Monitoring and managing the unpredictable.

Energy sector investments in big data technologies have exploded. In fact, according to a study by BDO, the industry’s expenditure on this technology in 2017 has increased by ten times compared to the previous year, with the firm attributing much of this growth to the need for improved management of renewables. Here, Alan Binning, Regional Sales Manager at Copa-Data UK, explores three common issues for renewables — managing demand, combining distributed systems and reporting.

Renewables are set to be the fastest-growing source of electrical energy generation in the next five years. However, this diversification of energy sources creates a challenge for existing infrastructure and systems. One of the most notable changes is the switch from reliable to fluctuating power.

Implementing energy storage
Traditional fossil-fuel plants operate at a pre-mitigated level, they provide a consistent and predictable amount of electricity. Renewables, on the other hand, are a much more unreliable source. For example, energy output from a solar farm can drop without warning due to clouds obscuring sunlight from the panels. Similarly, wind speeds cannot be reliably forecasted. To prepare for this fluctuation in advance, research and investment into energy storage systems are on the rise.

For example, wind power ramp events are a major challenge. Therefore, developing energy storage mechanisms is essential. The grid may not always be able to absorb excess wind power created by an unexpected windspeed increase. Ramp control applications allow the turbine to store this extra power in the battery instead. When combined with reliable live data, these systems can develop informed models for intelligent distribution.

Britain has recently become home to one of the largest energy storage projects to use EV batteries. While it is not the first-time car batteries have been used for renewable power, the Pen y Cymoedd wind farm in Wales has connected a total of 500 BMW i3 batteries to store excess power.

Combining distributed systems
Control software is the obvious solution to better monitor this fluctuating source of power. However, many renewable energy generation sites, like solar PV and wind farms, are distributed across a wide geographical scope and are therefore more difficult to manage without sophisticated software.

Consider offshore wind farms as an example. The world’s soon-to-be-largest offshore wind farm is currently under construction 74.5 miles off the Yorkshire coastline. To accurately manage these vast generation sites, the data from each asset needs to be combined into a singular entity.

This software should be able to combine many items of distributed equipment, whether that’s an entire wind park or several different forms of renewable energy sources, into one system to provide a complete visualisation of the grid.

Operators could go one step further, by overlaying geographical information systems (GIS) data into the software. This could provide a map-style view of renewable energy parks or even the entire generation asset base, allowing operators to zoom on the map to reveal greater levels of detail. This provides a full, functional map enabling organisations to make better informed decisions.

Reporting on renewables
Controlling and monitoring renewable energy is the first step to better grid management. However, it is what energy companies do with the data generated from this equipment that will truly provide value. This is where reporting is necessary.

Software for renewable energy should be able to visualise data in an understandable manner so that operators can see the types of data they truly care about. For example, wind farm owners tend to be investors and therefore generating profit is a key consideration. In this instance, the report should compare the output of a turbine and its associated profit to better inform the operator of its financial performance.

Using intelligent software, like zenon Analyzer, operators can generate a range of reports about any information they would like to assess — and the criteria can differ massively depending on the application and the objectives of the operator. Reporting can range from a basic table of outputs, to a much more sophisticated report that includes the site’s performance against certain key performance indicators (KPIs) and predictive analytics. These reports can be generated from archived or live operational data, allowing long term trends to be recognised as well as being able to react quickly to maximise efficiency of operation.

As investments in renewable energy generation continue to increase, the need for big data technologies to manage these sites will also continue to grow. Managing these volatile energy sources is still a relatively new challenge. However, with the correct software to combine the data from these sites and report on their operation, energy companies will reap the rewards of these increasingly popular energy sources.

Thames to sparkle under its own power


W.S. Gilbert in one of the librettos for the famous Gilbert & Sullivan operettas prophesies:

“…they’ll set the Thames on fire
Very soon; very soon.”

Well this story, while not an exact fullfilment, strikes us as perhaps been something Mr Gilbert might have appreciated.

...the start of the future?

A small proportion of the Thames is to be illuminated using power generated by the flow of the river itself, as Kingston University tests prototypes of a new hydroelectric turbine design.

The turbine will sit on a pontoon and will provide a floating test and measurement laboratory. On this will be an array of sensors and monitors, including a TorqSense the wireless torque sensor from Sensor Technology Ltd.

“To say that this is a harsh environment for laboratory equipment is a bit of an understatement,” says Rod Bromfield, Senior Lecturer, of the Faculty of Engineering, Kingston University. “We can only use robust kit with a proven industrial pedigree.”

The turbine under test has been developed by Hales Marine Energy near Eastbourne on the English south coast and is expected to be deployable in tidal seas as well as rivers. The design application of this turbine is to sit on a submergible tank that will sit on the sea bed and can be floated up to the surface when required. Significantly, the design is almost infinitely scalable: the unit under test is 1m diameter and produces about 1kW; 5m turbines suitable for inshore deployment would generate round 20kW; smaller units would be ideal for river use.
With access to the test site being by small boat, Rod knew that his test regime had to be both simple and comprehensive.

“The critical measurement is torque, as this indicates the power we can derive from the system. We had to be certain that we would get continuous measurements over an extended period of time, because we need to map power production against actual river flow. Also for this technology to succeed in the emerging green power market it must be capable of continuous and predictable energy production.”

One of the engineering issues that Rod faced was the relatively slow revolution of the turbine, in this test below 50rpm. This helped define the choice of the TorqSense, but it is also a key feature of the Hales turbine – the slow speed means less stress on moving parts and therefore less servicing. It also minimises habitat disturbance, so that the ecological impact is low.

“When I contacted Sensor Technology I was very concerned about vertical mounting and harsh environment performance,” recalls Rod. “Fortunately there have been TorqSenses installed vertically, including several high up on vertical axis wind turbines, where they have to withstand gales, hurricanes and lashing rain.”

In a Torqsense transducer, surface waves are produced by passing an alternating voltage across the terminals of two interleaved comb-shaped arrays, laid onto one end of a piezoelectric substrate. A receiving array at the other end of the transducer converts the wave into an electric signal.

The frequency is dependent upon the spacing of the teeth in the array and as the direction of wave propagation is at right angles to the teeth, any change in its length alters the spacing of the teeth and hence the operating frequency. Tension in the transducer reduces the operating frequency while compression increases it.

To measure the torque in a rotating shaft, two saw sensors are bonded to a shaft at 45deg to the axis of rotation. When the shaft is subjected to torque, a signal is produced which is transmitted to a stationary pick up via a capacitive couple comprising two discs, one of which rotates with the shaft, the other being static.

The design of the Hales turbine is reassuringly simple, and therefore likely to survive underwater installation with long service intervals. It was developed by Paul Hales, a design engineer who has spent a career associated with the sea.  “It’s based on the traditional water wheel, but mounted on a vertical axis – on its side,” he explains.

“Using modern engineering and materials it is possible to take this effective early turbine and by turning the output shaft to the vertical to immerse the whole turbine into the tidal flow. To overcome the high resistance on the wheel blades that on one side are trying to move against the water flow, they are shaped and hinged to present a minimum resistance. The large blade area on the drive side produces very high amounts of torque (rotational force) at low speed, in the range of 10 -20rpm.
Coupled with modern permanent magnet generators that can start producing electricity rotations as low as 2rpm, my turbine can offer the possibility of tidal generation worldwide.”

Paul continues: “Water is nearly 800 times denser than air so it carries far more energy, making water turbines a very attractive alternative to wind energy. Notably seabed systems are not an impediment to shipping, nor do they have any visual impact and ecological issues are minimal for low speed systems.”

Paul says that he could envision an array of his turbines on every headland along the English Channel and at intervals down the Thames.

“Of course, that is just the start. The simplicity of the design, its robustness and low maintenance, relative ease of installation all add up to making it suitable for deployment in remote and less developed areas. Its low ecological footprint addresses many of the issues raised by environmentalists. Its continuous and utterly predictable power output overcomes the intermittency associated with wind, wave and solar power.

“When, over the test period, people stand on Richmond Bridge and watch a modest array of lights bobbing about on a buoy, they may not know it but they will be seeing the future!”

And so we get back to W. S. Gilbert:

“…they’ll set the Thames on fire
Very soon; very soon.”

See also Power from the Sea and Tidal turbine developement in Ireland & Canada published earlier this year