Info

Notes, explainers and post-mortems on commercial solar and battery storage – the parts that decide whether a project earns what the model promised. Written for owners, facility engineers and the people who have to sign the contract.

50 articles

Procurement & Contracts

Three Quotes, Forty Percent Apart: How to Read Commercial Solar BidsWide price spreads on the same roof are normal and usually explainable. Here is what to compare before you assume the cheapest bid is the same system.The Six Clauses That Decide How Your Solar EPC Contract EndsMost disputes on commercial solar projects trace back to the same handful of contract terms. What each one should say, and the wording that causes trouble.Why Most Solar RFPs Get the Wrong AnswerAn RFP that specifies the solution instead of the problem produces bids you cannot compare. How to write one that gets useful responses.Performance Guarantees: What They Actually CoverA performance guarantee is not a promise of output. Understanding what it measures, and what it deliberately excludes, before you rely on it.Tier 1 Is a Financing Term, Not a Quality RatingThe Tier 1 module list is widely misunderstood. What it measures, what it does not, and what to check instead when selecting modules.Load Profiling: The Step Almost Everyone SkipsSizing a commercial solar system from annual kWh totals produces systems that generate at the wrong times. What interval data reveals that a bill cannot.

Engineering & Design

How Much DC Should You Put Behind an Inverter?Oversizing the array relative to inverter capacity is standard practice, but the right ratio depends on your climate, tariff and export limits.String or Central Inverters for a Commercial Roof?The choice affects failure behaviour, maintenance access and how much of your plant goes dark when something breaks. A practical comparison.When Bifacial Modules Actually Pay on a Commercial RoofBifacial gain depends almost entirely on what is underneath the array. On most flat commercial roofs the honest answer is: less than the brochure suggests.Ballasted or Penetrating: Choosing a Flat Roof Mounting SystemThe mounting decision touches structural capacity, roof warranty, wind design and long-term leak risk. What drives the choice on commercial roofs.What a Structural Assessment for Rooftop Solar Should ContainAdding permanent load to an existing industrial roof is an engineering question, not a formality. What the assessment must cover and the findings that stop projects.Cable Sizing and Voltage Drop: The Loss Nobody NoticesUndersized DC cabling quietly costs energy for twenty-five years. Where the losses come from and what to specify instead.

Performance & Operations

Performance Ratio, and What a Good Number Actually Looks LikePR is the standard measure of how well a solar plant converts available sunlight. What drives it, what a realistic figure is, and how it gets misreported.Your Plant Was Fine in Year One. What Changed by Year Three?Gradual underperformance rarely has a dramatic cause. The usual suspects, in the order they are worth checking.Soiling Losses and When Cleaning Is Worth Paying ForCleaning schedules are usually set by habit rather than measurement. How to work out what soiling is costing you and what the right frequency is.The Monitoring Numbers Worth Watching, and the Ones That Waste Your TimeMost solar monitoring platforms show far more data than anyone acts on. A short list of what genuinely indicates a developing problem.Thermal Imaging: The Inspection That Finds What Monitoring MissesAn infrared survey locates hotspots, failing connectors and cracked cells before they become failures. How it is done properly and what the results mean.Commissioning Tests That Catch Problems While They Are Still FreeThe handover window is the last point at which defects are unambiguously the contractor's responsibility. The tests worth insisting on.

Battery Storage

Sizing a Commercial Battery: Power, Energy, and Which One BindsStorage is specified in two dimensions and confusing them produces expensive mistakes. How to work out which constraint actually governs your site.Demand Charges: The Bill Line Solar Alone Will Not TouchOn many commercial tariffs, demand charges are a third of the bill and solar barely reduces them. Why that happens and what does work.Battery Degradation: Reading the Warranty Against RealityEvery lithium battery loses capacity. What drives the rate, what warranties actually guarantee, and the operating choices that decide where you land.LFP or NMC for Commercial Storage?The two dominant lithium chemistries trade energy density against thermal stability and cycle life. For stationary commercial use, the choice is usually clear.Battery Fire Safety: What Codes Require and WhyStorage installations face specific fire safety requirements covering spacing, detection, suppression and ventilation. An overview of the reasoning behind them.DC-Coupled or AC-Coupled Storage: What ChangesWhere the battery connects relative to the inverter affects efficiency, clipping recovery, retrofit feasibility and control complexity.Replacing Diesel Backup With Storage: Doing the ArithmeticBatteries can displace generator running hours, but the case depends on how the generator is actually used. How to work out whether it stacks up.

Finance & Ownership

Own It or Buy the Power? Comparing PPA and Direct PurchaseA power purchase agreement removes the capital cost and most of the risk, and takes a large share of the return with it. How to compare the two honestly.US Federal Incentives for Commercial Solar: How the Pieces FitThe investment tax credit, bonus adders and accelerated depreciation interact in ways that change project economics substantially. An orientation, not tax advice.European Support Schemes for Commercial Solar: What Varies and WhySupport for commercial solar in Europe differs sharply by country and has shifted from feed-in tariffs toward self-consumption and market exposure.Corporate PPAs Below Utility Scale: What Mid-Market Buyers Should KnowOffsite renewable power purchase agreements were built for very large buyers. Aggregation and sleeved structures have opened them up, with caveats.Insuring a Commercial Solar Asset: The Gaps Worth ClosingStandard property cover often handles rooftop solar poorly. What to check, and the exclusions that surface after a claim.Repowering an Ageing Solar Plant: When It Makes SenseOlder commercial arrays often sit on good sites with good connections and underperforming hardware. What repowering involves and how to judge the case.

Grid & Compliance

Why Grid Connection Takes Longer Than Building the PlantInterconnection has become the critical path for most commercial solar projects. What the process involves and how to avoid the worst delays.Export Limits and Curtailment: Designing Around a Capped ConnectionA connection that caps export changes optimal system design substantially. How to make a constrained connection work harder.Power Factor and Reactive Power: What Solar ChangesAdding solar can worsen your power factor and trigger charges even as consumption falls. Why that happens and what to do about it.Harmonics and Inverters: A Power Quality Primer for Site EngineersInverters are switching devices and they inject harmonic current. Usually harmless, occasionally not. What determines which.Permitting a Commercial Solar Project Without Losing Six MonthsPermitting runs in parallel with design and connection, and each has its own dependencies. How to sequence them so they do not stack.Anti-Islanding and Protection Settings: What the Utility Is Protecting AgainstGrid protection requirements exist for specific safety reasons. Understanding them makes commissioning smoother and nuisance tripping easier to diagnose.

Applications by Sector

Cold Storage and Solar: An Unusually Good MatchRefrigerated warehouses have a load profile that suits solar better than almost any other building type, plus thermal storage most operators overlook.Solar on a Manufacturing Site: The Constraints That Are Not on the RoofIndustrial sites bring process loads, power quality sensitivity and shutdown windows that domestic and office installations never encounter.Microgrids for Facilities That Cannot Afford to StopA microgrid is a controls problem more than a hardware problem. What separates a genuine islanding capability from solar plus a battery.Fleet Charging, Solar and Storage: Managing the Connection ConstraintDepot charging can double a site electrical demand. Where solar helps, where it does not, and why storage is often the enabling piece.Solar Carports: When the Extra Cost Is JustifiedCarports cost substantially more per kW than rooftop and deliver benefits a roof cannot. Working out whether those benefits are worth it.Agrivoltaics and Dual-Use Land: Where It Works and Where It Is MarketingCombining solar with agriculture is technically real and commercially specific. What genuinely works versus what is sold as dual use.Warehouses: Big Roofs, Small Loads, and What to Do About ItDistribution buildings offer enormous roof area and often modest electrical consumption. The mismatch defines the design problem.

Lifecycle & Risk

What Happens to Solar Modules at End of LifeRecycling infrastructure is developing unevenly and regulatory obligations differ by region. What an asset owner should plan for.Hail Damage: The Loss That Does Not Show Up ImmediatelySevere hail can crack cells without visibly damaging glass, producing degradation that appears years later. How to assess and document it.Solar in Cold and Snowy Climates: What Actually ChangesCold improves module efficiency and snow interrupts production. Designing for northern climates means handling both, plus structural loading.How a Solar Warranty Claim Actually GoesWarranties are enforceable, but the process is slower and more evidence-dependent than most owners expect. What to prepare in advance.What an O&M Contract Should Actually Commit ToMaintenance contracts vary from meaningful to decorative. The provisions that determine whether yours does anything.A Handover Checklist Worth Insisting OnThe documents and data to obtain before final payment, and why each one matters years later.