[RE-wrenches] Off-grid in Tanzania

Wed Nov 6 18:07:40 PST 2013

Although it's more expensive, I'd go with AC Coupled SMA. Contact the owner of http://standardmicrogrid.com/ for more info on his recent work in Zambia...wait, I think he's there now. They have a pretty sleek set-up for a Sunny Island-based system, monitoring included. I'd go with ground-mount but be aware of theft (goes without saying, right?). You can also check out Volunteers for International Aid (VIDA) http://www.thevida.org/

And hey, get me involved! It's been years since I've been to A-land and I've been trying to get back ever since. So much so that I've recently formed a non-profit, Good Sun, to go back to places like Africa and do good work for good people.

My bags are packed...

Eric Stikes
Owner
SunHarvest
001.530.798.3738 (Cell)

  ----- Original Message ----- 
  From: Andrew Truitt 
  To: RE-wrenches 
  Sent: Wednesday, November 06, 2013 3:43 PM
  Subject: [RE-wrenches] Off-grid in Tanzania

  Wrenches - I am working with Lee Bristol and Ray Walters on 20 off-grid PV systems in Tanzania at various types of remote health care facilities.  There will be 3 system offerings: 2, 4, and 6 kW, all 230V, 50Hz.  We are currently considering the following issues and would appreciate input:
    a.. AC coupled SMA system vs. DC coupled Outback/Midnite system: We have had positive experiences with Sunny Boy / Sunny Island systems in GT w/ battery back-up applications and we like the SMA production monitoring (more on that later), but we are not sure how appropriate the system is for off-grid.  Cost is a consideration, as well as energy harvest, simplicity for in-county technicians, future system expansion, battery SOC remote monitoring, integration of generators, running power to multiple buildings, inverter over-sizing to increase equipment lifetime, reliability, battery over/under-charging prevention, ease of use for the customer, surge capability, and programable load shedding.  We have had numerous internal discussions about this particular decision and would appreciate additional viewpoints. 
    b.. Ground mount vs. Pole mount: The roofs at the sites are far from ideal in both construction and solar access so we are planning to locate all the arrays on the ground.  Soil types and slopes vary.  Manual labor will be readily available but heavy equipment will be hard to come by.  We would like to have a standard, replicable system which might be more achievable with a pole mount (e.g. [8] 250W modules per pole for 2kW; 1, 2, or 3 poles per system), and poles might be easier to have pre-installed before we arrive (e.g. you can't get the orientation wrong; less spacing measurements to consider), but the cost difference is significant (about $0.40/watt for S-flex ground mount vs. $1.05/watt for DP&W TPM all in).  The pole mount would be adjustable (east/west to account for micro-climate variations, north/south for seasonal adjustments), but how much of a value does that add at 10 degrees south latitude?  A ground mount could be ballasted which could be a big benefit in some locations. 
    c.. Monitoring options: This is a tough one.  Obviously there is not robust internet access so we are looking at cell modems for data transmission.  Does anyone have a recommendation for a 3rd party off-grid full system remote monitoring provider?  Pentametric is an option - anyone have experience with the on-line interface or remote monitoring reliability?  All the OEMs have monitoring options for production and battery SOC, but we want to have an additional system to compare data and provide redundancy. 
  Clearly there are many more factors that go into these decisions than I have conveyed here, but we are just hoping to get some thoughts on the issues from the extensive off-grid knowledge base on this list, particularly from anyone with experience in Africa.

  Thanks in advance!

  For a brighter energy future,

  Andrew Truitt 

  Principal
  Truitt Renewable Energy Consulting, LLC

  (202) 486-7507

  LinkedIn Profile

  Company Website

  NABCEP Certified PV Installation Professional ID: 032407-66

  Colorado Journeyman Electrician License No.: 600132

  "Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless!"

  ~William McDonough

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