Sometimes I just can’t resist…

Solar products still expensive despite duty waiver

Despite efforts by the government to remove import duties and increase access to renewables energy the cost of solar panels, batteries and other accessories have remained high. In some instances, even increasing, leaving many of the poor who would benefit the most without alternatives to the country’s main utility, Zesa. Unreliable supply and surging prices of Zesa power is driving consumers and businesses off the grid as renewable energy becomes a top priority.

To combat frequent load shedding people have resorted to renewable energy, namely solar, but most still cannot afford to buy them. A snap survey by The Herald showed that prices of most home solar systems have actually increased from $25000 (US$2500) to around $45000 (US$4500) or more for a full home solar system installation. As suppliers battle to meet demand, prices have shot up.

When Government removed duty on solar products last month, many thought it would bring down prices and make them widely accessible to the majority of the people in the country. Many people applauded the Government’s help. The Government removed duty on solar equipment to reduce dependence on the national grid as individuals and companies would now have alternatives. Zesa’s rolling blackouts have led to a huge spike in demand for solar panels and storage batteries, pushing up prices beyond the reach of many.

Blackout that now last up to 18 hours a day have attributed to a massive demand for solar products resulting in rampant profiteering by dealers. The lowest paid civil servant earning $665 and cannot afford to buy a solar systems. Even workers in the private sector are affected. Given the cost, the majority of the poor are now relying heavily on charcoal and wood fuel for cooking and heating, something which has led to massive deforestation across the country.

At press time, a solar system for an average size home, a 60 SL-SK 403, cost $999, while a 120 system SK-407 cost $1319. Solar powered lamps run from $89 to more than $500. A full featured solar system starts around $6999 and can top out at $45,000 depending on the brand and output. Consumers should get a professional to work out what their electricity consumption was, where they could reduce and what they needed. “This helps a lot and can save consumers money,” said a solar trader in Harare. With most prices being rated in US dollars – US$1 – $10, parallel market foreign currency rates have also made the situation worse. Analysts say the cost of putting solar systems in place in Zimbabwe still remains high, holding back expansion of the clean power source.

Another consequence, is the influx of inferior products.  “The market is awash with so many fake solar products,” said one Harare dealer. “These products often break down creating friction between buyers and suppliers. I’m not sure how the Government or the Standards Association of Zimbabwe can deal with this. People are being robbed and something must be done.” As a result people are finding other sources. ”I bought mine in South Africa for about US$1200. I have encouraged many to go there because local dealers are ripping us off.”

A Solar City Shop trader said importing solar equipment was still very expensive despite duty easement. “The equipment is generally heavy and this tends to push up freight charges. This forces us to increase prices too,” he said. “Only solar panels and batteries are duty free, BOS (balance of system – encompasses all the other components) still incur charges.”Removing duty has been a great step forward for the country but as dealers we have other cost – buying forex on the black market, bills, fuel and other overheads that we need to cover.”

Some people have resorted to importing solar products from South Africa and Botswana, where the prices are almost half of those being charged locally. “Demand for home solar systems in South Africa and Botswana is unprecedented. Many…are going there because its cheaper,” said a Harare-based banker. Manufacturing solar products locally could be one better way for Zimbabwe to cut down costs, create jobs and widen access to renewable energy.

Those wanting to take advantage of the duty abatement but still unable to afford a full system are instead opting for backup power storage; inverters and batteries. The batteries can be charged with Zesa power when there is electricity and then used to power some household appliances during the rolling blackouts. Energy experts say this means consumers will be using more Zesa power in order to charge their batteries. The average charged battery could give up to four hours supply depending on size and brand. “When there is load-shedding, you can use Zesa power stored in the battery to keep the lights on and the TV and Wi-Fi,” said Mavis Moyo of Greendale. “I use the batteries and inverter because I cannot afford solar panels.”

Competition and partial improvement of Zesa power supply may drive prices of solar products down over time. Mass migration into solar will reduce heavy reliance on Zesa giving the country a long-term sustainable solution to the power crisis. The Government has set a target to get at least 1575 megawatts of power from solar by 2030, about the same amount of electricity the country produces today from a range of sources. Renewable energy investors, however, say they would like to see even more change in Zimbabwe’s clean energy policies, such as more relaxed licensing rules for small producers.

This, they hope, could see a rapid adoption of renewable energy in the country. So Zimbabwe needs to refine its energy investment policies, explore ways to bring about competitive prices for solar products as well as invest more into research on solar innovation. Only through such strategies, can the country widen access to renewable energy to the majority of the people.

Disclaimer: I did not “write” this article, I came across it and just wanted to edit it. Thanks to the original site and their staff reporter for their content.

#Webinar – Assessment of Benefits Derived from Improved Reliability and Resiliency in Utility-owned #Microgrid

Burns & McDonnell is partnering with Transmission & Distribution World magazine


Recent efforts by electric utilities to implement new technologies in existing systems are changing our understanding of the electric grid. New capabilities are being introduced by these technologies and have resulted in the design of innovative system configurations. The deployment of microgrids exemplifies this, and is considered an important turning point for distribution system engineering. Because microgrid development empowers several technologies such as distributed generation (DG) (e.g. combined heat and power (CHP), solar photovoltaic (PV), and wind), energy storage and demand response capable devices, their implementation process is more efficient. ComEd, an electric utility serving the north of Illinois and the city of Chicago, has proposed a microgrid pilot program that will deploy utility-owned microgrids in five different locations within the city of Chicago. The system performance goals established for the microgrids consist of reducing outage time for critical loads, reducing emissions and improving energy efficiency.

This webinar will review the technical and financial assessment of the reliability improvement expected in a public-purpose community microgrid owned and operated by an electric utility. The results of the study include the estimated value of reliability improvement, distribution of benefits by type of customer, and forecast of total sustained interruption costs.

Design and Research on the LCL Filter in Three-Phase #PV Grid-Connected #Inverters

Abstract—Aiming at the problem of filtering in the three-phase PV grid-connected inverters, the mathematics models for L filter and LCL filter are established. The values of capacitances and inductances are calculated by analyzing the related constraint conditions for the main parameters of LCL filter. There are two ways to increase the value of damping resistor of the filter capacitor. The impacts on the stability and filtering property, in both ways, are analyzed. The simulation result indicated that the LCL filter achieve the best performance than L filter and LC filter. Under the prerequisite of increasing system stability, parallel resistor is even more advantageous than series resistor. And the validity of theoretical results is confirmed.

Design and Control of LCL Filter Interfaced Grid Connected #Solar #Photovoltaic System by Using Power Balance Theory

Abstract: In this paper solar photovoltaic system connected to the utility grid is design and simulated. The utility grid and SPV system are coupled with current controlled voltage source (VSC) and LCL filter. LCL improves stability of the system .The system is controlled through power balance theory method. For grid synchronization and power control, control algorithm is required also requires power conditioning unit for smooth operation, Power balance theory (PBT) is used as control strategy. PBT is simple and can be achieved easily. The grid connected pv system consist of – Photovoltaic (PV), Incremental Conductance MPPT method, LCL filter, three phase utility grid, power balance theory. Source/grid voltages are used as reference for generating templates. This is the principle behind the algorithm implementation. In order to generate templates mathematical equations are required. Incremental conductance method is used for simplifying the implementation of the system the grid connected Photovoltaic system (PV) is connected to a non linear load having intermittent components as dc/dc. This system is capable of eliminating harmonics and compensating the reactive power.SPV array using indirect current control scheme. MATLAB/SIMULINK is used for demonstrate the system.

Maximizing Output Power from #Solar Cells/Panels through the Development of an Integrated Voltage Regulator/MPPT Circuit

Abstract—This paper presents the initial results of our research effort to fully integrate a voltage regulator with a Maximum Power Point Tracking (MPPT) circuit in order to harvest maximum power from solar cells or panels. We take a novel approach to emulate the inductor in a buck-boost voltage regulator using a Generalized Impedance Converter (GIC), thereby eliminating the requirement for the grounded inductor which impedes full integration. LTSPICETM models are developed to compare a traditional “inductive” voltage regulator with a “GIC” voltage regulator, and experimental results are discussed. Component size, switching frequency, and loadmatching are optimized to achieve maximum efficiency; however, GIC operational-amplifier power consumption was an obstacle to high-efficiency operation.



Energy storage systems coupled to solar photovoltaic arrays are set to play a major role in the future energy landscape, both on and off the grid. The high variability of solar power and consumer loads can be overcome with rapid battery response rates. In this work power data measured at 1 Hz from the densely clustered arrays of the KIT 1 MWp solar installation are analysed using statistical techniques in order to characterise the variability of single arrays as well as that of the system as a whole. The relationship between correlation and distance is examined in detail: the smoothing that results from decorrelation can be used as an additional mitigation factor in the design of small-scale collections of solar systems, especially in the context of residential and district storage solutions. In this context, the preliminary results of impulse- response tests performed on several commercially available household storage systems show a large discrepancy in the ability of different systems to successfully compensate power fluctuations. While the economic effects of sluggish control algorithms are relatively small in the grid-connected context, in off-grid scenarios they can affect power quality, so that the widespread deployment of such systems necessitates fast response rates.



The solar resource remains extremely underutilised in a synthetic fashion. With increasing clean water demands and decreasing clean water sources, solar desalination becomes all the more relevant. Direct absorption solar collectors offer improved efficiency over traditional surface absorbing collectors because they have fewer heat resistance steps and have the ability to utilise higher radiation fluxes. Carbon black- based nanofluids, with concentrations below 0.1%, were compared with each other and with the base fluid of salt water in a concentrated solar power scenario. A 1 m2 concentrating unit using a two-axis tracking system with two mirrors and a 1 m2 Fresnel lens was used to concentrate solar radiation on a 10 cm2 direct absorption solar collector flow cell. An optimum concentration of 0.001 vol % carbon black was found to show a 94 % increase in heating rate compared to that of salt water. This was accomplished with a collector efficiency of 59 %, 28 % higher than that of salt water. The overall efficiency of the system was 28 %. This low efficiency can be attributed to the high optical losses (50 % − 70 %) present in the concentrating unit.

Towards an International Guideline for Yield Analysis for #Solar Thermal Power Plants – PDF

Markus Eck, Tobias Hirsch

University of Applied Science Osnabrück, Germany,

German Aerospace Center (DLR), Institute of Solar Research, Germany, 


Solar Thermal Electricity (STE) Plants are a utility scale technology for solar electricity production that offer full dispatchability thanks to integrated storage capacity. Due to the huge capacity and thus investment, each project is subject to a sound project development process. In each step of this process an adequate yield analysis is a crucial task to estimate the expected electricity yield and the achievable levelized cost of electricity (LCOE) or internal rate of return (IRR).
Despite the significance of this task no international guideline exists for the yield analysis of STE plants. This situation causes investors to increase their risk surcharges and with that increase the LCOE or reduce the IRR accordingly. To improve this situation an international working group has been established to develop a guideline for yield analysis that may serve as a basis for an international standard in the future.
The intention of this conference paper is to introduce the guideline document to the South African STE community. The paper will provide a meaningful introduction to the concepts of the guideline, its structure, and the status of its documents. It will also invite to contribute to future extensions of the guideline, e.g. by providing modeling approaches and system parameters for present and upcoming STE technologies

Critical weather situations for renewable energies – Part B: Low stratus risk for #solar power

Accurately predicting the formation, development and dissipation of fog and low stratus (LS) still poses a challenge for numerical weather prediction (NWP) models. Errors in the low cloud cover NWP forecasts directly impact the quality of photovoltaic (PV) power prediction. On days with LS, day-ahead forecast errors of Germany-wide PV power frequently lie within the magnitude of the balance energy and thus pose a challenge for maintaining grid stability. An indication in advance about the possible occurrence of a critical weather situation such as LS would represent a helpful tool for transmission system operators (TSOs) in their day-to-day business. In the following, a detection algorithm for low stratus risk (LSR) is developed and applied as post-processing to the NWP model forecasts of the regional non-hydrostatic model COSMO-DE, operational at the German Weather Service. The aim of the LSR product is to supply day-ahead warnings and to support the decision making process of the TSOs. The quality of the LSR is assessed by comparing the computed regions of LSR occurrence with a satellite based cloud classification product from the Nowcasting Satellite Facility (NWCSAF). The results show that the LSR provides additional information that should in particular be useful for risk adverse users.