The opportunity to create energy efficiencies by cycling batteries during peak tariffs has prompted China Tower Corporation (CTC) to research and deploy secondary use EV Lithium-ion to replace the lead acid batteries at 70-80,000 of their cell sites. CTC has innovated a unique strategy named the ‘energy recycle circle model’ to leverage recycled batteries from electric vehicles. In this exclusive interview with Mr Gao Jian, Head of the Energy Innovation Centre in CTC, TowerXchange has learned how secondary used EV batteries can be economically and practically beneficial for tower owners.
TowerXchange: Please introduce yourself, your role at CTC, and the structure of the energy management team across your vast portfolio and geography.
Gao Jian, Head of Energy Innovation Centre, CTC:
I have been working in the telecom industry for many years. I have been working at the energy management division at CTC since the establishment of the company in 2014. Now I am a head of the energy division in CTC based in the head office in Beijing. Currently our team and I are all working in the head office and are frequently traveling to the sites.
TowerXchange: What are the guiding principles of CTC’s energy strategy?
Gao Jian, Head of Energy Innovation Centre, CTC:
In preparation for the 5G infrastructure rollout, CTC has set up strategic partnerships with 31 provinces, regions and cities across China. With 1.92 million towers, CTC promotes and practices the co-sharing resources, enabling the more efficient upgrade of towers, power generation, and other equipment on sites to support the requirements of 5G.
CTC’s energy strategy is to keep expanding the established energy recycle circle, which is a model to maximise the value of electric vehicle batteries, and to reduce waste, by reusing them in cell sites. After being utilised for approximately eight years in the cell sites, the batteries are recycled again. This model is exclusively designed by CTC for our domestic tower market. In future, all energy storage for our cell sites will be reliant on secondary use lithium-ion electric vehicle batteries.
One of the main reasons that CTC has created an energy recycle circle model is to support the central government’s strategy for the recycling and reuse of electric vehicle batteries. A few years ago, China had produced huge numbers of electric vehicles for the domestic market to cut down carbon emission levels. Car makers were gearing up to cater for the growing demand for environmentally-friendly cars. Now the batteries in these vehicles are approaching the end of their lives. However, from a commercial point of view, the cost of recycling these batteries is very expensive. As a state owned corporation, CTC has taken the responsibility to support the government to solve the issue. We have been collecting these batteries and reuse them to increase the efficiency of the electricity supply to our cell sites.
Reducing the energy cost for our cell sites is another key area that we have been looking into. By creating an energy recycle circle model we not only solve the issue of retired EV batteries, we can also significantly reduce energy costs for our cell sites.
On the basis of these main reasons, we have been working on the energy recycle circle model and have made a great progress on the development of this secondary use-case for EV batteries since we started recycling and reusing EV batteries to replace lead-acid batteries on our sites. Its development showed that recycled EV batteries can be economically and practically beneficial to the cell sites. By now CTC has already consumed 600MW EV batteries: 200,000 EV batteries have been deployed to approximately 70–80,000 cell sites across 31 provinces in China.
We are continuously developing and refining our energy strategy to create an industry recycling regime we call the ‘Circle Economy’.
TowerXchange: We understand CTC has achieved considerable success in reducing reliance on peak grid power in favour of cycling batteries during peak hours, and recharging off-peak. What are the key objectives of this strategy?
Gao Jian, Head of Energy Innovation Centre, CTC:
Yes, we have been taking advantage of off-peak periods to recharge our batteries.
There are three objectives explaining why we do it this way. First of all, we reflect the central government strategy on saving energy, reducing carbon emissions to minimise the pressure on the national grid. Secondly, off peak grid power is at a more powerful Voltage than during peak periods, such that it shortens the battery recharging time, thereby increasing efficiency. The last but not least, we recharge the batteries in the off-peak time period to lower the electricity cost, because the electricity charge in the off-peak hours is cheaper than during peak hours. If we count this year on year, it can save a significant amount of the energy opex on cell sites.
TowerXchange: Can we talk specifically about energy storage and batteries. CTC has made commendable progress in recycling EV batteries to use a cell sites – can you tell us about the scale and success of that project? In general terms, what proportion of CTC’s cell sites use lithium-ion (secondary use EV batteries or primary use) compared to lead-acid batteries? What use cases define which energy storage technology works best?
Gao Jian, Head of Energy Innovation Centre, CTC:
To maximise the usage of clean and renewable energy, we have put a great deal of effort to progress the development and utilisation of lithium-ion batteries (specifically secondary use EV batteries) for our cell sites. So far we have about 70-80,000 cell sites using lithium-ion batteries which only represents 4% of the total of CTC towers. However, this percentage keeps growing.
Compared with lead-acid batteries and alternate chemistries, we have seen that lithium-ion batteries deliver some great metrics. Lithium-ion batteries are a smaller size and occupy less space, and can be more practically located within the cell sites. On top of that, they also lowered our capital costs and saved opex for our cell sites.
Lithium-ion batteries are a smaller size and occupy less space, and can be more practically located within the cell sites. On top of that, it also lowered the capital cost and saved opex for our cell sites
As we all know, energy storage is an important part of energy supply. We have a technical team to keep developing energy storage technologies and battery management systems especially for our various cell sites. We are also undertaking further research and studies into how to be more efficient managing the batteries, with a view to extending battery lifecycles. We are working hard on these studies and are constantly testing new technologies on our cell sites. Once we gain more confidence and are satisfied with the test results, we will put the new technologies into practise in our cell sites first, then we will expand and share the innovative battery technology into the telecom industry value chain as well as related fields.
TowerXchange: CTC has been planning to maximise the usage of the renewable energy, please could you tell me more about this?
Gao Jian, Head of Energy Innovation Centre, CTC:
Renewable energy is one of the key areas that CTC has been looking into. As I mentioned earlier, we created an energy recycle circle model. This is a unique business model that CTC has developed for our domestic market needs.
The process of the circle is that CTC buys retired lithium-ion batteries from car manufactures and sends them to CTC’s technical centre to reassemble them ready to meet the needs of our cell sites. Once the reassembly process is completed, the batteries will be delivered to the CTC’s cell sites. We have professional technicians to install the recycled EV batteries into the cell sites to replace lead-acid batteries. We anticipate secondary use EV lithium-ion batteries will last approximately eight years in our operating environment. Currently we are using a battery charge-discharge regime named ‘Xue Feng Tian Gu’ which means to split each 24 hour day into three time slots: this regime runs non-stop.
When the batteries are due to retire, we will outsource battery processing to specialists and send these batteries out for recycling.
TowerXchange: How have you balanced the need to custom power systems for the unique requirements of each cell site, with the economies and efficiencies of standardisation?
Gao Jian, Head of Energy Innovation Centre, CTC:
It is true that each cell site has different needs in terms of power systems. Much depends on the locations of the cell sites. For example, in some less developed and remote areas, the electricity supply from the national grid might not always be powerful enough. At these cell sites, it takes longer to fully recharge the batteries. In this circumstances, the people working on site need to figure out the best time of the day for recharging the batteries to improve productivity. However, if the cell sites are located in the regions which can access to more powerful national grid, then they would not face this issue.
TowerXchange: What is the typical maintenance regime for CTC’s cell sites, and how are you working to reduce maintenance opex?
Gao Jian, Head of Energy Innovation Centre, CTC:
In terms of maintenance, we have innovated a centralised operational platform combining wireless, network and platform. In this platform, the maintenance work for each cell site can be remotely managed and controlled. The platform manages 1.9 million tower sites and 70,000 staff in various locations in China. If we identify an issue on a site through our central platform, we are able to take an action as quickly as we can to liaise with local support and take remedial action. One of the massive benefits of this remote maintenance management is that it has reduced the operating cost of each cell site and improved staff productivity.
TowerXchange: How do you foresee your energy requirements evolving as we move into the 5G era?
Gao Jian, Head of Energy Innovation Centre, CTC:
The 5G era is already under way in China. This will be a revolutionary period in the telecommunication industry, and while more and more 5G cell sites are deployed, there will be a massive increase in energy demand in the market. It is expected that the energy requirements from cell sites will be rising two to three times more than now we are consuming. CTC has taken a lead in this trend and has already been recycling EV batteries for cell sites, and this year we have started to discontinue purchasing lead-acid batteries, with an aim to eventually replace all our lead-acid batteries with lithium-ion batteries.
By 2020, our domestic market will have 24GW of recycled lithium-ion batteries from electric cars. All of them will be absorbed into CTC’s cell sites. In October this year, CTC has reached an agreement with eleven major electric car producers in China. These car producers and CTC will work together to maximise the usage and productivity of the energy recycle circle.
In conculsion, I would like to say that we are also open to communicate with the international tower industry to hear their experiences of optimising energy management for cell sites!
