Sunday, 25 June 2017

Cute timber bench

We've done a number of posts on wood. Growing trees for wood, making things from wood, wood used in various ways, firewood and so on. I was at the University of Melbourne School of Design the other day to meet an Environmentally Sustainable Design (ESD) consultant who tutors at the Uni. While waiting by one of  the main entrances I noticed this cute bench made of small wood pieces:

We think this is great. It's playful, practical, attractive, made from a renewable, low carbon material, with small pieces of wood that could be offcuts from other timber processing and uses wood to make a sinuous curve as against a more common straight line. And it passed the PragSust comfort test ... at least for the short time I was sitting on it. The ESD consultant told me it was made as a student project. It's nice to see clever students making great stuff. Hope whoever it is has a great career making more delightful pieces.

Saturday, 24 June 2017

Battery storage for PragSust HQ

Previous PragSust posts have discussed what we've done about reducing the GHG emissions from stationary energy use at PragSust HQ. And I wrote a high-level guide to how to tackle stationary energy GHG emissions at various scales.

We've finally started work on installing storage at PragSust HQ.

The battery in the photo was bought 2nd hand from a demonstration installation as part of a commercial project I worked on looking at a wide-scale rollout of residential PV-storage. I did the financial and system performance modeling for this project. This battery is going in an off-grid system at the block but we will also be getting more PV and storage installed as a grid-connected system at PragSust HQ.

I'll put up some modeling to give an idea of what we might expect from this battery and a larger PV installation based on our electricity consumption interval data. We're also going to use a leading inverter - made right here in Melbourne - supporting advanced charge/discharge capability. The company manufacturing the inverter has been quietly making increasingly capable kit for the offgrid market for decades. More about the inverter capabilities in a later post.

There's a lot of nonsense in the noosphere about batteries and PV. Storage is near enough essential for cost-effective grids with high-penetration of intermittent renewables like wind and solar. But granular control of charge/discharge is critical for optimal performance. Simple battery systems may have a crude control system that first allocates energy from PV to site use, followed by battery supply to onsite consumption with little or no control over when this occurs. In these simple systems when the battery charges is also uncontrolled. I've done a lot of modeling for various sites to optimise the benefits from PV/storage systems. But achieving these benefits needs more sophisticated control.

We will look at making available online operational data available from the battery. I'm tired of reading uninformed, doom and gloomer, apocalypterati cant and I'm also tired of reading unrealistic, over-enthusiastic rubbish about various potential technological pathways. What matters is the facts; not selective, poorly researched polemics channeling various authorial or sectoral bias.