Deep dive: Renewables innovation (solar, wind, geothermal) — what's working, what's not, and what's next

Global renewable energy capacity additions reached 620 GW in 2025, a 14% increase over the previous year, with solar photovoltaics alone accounting for 420 GW of that total according to the International Renewable Energy Agency (IRENA, 2026). Asia-Pacific dominated installations, contributing 68% of new solar capacity and 55% of new wind capacity. Yet beneath these headline figures lies a more complex story: cell efficiency records continue to fall, but grid integration bottlenecks are intensifying; wind turbine manufacturers are scaling hardware to unprecedented sizes while grappling with quality control failures; and geothermal energy is finally attracting venture capital after decades of stagnation. For investors evaluating the renewables sector in 2026, understanding what is genuinely working, what remains stubbornly broken, and where the next wave of value creation will emerge is essential to allocating capital effectively.

Why It Matters

The renewables sector is no longer a niche: it represented $560 billion in global investment in 2025, surpassing fossil fuel supply investment for the third consecutive year (BloombergNEF, 2026). Asia-Pacific is the center of gravity. China installed 290 GW of solar in 2025 alone, more than the entire world installed in 2022. India added 38 GW of renewables, driven by its target of 500 GW non-fossil capacity by 2030. Australia, Japan, South Korea, and Southeast Asian nations collectively added another 45 GW.

For investors, three dynamics make this assessment critical. First, the cost learning curves that drove returns over the past decade are flattening in mature technologies while accelerating in emerging ones, creating a divergence between incumbent and next-generation investment opportunities. Second, policy environments across the Asia-Pacific are shifting from deployment subsidies to grid integration mandates, changing the risk-return profile of renewable projects. Third, supply chain concentration, particularly in polysilicon, wafer production, and rare earth processing, introduces geopolitical risks that differ fundamentally from the commodity price risks investors managed in previous cycles.

Key Concepts

Perovskite-silicon tandem cells layer a perovskite absorber on top of a conventional silicon cell, capturing different portions of the solar spectrum to push theoretical efficiency limits beyond 43%. LONGi Green Energy achieved a certified 34.1% efficiency on a perovskite-silicon tandem cell in late 2025, up from 33.9% six months earlier (LONGi, 2025).

Heterojunction technology (HJT) combines amorphous and crystalline silicon layers to achieve higher voltage and lower temperature coefficients than conventional PERC cells. HJT cells reached 27.1% efficiency in mass production in 2025, with manufacturing costs declining to $0.018 per watt, narrowing the gap with PERC/TOPCon (InfoLink Consulting, 2026).

Floating offshore wind uses semi-submersible, spar-buoy, or tension-leg platforms to deploy turbines in water depths exceeding 60 meters, opening vast wind resource areas inaccessible to fixed-bottom foundations. The global floating wind pipeline reached 85 GW of announced projects by the end of 2025 (Global Wind Energy Council, 2026).

Enhanced geothermal systems (EGS) create artificial reservoirs by hydraulically stimulating hot dry rock formations, extending geothermal energy production beyond naturally occurring hydrothermal resources. Fervo Energy's Project Red in Utah demonstrated sustained power production from a commercial-scale EGS well in 2025, producing 8 MW of continuous output (Fervo Energy, 2025).

Bifacial modules capture reflected light on the rear surface of solar panels, increasing energy yield by 5 to 25% depending on ground albedo and mounting height. Bifacial modules accounted for 72% of global module shipments in 2025, up from 55% in 2023 (Wood Mackenzie, 2026).

What's Working

Solar Manufacturing Scale and Cost Reduction

The solar industry's manufacturing engine continues to deliver extraordinary results. Global module manufacturing capacity reached 1,100 GW in 2025, creating significant overcapacity that drove average module prices to $0.09 per watt, a 35% decline from 2023. Chinese manufacturers, led by LONGi, JA Solar, Trina Solar, and JinkoSolar, have scaled TOPCon cell production to over 400 GW of annual capacity, achieving mass-production efficiencies of 26.0 to 26.5%.

For investors in the Asia-Pacific, this manufacturing dominance creates opportunities in downstream integration. Indian developers procuring modules at $0.08 to $0.10 per watt are achieving utility-scale solar levelized costs of $25 to $30 per MWh without subsidies, making solar the cheapest new electricity source in every major Asian market. The Khavda Renewable Energy Park in Gujarat, being developed by Adani Green Energy, is deploying 30 GW of solar capacity using domestically assembled modules with TOPCon cells, targeting a blended energy cost below $28 per MWh (Adani Green Energy, 2025).

Onshore Wind Maturity and Repowering

Onshore wind technology has reached a plateau of performance optimization where incremental gains come from larger rotors, taller towers, and site-specific tuning rather than fundamental technology shifts. Vestas, Goldwind, and Envision Energy are shipping 6 to 7 MW onshore turbines with rotor diameters exceeding 180 meters, achieving capacity factors of 35 to 45% at moderate wind sites.

The repowering opportunity is emerging as a significant investment theme. An estimated 78 GW of onshore wind capacity in China was installed before 2015 using sub-2 MW turbines. Replacing these with modern 6 MW platforms on existing grid connections can triple energy output per site while reducing operations and maintenance costs by 30 to 40%. Goldwind's repowering program across Inner Mongolia demonstrated a 2.8x increase in annual energy production per megawatt of rated capacity at repowered sites (Goldwind, 2025).

Geothermal Renaissance Through Enhanced Systems

After decades of limited growth, geothermal energy is experiencing a genuine innovation inflection. Fervo Energy's success at Project Red demonstrated that horizontal drilling techniques borrowed from the oil and gas industry can create productive EGS reservoirs at commercially viable costs. The well pair produced 8 MW of continuous power at a reservoir temperature of 190 degrees Celsius, with drilling costs 40% below initial projections due to learning curve improvements across successive wells.

In the Asia-Pacific context, Indonesia and the Philippines hold 40% of global conventional geothermal potential, with Indonesia targeting 8 GW of geothermal capacity by 2030, up from 2.4 GW in 2025. Pertamina Geothermal Energy, the world's second-largest geothermal operator, commissioned 155 MW of new capacity in 2025 across the Lumut Balai and Hululais fields in Sumatra (Pertamina, 2025).

What's Not Working

Offshore Wind Cost Escalation

The offshore wind sector is experiencing a severe cost crisis that has undermined investor confidence. Inflation in steel, copper, and specialized installation vessels drove offshore wind capital costs 35 to 50% above pre-2022 levels in most markets. Orsted wrote down $5.6 billion in US offshore wind assets in 2023 and 2024, while Vattenfall halted the 1.4 GW Norfolk Boreas project in the UK due to uneconomic returns at contracted strike prices.

In the Asia-Pacific, this cost pressure manifests differently but is equally challenging. Japan's Round 1 offshore wind auctions in 2021 awarded three projects at feed-in tariff rates of approximately $100 per MWh, but construction costs have since escalated 25 to 30%. Taiwan's offshore wind program, which targeted 20 GW by 2035, has seen developer exits and project delays as the combination of typhoon-resistant design requirements, limited local supply chain, and challenging seabed conditions pushes costs 40% above European benchmarks (4C Offshore, 2026).

Grid Connection Bottlenecks

Across the Asia-Pacific, grid infrastructure is failing to keep pace with renewable deployment. China curtailed an estimated 60 TWh of wind and solar generation in 2025, representing roughly $3 billion in lost revenue, because transmission capacity from resource-rich western provinces to demand centers in the east remains insufficient. India's renewable energy curtailment reached 8% of potential generation in 2025, concentrated in Rajasthan and Tamil Nadu where solar and wind installations have outpaced grid reinforcement.

Australia exemplifies the challenge at the distribution level. The Australian Energy Market Operator (AEMO) reported that 35% of new solar and wind projects experienced connection delays exceeding 24 months in 2025, with average connection costs rising to $45 per kW of installed capacity, up from $25 per kW in 2022. These delays and costs erode project returns and create stranded development capital.

Solar Module Quality and Degradation

The rapid transition from PERC to TOPCon cell technology has introduced quality control challenges. A 2025 PV Evolution Labs reliability scorecard found that 18% of TOPCon modules from second-tier manufacturers exhibited light and elevated temperature-induced degradation (LeTID) rates exceeding 2% in the first year, compared to the industry standard assumption of 0.5% annual degradation. For a 100 MW solar farm with a 25-year power purchase agreement, the difference between 0.5% and 2% first-year degradation translates to $4 to $6 million in lost lifetime revenue.

Perovskite stability remains an unresolved barrier to commercialization. Despite efficiency records in laboratory settings, no manufacturer has demonstrated perovskite or perovskite-tandem modules that maintain performance for the 25-year warranties that project finance requires. Oxford PV, the most advanced perovskite-tandem manufacturer, reported accelerated aging test results equivalent to 15 years of field exposure with 8% power loss, but field validation data beyond 3 years remains unavailable (Oxford PV, 2025).

Key Players

Established Companies

LONGi Green Energy: the world's largest solar manufacturer by revenue, leading commercialization of both TOPCon and perovskite-tandem technologies with over 100 GW of annual cell production capacity.

Vestas Wind Systems: the global leader in onshore wind turbine installations, with a 28% market share in 2025 and an active repowering business across mature wind markets.

Goldwind Science and Technology: China's largest wind turbine manufacturer, dominating the domestic onshore market and expanding into offshore platforms with a 16 MW turbine in development.

Pertamina Geothermal Energy: Indonesia's state-backed geothermal developer operating 1,877 MW of installed capacity across 13 geothermal working areas.

Orsted: the world's largest offshore wind developer by installed capacity despite recent asset impairments, with 15.5 GW of operational and committed projects globally.

Startups and Emerging Players

Fervo Energy: a Houston-based EGS developer that has raised over $430 million to commercialize horizontal well geothermal systems, with Project Red delivering the first commercial-scale EGS power in the US.

Oxford PV: a UK-headquartered perovskite-tandem cell developer that began commercial module shipments in late 2025, targeting the premium rooftop segment at 27%+ module efficiency.

Eel Energy: a French developer of tidal energy converters using biomimetic membrane technology, with a 1 MW demonstration unit deployed off the coast of Brest.

Quaise Energy: a deep geothermal startup developing millimeter-wave drilling technology to access superhot rock resources at depths of 10 to 20 km, backed by $75 million in venture funding.

Investors and Financiers

Breakthrough Energy Ventures: Bill Gates-backed climate fund with investments across EGS, next-gen solar, and long-duration storage totaling over $2 billion deployed.

Macquarie Asset Management: the world's largest infrastructure asset manager with $45 billion in renewable energy assets under management, actively investing in Asia-Pacific wind and solar.

Temasek Holdings: Singapore's sovereign wealth fund with significant renewable energy portfolio exposure across Southeast Asia, including investments in floating solar and offshore wind supply chains.

Action Checklist

• Evaluate TOPCon module suppliers using independent reliability data (PV Evolution Labs, TUV Rheinland) before committing to procurement contracts for utility-scale projects
• Model grid connection timelines and costs as explicit risk factors in project financial models, adding 18 to 24 month connection delay scenarios to base cases
• Monitor perovskite-tandem field performance data as it accumulates through 2026 to 2028, with commercial-scale investment decisions contingent on 5-year field validation
• Assess repowering opportunities in markets with aging wind fleets, particularly China (pre-2015 installations) and India (pre-2017 installations)
• Track EGS cost curves as Fervo Energy and other developers publish data from commercial projects, with particular attention to drilling cost reductions per successive well
• Conduct supply chain concentration risk analysis for polysilicon, wafer, and inverter procurement, including second-source qualification for non-Chinese alternatives
• Review offshore wind portfolio exposure in light of cost escalation trends and consider hedging strategies for steel, copper, and installation vessel charter rates
• Engage with grid operators and transmission developers in target markets to assess realistic interconnection timelines before committing development capital

FAQ

Q: Are perovskite-silicon tandem cells ready for commercial-scale deployment? A: Not yet. While laboratory efficiencies have surpassed 34%, commercial deployment requires resolution of three challenges: long-term stability under real-world conditions (current field data covers only 2 to 3 years), manufacturing scale-up from pilot lines to GW-scale production, and bankability (project lenders require 25-year performance warranties backed by rated manufacturers). Oxford PV began limited commercial shipments in late 2025, but volumes remain below 100 MW annually. Investors should monitor field performance data through 2027 before committing significant capital to perovskite-dependent business models.

Q: What is the realistic cost trajectory for enhanced geothermal systems? A: Fervo Energy's Project Red achieved drilling costs of approximately $10 million per well pair, producing 8 MW of continuous output for a drilling-only cost of roughly $1,250 per kW. Including surface plant, transmission, and development costs, total installed cost is estimated at $4,500 to $6,000 per kW for early commercial projects. Fervo projects costs declining to $3,000 to $4,000 per kW by 2030 as drilling speeds improve and well designs are standardized. For comparison, conventional geothermal in Indonesia achieves $2,500 to $3,500 per kW, while offshore wind ranges from $3,500 to $5,500 per kW. EGS becomes competitive on a levelized cost basis at $45 to $65 per MWh by 2030 if learning rates follow the trajectory observed in Fervo's first four wells.

Q: How should investors assess offshore wind risk in Asia-Pacific markets given recent cost overruns? A: Investors should apply three filters. First, evaluate contracted revenue mechanisms: projects with inflation-indexed contracts for difference (CfDs) or feed-in tariffs with escalation clauses offer better protection than fixed-price PPAs signed before cost escalation. Second, assess supply chain localization requirements, which can add 15 to 30% to project costs in markets like Taiwan and Japan that mandate domestic content. Third, factor in typhoon and seismic design requirements specific to the Asia-Pacific, which add 10 to 20% to turbine and foundation costs versus European designs. Projects with strong grid connections, experienced developers, and revenue certainty remain investable, but returns have compressed from the 10 to 12% equity IRRs projected in 2021 to 7 to 9% under current cost assumptions.

Q: What role does bifacial module adoption play in improving solar project economics? A: Bifacial modules increase energy yield by 5 to 25% compared to monofacial modules at a cost premium of only 2 to 5%. The yield gain depends heavily on ground albedo (white sand or concrete reflectors deliver 15 to 25% gains, while dark soil delivers 5 to 8%) and mounting configuration (elevated trackers outperform fixed-tilt ground mounts). For utility-scale projects in the Asia-Pacific, bifacial modules on single-axis trackers with optimized row spacing and ground treatment can reduce levelized cost of energy by $3 to $7 per MWh. With bifacial modules now representing 72% of global shipments, the technology premium is effectively zero for Tier 1 manufacturers, making monofacial procurement difficult to justify on a cost basis.

Sources

• International Renewable Energy Agency. (2026). Renewable Capacity Statistics 2026. Abu Dhabi: IRENA.
• BloombergNEF. (2026). Global Energy Investment Outlook 2026. London: Bloomberg Finance LP.
• LONGi Green Energy. (2025). 2025 Technology White Paper: Perovskite-Silicon Tandem Cell Development Roadmap. Xi'an: LONGi Green Energy Technology Co., Ltd.
• Global Wind Energy Council. (2026). Global Offshore Wind Report 2026. Brussels: GWEC.
• Fervo Energy. (2025). Project Red Commercial Operations Update. Houston, TX: Fervo Energy Inc.
• Wood Mackenzie. (2026). Global Solar PV Market Outlook: Module Technology Trends and Pricing. Edinburgh: Wood Mackenzie Ltd.
• Adani Green Energy. (2025). Khavda Renewable Energy Park: Project Update and Cost Benchmarking. Ahmedabad: Adani Green Energy Ltd.
• Goldwind Science and Technology. (2025). China Wind Repowering Program: Performance Results and Market Outlook. Beijing: Xinjiang Goldwind Science and Technology Co., Ltd.
• Pertamina Geothermal Energy. (2025). Annual Report 2025: Operational Performance and Expansion Program. Jakarta: PT Pertamina Geothermal Energy Tbk.
• 4C Offshore. (2026). Asia-Pacific Offshore Wind Market Intelligence Report. Lowestoft: 4C Offshore Ltd.
• InfoLink Consulting. (2026). Solar Cell Technology Market Share and Cost Analysis: PERC, TOPCon, HJT. Taipei: InfoLink Consulting Co., Ltd.
• Oxford PV. (2025). Perovskite-Silicon Tandem Module: Accelerated Aging Test Results and Commercial Deployment Update. Oxford: Oxford PV Ltd.