PHINZ’s annual conference has just finished in Wellington—it was a great weekend and a welcome opportunity to catch up with colleagues-friends.
The programme dived deeply into carbon emissions and how to slash them—embodied as well as operational emissions. Various presentations reinforced a series of important facts:
- Net zero targets/emission caps can’t be met without significantly reducing the total carbon associated with buildings.
- Residential heating is a significant contributor to winter energy demand.
- Electrifying everything means electricity demand will increase.
- Distributed PV generation is great but not a magic bullet: there are mismatches between generation and demand at a household and national level.
- In southern regions, more household PV generation will make the winter energy peak worse.
- There is no such thing as an emissions-free electrical grid.
I took up this last point with Lloyd Alter during a break. There are significant CO2 emissions related to operation of the electricity grid that do not evaporate even if New Zealand achieved 100% renewable energy generation. I discussed this in a post back in 2020.Graphs from two presentations highlight a way to help address the winter energy peak threatening New Zealand’s energy supply. Here’s Joe Lyth’s graph showing energy use in the draughty villa where his family of five used to live vs their use in their certified Passive House (details of Lower Saddle House here). Of interest of course is the difference between the two but I was struck by how little variance there is between summer and winter in their Passive House. No winter peak here. Just a tiny, short-lived blip.
It was the same picture in Tim Ross’ comparison between his former and current family home (Toiora co-housing project): far less energy overall now and a very shallow curve across the year.
I was pleased Michael Jack from the University of Otago was at the conference, his research into the dry winter/winter peak problem is really important.
If the gap between summer and winter demand was significantly reduced, New Zealand stands to save many billions of dollars on energy generation infrastructure that would otherwise be required. Don’t forget large-scale generation doesn’t just cost dollars: there will be massive embodied CO2 emissions from concrete dams and flooded forest will give off methane for decades as the wood decays.
You can look forward to lots more from us about the conference in future newsletters, including the details of the research several Sustainable Engineering folk presented this weekend.
Huge thanks to the volunteer board members of PHINZ and its very capable general manager who made this event happen.