Wind and solar power are variable sources of energy that require storage and transmission capacity. But the benefits outweigh the disadvantages.
RENEWABLE ENERGY: The wind doesn’t blow on demand. Sunshine isn’t constant. Unlike fossil fuels, we can’t regulate wind and solar energy production, so future power systems need be able to handle their variability. At the same time, these power systems need to be as climate and environmentally friendly as possible. So what happens to emissions when the use of renewable energy grows in Europe?
A new study looks at scenarios for how different types of power plants, transmission networks and other components can be combined into integrated power systems. A life cycle analysis for each scenario allowed us to calculate the total emissions.
These analyses take into account emissions from the entire life cycle (production, construction, use and disposal) of the components, and related value chains (such as the recovery of materials). By fitting together all the pieces and taking into consideration the variations in energy output from wind and solar power, we get a life cycle perspective on the emissions from entire power systems.
Previous analyses have been incomplete
Researchers – including the UN’s Panel on Climate Change – frequently use life cycle analyses to compare the emissions impacts of alternative ways of generating electricity. However, the results do not address how power systems will handle highly variable electricity production.
As a society, we can address the variability problem in a number of ways. Among the options are extensions and improvements to the power grid to increase geographic distribution, combining wind and solar power to even out fluctuations in production, investing in energy storage such as batteries or pumped hydro, and investing in overcapacity from flexible gas power that is ready for use when needed.
Or, as is usually the case in the real world, we can combine multiple strategies. A realistic analysis must capture the interaction between the technologies that constitute the power systems, as well as variations over time and from place to place.
Emissions don’t undermine gains
The study combines two computer models to create integrated scenarios. Applying assumptions about future technological developments, one model simulates the operation of power systems in 2050, while another type of data model analyses the life cycles of differing technologies.
This study is the first life cycle analysis of entire power systems that considers both the increased need for energy storage and transmission, as well as greater losses in scenarios assuming high levels of variable renewable electricity.
Findings provide great benefits
The study shows that a shift to renewable energy would have big climate and other emission-reducing benefits. Although extensive use of variable power leads to somewhat greater losses and storage and transmission capacity needs, the resulting emissions do not significantly compromise the gains when renewable energy replaces fossil fuels. Solar power causes more emissions impacts than wind power.
The findings may help to allay concerns that variable wind and solar power would result in substantial unanticipated emissions. Furthermore, even with a considerable increase in renewable capacity, getting rid of fossil fuels entirely is a difficult proposition. This could be problematic if reaching the 1.5-degree target from the Paris climate agreement requires adjusting the electricity supply, because in that case, any net emissions from electricity significantly greater than zero would be unacceptable.
Sources: This study is based on the MSc thesis of Peter Berrill, who is first author of the study. The work is related to and has received support from the Centre for Sustainable Energy Studies (CenSES), which is one of Norway’s Centres for Environment-friendly Energy Research (FME). Click on this link to download the study.
This post was first published in Norwegian in Aftenposten Viten on 24 May 2016.