Remote Cellular Stations generate power that they convert to radio waves to provide coverage to their consumers.  Such stations are well distributed throughout countries, and growth projections worldwide are excellent.  Cellular Service providers are actively replacing old diesel generators with renewable energy solutions to improve on service reliability, reduce operating costs, and meet Corporate Social Responsibility objectives.  Meanwhile, cold chain storage points are often in proximity to Cellular stations, and have insufficient power to adequately conserve vaccines.  Are there scenarios in which the cold chain could tap into power from Cellular stations?

Do Cellular Station Generators (CSG) produce excess power, or have excess capacity? 

⚡ In the case of older diesel generator systems, oversized for growth that didn’t occur or was taken on by a newer installation, there could in theory be a surplus of energy when it is operating.  When sizing a Renewable Energy system for a telecom application, much depends on the precision with which the integration was done in terms of assessing loads and duty cycles.  If the RE generator was built assuming a 24 hours active duty cycle on all channels, then there is a possibility that there is indeed excess energy produced and available.

⚠ Most newer diesel generators scale their power output with the demand, which greatly minimizes energy wastage.  Due to the high capital cost of RE systems, and their modular nature which allows for later expansion to meet increased demand, it’s unusual that RE generators are substantially oversized for a telecom load.  Reliability is critical for cell towers, and they will want to keep 100% of their battery autonomy for themselves.  Furthermore, professionally designed PV generators for telecom stations use redundant controllers and battery banks so that if one fails, the other keeps the cell tower in service.  Tapping into existing RE installations will be challenging as to not compromise the proper function and reliability of the cell tower;  energy for the cold chain would only be made available when telecom batteries were 100% charged and sun/wind are producing energy which would be stored in an independent battery bank. While a single fridge could potentially be powered from cell tower excess power, building an intermediate storage point for vaccines would hardly be justified for a single refrigerator; one would envisage a minimum of 3-4 fridges and 1-2 freezers, which are likely to need more energy than just the excess capacity/production of most stations.

Do Cellular Service Providers (CSP) have an interest in facilitating this? 

⚡ In many cases, yes.  It helps them to meet their Corporate Social Responsibility (CSR) humanitarian objectives and provides excellent Publicity / PR.  More likely to appeal to large international conglomerates with western HQ’s than to national networks though.  It’s also possible that the CSP foundations could help IPP’s with financing/grants.

⚠ Unlikely though that they would expand capacity at a site specifically to power the cold chain.  Daily power consumption for the cold storage would need to be capped, especially if the CSG is solar/wind without diesel genset.

Could an Independent Power Provider (IPP) take over power generation for a Cellular station?

⚡ Most certainly, and there are many advantages to this for all parties.  CSP’s are rapidly replacing old Diesel Generators with Renewable Energy Generators to improve reliability, cut costs, and meet PR/CSR environmental objectives.   The IPP would bear the capital cost of the transition and operational responsibility for the CSG, with a guaranteed Power Purchase Agreement (PPA) from the CSP.  The IPP approach also is more likely to be a sustainable effort since it will be driven by power sales rather than CSR/PR image benefits, and has the added benefit of also serving the community. While  CSP could be open to supplying cold storage adjacent to their generator (Scenario 1), it’s unlikely that they would build a mini-grid (Scenario 2), or engage in the supply and servicing or PowerPacks (Scenario 3). CSP would keep old diesel generator on standby as insurance.

⚠ This would best be implemented at sites with pre-existing Diesel generators only. Acquisition of an existing RE plant would be complex, and the constraints on expansion would be numerous.  CSG’s may also not be comfortable depending on a third party for power, or might prefer to make the capital investment into RE themselves to take full advantage of the long term economics of such installations.

How can this energy, whether from the CSP or IPP, be used to benefit clinics?

On-site Cold storage

Build a Cold storage facility next to a CSG, and integrate it into the cold chain as an intermediate storage facility to reduce the length of overland transport legs, and reduce vaccine loss due to high inventory levels at health facilities without power.

⚡ Introduction of intermediary vaccine storage facilities at certain points in the cold chain could be highly beneficial, but should compliment the existing infrastructure, not aim to replace it. 2-3 fridges + 1-2 freezers would like be appropriate.

⚠ Locations would need to be very carefully selected in terms of number of satellite clinics, proximity to them, and population of catchment area.  Facility would require it’s own operator, who would not be under the direct daily supervision of the Health Facility Administrator.  Many telecom installations use compact weatherproof housing for communication and power components, which would require construction of a cold storage building on site.

Mini-grid

Extend DC or AC power lines from a CSG to health facilities and consumers.

⚡ For CSG’s inside of densely populated towns/villages with Health Facilities, this is an ideal setup.  The combination of  a long term PPA and prepayment technology for energy provides the IPP with the revenue flow to grow sustainably, while helping the CSP to improve on power reliability and meet CSR/PR objectives.

⚠ Unlikely to be cost effective unless the CSG is <500m from the clinic, and complimented by paying consumers. Infrastructure includes permits, distribution lines, voltage transformers, and metering and will be complex to implement.

Battery & Accessory charging

Clinics bring their Deep cycle batteries to the CSG for charging.  Either done with alternating battery sets, or with single sets if health facility has high holdover CC equipment.  Also supports charging of cell phones, lights, laptops and more.

⚡ Builds on current practice in developing countries - people are accustomed to taking batteries for charging. IPP would get a lot of business from the community.  Scope for the IPP to also service batteries for a fee, and log clinic battery condition.  Accessory charging attractive for the CSP since charged phones can make calls and spend credits.

⚠ Battery life is substantially reduced (as low as 1-2 years instead of 5+) from transportation. Refrigeration systems tend to typically use 2+ batteries and motorized transportation would likely be required.  Big danger of batteries remaining flat for too long and not being recoverable.

Power-pack leasing

CSG provides and maintains mobile battery banks to clinics and consumers

⚡ Good flexibility as far as location choice.  Excellent scope to ensure that batteries are of adequate quality and well maintained.  Power-packs charge directly from the RE generator, which is an efficiency again over charging batteries from batteries.  Also suitable for the community, and more predictable cash-flow from scheduled charges. Power-packs are equipped with a Low Voltage Disconnect and tamper resistant connectors to avoid abuse.  Swap-out of Power-Packs done with IPP owned and operated Electric All Terrain Vehicles (EATV’s) on a set schedule.

⚠ Will not necessarily cater to very low income community consumers.  Power-Pack design will have to be intelligently conceived as to allow re-insertion for charging into the main RE generator energy storage bank, and be in a shockproof casing to minimize wear and tear from transportation.  ETAV’s will need routine maintenance and repair and perhaps an integrated solar module in case of low power away from CSG.

EATV charging

CSG has Electric All Terrain Vehicles and uses them to move PowerPacks to and from clinics and consumers, or vaccines to clinics from onsite cold storage.

⚡ EATVs eliminate dependency on fuel, and potential interruptions in service.  They also take fuel siphoning and related corruption off of table, while building demand for the core product of the IPP -- Power.  Their limited range also dissuades staff from using them for other purposes.  For onsite cold storage, small EATVs for single riders wearing Coldpack backpacks would work well. For Power-Packs, full scale EATVs capable of carrying 8+ powerpacks would be required.

⚠ ETAV’s will need routine maintenance and repair and perhaps an integrated solar module in case of low power away from CSG.

How does the IPP ensure revenue collection and avoid corruption?

⚡ Ideally, energy would be purchased with cell phone pre-payment card technology.  This avoids cash for services at power distribution points, and provides the CSP with an additional revenue stream from processing energy sales.  Several technologies are in use in the field - IRG developed a grid in Liberia using this model a few years’ back.

⚠ This will require some setup, and not all CSP’s will have such a program in place.

Further development

These scenarios merit further consideration, feasibility assessments, and subsequent exploration as pilot projects.
• Onsite Cold Storage with small EATV distribution
• Mini-Grid
• PowerPack Service Provider with EATV distribution

More details on these scenarios are available in the annex of the original paper written for Project Optimize in April, which you can read or download here.