The venue, a park below Mauao in Mount Maunganui, proved a magnet for families looking for somewhere to gather on Friday night, and hot food stalls proved popular.
With fellow zero waste zealot Sam Grey she looked for packaging that could be composted, and then found someone to compost it.
That wasn't an easy task, because past attempts had resulted in a high level of unrecyclable rubbish.
"The solution we agreed was the rubbish would be picked up on Friday night, and on Monday morning we would go through it by hand at the compost plant and pull out any contaminants.
"As an event manager it opened my eyes and helped me understand the challenge.
"In the beginning we would say 'let those guys use tinfoil, it helps their product,' but when I found I was pulling a whole pile of tinfoil out of the compost, I said they can find something else to use.
"In the end we created a really good waste stream so 100 per cent of what was used had to be compostable or recyclable, it can't go to landfill."
There's still some waste that must be removed, but Renshaw says it's what people bring from home - glad wrap, disposable nappies.
"People do come and bring their own food, you can never get rid of that and I don't mind, but it's always a really small amount," she says.
For the second season Renshaw and Grey documented the suitable packaging options, compared prices and held a workshop for vendors.
"All of them got on board once they could see the benefits. A lot of them changed products."
Many had tried to do what they thought was right, but had to be told that, for example, biodegradable plastic wasn't suitable because there was no suitable recycling facility in the region.
The tough rules haven't scared off vendors. Renshaw opened applications for this summer's market this month, and within days had more than 80 applications for the 45 sites.
"What is really cool is other events locally caught on, and people came to me saying 'We want to do what you are doing, how do we do it?'"
WOMAD over in New Plymouth also heard, and contracted the pair to rejuvenate their waste minimisation approach.
"We talked to vendors, changed the products, and then put together a big team of volunteers to hand sort, and we sent almost six tonnes to compost," she says.
Back in Tauranga a speaking engagement brought an invitation from the Toi Toi Manawa Trust to apply for a social enterprise grant.
"I said the Gourmet Market didn't need grants but it could be an opportunity to share the message wider with other events," Renshaw says.
A proposal for Beyond the Bin scored a $20,000 grant, which has been used to develop a business running workshops for market vendors and event organisers and offering consultancy for large events.
"It's not a traditional commercial model. I see it as a social project more than a social enterprise.
"We will train a bunch of event managers and once they are all trained and self-sufficient we won't need to keep training."
The idea caught the attention of Tauranga City Council, which set up a waste minimisation event fund which buys workshop places so event managers can learn from the experience of Renshaw and her team.
Renshaw says the expectation events and festivals will strive towards zero waste is growing.
"Sustainability doesn't sell tickets but it is a feel good, so if we get to the stage where festivals think they have got to be the best at this, it's a win-win for everyone."
She expects that within five years compostable packaging will be the norm. "All the vendors will know how to do it and the economies of scale means it will be the same price as the other stuff."
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