Outages are a fact of life for renewable energy assets, but they don't have to be a major source of frustration. By accurately tracking outages and availability, owners and operators can better manage their impact on operations. In this article, we'll explore how capacity factor and availability are calculated, and how to effectively track and manage outages for renewable energy assets.
Let's start with some definitions.
Capacity factor is a measure of how efficiently a renewable energy asset is producing energy. It is calculated as the ratio of actual energy produced to the theoretical maximum energy that could be produced over a given period of time, assuming the asset is operating at fullcapacity continuously (a.k.a.nameplate capacity).
There are two main categories of external factors that can reduce capacity factor. The first category includes environmental conditions, such as lack of wind or sun, or too much wind, which can limit the power plant's ability to produce energy. The second category includes grid-induced imbalances, which can also impact the power plant's production and thus its capacity factor. These imbalances can be caused by a variety of factors, such as fluctuations in demand or unexpected outages in other parts of the grid.
In addition to external factors, there are also availability-related factors that can impact capacity factor. These factors include planned and unplanned maintenance activities, as well as downtime for repairs or equipment replacements. By accurately tracking these factors and managing them effectively, asset owners and operators can improve their capacity factor and maximize the performance of their turbines.
Availability is a crucial measure of how effectively a renewable energy asset is producing energy. It is calculated as the amount of time a plant is able to produce energy divided by the total amount of time during a given period. This measure is also known as Time Based Availability. In recent years, other availability concepts have emerged, such as Energy Based Availability (energy produced / total amount of energy that could have been produced) and Revenue Based Availability (revenue achieved / total revenue that could have been achieved).
While external factors like weather conditions are mostly beyond the control of a power plant owner / operator, availability is an area where improvements can be made through effective operations and maintenance (O&M) activities. These activities can be planned, such as scheduled maintenance, or unplanned, such as repairs in case of a failure. By effectively managing maintenance activities and prioritising them based on their impact, asset owners and operators can enhance the availability of their renewable energy assets, ultimately maximising their performance.
In the renewable energy industry, plant owners typically have availability-based agreements with the party providing operations and maintenance (O&M) services for the plant. In the wind industry, for example, the O&M service arm of turbine manufacturers (OEMs) often guarantees 97% (time-based) availability. However, this guarantee comes with various exclusions.
For instance, if an outage is caused by the client, it is excluded from the calculations. In more complex scenarios, the initial outage maybe due to a component failure (which is not excluded), but repairs cannot be performed for a long time due to weather conditions or supply chain issues. In such cases, the O&M service provider may argue that at least part of the outages should be excluded from the calculations.
It is important for plant owners to understand the exclusions in their availability agreements and ensure that they are being applied correctly. Accurate tracking of outages and their causes can help owners and operators identify areas for improvement and ensure that they are getting the most out of their O&M service agreements.
According to a study* performed by IHS Markit in the North American market, which analysed more than 10,000 wind turbines, at age 3 the ratio of downtime due to failures (i.e., ratio of unplanned outages to all outages) is on average 20%, while this number reaches 65% as the turbines reach 10 years of age. In other words, unplanned outages become more prominent as turbines age.
(*Reference:IHS Markit. (2018). 2018 IHS Markit Wind O&M Benchmarking in North America: Aging Turbines, Rising Costs. Retrieved from here.
Effective tracking and management of outages is critical for renewable energy asset owners and operators, as it directly impacts their financial performance. To achieve this, a three-pronged approach is needed:
1. Predicting outages in advance to avoid and/or minimize them (see our series of blogs on predictive maintenance for strategies on how to achieve this through data and domain know-how).
2. Identifying the reasons for outages and their financial impact so that they can be prioritised for resolution (alarm-based loss analysis is a useful tool for achieving this).
3. Accurately categorising outages for use in contractual availability conversations with the O&M service provider.
However, accurate categorisation of outages is a time-consuming and challenging task. While many asset owners use Excel sheets to keep track, this approach can be unreliable at times, leading to having to rely on the O&M service provider's data and calculations.
To ensure accurate categorisation, asset owners and operators can leverage specialised software tools that automate the process, provide real-time monitoring, and offer customisable reporting. These tools can help asset owners and operators gain better visibility into their outages, prioritise their resolution, and achieve higher availability and performance for their renewable energy assets.
To address the challenge of accurately categorising outages, we have developed a new module called "Outages," which automates the process and saves time for asset owners and operators. Here's how it works:
1. Data is automatically extracted from the SCADA system.
2. Each outage is automatically categorised based on the settings specific to each power plant.
3. Users can make modifications if necessary to cover edge-case scenarios.
4. Reports are generated for requested time periods.
Outages offers the following main benefits:
-Reliability: Data is stored in a database structure with user access controls, ensuring the data is reliable.
-Time-saving: With automated visual representation and categorisation, users no longer need to manually enter every outage, start-end times, and categories.
-Preparedness: Reports are ready at the push of a button, providing users with all the necessary input for contractual availability discussions with the O&M service provider.
Using Outages can help asset owners and operators gain better visibility into their outages, prioritise their resolution, and achieve higher availability and performance for their renewable energy assets.
To summarise, here are the 3 key takeaways when talking about availability and outages:
1. Outages are an undesired reality that have a direct financial impact on power plant management.
2.There are many reasons why assets have outages, some of which are unavoidable while others can be better managed.
3. Accurate categorisation of outages is now possible in an easy-to-use fashion, providing a reliable, data-supported position for contractual availability discussions.
By understanding the impact of outages, addressing their root causes, and using tools like Outages to accurately categorize and manage them, renewable energy asset owners and operators can improve their availability and performance and maximize the financial returns on their investments.