Posts Tagged ‘solar’


Rural electrification in South Africa

Wednesday 20 February, 2013

Those crazy krauts are @ it again.  The German-South African Chamber of Commerce put on a seminar on rural electrification here in Durban, South Africa, so I sat in on as many sessions as I could.  Most of the content seemed to be provided by Renewables Academy.  This was a comprehensive 4 ½ day seminar, covering photovoltaic (PV) systems, solar resources, cells, modules; batteries & energy storage; electronics, installations, wiring, fuses, loads, applications; off-grid system design & sizing; hydropower systems, & project design.  The featured speakers were Peter Adelmann & Ivan Karau Kisembo.

There are a number of off-grid PV applications:

  • Solar home systems (SHS)
  • Clinics, schools,
  • Rural businesses
  • Tourism
  • Solar water pumping
  • Telecom, 2-way radio
  • Street lighting & signs
  • Back-up
  • Mini-grids
  • Small portable appliances

There are also many different configurations of PV systems:

  • Off-grid & tied to the grid
  • Off-grid wind powered & grid-tied wind powered
  • PV-only off-grid
  • Wind-only off-grid
  • Hybrid off-grid
  • Pico & micro-hydro off-grid
  • Ac- & dc-coupled micro-grids
  • grid-tied PV & wind

It’s important to choose the correct pv module to match the system type.  Modules for off-grid & grid-tied are not usually the same.  Mistakes can be expensive.

Photo-voltaic modules & arrays can be mounted many ways off-grid:

  • Roof
  • Free standing-ground & flat roof
  • Pole
  • Tracks
  • BIPV (building integrated PV)
  • PV slates & tiles

Mounting structures can be made locally out of steel or wood, & aluminum is easy to work with, but expensive.

Batteries can compose 70-80% of the cost of a PV system, so battery management is a key factor.  Charge controllers in off-grid PV systems protect the battery from being overcharged & overdischarging.

Lighting & small appliances are some of the most desirable uses for off-grid PV systems.  Computers, refrigerators, & hvac use too much energy to make sense for off-grid applications.  Adelmann found 100% of rural residents in Ethiopia charged their cell-phones & listened to radios, 30% watched TV, & none used dishwashers or washing machines.  (There they have ample hydroelectric energy-energy distribution is the problem.)  LED’s offer less light, but use little energy.  Incandescents use far more than low-energy bulbs.  Fluorescents last 5-10,000 hours while halogens are cheaper than fluorescents, but not recommended.  How lights are installed can make a big difference in energy consumption.  Areas should be lit with the appropriate level of light & light only areas that require lighting.  Reflectors multiply light.  Avoid wall lights generally as less efficient.

DC appliances, such as lights, tv’s, 2-way radios, fridges, & pumps,  are designed to be run on batteries & are generally more efficient than AC equivalents.  Although DC appliances are more expensive & not easy to find, some mobile home & boating suppliers stock them.  Adelmann worked on a solar project in western China with Shell Solar.  They hired a Chinese company to do the installation.  The Chinese firm then sold the users big TV’s that were big power consumers which overloaded the system, resulting in the project being called a disaster.  People will connect whatever they can to the system, which ruins the reputation of solar energy.

Solar water pumping can be expensive.  Making the borehole can cost more than the PV system.  These are generally more suitable for humans & animals than for crop irrigation.  Mechanical wind pumps are used in South Africa extensively.

Site surveys for off-grid systems are available from renac.  Designing & sizing off-grid PV systems involves the following:

  • Determining the exact energy/power requirements
  • Obtaining information on irradiation @ location
  • Determining output of PV array
  • AC or DC or both?
  • Charge controller?
  • Inverter?
  • Battery type & size
  • DC cable sizes/voltage drop

To plan for sustainable systems that will have a long life, i.e. longer than the 1st battery bank, take into consideration technical, financial, & organizational issues.  Many systems in developing countries, major markets for off-grid systems, last no longer than the original battery bank.  Trying to replace or compete with the grid can be problematic.  According to Mark Hankins of African Solar Designs in Kenya, small PV systems fail for both technical & social reasons:


  • Poor design for
  • Quick sales
  • Lack of thought about system use
  • Poor sizing-too small
  • Lack of money to buy a complete system
  • Poor installation
  • Poorly matched components


  • Lack of plan for energy balance
  • Poor consumer understanding of technology-appliances, batteries, inverters
  • Load creep

He compares small PV systems with electricity from the grid this way:

Small pv system Grid electricity
Power sources multiple Single
Limits many None
Voltage drop possible None
Appliances Select carefully Use any
Energy management necessary Not needed

Here are some best practices for small hydro-electric power construction:

  • Avoid bends in pipe to prevent water velocity loss
  • Use anchors for support @ bends
  • Be sensitive to regional environmental authorities for, e.g. fish migration
  • Pay attention to all these risks:  completion, technological, operations/maintenance, market/distribution, resource, regulatory framework, country, interest, inflation risks
  • Test pipes to the maximum to assure they won’t burst & harm the environment
  • Take all this into account in the design stage

Here are some online resources

sizing tools

commercial systems

solar pumping

renewable energy software

Although the country of Malawi provides a free solar system if a family plants 200 trees, Adelmann’s main thrust was that rural electrification should be left to the private sector in South Africa.  The problem is not that people can’t /won’t pay:  the proliferation of cell-phones proves that.  Many consumers now pay more for energy for less service, for example, for kerosene.  The next issue will be productive use, i.e. how to enable those in the countryside to make money, which requires much higher productivity.  We must improve the countryside to fend off urbanization, but South Africa has no commercial farming.


northern German green technologies

Thursday 18 August, 2011

It’s appropriate that the last international event I attended in Chicago before I left for India was with the Krauts, the 1’s who got me started in all this international stuff. They hosted this event: GREEN TECHNOLOGY: COOPERATION PERSPECTIVES FOR THE US MIDWEST REGION AND NORTHERN GERMANY  Part of the visiting delegation was stuck in Hamburg because of bad weather, but the show did go on.

Chicago’s new mayor Rahm Emanuel made a showing  before he ran off to open a school & noted that German firms employ 36K employees in the Chicagoland area.  On environmental notes, he added that Chicago has the most headquarters of wind companies & the most urban solar farms in the U.S.   He also wants to double the number of LEED certified buildings in Chicago.

You should be able to find most of the information presented @ the conference on the GACCOM website, so I’ll just hit the highlights here.

Frank Horch of the city of Hamburg kicked off by letting us know that his city is the 3rd largest port in Europe & 3rd largest aviation location in the world.  Jan Rispens of Renewable Energies Hamburg (erneuerbare energien hamburg, gmbh) said Germany has set a target of 20% of it’s energy needs served by renewable sources by 2020.  Investments of €20B has created 340K jobs & now creates 17$ of total energy production.  Solar is still expensive, but they are building solar photo-voltaic cell farms.  25 renewables companies in Hamburg employ 4K with a turnover of €5B.  60% of the world’s wind energy know-how is within 2.5 hours drive from Hamburg.

Panel 1:  Vattenfall is the #2 generator of wind power.  15% of their electricity comes from renewables & now they must replace the 20% of electricity that was generated by nuclear power.  Nordex created 200 jobs when they opened their new plant in Arkansas.  They see 25% better wind potential than in Germany.  AWEA has 2500 members & collaborates with EWEA.  Commonwealth Edison will be required by law to provide 20-25% of it’s energy via renewables by 2050.

Panel 2:  Buildings consume 1/2 of all energy consumption & create 1/3 of CO2 emissions.  Heating & cooling take the most energy, so investment in insulation is needed.  While green building of CO2 neutral houses mitigates environmental impact, the more pressing issue is how to make the existing housing stock more efficient.  1.6M ft2 are LEED certified daily in the US.  According to energy modeling data, predicted energy use occupancy goals are not being met.

Panel 3:  Energy transmission & storage are still challenges.  Hydrogen fuel cell technology is coming in the next few years.  There are 3 criteria for electrical/utilities issues:

  1. Whether or not it’s clean energy is a political issue.  Rechargers are 100% renewable.
  2. All users should be entitled to free access.
  3. Charging stations must fit with urban development.

Battery-operated cars are coming to the market before hydrogen powered cars, but hydrogen filling stations are expensive & it’s not certain that there’s a market there yet. Changing traffic lights to LED’s saved 70%.  Hamburg’s Climate Action Plan devotes €25M to these issues from the public budget.  We need to use the 3 S’s:  save, store, & substitute.


israeli environmental research

Friday 15 May, 2009

I attended this lunch presentationFrom the Desert, Sun and Sea…for the World sponsored by American Associates, Ben-Gurion University of the Negev.

Avigad Vonshak, Director of BGU’s Jacob Blaustein Institutes for Desert Research (BIDR),  led off talking about algae in the desert.  1/2 of the US & all of Israel & Australia archaracterised as arid or dry, so desert locations are important.  Our current rate of desert utilization is unsustainable because we are taking out more than we are putting back.  Effects are far-reaching, in that sand storms in the Sahara have led to eye infections in the US.  Deserts differ in that Israel has stable dunes, while the Sinai Peninsula has shifting dunes.   Algae harvested from these deserts feeds biomass production in Mexico, California, China, & Thailand, which ends up in health food stores.

Dr. Nadav Shashsar,  head of the BGU Dolphin Reef Laboratory, was up next to talk about coral reefs, which are deteriorating at an accelerating rate due to human intervention.  He’s investigating building artificial reefs out of metal reinforced concrete with rough surfaces, which create new habitats.  The USAID-funded program created mutual interests-conservation & tourism.  These reefs grow slowly, to their growth needs to be enhanced, which they’ve accelerated up to 5X in Israel, the Phillipines, Singapore, Thailand, Tanzania, & Jordan.  They’ve experimented in the Red Sea, which is open to public divers.  This is even cultivating peace with Jordan.

David Faiman, chair of Solar Energy & Environmental Physics @ BGU’s BIDR, finished up by addressing solar energy.  In earlier generations of solar power products, much energy was lost & photovoltaic cells were expensive @ $1000 for a 4’x6′ panel & 80% of the cost.  At those rates it takes 1 year to save a barrel of oil.  Solar is a dilute form of energy, so by converting light into electricity & separating the collection from the conversion, they’ve made it much more affordable, generating electricity even cheaper than with fossil fuels.  They created the world’s largest solar disk 4’x4′ 200 ft2 of panels.  Here‘s a video which features Faiman’s work.


Sustainable energy in Germany

Wednesday 18 February, 2009

I attended this event last week Sustainable Energy Technology in Germany and the U.S sponsored by the German Federal Ministry of Education & Research, Baden-Wuerttemberg International, & Research in Germany-Land of Ideas.  Links to the presentations & video of the conference should be available here

Here’s what’s not included in the presentations:

Dirk Lohan of Chicago set the goal, in typical German fashion, to achieve harmony & balance with nature.


  • aim is to make applications for renewables as vast as possible
  • renewables are no longer alternative energy
  • we need to find renewable energy yields every day
  • we need more communication between architects & engineers
  • monitoring is needed to show payback,/ROI,, etc.


  • energy consumption by buildings is the same the world over
  • climates differ, reflected in more humidity here
  • lighting accounts for 26% of commercial energy, which should be simple to economize, e.g. with motion sensors
  • Germany implemented its 1st energy code in 1977, while there is no federal legislation
  • the US is comparable to Europe in green building certification systems-it’s a global movement with LEED adopted in 67 countries
  • drops in the price of oil are bad because they cause less emphasis on conservation


  • projects are 5-6 years in duration so they can be monitored over time
  • solar chillers help with heat in summer
  • 3 years ago they had no energy data from varied automation systems
  • passive consumption is reaching 0
  • triple glazed windows is needed for optimal insulation
  • even if buildings are made airtight, mold problems can develop if ventilation not up to speed
  • heating/electrical varies tremendously, depending on users
  • biomass quality varies, depending on the input
  • to go to net 0, electricity is still required, but can be solved by photovoltaic panels


  • there is no linear relationship between heating a cool space & cooling a warm space
  • there is a variance of +/- 5% for energy radiation


  • they monitor 1300 data points in their low-energy school building
  • heat generated from computers in classrooms is reused

The Germans are way ahead in developing sustainable energy.  We can learn a lot from them, & not just from their technologies & not just from those in Baden Wuertenberg.  Their approach is typically German-comprehensive & long-term.  We can learn from that as well.