Renewable Energy Systems

In solar PV system design, many engineers focus heavily on panel orientation, inverter sizing, and irradiance levels but often overlook the impact of distant objects like hills, mountains, or trees on early morning and late afternoon solar access. This is where horizon simulation, also known as far shading analysis comes in. What is Horizon Simulation? It’s the process of analyzing how distant obstructions affect the availability of sunlight at your PV site, especially at low sun angles (sunrise and sunset). This is typically represented by a horizon line in your simulation software (e.g., PVsyst ) What Happens If You Ignore It? 1. Delayed generation startup: Your system may receive less sunlight in the early morning due to horizon obstructions, which isn't accounted for if you skip this step. 2. Early generation shutdown: Evening production is also affected if far shading occurs, cutting off useful sunlight earlier than expected. 3. Overestimated energy yield: Without accounting for these losses, your simulation will over-predict energy output, which can mislead investors and operators.  4. Underperformance risk: Actual performance may fall short of P50/P90 expectations due to these unaccounted shading losses. Always include a horizon profile using digital elevation models (DEM) or site visits with a clinometer or drone. Import this into your simulation to accurately model far shading losses. PVsyst allows you to input real horizon lines for more realistic performance simulations. As solar designers, accuracy in forecasting is not just a technical detail, it's a responsibility to investors, operators, and the future of clean energy. #SolarDesign #PVPerformance #PVsyst #ShadingAnalysis #SolarEngineering #RenewableEnergy #GreenVoltAcademy #FarShading #SolarSimulation #SolarPlantDesign

A Practical Solution to Meet Data Center Energy Demand: Rather than expanding generation and transmission capacity to meet the rapidly growing energy demand of data centers, I propose here a more efficient and resource-saving alternative. This approach involves optimizing the design of a Solar PV-Battery Energy Storage (BES) system to supply 80-85% of the daily energy requirements of a data center, while limiting grid dependency to a maximum of 20%. This hybrid system significantly reduces the need for large-scale infrastructure upgrades. Here’s an illustrative example I designed for a 1 GW data center in Saudi Arabia: - Solar PV System: 3.9 GWdc / 3.52 GWac - Battery Energy Storage (BES): 3 GWac / 5.6 GWh - Transmission Line Capacity: 200 MW (20% of the load) The system configuration, as shown in figure, is an AC-coupled system. The PV-BES management system is programmed to ensure that the load power drawn from the grid never exceeds the transmission line capacity of 200 MW. To validate this design, I conducted a full-year simulation with a 5-minute time step for a specific location in Saudi Arabia. Results demonstrated that the State of Charge (SOC) of the battery system never dropped below 15%. The system was designed with the PV and BES capacities approximately three times the load to provide additional power and energy redundancy, achieving an optimal balance between reliability and cost-effectiveness. This optimized hybrid system represents a sustainable and scalable solution to meet the increasing energy demands of data centers while minimizing grid strain and infrastructure costs. Another potential solution involves deploying Battery Energy Storage (BES) systems and data centers adjacent to existing utility-scale PV plants. This approach leverages already-developed infrastructure, optimizing the utilization of renewable energy while minimizing additional land use and transmission requirements.

A retrofit can boost solar yield by up to 15%. Most people have no idea this is possible. Here’s the truth: When people talk about solar growth, they talk about new builds, new projects, new records. But the real revolution is happening somewhere else-quietly, and with far more impact. Europe installed tens of gigawatts of PV between 2010 and 2015. Those assets are now 10–15 years old. Still working, but nowhere near their original specs. Here’s what you see on site: → Modules, degrading faster than planned. Output drops, year after year. → Inverters, out of warranty, unsupported, spare parts hard to find. → Trackers and wiring-fatigue, corrosion, sometimes outright failure. → Safety and yield: both can be improved massively with modern components. Sounds great, but here’s the reality: Most owners and operators still run these plants as if nothing has changed. They accept lower yields, higher O&M costs, and more downtime. But a well-executed retrofit can add 5–15% yield and extend the asset’s lifetime. That’s not theory. That’s proven-across hundreds of megawatts, in real projects. The second lifecycle of solar assets is here. Engineering, not installation speed, will define success. The old playbook-build fast, hand over, forget-doesn’t work anymore. What does a successful retrofit look like? - Replace modules with higher-efficiency units, designed for today’s weather and grid needs. - Upgrade inverters to smart models. Better yield, better grid support, fewer failures. - Rework trackers, wiring, and safety systems to prevent the next big outage. - Align O&M and EPC teams around long-term reliability, not just COD. Bottom line: Retrofits turn aging assets from yesterday’s problem into tomorrow’s opportunity. For investors, EPCs, and O&M companies, this is the next growth lane. I’ll talk about this in Prague at the Smart Energy Forum this week-how to turn legacy PV into high-performance assets that last. What’s your experience with PV retrofits? Where did you see the biggest gains-or the biggest headaches? #AndreasBach #SolarEnergy #Renewables #EPC #BESS #Czechia #Retrofit

Looks the same? Think again. Two solar systems. Same size. Very different risks. We recently released a white paper that reveals a critical—but often overlooked—factor in system design: connector configuration. At first glance, two 1 MW PV systems may look identical. But dig deeper, and the risk profile can differ by a factor of 20. Yes—20 times the risk, depending on the combination of: - Factory-made vs. field-made connectors - Selection of MLPEs - Module lead lengths - Jumper and home run configurations In one example, a system using short-lead modules and extensive MLPEs required over 4,000 field-made jumpers. The resulting normalized risk score? 19. By contrast, a system with well-matched components, sufficient leads, and fewer field terminations scored just one. This analysis isn’t hypothetical. It’s grounded in data and real-world design choices that impact safety, reliability, and long-term performance. If you’re designing or specifying PV systems, this is essential reading.

In California, if you have a solar system with a sweet NEM 1.0 or NEM 2.0 deal, you’re basically sitting on a golden ticket for 20 years from the day you plugged in. But if you decide to upgrade or expand, the solar gods (aka your utility company) might rain on your parade. Before you consider repowering a solar system on a home or business, here's what you need to know. 1. System Capacity Increases Small Expansions: Adding a few extra panels—less than 10% or 1 kW of your system size (whichever is bigger)—is usually okay. For example, if your system is 500 kW, you can tack on 50 kW and keep your NEM "grandfather" rates. No harm, no foul. Large Expansions: Now, if you go big and increase your system by more than 10% or 1 kW, prepare for a reality check. The new portion will be judged under NEM 3.0. 2. What Happens Under NEM 3.0? Lower Payments for Extra Energy: Remember the good old days when utilities paid you retail rates for extra energy? NEM 3.0 says, “Nah, we’re good,” and only credits you based on their costs, not yours. Translation: You’re getting paid in pennies instead of dollars for all that sun power you send back. Time-of-Use Rates (TOU): Under NEM 3.0, the value of your exported energy changes depending on the time of day. If you send energy during low-demand hours, the utility basically shrugs and gives you pocket change. 3. How to Keep Your NEM Benefits Design a Zero-Export System: A zero-export system is like keeping your energy to yourself. It stops extra energy from going to the grid, which means your utility doesn’t get a chance to yank you into NEM 3.0. Add Battery Storage: Batteries are like the piggy bank for your solar energy. Instead of letting the utility undervalue your investment, you store the extra power and use it when needed. Regarding repowering, we are seeing a high demand for homes, and businesses are coming in a close second. 4. What Should You Do? Talk to Your Utility Company: Before you start tinkering with your system, give your utility a call. Yes, we know it’s like calling the DMV, but it’s better than accidentally losing your sweet NEM deal and being forced into NEM 3.0. Run the Numbers: When it comes to commercial and industrial (C&I) systems, repowering is rarely driven by financial incentives alone. It’s typically a response to a degraded or underperforming system. For residential systems, adding a second system and battery can significantly boost energy independence and maximize your investment. However, be cautious—your return on investment (ROI) could take a hit if the economics don’t add up. If you’re considering upgrading your solar system, consult an expert, talk to your utility, and analyze the numbers, or better yet, reach out to me—I’ll handle it all for you!

Do solar power plants really operate for 25 years? Here's how they can live even longer! After 12–15 years of operation, it becomes profitable to invest in a full-scale upgrade with a payback period of just 2–5 years. This can extend the lifespan of solar plants for another 12–15 years. Why does this work? The key driver here is the decreasing cost of solar modules. When module prices drop to €0.055–0.045 per watt, it becomes more economical to rebuild existing plants than to construct new ones. In November, I received a quote for €0.065 per watt, and it seems realistic that we’ll reach €0.045 in the near future. At the same time building new plants involves rising costs for land development and grid connections, while upgrades avoid these challenges. How does the payback happen? Modern solar modules are far more efficient than older ones. Let’s compare: Modules from 10 years ago were typically 250–270 W with about 7% degradation due to the 10+ years of use. These were often installed on metal structures in two layers. Today’s bifacial modules reach 710 W, slightly smaller in size than two older 270 W modules. These newer modules can be installed in the same place without replacing the metal structures. The result? Approximately 20% more energy is generated per kW of installed capacity. This extra approximately 200 kWh per kW forms the source of additional cash flow to pay back for modernization. What happens to the old modules? The “old” modules are still functional and can be sold in the second-hand market. While the used module market is not fully developed yet, I found prices of €0.1 per watt for retail sale. Even if it will be just €0.025/W, these used modules could find high demand in the private sector. This second-hand market improves the economics of module replacement and gives us at least 10 more years to find sustainable recycling methods. It’s likely we have up to 15 years before disposal becomes a major issue. Another key factor: Inverter replacements Most inverters are designed to work about 10–12 years, which aligns perfectly with a plant’s mid-life upgrade. It’s often hard to find one-for-one replacements for older models of inverters, so a full reengineering approach allows seamless upgrades to modern inverter solutions. Another conclusion - the reengineering should be a stage for any solar IPP strategy. When the standard IPP process means delivering projects from development to construction and then to assets ownership teams, it is necessary to redevelop projects after 10 years of operation. And it increases demands for asset ownership adding the necessity of engineering expertise at this stage. #SolarEnergy #RenewableEnergy #EnergyTransition #SolarPower #SolarModules #FutureOfEnergy

There’s no universal playbook for solar PV layout design. The right strategy depends on context—boundary complexity, terrain data, hydrology, geology, and more. These define the order of design optimisation. For example, tough terrain can drive up civil costs, making it important to address grading and access early. On the other hand, complex boundaries can increase electrical costs, making it smarter to prioritise array-to-inverter connections first. In one project, we tested two different sequences (blocks introduced first and last): ▪️ Option 1: Maximise DC → create blocks → remove blocks with the worst grading → add roads → check if the target is still met → remove remaining arrays with high grading impact to meet the target ▪️ Option 2: Maximise DC → remove just enough grading to meet the target with room for access and blocks → add access roads → check target → create blocks Each produced a completely different layout—with a $22.5M difference, purely based on the order in which we optimised the design. The takeaway: Don’t rely on what worked last time. 🔺 Let the context define the order of design optimisation. 🔺 Let the absence of context data define your risk strategy.

💡 The principles of solar field design have changed—and most of the industry isn’t ready The solar industry is at a critical inflection point. Over the past decade, the cost of panels has plummeted by more than 90%, driving unprecedented growth. But while hardware costs have fallen, land acquisition costs are rising rapidly —fundamentally reshaping project economics. This shift is rewriting the solar playbook, and companies that fail to adapt risk falling behind: ❌ Projects that don’t prioritize land-use efficiency will become prohibitively expensive. ❌ Fixed-tilt systems will miss out on the most valuable energy pricing opportunities. ❌ Developers relying on traditional trackers—designed for a world of cheap land—will struggle to stay competitive in the new era of power density optimization. Here’s the new reality: 1️⃣ Land is now the bottleneck. Rising costs make it critical to optimize every acre. Yet, most trackers in the industry were designed for an era when land was cheap and abundant, focusing on yield per panel rather than land utilization. 2️⃣ Time-of-day pricing is changing the value of energy. The introduction of solar has created an excess amount of energy during the middle of the day. Some countries even have negative pricing schemes to address this. The highest energy prices are now in the late afternoon, exactly when trackers significantly outperform fixed-tilt systems. 3️⃣ The old strategies aren’t working anymore. Designs focused solely on yield per panel fail to account for the realities of rising land costs and changing energy markets. This is the new reality. Developers who fail to adapt won’t just face higher costs —they’ll face shrinking margins, uncompetitive projects, and fewer opportunities. We need to reimagine what trackers can do for this new world. The future will belong to versatile and adaptable trackers emphasizing: ✅ Power density optimization: Designed to maximize output per acre, even on constrained or irregular sites. ✅ Peak value production: Outperform fixed-tilt systems during critical afternoon hours, capturing the value of time-of-day pricing. ✅ Flexible layouts for high-cost land: Adaptable configurations that enable more efficient use of challenging parcels. ✅ Future-proof design: Trackers engineered to thrive in a world where land is expensive, and every square meter counts. The days of “one-size-fits-all” trackers are over. In today’s market, versatility, adaptability, and land-use efficiency aren’t optional—they’re essential. Companies that embrace this shift will thrive in the new world of solar. Those that don’t? They risk falling behind as the industry moves forward without them. Agree? Disagree? #solartrackers #solarpv #solarenergy #cleantech #solargik Solargik 

Inverter and String Configuration in a Solar Power Plant In a utility-scale solar power plant, solar modules are connected in series to form a string, which increases the voltage while keeping current constant. Multiple strings are then connected in parallel to increase the overall current, feeding into an inverter. The inverter is a power electronic device that converts DC (Direct Current) output from the PV strings into AC (Alternating Current) suitable for grid injection. It also handles MPPT (Maximum Power Point Tracking) to optimize energy harvest based on irradiance and temperature conditions. There are three main inverter architectures: 1.Central Inverter– Handles multiple MWs, suitable for large plants, but can be less efficient if string mismatch occurs. 2.String Inverter – Each inverter handles fewer strings (typically 8–24), improving modularity and reducing single points of failure. 3.Microinverter – Mounted on individual panels, used in rooftop applications for maximum control and monitoring. Key Design Considerations: -String sizing: Based on module Voc, temperature coefficients, and inverter input voltage range. -Inverter loading ratio (ILR): Ratio of installed DC capacity to inverter AC rating, typically 1.1–1.3 for optimized performance. -DC/AC ratio: Impacts clipping losses and energy yield. - Thermal performance: Overheating can reduce inverter efficiency. - Monitoring & diagnostics: Advanced inverters offer string-level monitoring, aiding O&M. Proper inverter-string configuration ensures: - High system efficiency - Reduced mismatch and shading losses - Improved O&M through better fault localization

Solar Panel and Batteries Wiring Wiring Solar Panels and Batteries in Series Wiring in series refers to connecting the plus of one panel or battery to the minus of another (+-). This adds the voltages of all panels together but leaves the current (amps) the same. For example. if you have four panels wired in series. each with 20 volts and five amps. the output would be 80 volts and five amps. Advantage - Wire simplicity: With a low-amperage system (wired in series), you can use smaller-gauge wires. which are relatively inexpensive and easier to organize and manage. They can be more easily kept out of sight when running them from the panels to the other components of your solar system. Disadvantages - More expensive controller: When wiring panels in series. it's necessary that you use a Maximum Power Point Tracking (MPPT) charge controller. This controller regulates high voltage to match that of a battery bank without resulting in power loss. However. MPPT controllers tend to be more expensive (by approximately $200) than Pulse Width Modulation (PWM) controllers. Only for unshaded conditions: Unshaded conditions are best for series wiring, as each panel's performance in a series connection impacts the performance of the entire system. Wiring Solar Panels and Batteries in Parallel Wiring in parallel, on the other hand. refers to connecting two batteries' or two panels pluses together (++) or minuses together (--). This adds the currents (amps) of all panels together but leaves the voltages the same. For example, if you have four panels each with 20 volts and five amps wired in parallel, the output would be 20 volts and 20 amps. Advantages - Cheaper: As long as the voltage of your panels matches the voltage of your battery. you don't need to worry about regulating your voltage when storing solar energy from parallel-wired panels in a battery. This is because your voltage doesn't get added together when wiring in parallel. For this reason. you can use a less expensive PWM charge controller rather than investing in an MPPT controller. - Independent output: With parallel wiring. each panel operates independently of the other panels in the system. This means that. if shade covers one or two panels. the remaining panels will continue to operate unimpeded by the shaded panels lower performance.