Impact of Solar Energy on Midday Power Prices

In a significant boost to the transition to renewables, AGL has successfully trialled shutting down a coal unit in the middle of the day. This news hasn't been widely reported, but last weekend Unit 2 at the Bayswater coal-fired power station was taken offline around 8am and then brought back online at 3pm. This is a process known as "two-shifting", and it is something AGL first tested about a year ago, following months of pre-testing, simulation training, and detailed planning. Since then, it has been quietly extending the practice through tests on other units. The output of these units is already being dialled down to 20% on a daily basis, and now it is being shut off completely on occasions such as last weekend, when demand was low and solar output was high. The significance of this should not be underestimated. Currently, the main reason wholesale prices go negative in the middle of the day is because coal generators are prepared to bid negative prices to ensure they are dispatched and stay online through the solar peak. And this has ramifications for other generation due to economic curtailment. Wind and solar farms are often forced to shut down because their contracts require them to do so when prices go negative. This has led to more than 90% of large scale solar farms being switched off at times. In theory, if more coal units start going offline in the middle of the day, it will make room for more wind and solar on the grid, as well as incentivising more investment in new projects. It's likely there is a cost to the coal generator of two-shifting, but this may be outweighed by the savings from not continuing to run through periods of negative prices. It effectively enables the coal generators to maximise their market involvement during peak times and avoid low-price periods. Coal in Australia is no longer operating only as inflexible baseload generation — it is adapting into a more flexible role before eventually being retired. #energy #renewables #energytransition

⚡ Ten days. That’s all it took for Germany’s 15-minute market to expose our next big energy problem. When Germany switched from hourly to 15-minute spot market prices, it wasn’t just a technical change. It was like turning up the sensitivity dial on the entire energy system. Suddenly, the grid started telling us the truth… every 15 minutes. And it’s fascinating what that truth looks like. 1️⃣ Prices now move with the weather Every passing cloud, every burst of sunshine, you can see it reflected in the market. Prices spike, dip, recover, all within minutes. It’s messy, yes. But it’s also honest. 2️⃣ Flexibility has become the real star In a world that moves every 15 minutes, flexibility isn’t a nice-to-have. It’s everything. Batteries, smart EV charging, flexible industrial loads… These aren’t “future tech” anymore. They are what keep the grid balanced in real time. 3️⃣ Renewables are setting the rhythm Midday prices drop when solar floods the grid. Evenings see the classic ramp-up as the sun fades but demand stays high. The market is finally dancing to the rhythm of the sun and wind. 4️⃣ The Flexibility Gap is showing There are a few moments, very few (marked in golden circles), when renewables actually exceed demand. Those moments whisper: “We could have run on 100% renewables… if only we had more flexibility.” Storage, smart demand, and hydrogen can turn those whispers into everyday reality. 5️⃣ Efficiency is quietly improving More granular trading means fewer mismatches, less waste, and better alignment between generation and demand. The system is learning to breathe more naturally, in smaller, faster rhythms. 6️⃣ It’s not just about power anymore. It’s about timing. In a 15-minute market, the question isn’t “how much energy do we have?” It’s “when do we have it?” That’s a mindset shift for utilities, for industry, and for all of us watching this transition unfold. 💭 My takeaway Germany’s 15-minute market is teaching us that the energy transition doesn’t just need clean power. It needs quick reactions. We’ve built renewables. Now we need to build flexibility. Because in this new world… every 15 minutes counts. ⚡

Don’t mess with Texas ... solar, or market economics! In February 2026, Texas took the crown as the #1 state for utility-scale solar: Solar went from 2% in 2020 to out-generating coal They said it couldn't be done in the land of oil and gas. They were (of course) wrong 1. Texas solar exploded to 40GW+, or 14%+ of total power, pushing coal into the rearview mirror in the ERCOT mix (14% vs 13%) 2. Texas now leads the US in utility-scale solar capacity, moving past California's long-standing reign 3. Texas now also has over 15 GW of operational battery storage which acts as the shock absorber for solar when the sun sets, capturing midday solar surplus and discharging during the critical 7-9 PM evening ramp. Texas is taming the Duck Curve in real-time 4. During the record-breaking Summer of 2025, ERCOT issued zero conservation alerts. Why? Solar and batteries performed with nearly 99% availability during peak demand hours and kept the grid stable while traditional plants struggled with thermal stress 5. Texas has at least $30b in planned solar & storage investment through 2027: Decoupling growth from emissions while keeping a lid on prices. The sun is now the most reliable hedge against price volatility in the Lone Star State 6. Businesses: Rates significantly lower than the national average. Businesses that can shift their heavy operations to solar hours (midday) seeing big wins 7 . Citizens: Prices flat. Solar and BESS prevented catastrophic price spikes during the record-breaking heat of 2025 Market economics, not mandates, drove this shift - which is accelerating In Texas, if it’s cheaper, it wins. It helps that it's also better, healthier and more reliable.

10 GW of batteries just collapsed California's duck curve. Here's what the 2026 data shows. I compared CAISO wholesale pricing and curtailment data for Jan-Mar 2025 vs 2026. Curtailment dropped 27%. Prices dropped 32%. The hourly price shape that has defined California's grid for a decade is flattening fast. Wholesale prices are set hourly by the most expensive generator still needed. As solar and batteries displace gas from more hours, they push prices down -- and undercut each other. The first dynamic is well-documented: solar eats solar. The Breakthrough Institute showed solar's wholesale value in California has fallen 37% since 2014, as each new MW depresses the midday prices all solar depends on. The second is less discussed: batteries eat batteries. CAISO pricing, Jan-Mar 2025 vs 2026: Midday solar hours: $27/MWh -> $19/MWh. Solar eating solar. Evening peak hours: $55/MWh -> $36/MWh. Batteries eating batteries. The evening collapse ($19/MWh) is 2.3x larger than the midday drop ($8/MWh). The peak-to-midday spread shrank from $28 to $18/MWh in a single year. Here's what this means if you manage energy for a building portfolio. On a TOU rate, the peak vs. off-peak gradient is built on this wholesale spread. As batteries compress it, expect utilities to narrow the TOU differential in future rate cases. On direct access or hourly pricing, you're already seeing it. The arbitrage between a 1pm kWh and a 7pm kWh is a third smaller than last year. Some of this is already underway. NEM 3.0 slashed rooftop solar export credits precisely because midday wholesale prices had cratered. The same dynamic is now coming for investments that depend on steep TOU differentials: 🔋 BTM batteries that arbitrage peak vs. off-peak ⚡ Managed EV charging timed to avoid peak rates 🏢 Thermal storage sized for off-peak rates If the spread keeps compressing, the payback periods on these investments stretch. Solar ate solar. Now batteries are eating batteries. Building operators who understand these rate trends will avoid over-investing in economics that are already fading.

Average four-hour Energy price spreads (TB4) in CAISO have declined 21% year-on-year. The duck is getting flattened 🦆. Prices during peak hours haven't budged, BUT the price to buy energy in the lowest-priced hours, typically the middle hours of the day, has almost doubled! ☀️🆙 And this is despite average peak output from solar generation increasing from 18 GW in June 2024 to 20 GW in June 2025. How? 🔋 Peak battery charging consumption has increased by nearly 50% - 4.2 GW to 6.1 GW - during the midday hours. With these batteries increasingly competing during the same hours to charge for as cheap as possible, they mitigated curtailment and lifted the very price floors they were trying to capture. 🪫 These compressed arbitrage margins hurt battery revenues in a market where currently 90% of a battery's revenues typically come from energy arbitrage. However, the new 'Slice of Day' Resource Adequacy structure, a 5% increase in the Planning Reserve Margin in 2026 and an expected 10-15% peak demand growth could still provide decent market opportunities for batteries to make good money in California. #CAISO #EnergyArbitrage #MiddayMunchMadness

Why are Indian solar generators selling electricity for free? India's solar capacity hits record generation of 12.3 billion units in May 2025. The result? Electricity prices are crashing toward zero during peak solar hours. Here's what's happening: 🦆 The "Duck Curve" hits India Midday solar output peaks while demand drops 30% Rajasthan's 18 GW solar capacity could only export 5% of midday power in May 2025 (down from 12% in 2024) 🌍 Global parallels everywhere: Germany: 475 hours of negative pricing in 2024 Australia: 24-26% of hours with negative prices California: 13% negative pricing hours in 2024 🔋 The obvious fix? Battery Storage. The problem? Economics. India had just 220 MWh of battery storage as of March 2024 - practically nothing for thousands of MW of daily surplus. Battery costs fell to $120/kWh, but upfront investments remain massive. 🎯 Why this matters beyond today's grid: As we scale toward 100% renewable energy globally, the battery storage constraint becomes the ultimate bottleneck. Without solving energy storage economics, the renewable transition hits a ceiling - no matter how cheap solar panels become. ⚡ Policy experiments underway: ✅ Time-of-day pricing trials in few states ✅ Massive transmission projects to move surplus between states ❌ Progress remains slow due to regulatory hurdles and costs The irony is perfect: solar has become so successful that we have too much cheap, clean electricity. As India targets 500 GW renewables by 2030 (requiring 40 GW annual solar additions), solving the "abundance problem" becomes critical. Sometimes success creates new challenges. 🔋 *** At Opten Power, we help clients procure clean energy and deploy capital in green assets. #RenewableEnergy #Solar #India #EnergyTransition #CleanTech

18.5% of the solar generation happened during hours with negative prices in Germany in 2024 (up to 18 December). Obviously, some hours are much more impacted, going up to a third for 2 PM. This is an important feature, especially for the support schemes (such as Contract-for-Differences) that stop payments when the spot market turns negative, as it introduces a non-negligible volume risks. As Europe as whole has installed another 60+ GW of solar in 2024, it is likely that more hours will be with negative spot prices, which would increase the volume of solar production produced under negative prices. The logical consequence will be an increase of curtailments or hopefully, an increase of consumption during these hours (via demand shifting and/or storage). Of course, curtailments can only happen if it is technically feasible and if economic incentives are present, which is not always the case with solar installation. Here for more: https://lnkd.in/d6w2xm3T

Solar prices are no longer moving with baseload power — and that changes quite a few things! The chart below shows how the realized price of solar (as a % of baseload power) has declined steadily across major European markets (DE, ES, FR). For years, the capture factor hovered close to 100%. But since 2022, we've seen a steep drop — with volume-weighted averages now below 70%. This is more than a pricing trend — it's a structural shift. What’s driving it? 🔸 Surging penetration of wind and solar (bottom line in chart) 🔸 Midday oversupply 🔸 Less correlation between solar output and power price peaks This means corporate buyers and developers can’t rely on traditional pricing assumptions. New contracting models — shaped delivery, load-shifted PPAs, hybrid solar+BESS — are becoming essential. 💬 If you want to explore how this can be priced — or how to best combine solar + storage under one PPA — feel free to reach out for a chat. https://lnkd.in/eqrmvycy

It's not even spring yet, but capture rates for solar in Southern Europe are already in the doldrums.  The mid-day power price in Spain has been effectively zero (or near-zero) for all of last week.  In February solar made less than 80% of the average baseload power price. The only other time the figure dipped below 80% was last April. Shoulder months are particularly tricky for solar because it is already sunny, but there is no aircon demand yet.  With 26% more PV on the grid than last April, cannibalization is bound to be a lot punchier this year.   Are you monitoring capture risk? Source: Pexapark, ENTSO-E, OMIE

⚡️ European Power Price Update - Summary of May 2025 Average Spot The biggest story (one that’s not immediately visible in the map) is the impact of solar. 💥 In Germany, zero or negative prices almost every single day in May. The midday solar generation is now regularly overwhelming demand. 💥 It seems like Spain is enjoying lower prices, but the dynamic is very similar: low average prices come from midday negative prices, followed by much higher evening peak prices. Beyond that: ➡️ Gas prices have remained relatively stable (around 35 EUR/MWh), so not much volatility from the fuel cost side ➡️ Exceptionally low prices in Northern Scandinavia are linked to very full hydro reservoirs. NO4 and NO3 had prices in single digits almost every day in May. Lots of water, lots of cheap power... and that is not making any headlines in the newspapers... Curious to see if the upcoming heat waves and A/C demand will transform the European duck curves into batman curves (📷 from EnergyCharts) #powerprices #solar