The release of a Brattle report by the Natural Resources Defense Council (NRDC) resulted in a Twitter storm and much commentary over the meaning of ‘baseload’. Mark Diesendorf had pushed back against the term more than 10 years ago. But some anti-coal proponents embraced the concept of baseload, including Beyond Zero Emissions with the concept of ‘baseload solar’, Geodynamics with ‘baseload geothermal’, and AlignedEnergy with ‘baseload biomass’.
Engineers have a clear understanding of the technical terms, but many non-energy specialists and politicians have sought to infuse technical jargon with a value-based social meaning. For example, baseload is often used generically (but incorrectly) to refer to dispatchable power, often with a loaded meaning to imply that renewable energy is ‘not baseload’ and therefore has no value. But equally, critics of coal (and nuclear) use the term disparagingly to suggest, naively, that ‘inflexible baseload’ is a dinosaur past it’s use-by date. In this context, baseload is probably being referred to as generation that includes a steam-cycle, forgetting (or not appreciating) that concentrated solar thermal power, biomass, and geothermal also utilise a steam-cycle with synchronous generators.
The dinosaur descriptor is not very helpful. A comparison with passenger trains illustrates the point. Trains could easily be framed as artifacts of the early nineteenth century industrial revolution. Trains are the ultimate inflexible transport mode, being stuck to pre-determined routes, running on heavy steel rails that can’t be used for anything else, and consuming valuable inner urban real estate. Fare cost recovery of Australia’s suburban train services typically averages around 15 to 30%, despite overcrowding and rising patronage. Large and heavy, high fixed costs, and stuck in the past. Why would you bother? They do one thing exceptionally well – shift thousands of commuters in and out of city centres rapidly and safely, with hundreds of people being able to embark and disembark simultaneously. Robert Stephenson (and others) came up with a formula that has proved remarkably resilient. Few would argue about the contribution that our expensive, inflexible dinosaurs make to the public good. Here’s an idea – what about the ultimate flexibility and lifestyle of passenger cars, suburban sprawl, and freeways? It’s all in the framing.
So what is baseload? Baseload can refer either to electricity demand or supply. In the case of demand, it simply refers to the minimum overnight load. In the case of supply, it refers to always-on generation that meets the minimum demand. There is no a priori need for baseload – it is simply an engineering-economic solution for providing the greatest amount of energy as economically as possible. Baseload generators are characterised by high capital cost, low operational costs, and run at high capacity factor to maximise the utilisation of assets. A baseload generator can be implemented as flexible or inflexible as required for the context and depending on the business case. Much of the French nuclear fleet was implemented as flexible load-followers because of the high penetration of ‘baseload’ nuclear.
What is the point of all this? In the context of a low-emissions transition, overlaying technical jargon with socially constructed values is not particularly helpful.