There are multiple academic approaches to the inevitable transformation to a 100% renewable future. They overlap and provide strong support for thesis that electrical generation, and by extension all primary energy needs, will be met by a combination of renewables. The four this article will cover briefly are the work of Dr. Jacobson of Stanford, the IPCC perspective, Dr. Mark Diesendorf’s work from Australia, and finally a gloss on the current state of large-scale grid integration and transmission.
The most obvious example of a strong academic approach to a 100% renewable solution is Dr. Mark Jacobson and team’s work from Stanford. In 2017, they took their model for renewable generation for all 50 US states, and extended it to the majority of the countries in the world. Jacobson et al show clearly that transitioning to 100% renewables is viable by 2050.
This isn’t without controversy and criticism. the team has come under attack from various sources. The arguments have varying merits. Jacobson is fiercely defending the assertions made that the models used are broken, quite rightly pointing out that they are robust, accurate, peer-reviewed, iterated, and based on predecessor models which had stood the test of time. Also fiercely, and with some merit, he’s attacking his critics who are asserting that technologies which they perceive as necessary aren’t in the mix, specifically nuclear and carbon capture and sequestration (CCS).
I’ve written extensively on both nuclear and CCS. My perspective is that nuclear is unnecessary to the energy mix by 2050, that Jacobson’s exclusion of it was reasonable as the intent was to show a completely renewable future as an aspirational target, that nuclear is much more expensive than renewables, and that there will still be some nuclear around by 2050, but just less of it. My perspective on CCS is that it has proven itself to be an uneconomic fig leaf incapable of doing more than drawing down the tiniest fraction of the CO2 created by fossil fuels and that any CCS in existence by 2050 will be a rounding error.
My perspective on the discourse is that Jacobson is completely right about the academic merits of the scenario and models he uses, and that his critics are wrong. Jacobson and team have the right to define any set of technologies that they choose as part of the solution, and opting for a scenario of only renewables is a completely reasonable choice.
I noticed one very important point about the tempest in a teapot. All the serious critics agreed that 80% was achievable with renewables. The disagreement was mostly about the cost of the last 20%, with Jacobson and team asserting viability and their critics insisting that other technologies would be required and that it would be more expensive. My perspective is that when people are arguing about the last mile near the beginning of the journey, the last mile will be a lot easier than anyone thinks.
Next, the IPCC is always a good place to look for information. The IPCC AR5 deals with reducing supply-side CO2 emissions. It’s worth reading, but is dated and doesn’t lay out specific mixes of renewables versus other lower-carbon approaches to energy, just assertions of the potential to reduce emissions.
This chart from p. 561 of AR5, Chapter 7: Energy Systems lays out three scenarios for primary energy.
Parsing it makes it clear that there is a high expectation of nuclear and carbon capture and sequestration (CCS) being viable options. Even in the AR5 report, the challenges and decline of nuclear were noted, but subsequently nuclear just continues to increase in expense, shut downs continue to increase and the viability of the sector decreases. Even more challenging for these scenarios is the fairly complete failure of carbon capture and sequestration approaches associated with fossil-fuel generation.
Similarly, while AR5 acknowledged the maturity and cost reductions of renewables, both wind and solar have vastly exceeded conservative expectations of their continued growth, reductions in cost and lack of impacts on grid reliability and stability.
I would expect the next IPCC report will shift more of the requirements in their scenarios to renewables from nuclear and CCS. But once again, these are scenarios of requirements to achieve certain emissions reductions goals, not projections of actual deployment of renewables.
The work of Dr. Mark Diesendorf is always worth considering. He and his team have done parallel work to Jacobson et al to assess whether there is any need at all for non-renewable resources. Their resounding answer is “No”.
Ben Elliston, Iain MacGill and I have performed thousands of computer simulations of 100% renewable electricity in the National Electricity Market (NEM), using actual hourly data on electricity demand, wind and solar power for 2010. Our latest research, available here and reported here, finds that generating systems comprising a mix of different commercially available renewable energy technologies, located on geographically dispersed sites, do not need base-load power stations to achieve the same reliability as fossil-fuelled systems.
Their work shows, as does Jacobson’s, that the most cost-effective solution is a renewable solution. It does assume that carbon has a cost which is internalized, something the current government of Australia dismantled upon assuming power with their revocation of the Australian carbon tax.
Finally, it’s important to note that a key enabler of a renewable future is high-efficiency transmission of energy from where it is generated to where it is in demand over large areas. There has been substantial work done on modeling high-voltage direct current (HVDC) implications as a high-capacity, low loss transmission work, and the current technology is moving forward rapidly.
HVDC continues to be an area of innovation and growth globally. From the first installation in Sweden in 1954, there are now dozens of implemented HVDC lines.
Unsurprisingly China alone will have more HVDC kilometers and capacity than any other country in the world and is a subject of study and lessons learned.
What the different sets of academic material show is that using different models and approaches, a zero-carbon future based dominantly or 100% on renewables is viable and achievable within the next few decades.
Almost all existing fossil fuel and nuclear generation assets are coming to end-of-life by 2050. They will have to be replaced. Academic studies show clearly that renewables will replace them close to 100% of the time. Large-scale grid integration and multiple forms of renewable generation eliminate most of the purported requirement for storage which critics like to assert is necessary.
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