Five essential questions for monitoring renewable energy
As renewable energy sources get smaller, so should the remote telemetry units (RTUs) used to control them.
Diversification of the energy sector is a double-edged sword. While the benefits of reducing our reliance on fossil fuels are increasingly clear, many of these alternative energy sources don’t have the same level of control as traditional plants. Here, Matthew Hawkridge, chief technology officer at Ovarro, looks at why remote telemetry units (RTUs) that are smaller and more economical will be essential for effectively monitoring and controlling diversified energy networks.
Renewable energy sources — like solar power plants and wind turbines — now produce a growing proportion of most developed countries’ total energy output and now exceeds 20 per cent in the UK. However, renewable energy operators must manage a wider portfolio of assets compared with coal, gas or nuclear, with much smaller demands at each location.
Given that a typical power station is around 1 Gigawatt (1GW), RTUs used to monitor connections between conventional energy-powered facilities and the power grid are not suitable for the vast range of smaller, renewable options like solar, biomass and wind that are measured in kilowatts.
This creates a need for smaller RTUs ― and here are five reasons why.
Is monitoring smaller power plants less complex?
Not necessarily. Smaller power plants can have a more complex set of communication demands than traditional plants. What’s more, small sites are often independently owned and managed and must share data with numerous stakeholders. That’s why the ability of RTUs to collect data from numerous sources, and distribute it to numerous stakeholders, is so advantageous.
What is the RTU responsible for on-site?
For small sites, the RTU provides both the site control technology and the site communications gateway. Aside from collecting data directly, it can also provide a secure virtual private network (VPN) to other devices operating onsite — for example, programmable logic controllers (PLCs) managing solar panel tilt and azimuth control, weather stations and digitally networked power relays.
As the collected data is made available to the grid operators, they can issue commands back to the RTU and regulate the station while relaying key information to the asset owner, investor or maintenance crews. Take Australia, for example, where data is sent in parallel to cloud-based data servers for local communities and schools, for educational purposes.
Can RTUs be used with non-grid power networks?
Yes, large facilities like hospitals, universities, airports and railways often have their own internal power networks. They need managing with the same control and communications requirements as large main power grids, although with less complexity.
Electrified rail networks source their main supply from the grid and then distribute the power along the railway network. The demands on the RTU are similar to a main power network: remote environments, occasional voltage spikes, large volumes of data and , above all else, a vital need to control the local switchgear.
Are smaller RTUs resilient to network environments?
Yes, resilience to the site environment is an important feature of any RTU. Ovarro RTUs can operate in rugged conditions at temperatures of between -40 and +85 degrees Celsius. They have up to 5,000 volts of isolation on I/O cards, which protects the CPU from compromising electrical events.
RTUs should also have layers of redundancy so it can continue to operate even if a major event damages one piece of the system. The Kingfisher RTU for example, can be configured with fully redundant Power Supplies, CPUs and multiple communication paths. It means they can continue to manage intensive SCADAand telemetry applications, even in the event of a partial system failure.
What if the power generator fails?
RTUs have always operated in areas where power is either unreliable or unavailable. Each Ovarro RTU draws only a few Watts, so can run easily off a solar power system or a small feed from the site generator. Ovarro RTUs also incorporate a battery management system and can run off a small rechargeable battery for extended periods, which removes the need for an uninterruptible power supply (UPS) for the RTU.
Ovarro’s Kingfisher RTU, for example, supports multiple power supplies so that parallel connections to AC and DC supply systems can be used. This diversifies the supply and minimises the risk of total failure ― and helps ensure that diversification isn’t such a double-edged sword.
Ovarro is the new name for Servelec Technologies and Primayer. Ovarro’s technology is used throughout the world to monitor, control and manage critical and national infrastructure.
Our connected technology is always there, always on. Secure, proven, trusted; integrating seamlessly with our clients’ assets. Collecting and communicating data from some of the most remote locations and harshest environments on the planet. Enabling businesses to work smarter and more effectively.
Ovarro works with customers across water, oil & gas, broadcast and transportation to help monitor, control and manage their assets.