Solar energy panels

Why Solar May Not Always Be the Answer

Posted by: Raakesh Parmar, on September 8, 2016

Economic and Technical Feasibility of Using Photovoltaic Panels at Off-grid Telecom Sites

All off-grid and bad-grid telecom tower sites are not created equally. The decision to deploy a solar (Photovoltaic, PV) energy solution should be taken on a case-by-case basis. Planetary Power’s business and technology teams have looked carefully at the feasibility of PV solutions at telecom sites. While our HyGen hybrid generator does integrate with renewable sources including PV, it’s important to consider the angles of this before assuming the addition of PV is right for your location. Our team has written an article on the topic:

Introduction

The scope of this article is to analyze whether the introduction of photovoltaic (solar) panels in off-grid telecom sites is economically and technically feasible. We compared a solution based on photovoltaic (PV) panels with lead-acid batteries to Planetary Power’s HyGen hybrid generator.

We did a 10-year financial forecast of all the cash flows and discounted them accordingly to the industry average weighted average cost of capital (12%) to come up with a total present cost for each solution.

Simulation

We assumed that the HyGen’s expected operational life is 5 years and that the PV panels expected operational life is >10 years. For the lead-acid batteries used in the PV solution we considered a 5-year expected life [1].

We also assumed that a PV-Lead Acid Batteries solution has a global performance loss of 27% based on the rated power of the panels.

pv-blog-post-table-1-updated

We also assumed for HyGen a $100 refueling event cost, a $100 maintenance event cost, a $0.80 /L diesel cost, and for the PV-Lead Acid Batteries system a $500 annual maintenance cost.

For the simulation we used a Mitsubishi PV panel (model PV-MLU255HC) with a monocrystalline silicon technology and a maximum power rating of 255 pk per panel.

We considered an annual solar radiation of 4.5 kWh/m2/day, which is consistent with most of the countries in the Caribbean and Latin America.

A typical radio base station (RBS) consumes approximately 2 kW of continuous power, 48 kWh/day.

To prevent RBS downtime in the toughest solar conditions, we selected a 48 kWh battery, which provides enough energy for a full day of operation.

Results

Taking into consideration the losses on Table 1, we need 58 PV panels with a total footprint of 97 m2 to provide 48 kWh/day. Since most of the off-grid sites are in places with difficult accessibility, the installation costs of the PV panels are going to be high and the entire solution is going to cost approximately $91,025 [3]. The HyGen on the other side has a list price of $45,000.

Conclusion

Even though the PV-Lead Acid Batteries solution seems to be economically advantageous, there are technical disadvantages that should be taken into consideration before making a decision.

  • Large Footprint (possibility of not having available space or having to rent space to install the PV panels)
  • Prone to theft and tamper
  • Prone to damage from natural disasters
  • More exposed to surge voltages
  • Capital Intensive Project
  • Lifetime of the project
  • Solar radiation unpredictability
  • High import tariffs in some African Countries

The right solution depends on the location, terrain, socioeconomic factors and the qualification level of technicians for each site. A full study and site survey should be conducted before deciding which solution to implement.

Our team is here to help you find the right energy solution for your telecom tower site. Contact us to find out what will work best for you.

 

 

References:

  • Spiers, A. Rasinkoski, “Limits to Battery Lifetime in Photovoltaic Applications” Solar Energy Vol. 58, 1996
  • National Renewable Energy Laboratory, http://www.nrel.org
  • Hellgren, A. Lindquist, “The interest for green telecom in East Africa”, 2014

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