This article (by Barry Brook) was originally published on The Conversation website until the title: “Low-carbon electricity must be fit-for-service (and nuclear power is)“. You can wade through the 224 comments over there (if you dare…) See also the comment here by Keith Orchison.
To paraphrase George Orwell, “All electricity is created equal, but some of its generating technologies are more equal than others”. This is a key point – emphasised but typically overlooked – in the new report Australian Energy Technology Assessment (AETA) on current and future costs of electricity options for Australia, released yesterday by the Bureau of Resources and Energy Economics.
Assessing the ‘levelised’ costs of existing energy technologies is already surprisingly difficult, given the array of assumptions that need to be made, on capital and owner’s costs, financing terms and associated risk, facility lifespans, fuel supply, government policy interventions, and so on. It gets even more challenging when projecting future cost changes, because learning curves and settled-down costs, uptake rates, future fuel and material supply bottlenecks, training, price incentives, social license, and other ‘known unknowns’ need to be factored into the economic modelling.
So the AETA authors had a difficult task on their hand. Perhaps the most contentious, yet important task, is defining the relative market value and role for technologies within a national electricity system. From the perspective of replacing fossil-fuel combustion with alternatives, a crucial issue is how effective it is, at a large scale, in providing a fit-for-service replacement for existing coal plants.
In a recent paper I co-authored with two colleagues in the journal Energy, we assessed technologies against a range of criteria intended to determine their suitability as a baseload alternative. These were:
Proven: Has the technology been used at commercial scale?
Scalable: Can the technology be built in sufficient quantity to replace significant proportions of existing fossil-fuel generators?
Dispatchable: Can the output be allocated by the system operator to meet the anticipated load?
Fuel supply: Is the energy source reliable and plentiful, even when, as with some kinds of renewable energy, it varies with time?
Load access: Can the generator be installed close to a load centre?
Storage: Does the technology require electricity storage in order to deliver a high capacity factor?
Emission intensity: Is the emission intensity high (>300 kg CO2e/MWh), moderate or low (<100)?
Capacity factor: Is the capacity factor high (>70%), moderate or low (<40%)?
For a technology to be considered fit-for-service as a baseload generator (i.e., a direct replacement for coal or combined-cycle gas power plants) it needs to be scalable, dispatchable without large storage and have a reliable fuel supply, low or moderate emissions intensity and a high capacity factor. The only current technologies that score well enough to meet these criteria are nuclear power and solar thermal with thermal storage and/or hybrid gas. Coal and gas with carbon capture and engineered geothermal could also qualify but are only at the pilot plant stage of development.