Providing performance opportunities 

Renewable energy assets account for 130GW of clean energy generation globally, with North America providing around 25% (30GW). 2015 saw a record number of clean energy investments totalling $329 billion internationally, with the US ranking second in the top 10 clean energy investment markets.

With continually growing investment in clean energy, more mature understanding of technology and natural resources, combined with a global push towards combatting the effects of climate change, new solutions, such as real time monitoring, are emerging to maximize energy asset efficiency.  

Simple vs complex - power plant monitoring
For years, coal and gas plants dominated the energy mix, and featured several large plants generating huge volumes of power for wide areas. This common structure meant generation was dealt with at a national level. Monitoring and control of these large-scale power plants was operated on-site and, with only a few plants, this was a feasible and natural option.

Traditional energy generation from coal or gas is considered non-complex as both the fuel and the technology are reasonably simple and well-understood. As a result, the monitoring and control of these plants is also relatively straight forward. The fuel used in a nuclear power station can be considered relatively simple, while the technology used to convert it is considerably complex, leading to a far more challenging plant monitoring and control system.

Renewables requirements
Renewable energy assets are made up of wind farms, solar plants, and wave and tidal projects in their thousands. Each type of clean energy generation holds its own challenges and can be considered complex, both in terms of the fuel type and the behavior of the resource. Following the rule for traditional energy generation, the more complex the technology, the greater the need for complex monitoring and control systems in order to maximize production. 

Looking at wind energy, while the method of capturing the wind and subsequently generating power is relatively well understood, the complexities of the wind resource, and our understanding of them, cause the process to be considered complex. As a result, wind energy assets require significant control and management. Recent advancements in real time monitoring are transforming the ability to optimize wind energy generation. 

The demand for monitoring
Wind farms are generally developed in remote locations, designed to operate autonomously, without a site presence and be visited periodically for planned maintenance. Unlike traditional energy models, there is no need to routinely feed the burner with coal; the wind is a free and natural resource, and despite variations, it will keep turbines spinning whenever present.

The role of technological advancements
Historically, as long as wind turbines were generating energy, asset owners weren't concerned with their greater possible achievements. The increase in understanding of the complex nature of the wind resource has made owners and operators aware of optimization and the potential increase in return when it's applied to operating projects.

Advancement in measurement technology is a huge contributor to wind farm optimization and combined with improvements in monitoring, sites are now able to uncover an accurate, well-rounded picture of real conditions. The complex nature of the wind has been studied by academics for many years, but only in the last few has the industry been able to accurately measure and characterize the wind in real time, using technologies such as lidar. 

Before the availability of highly accurate lidar measurements, analysts predicted wind flow by modeling it across complex terrain, with point in space measurements. Now, real time accurate measurements can be applied to operational wind farms which are known to be underperforming. 

What real time monitoring has to offer
Wind energy assets can be monitored via the Original Equipment Manufacturer (OEM) Supervisory Control and Data Acquisition (SCADA) system, or on a separate Open Platform Communication (OPC) connection to the wind farm. However, it is third party, independent performance monitoring systems which appear to be offering true value in terms of optimization capabilities. 

Independent 'control centers' and performance tools monitor all sites on the same online platform regardless of asset make or model, meaning operators don't need to draw down and analyze SCADA data separately for each OEM. 

These systems allow operators to monitor assets quickly on a turbine-by-turbine basis or as a full 'birds eye view' of their portfolio where key data signatures and trends can be viewed and analyzed. 

Visualization of both current and historical data can be accessed on these platforms, including; power curves, energy against wind resource, availability, capacity factors, production ratios, and event energy yield deficit. 

Being able to access this kind of detailed information 24/7 gives real insight into performance, delivering the opportunity for significant operational improvements which were previously unavailable.

Taking control
Other technology advances allow us to improve the control of wind turbines, enhancing performance as well as better manage component loadings. The application of real time monitoring facilitates the selective control of an individual turbine's power output to reduce potential damage and maximize energy capture. Devices including sensors and controller add-ons can be fitted to a wind turbine to monitor surrounding conditions and control it in a more efficient manner. These devices combine condition monitoring, data processing, and control. 

Advanced control solutions effectively maximize energy capture and extend turbine lifetime while providing exceptional levels of safety and operational flexibility. Wind farms which have been operating for a number of years can benefit from a controller upgrade to improve the operation and efficiency of the asset. Used alongside real time monitoring solutions, a complete picture is drawn of the potential performance enhancement that can be realized for aging assets.

The ability to control a wind farm as effectively as a power station, as a single unit integrated to the grid, is something made possible through the ability to react to conditions as they change. Many wind farms are simply an aggregation of wind turbines which are controlled and optimized individually, rather than operating as one well-optimized, efficient grid asset. Monitored and managed properly, wind farms can be controlled in real time, providing support to the grid under conditions such as system faults, and dips in voltage or frequency. Advanced wind farm control can also manage constraining factors more optimally, such as turbines being shut down due to noise limits or shadow flicker effects.

So what's next for real time monitoring? 
It has now become commonplace to use lidar technology to accurately characterize the resource of wind farms in the feasibility and development phase. Lidar is supporting the theory that knowledge is power. As monitoring practices of operational wind farms evolve, it is likely lidar will play an increasingly integral part in the real-time monitoring and control of operational wind farms.  

Advancements in lidar, monitoring, and control technology are all important, and the aim is for the industry to reach an acceptable price point to facilitate deployment of these technologies on all current assets and to further develop improved methodologies used to monitor the wind and control the turbine. Asset owners should always be questioning the current operational performance of their assets and looking to improve with the help of the ever-evolving tools and solutions available. They no longer have to accept the performance of aging assets and can instigate effective optimizing solutions through real time monitoring to radically improve their return on investment.  

Robbie Gibson has over ten years of experience in the renewable energy industry and leads the measurement and active asset management groups within SgurrEnergy as an associate director. Robbie's expertise lies in the fields of wind and power performance monitoring and he is hands-on as project director, providing support and direction for key projects.

SgurrEnergy | www.sgurrenergy.com