Episode Summary
Executive Summary: David Roberts interviews Jan Pepper of Peninsula Clean Energy about the utility’s effort to reach 24-7 clean energy—matching electricity use with clean generation every hour, not just annually. They discuss Peninsula’s public-agency structure, the custom open-source Match model, why winter nighttime hours are hardest to cover, how 99% hourly matching is achievable today with existing tech, and why the move could cut emissions, reduce price volatility, and help the broader grid.
Main Topics: Peninsula Clean Energy’s structure and mandate (Priority: 5/5): Jan Pepper explains that Peninsula Clean Energy is a community choice aggregator serving San Mateo County and Los Baños. As a public agency with board oversight from local elected officials, it can set long-term clean-energy goals more aggressively than investor-owned utilities. Why 24-7 clean energy is different from 100% annual clean energy (Priority: 5/5): The conversation distinguishes annual renewable/clean procurement from hourly matching. Roberts and Pepper emphasize that 24-7 clean energy is much harder because it requires aligning supply and demand every hour, especially when solar and wind are unavailable. The Match model and data-driven procurement (Priority: 5/5): Peninsula built an open-source optimization tool called Match (Matching Around the Clock Hourly Energy), adapted from Switch, to simulate hourly load, resource profiles, contracted prices, LMPs, weather, and storage behavior in order to find the lowest-cost path to hourly matching. Resource mix and the hardest hours to serve (Priority: 5/5): The model shows that excess summer solar can charge batteries, but the toughest periods are winter nighttime hours. The utility relies on solar, wind, geothermal, storage, and a little hydro, while watching emerging technologies like offshore wind and long-duration storage. Costs, excess procurement, and the 99% vs. 100% gap (Priority: 5/5): Pepper argues that 99% hourly matching is reachable with only a modest cost premium over business as usual, largely because renewables are cheap and prices can be locked in. The final 1% is disproportionately expensive because it requires much more extra capacity and over-procurement. Grid, emissions, and market implications (Priority: 4/5): Hourly matching lowers emissions much more than annual accounting suggests, reduces peak demand and ramping on the California grid, and helps displace peaker plants. The conversation also connects the effort to broader electrification of transportation and buildings.
Key Arguments: Hourly clean-energy matching is far more meaningful than annual renewable accounting because it addresses the actual carbon intensity of each hour of load. Peninsula Clean Energy can pursue this goal because it is a public, not-for-profit CCA with local governance and a mandate beyond profit maximization. A custom optimization tool, Match, makes 24-7 planning practical by using real hourly data, market prices, and weather information. The hardest period to decarbonize is winter nighttime hours, not the obvious sunny daytime gaps, which makes the last increment toward 100% disproportionately costly. 99% hourly matching is achievable today with existing technologies—solar, wind, geothermal, storage, and small hydro—without waiting for speculative future breakthroughs. Renewables reduce risk and price volatility because their costs are mostly upfront and fuel is free, unlike gas-fired generation exposed to commodity shocks. Even in a conservative 2025 market scenario, the utility estimates only about a 2% cost increase versus its current portfolio. Over-procurement is not just waste; excess clean electricity can help the wider grid by displacing fossil generation and reducing net peak demand and ramping. Longer-term, demand-side resources, EV batteries, offshore wind, advanced geothermal, and long-duration storage could make 24-7 even easier and cheaper. The real end goal is to use clean electricity to decarbonize transportation and buildings, not just electricity supply itself.
Data Points: Customer accounts served: 310,000 - Peninsula Clean Energy’s customer accounts People served: About 810,000 - Population served across San Mateo County and Los Baños Annual electric load: About 3,600 GWh/year - Utility’s total electricity demand Renewable procurement (annual): 50% - Share of energy procured as renewable Clean procurement (annual): 100% - Utility’s annual clean-energy supply mix Goal year: 2025 - Target for 100% renewable and 24-7 hourly matching Hourly matching target: 99% of hours - Peninsula’s adopted practical target for hourly clean-energy matching Extra renewables needed for 100% vs. 99%: About 50% more additional renewables - Marginal cost of covering the last 1% of hours Capacity today: Just under 1,300 MW - Current portfolio capacity Added capacity to reach 99%: About 600 MW - Increment needed beyond current portfolio Additional capacity to reach 100%: Another 600 MW or so - Extra increment required for the final 1% of hours Emissions on annual accounting basis: 5 lb CO2/MWh - Reported using current annual method Emissions on hourly basis: 222 lb CO2/MWh - Actual emissions when examined hour by hour before hourly matching improvements Emissions after 99% hourly matching: 26 lb CO2/MWh - Expected emissions level after implementing hourly matching Estimated cost increase: About 2% - Conservative case relative to current business-as-usual portfolio Price position vs. PG&E: 5% below PG&E - Peninsula’s generation rates since launch EV share of car sales: 50% - San Mateo County last year, as cited in the discussion Battery duration example: 8-hour storage - One storage contract mentioned as lithium-ion based California hourly reporting start: 2026 - SB 1158 begins requiring LSEs to start examining hourly emissions then
Pivotal Quotes: "We are 100% renewable on a 24-7 basis." — Jan Pepper: Describing Peninsula Clean Energy’s stated goal to match clean energy every hour by 2025 "The hours that are the most difficult to serve are actually the winter nighttime hours." — Jan Pepper: Explaining the key modeling result about when hourly clean supply is hardest to line up with demand "We can get to cleaner energy for everyone and it can be less expensive for everyone." — Jan Pepper: Summing up why 24-7 clean energy is economically and politically attractive
Implications: The episode suggests 24-7 clean power is already feasible at scale with existing tech and modest added cost, especially for CCAs. It could accelerate grid decarbonization, reduce price volatility, and speed electrification of transport and buildings.