Eskom Battery Site Visit
5 February 2019
For the third chapter within this series and one of the highlights of an extensive itinerary, our journey takes us from the heartlands of Bushveld Minerals' Vanadium operation at Vametco, and on to Bushveld Energy's vision for the future of South Africa's major utility supplier, Eskom.
Following insightful tours of Vametco's mining operations and processing plant, our intrepid team were privileged to be invited to visit Eskom's battery test and appraisal facility at their impressive Rosherville campus.
Our arrival to the campus was heralded by the sight of large banks of solar panels, an unmistakable foreshadowing of the future for South Africa's energy economy. After coolly passing an unforeseen alcohol test and some rather stern words regarding photography, we were escorted to the battery testing site.
Before looking at the individual batteries under test it is important to understand the protocols that they will be tested against. We recommend this article by Langley and Clarke from 2017 which describes the 90 day Eskom test procedure as well as describing the control and monitoring system in detail. Some of the key criteria to be met are summarised below.
- Load shifting: six hours continuous output at 200 kW per battery, off-peak charging available for eight hours per day, each day for the 90 period.
- Wind smoothing: a typical wind farm daily profile established from a South African wind facility, (under afternoon storm conditions) which is used to supply the battery and/or grid, on a daily basis for 90 continuous days, with the battery expected to absorb and discharge to smooth the output.
- Solar smoothing: a typical solar output established from a South African photovoltaic facility (under cloudy conditions) is used to supply the battery and/or grid, on a daily basis for 90 continuous days, with the battery expected to absorb and discharge to smooth the output.
- Power quality: the battery will operate at the top end of its charge and smooth out frequency and voltage changes resulting from demand changes.
- Other: the facility is a tool for Eskom to simulate actual conditions and to complete predictive testing prior to selection, design and installation of battery energy storage systems on the network.
It is worth noting that the 90 day duration of this testing process is significantly shorter than the 18 month figure that some of the more occasional visitors to the LSE bulletin board have suggested.
Looking at the aerial view below of the test area, the small control unit (1) houses all the plant electronics and monitoring equipment. Impressively, more than 50 different parameters of each battery were being continuously monitored. Observable measures included current, voltage, reactive load and temperature.
The concrete pad at (2) is evidently new and has not had a battery installed on it. The multiple units at (3) shown in the satellite image comprise the high temperature Sodium Nickel-Chloride battery supplied by GE around 4 years ago. This is a different technology to the Sodium-Sulphur batteries made by NGK, although both are high temperature beasts as a result of requiring molten sodium to function.
The GE system is shown in the image to the left, below. The unit at the bottom of the same image, (also partially visible at the top left corner of the image to the right) is the DC 'battery' component of this which is no longer on site. We were informed that it was in the process of 'being replaced', however I believe that BigBiteNow correctly identified this as the battery when he observed that "one system under test is not suitable for use within Eskom." It may be that this component will never reappear.
The multiple (40ft+20ft) containers at (4) comprise the 200kW / 1.2MWh Lithium Iron Phosphate (LiFePO4) battery, also known as an LFP battery, supplied by BYD. We were told that current Lithium-ion technologies could squeeze the same energy capacity into a single 40 foot container.
Keen-eyed readers may have noticed the concrete piers providing elevation to the LFP battery. The rationale for lifting the batteries off the ground is to prevent floodwater from permeating the battery. This scenario appears somewhat unlikely given the hilltop locale of the Rosherville campus, however, it may also help with passive cooling of the containers. The LFP battery has been at the Eskom site for approximately 1.5 years and has clearly been thoroughly tested as it is described in more detail in the previous paper.
The star of this particular show, Bushveld Energy's VRFB installation (5), was introduced to us by Pat Frampton. Pat was an enthusiastic and knowledgeable host, with a huge repository of detail regarding the Eskom test system and the protocols being observed, having played a significant role in its creation. Alongside consultancy work for Eskom, Pat also lectures on Energy Storage and Renewable Energy at the University of Johannesburg. Also, to the benefit of all stakeholders in Bushveld Minerals, he now advises Bushveld Energy.
The Bushveld Energy / UET Vanadium Flow Battery is a 120kW / 450 kWh VRFB housed in the 20 foot container shown below. Behind Bushveld Energy CEO - Mikhail Nikomarov, is the silver coloured inverter which converts the DC output from the battery into the AC needed by the grid. The tan coloured unit on the left is an isolation transformer which eliminates ground loop issues. Importantly, both of these components, necessary in any battery application, have been sourced and installed by Bushveld Energy.
The VRFB contains 3x 45kW Power stacks and some $200,000 (3 tonnes at $70/KgV) worth of Vanadium in mixed-acid electrolyte. This electrolyte was made in China, no doubt made by Rongke or Dalian Bolong New Material Co, who both work closely with UET.
During a Q&A session, the much-discussed issue of the original electrolyte contamination was raised. Apparently whilst the VRFB was originally being filled with electrolyte there was a fire alarm elsewhere on the Eskom campus. Everyone on site, including the entire Bushveld Energy team, was required to vacate the premises in accordance with site policy. Upon returning to the installation, it was discovered that electrolyte within the power stacks had precipitated, causing the subsequent problems commissioning the battery.
Whilst it has not been possible to independently verify this explanation it does explain the delay in commissioning. It is certainly possible that as a result of this unforeseen event, one or more of the power stacks would need to be cleaned or swapped out. Furthermore, it is absolutely clear that this explanation would have been difficult to articulate convincingly through the corporate language and limitations of the RNS format, and thus is precisely why I am inclined to believe this explanation now. Shareholders should be reassured that this unique experience of electrolyte contamination engenders no fundamental, systemic risk to future installations. Whilst it could certainly be considered unfortunate, this occurrence was simply a freak event that no one could have predicted.
The Bushveld Energy / UET VRFB is currently undergoing commissioning and we can confirm that it was being charged at a power of 102 kW during our visit. Currently, electrolyte is being run-in which will take approximately two weeks. Once this process is complete the VRFB will be handed over to Eskom to conduct their own tests and monitoring. Time permitting, the test team will attempt a full 'black-start' operation, restarting the entire Rosherville campus using the VRFB. Crucially, this is a function which has been found to be impossible for all the other batteries previously tested.
Some of the analysts attending certainly appeared to appreciate the fundamental point of large scale energy storage. It may be that they have not previously understood that South Africa's grid and private industries may benefit from local energy storage irrespective of the rollout of increased renewables generation across the country. Although the Eskom 800/1440 MWh Battery Energy Storage tender may not have been mentioned explicitly during our visit, it was discussed at some length on our return journey and at the evenings company hosted dinner.
Falling just ahead of the Capetown Indaba, the timing of our visit ensured that many of our group were focused on mining rather than being energy or technology oriented. However, amongst the many analysts present there was a tangible sense of interest and excitement provoked by the VRFB battery system and the exciting future that it implies for both the company and the world at large. With a vision or ambition of this size, sometimes it takes contact with those people, such as Mikhail, Pat and Mike (another Bushveld Energy employee hosting the tour), the individuals actually bringing these enormous ideas to life, to truly see the potential impact that such new, game-changing and disruptive technologies such as these, can have.
Thanks go to Sanchez599 for his rapid and refined copy-editing which have greatly improved all three of these site reports.
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