Why solar reduces emissions, despite variability

The emissions impact of cycling – ramping up and down – power generation facilities don't outweigh the benefits of intermittent solar on the grid.

As a researcher, I’d like to come right out and thank the coal industry for creating a never-ending stream of research opportunities.

You’re awesome.

Like a constant conveyor belt of coal, they seem to be able to roll out a never-ending stream of myths and challenges that the renewables industry is compelled to respond to. Do they have a point? Could they be right? Do we need to reconsider our deployment strategies to genuinely deliver clean energy?

In the last few years as solar penetration and capacity has risen significantly and traditional models have been deeply challenged, the myths have come thick and fast – but the solar industry has real installations, new studies, fresh data and an intense hunger to get it right. The US National Renewable Energy Laboratory,  in particular, has been conducting some awesome research and today marks the end of another myth, thanks to their latest work.

The myth that is often rolled out is that 'Because renewables are intermittent as coal-fired generators ramp up and down, emissions do NOT decrease'. 

We have heard this from the anti wind lobby and even some of our esteemed leaders in government.

NREL recently concluded the second phase of a research study to determine the wear-and-tear costs and emissions impacts of cycling and to simulate grid operations to investigate the detailed impacts of wind and solar power on the fossil-fueled fleet in the western states of the US. Although it is US-based, the majority of findings can be directly translated to Australia due to the similarity in our coal generation facilities and emissions intensity. This is in addition to local studies conducted a few year ago specifically on GHG abatement from wind farms in Victoria.

Graph for Why solar reduces emissions, despite variability

In a nutshell, the NREL study busts the myth in two ways.

Firstly, the report highlights that cycling existing plants is not a new phenomenon. 

“Grid operators have always cycled power plants to accommodate fluctuations in electricity demand as well as abrupt outages at conventional power plants. Increased cycling to accommodate high levels of wind and solar generation increases operating costs by 2 per cent to 5 per cent for the average fossil-fueled plant. However, our simulations show that from a system perspective, avoided fuel costs are far greater than the increased cycling costs for fossil-fueled plants.” – Debra Lew, PhD.

Secondly, the report acknowledges that some inefficiencies are introduced, but dispels the myth that they cancel out any benefits at all. 

“The negative impact of cycling on overall plant emissions is relatively small . The increase in plant emissions from cycling to accommodate variable renewables are more than offset by the overall reduction in CO2, NOx, and SO2 . In the high wind and solar scenario (33 per cent penetration), net carbon emissions were reduced by one-third.”


Nigel Morris is the director of SolarBusinessServices.

InvestSMART FORUM: Come and meet the team

We're loading up the van and going on tour from April to June, with events on the NSW central & north coast, the QLD mid-north coast and in Perth, Adelaide, Melbourne, Sydney and Canberra. Come and meet the team and take home simple strategies that you can use to build an investment portfolio to weather any storm. Book your spot here.

Want access to our latest research and new buy ideas?

Start a free 15 day trial and gain access to our research, recommendations and market-beating model portfolios.

Sign up for free

Related Articles