advantage of the extra electricity production. The dual use of land is a promising concept: solar arrays are mounted several feet from the ground, and the space below can be used for purposes like parking, agriculture or raising small animals.
Corporations with ample rooftop areas and plenty of land can use both types of solar PPAs to maximise their clean power production. Fixed solar arrays are used in rooftops, while tracking solar arrays are used in undeveloped land.
Australia gets abundant sunshine, and every kilowatt of fixed solar panels produces between 1300 and 1800 kWh annually, depending on the local sunshine. Also, since Australia has some of the highest electricity tariffs in the world, the output of solar panels is very valuable. Single-axis solar tracking can increase both the kilowatt-hour output and power bill savings by over 20%, and the extra costs are assumed by the provider in a solar PPA.
Like with any investment decision, the installation of solar trackers must be analyzed in terms of cost and benefit. In general, they make financial sense when the additional electricity savings outweigh the additional installation and maintenance costs. The feasibility analysis is also delegated to the provider with a solar PPA, helping you reach the best possible decision.