Satellite powered estimation of global solar potential

Panel orientation & building design

• Debate on whether roofs should always aim panels due south (north in southern hemisphere).
• Some argue uniform orientation creates noon surges and volatility; others note south-facing maximizes annual output, with east/west worthwhile to shift generation to mornings/evenings and mitigate “duck curve” effects.
• Trackers are seen as mechanically fragile and usually not worth it versus adding more fixed panels.
• Roof orientation is often constrained by streets and architecture; it also interacts with heating/cooling loads and window placement.
• Passive design (overhangs/exterior shading, thermal mass, glazing choices, ventilation) is emphasized as part of whole-building optimization.

Units and scale of solar potential

• Strong complaints about writing “10.7k TWh” instead of using standard SI prefixes like PWh.
• Discussion of metric prefix rules, engineering notation (E3/E6, etc.), and whether Joules or Wh are better for energy.
• Some argue for plain scientific notation to avoid confusing large-number words.

Use cases and limits of Google’s solar mapping

• Some see the tool as mainly refining already-known siting choices in a world where PV is cheap.
• Others say high-resolution, quantitative mapping helps governments, grid operators, and installers prioritize locations, plan subsidies, and target marketing.
• Global DSM coverage remains patchy; people want open, standardized surface models akin to global elevation datasets.
• Frustration that the improved API is enterprise-only.

Rooftop vs utility-scale solar

• Ongoing tension: rooftop is seen as fragmented, soft-cost-heavy, and less cost-effective than big solar farms, yet valuable for speed of deployment, land-use efficiency, and resilience.
• Some argue rooftop solar is among the most expensive sources (before subsidies) and can be regressive if net metering overpays homeowners at retail rates.
• Others counter that rooftop can approach nuclear-level costs, bypass slow utilities, reduce transmission needs, and spread capital investment across many households.
• Examples from Australia show high rooftop penetration integrated successfully; critics note this is still mostly at midday and doesn’t solve nighttime coal reliance yet.

Economics, incentives, and soft costs

• Multiple anecdotes on payback: some claim 20–25+ years or poor returns in high-latitude regions; others report 5–10 year paybacks, especially with batteries and high retail prices.
• Discrepancies often trace to assumptions about system size, local tariffs, tax credits, inflation, and whether batteries are included.
• In the US, non-hardware “soft costs” (permitting, customer acquisition, labor, utility interconnection) are called out as the main barrier; other countries report plug-and-play balcony systems with minimal bureaucracy.
• Concerns about installers going bankrupt and warranties becoming unenforceable reduce confidence.

Grid integration, pricing, and resilience

• Several comments stress distributed solar plus batteries as critical for disaster resilience, citing experiences after storms and outages.
• Others note most grid-tied systems turn off during outages unless specially designed; lineworker safety rules demand islanding.
• Discussion of microgrids, community batteries, vehicle-to-grid (e.g., EVs powering homes/neighborhoods), and “virtual power plants” aggregating home assets.
• A detailed argument warns that widespread rooftop solar without matching pricing reform shifts grid costs to distribution only, makes utilities look expensive and “dirty,” and creates a cross-subsidy where solar owners rely on the grid at the most expensive hours.
• Proposed mitigations: dynamic pricing, widespread storage, and allowing more granular local grids.

Adoption barriers and future developments

• Non-technical blockers mentioned: inertia, unclear long-term ROI, roof damage fears, insurance and permitting complexity, and low trust in contractors.
• Some view subsidies as unfair transfers from non-owners to homeowners; others see them as necessary to overcome early soft-cost and inertia barriers.
• Thread references improving PV efficiencies (including tandem cells) and the historically exponential growth of PV versus often-linear institutional forecasts.
• Ideas like space-based solar and large-scale centralized renewables are mentioned but not deeply explored.