Green eyes: Hastings surgery yet to spend a dollar on power this year

A Hawke's Bay eye clinic is yet to spend a dollar on power this year, and has halved the amount of waste it generates per patient.

The Eye Surgery in Hastings has a roof filled with solar panels, and produces its own supply of hypochlorous acid as a gentle but effective disinfectant - and those are just a couple of the ways it is caring for the planet.

Run by Dr Sophie and Dr Alex Buller, ex-pats from the UK, the surgery sees more than 200 patients and performs about 24 cataract surgeries each week.

They moved into their current site in 2018, and installed the solar panels - a 45-kilowatt system made up of more than 120 panels - a few years later.

Then, following Cyclone Gabrielle in 2023 February, they added a series of large batteries to make sure they could function for days without pulling from the grid, and without sunshine.

Alex Buller said over the summer they produced so much power they sold it back to the grid, and had not paid a cent in power bills so far this year.

Even better, the solar panels provided 150 percent of the power they used to take from the grid, which had created opportunities to do things differently.

It would normally cost hundreds on the power bill to be repeatedly sterilising tools and equipment, rather than just opting for single-use alternatives - but with the solar panels producing more than they needed anyway, it suddenly meant more frequent sterilising was an option at no added cost.

"We [also] switched over from bottled air for cleaning the instruments," Alex Buller said. "We use an oxygen machine which makes oxygen in the operating theatre from the air in the operating theatre, rather than bringing bottles of oxygen."

They produced less than 700 grams per cataract surgery - compared to normal at 1.3kg - and had reduced their total waste output from 10 kilograms per 100 outpatients, to 1kg.

Meanwhile, a new cleaning method had reduced the need for harsh chemicals and single-use cloths.

Hypochlorous acid - made on-site using a small wall-mounted machine using just salt, water and electricity - is increasingly being used as a disinfectant in medical settings around the world.

They currently produced about five litres a day to clean their 500-square-metre building, wiping down chairs, chin rests, floors, and the operating theatre.

According to Sophie Buller, it was gaining popularity particularly in the beauty industry, because it was gentle on skin while still being antibacterial.

While it was an affective disinfectant, it was not suitable for high-level sterilization - that still required an autoclave.

RNZ asked if the introduction of greener practices had been a draw card for patients.

It seemed patients did not mind either way, Sophie and Alex Buller said, as long as they received the care they needed.

"Quality [of treatment] is the number one thing that people want," said Alex Buller. "If you can give them something else as well, then it's very helpful."

In order to help others take the steps they had taken towards greener healthcare, Sophie Buller said they had compiled a how-to document, of sorts, which would be available on their website.