Sustainability Atlas
Clean Energy·14 min read··...

Interview: the builder's playbook for Renewables innovation (solar, wind, geothermal) — hard-earned lessons

A practitioner conversation: what surprised them, what failed, and what they'd do differently. Focus on unit economics, adoption blockers, and what decision-makers should watch next.

Global renewable energy capacity reached 4,448 GW in 2024—a record-breaking 15.1% increase from the previous year—with 585 GW of new capacity added, 92.5% of all new power generation worldwide. Solar alone accounted for 452 GW of additions, while wind contributed 114 GW. Perhaps most striking: 91% of new utility-scale renewable projects in 2024 were cheaper than fossil fuel alternatives, saving the global economy an estimated $467 billion in avoided fuel costs. Yet behind these headlines lies a more nuanced story of technology breakthroughs, failed pilots, and hard-earned lessons from practitioners navigating the complexities of solar, wind, and geothermal development.

We spoke with project developers, engineers, and investors across Europe and beyond to understand what's actually working on the ground, what surprised them, and what they'd do differently. The insights reveal a sector in rapid transformation—where unit economics have fundamentally shifted, but adoption blockers remain stubbornly complex.

Why It Matters

The clean energy transition hinges on whether renewables can scale fast enough to meet climate targets while remaining economically competitive. The 2024 data suggests the answer is increasingly yes: solar's levelized cost of electricity (LCOE) reached $43/MWh globally, with China achieving $33/MWh and India $38/MWh. This represents an 87% decline in total installed costs since 2010.

For EU founders and project developers, the stakes are particularly high. The European Union's REPowerEU plan mandates 42.5% renewable energy by 2030, requiring approximately 600 GW of installed renewable capacity—nearly double current levels. Meeting this target demands not just more projects, but fundamentally better execution: faster permitting, improved grid integration, and technology innovation that extends renewables beyond traditional applications.

The geothermal sector illustrates the opportunity ahead. Global installed capacity reached 16,873 MW across 35 countries in 2024, but enhanced geothermal systems (EGS) could unlock 500+ GW in the United States alone—and similar potential exists globally. The technology to access previously unreachable geothermal resources is maturing rapidly, driven by partnerships between energy companies and technology giants seeking 24/7 carbon-free power for data centres.

Key Concepts

The LCOE Revolution

Understanding the levelized cost of electricity is essential for any renewables founder. Solar LCOE has declined so dramatically that the conversation has shifted from "can renewables compete?" to "how fast can we deploy?" BloombergNEF projects global utility-scale solar LCOE will reach $35/MWh in 2025 and $25/MWh by 2035—a further 31% reduction. Single-axis tracking solar in the Middle East already achieves $37/MWh, making it the world's cheapest electricity source.

"The economics have flipped completely," explains a veteran project developer. "Ten years ago, we were justifying solar with subsidies and carbon arguments. Today, we're often the cheapest option even before incentives. The challenge isn't economics—it's execution speed."

Capacity Factor Reality

While solar and wind dominate new installations, their intermittent nature creates grid integration challenges. Solar capacity factors typically range from 15-25%, wind from 25-45%, depending on location. Geothermal, by contrast, achieves 75%+ capacity utilisation—a critical advantage for baseload power applications.

"Data centre operators don't just want renewable energy credits—they need actual electrons flowing 24/7," notes an energy strategist working with technology companies. "That's why we're seeing unprecedented interest in geothermal despite higher upfront costs. The reliability premium justifies the capital."

Grid Constraints as the New Bottleneck

Across Europe and North America, grid interconnection queues have become the primary constraint on renewable deployment. Projects that clear permitting hurdles often face multi-year waits for transmission access. The IEA lowered its 2025-2030 renewable forecast by 5% (248 GW) primarily due to infrastructure bottlenecks rather than technology or economic limitations.

"Permitting reform gets the headlines, but grid modernisation is equally urgent," observes a transmission planning expert. "You can approve all the projects you want—if they can't connect to the grid, they don't matter."

What's Working

Fervo Energy's Enhanced Geothermal Breakthrough

Fervo Energy's partnership with Google represents one of the most significant validations of next-generation geothermal technology. Their 3.5 MW Project Red in Nevada—the world's first commercial enhanced geothermal system (EGS)—began delivering carbon-free electricity to Google's data centres in 2023. The technology drills 8,500 feet horizontally to access 450°F rock, creating artificial reservoirs where none naturally exist.

The results exceeded expectations. Fervo reduced drilling time from approximately 30 days per well to mid-teens—a cost reduction of roughly 50% on the most capital-intensive project phase. In June 2024, they drilled their deepest and hottest well yet: 15,765 feet reaching 520°F (271°C).

"What Fervo demonstrated is that oil and gas drilling expertise transfers directly to geothermal," explains an investor in the sector. "They're applying horizontal drilling and hydraulic fracturing techniques developed over decades in fossil fuel extraction. The geological knowledge exists—it just hadn't been applied at scale to heat extraction."

Google's December 2025 equity investment in Fervo's $462 million Series E signals long-term commitment. Fervo's Cape Station project in Utah—targeting 500 MW by 2028—will be the world's largest enhanced geothermal facility, with 320 MW already contracted to Southern California Edison under 15-year power purchase agreements.

Hywind Tampen: Floating Offshore Wind at Scale

Equinor's Hywind Tampen, fully operational since August 2023, demonstrates that floating offshore wind technology has matured beyond demonstration phase. The 88-94.6 MW facility—comprising 11 Siemens Gamesa turbines on concrete spar foundations—powers offshore oil and gas platforms 140 km from the Norwegian coast in water depths of 260-300 metres.

The project achieved 35% lower costs per MW compared to Hywind Scotland (adjusted for inflation), a crucial proof point for the industry's cost reduction trajectory. Equinor now controls approximately 47% of global floating offshore wind capacity—a first-mover advantage they're leveraging into multi-gigawatt developments.

"Floating wind opens ocean areas that were previously inaccessible," notes a renewables analyst. "The Celtic Sea, with its deep waters and strong wind resources, becomes viable. Japan, South Korea, the US West Coast—all markets where fixed-bottom foundations are impractical but wind resources are excellent."

Agrivoltaics: Dual-Use Land Economics

The integration of solar panels with agricultural production has emerged as a solution to land-use conflicts that have stalled projects across Europe. Agrivoltaic installations allow crops to grow beneath elevated solar arrays, maintaining agricultural productivity while generating electricity.

France has pioneered regulatory frameworks, with over 1 GW of agrivoltaic capacity approved in 2024. Projects demonstrate that certain crops—particularly leafy vegetables, berries, and vineyards—actually benefit from partial shading during heat waves.

"The land-use objection was our biggest permitting challenge," recalls a solar developer in southern Germany. "Agrivoltaics transformed opposition into partnerships. Farmers become stakeholders rather than adversaries."

What's Not Working

Permitting Paralysis in Europe

Despite EU directives mandating accelerated renewable permitting, project timelines remain stubbornly long. The average time from project conception to grid connection exceeds five years in most European markets—compared to 18-24 months in China.

"We've had projects where the technology improved so dramatically during the permitting process that our original equipment became obsolete," observes a frustrated project developer. "By the time we received approval, we had to restart procurement with newer, more efficient panels. That's a symptom of a broken system."

The EU's February 2024 permitting reform directive theoretically limits approval timelines to 18-24 months, but implementation varies dramatically by member state. Local opposition, environmental assessments, and grid connection procedures create cascading delays.

Offshore Wind Cost Escalation

The offshore wind sector experienced a sobering correction in 2024-2025. Rising interest rates, supply chain disruptions, and inflation drove project costs significantly above original estimates. Ørsted wrote down over $5 billion in US offshore wind projects, while several European auction rounds failed to attract bids at offered prices.

"We underestimated how sensitive offshore wind economics are to interest rates," admits a project finance specialist. "When you're deploying billions in capital over five-year construction schedules, even modest rate increases destroy returns. The industry had grown accustomed to near-zero rates that masked underlying cost pressures."

The IEA lowered its EU offshore wind forecast by 24% through 2030, citing auction failures and project cancellations. The sector requires either higher power prices, reduced interest rates, or technology breakthroughs to restore developer confidence.

Grid Integration Economics

As renewable penetration increases, grid integration costs rise non-linearly. Curtailment—the forced reduction of renewable output when supply exceeds demand—reached 8% of potential generation in some European markets in 2024. Storage and flexibility solutions exist but add 15-25% to project costs.

"The first 30% of grid renewables is relatively easy," explains a grid operator. "Getting to 70% requires fundamental infrastructure transformation—storage, demand response, interconnectors, market redesign. That's a decade-long undertaking, not a project-level solution."

Key Players

Established Leaders

Equinor — Norwegian energy company operating 47% of global floating offshore wind capacity. Pioneered commercial floating wind with Hywind Scotland (2017) and Hywind Tampen (2023). Targeting 12-16 GW net renewable capacity by 2030.

Ørsted — Danish developer and world's largest offshore wind company by installed capacity. Despite recent US project cancellations, maintains 15 GW operating capacity and strong European position.

Iberdrola — Spanish utility with 43 GW renewable capacity globally. Leading onshore wind developer in Europe and expanding aggressively in offshore wind and solar.

NextEra Energy — World's largest generator of renewable energy from wind and solar, with 34 GW operating capacity. Dominant position in US market.

Emerging Startups

Fervo Energy — Leading enhanced geothermal developer. Raised over $1 billion in 2024-2025, including Google equity investment. Cape Station project targeting 500 MW by 2028.

Sage Geosystems — Texas-based next-generation geothermal company. Raised $41 million Series A in 2024. Focuses on closed-loop systems compatible with existing oil and gas infrastructure.

Dandelion Energy — Residential geothermal heat pump company spun out of Alphabet's X. Targeting mass-market adoption through reduced drilling costs and financing innovation.

Principle Power — Developer of WindFloat semi-submersible floating wind foundation technology. Deployed in Portugal, Scotland, and California projects.

Key Investors & Funders

Breakthrough Energy Ventures — Climate-focused fund backed by Bill Gates. Major investor in Fervo Energy, Dandelion Energy, and numerous renewable technology companies.

EU Innovation Fund — €40 billion fund supporting first-of-a-kind clean technology projects. Awarded €3.6 billion to green industrial projects in 2024.

European Investment Bank — €750 million to H2 Green Steel, plus substantial allocations to offshore wind and solar manufacturing. Largest multilateral climate finance provider.

B Capital Group — Led Fervo Energy's $462 million Series E in December 2025. Increasing allocation to climate technology investments.

Action Checklist

  1. Map grid interconnection timelines before site selection. The permitting landscape has shifted; grid access is now the critical path for most projects. Engage with transmission operators early and design flexibility into project schedules.

  2. Build relationships with equipment manufacturers 18-24 months ahead. Supply chain constraints persist, particularly for transformers, switchgear, and specialised components. Secure allocation before finalising project financing.

  3. Evaluate hybrid configurations seriously. Solar-plus-storage, wind-plus-battery, and agrivoltaic designs increasingly outperform single-technology projects on risk-adjusted returns. The additional complexity pays off in revenue stability and grid services revenue.

  4. Monitor geothermal developments for baseload opportunities. Enhanced geothermal is transitioning from demonstration to commercial scale. Data centre customers and industrial offtakers are actively seeking 24/7 carbon-free power at premium prices.

  5. Stress-test financial models against interest rate scenarios. The 2024 offshore wind corrections demonstrated sector vulnerability to financing costs. Ensure project economics remain viable across realistic rate ranges.

  6. Engage local stakeholders proactively. Opposition-driven delays remain the most unpredictable project risk. Agrivoltaics, community ownership structures, and benefit-sharing agreements transform adversaries into advocates.

  7. Track EU permitting reform implementation by jurisdiction. Directive transposition varies dramatically; some markets will accelerate faster than others. Position for early-mover advantages in jurisdictions that genuinely streamline processes.

  8. Consider vertical integration for critical path components. As competition for equipment intensifies, developers with manufacturing partnerships or equity stakes in suppliers gain meaningful competitive advantages.

FAQ

Q: How have solar and wind economics changed for EU founders compared to five years ago? A: The transformation is dramatic. Solar LCOE has declined to $43/MWh globally, with European projects typically ranging from €40-60/MWh depending on location and configuration. Five years ago, most projects required feed-in tariffs or contracts for difference to be financeable. Today, merchant risk is increasingly acceptable because wholesale power prices regularly exceed solar and wind production costs. The challenge has shifted from proving economics to managing execution: securing grid connections, navigating permitting, and ensuring supply chain access. Unit economics favour renewables decisively; operational complexity is the new constraint.

Q: Is geothermal ready for mainstream investment, or is it still too early-stage? A: Enhanced geothermal has crossed a critical threshold with Fervo's commercial operations and Google's equity investment. The technology is proven; the question is cost trajectory. Conventional hydrothermal achieves $63-74/MWh, while EGS costs are declining toward parity as drilling techniques improve. For investors, the opportunity is analogous to solar circa 2012—proven technology with clear cost reduction pathways but not yet at grid parity everywhere. The data centre demand catalyst is real: technology companies need 24/7 carbon-free power and are willing to pay premium prices. Conservative investors might wait for Cape Station results (2026-2028); aggressive investors are moving now to secure positioning.

Q: What's the realistic timeline for floating offshore wind to achieve cost parity with fixed-bottom installations? A: Industry projections target 2030-2035 for floating wind to reach cost parity with fixed-bottom at equivalent water depths. Hywind Tampen achieved 35% cost reduction versus Hywind Scotland, demonstrating the technology's learning curve. However, achieving true parity requires serial production at scale—30-50 units per year versus current bespoke fabrication. The Celtic Sea developments in the UK (3 GW in development) and ScotWind allocations will drive volume. Founders should note that floating wind economics may remain premium even at parity because it unlocks superior wind resources in deep water, potentially delivering higher capacity factors that offset cost differences.

Q: How should founders approach the permitting challenges that are delaying projects across Europe? A: Three strategies are proving effective. First, site selection with permitting in mind—locations with existing industrial use, brownfield sites, or pre-approved renewable zones face fewer obstacles. Second, agrivoltaic or community-benefit structures that transform opposition into partnership; projects with genuine local stakeholder alignment move faster. Third, strategic patience combined with pipeline diversification; maintaining 3-5x development pipeline relative to target capacity accounts for attrition. Some founders are also exploring "permit acquisition"—purchasing projects from developers who've cleared permitting but lack capital for construction. The permitting landscape varies dramatically by jurisdiction; focus on markets genuinely implementing EU directive reforms.

Q: What's the most common mistake you see founders make in renewable energy development? A: Underestimating grid integration complexity. Founders often master technology and project finance only to discover that transmission access determines project viability. The interconnection queue in many markets now exceeds five years. Projects that assumed standard grid connection procedures face multi-million euro holding costs while waiting for capacity. The solution is engaging transmission operators and grid planners as primary stakeholders from project inception—before land acquisition, before equipment procurement, before detailed engineering. Grid capacity is the scarce resource; everything else follows from securing it.

Sources

The renewable energy sector has entered a new phase where technological viability and economic competitiveness are largely settled questions. The builder's playbook now focuses on execution: navigating grid constraints, managing supply chains, accelerating permitting, and identifying the emerging opportunities—like enhanced geothermal and floating offshore wind—that will define the next decade of the clean energy transition. For founders willing to master this complexity, the market opportunity exceeds anything the sector has previously experienced.

Topics

renewablessolarancillary servicesDERgrid reliabilitycapextransition plan

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