Pilgrims have been flocking to this Suffolk town
for more than a thousand years.
Today, it's not the Shrine of St Edmund I'm seeking out,
but a modern engineering marvel that's growing fruit
and veg on the heat emitted from waste.
My journey into this fresh food innovation
begins at a less than palatable source
just outside town, a plant treating wastewater and sewage.
So David, can you give me an idea of what
is actually going on here and kind
of how much waste you are treating
every day or every second?
Yeah, we're treating around about, well, up to 475 litres
per second on this actual site.
The movement and microbial action
that takes the solid dirty stuff out, heats the water up
to as much as 20 degrees celsius.
It's a natural part of the treatment process
and that would be wasted.
Here, that's heat, which would otherwise go to waste,
is extracted.
This is the heat exchanger building.
It's really the end of the process for us on the site.
The exchanger takes the heat out of the processed wastewater,
which is now clean and cool enough to go back
into surrounding waterways.
The heat left behind is transferred
into a separate sterile circuit pipe that
runs for almost 2 and 1/2 kilometres
under fields to this sprawling oasis, a greenhouse some 1.25
kilometres square.
Wow.
It's only when you get a bit higher that you really
appreciate the scale of this place.
This is the single biggest greenhouse unit in the UK
and is capable of producing 22 million peppers per year.
That's a hell of a lot.
It's one of two greenhouses built
to use heat emissions from adjacent sewage plants
to grow peppers, cucumbers, and tomatoes.
This one just outside Bury in Suffolk,
the other just over the county border in Norfolk.
Behind each greenhouse is an array
of pumps, which pushes that heat into the structures
all year round.
As the developers senior manager Ben Alexander explains,
93 per cent to 95 per cent of the heat needed
to maintain growth comes from the wastewater plants.
That reduces the overall carbon footprint
by an estimated 75 per cent compared
to a standard heated greenhouse.
We're taking heat from a heat pump
rather than burning fossil fuels.
And that heat, we're able to put around the greenhouse in order
to help us grow food and create the absolute perfect conditions
for growing fruit and veg.
The heating elements have been cleverly built into the rails
that run along seemingly endless rows of vibrantly coloured
peppers.
Can I try it?
You can try it now if you want to try.
Mm, it's good.
It's very sweet.
I think it's really nice straight off the plant...
Yeah.
...which is another advantage of growing in England.
Brian Hibberd is the long standing managing director
of Abbey View Produce, which has a 20 year lease
to grow crops here.
He says the peppers grown in this single greenhouse
alone could replace around five per cent of imports.
We've been supplying supermarkets for many years.
And this project is replacing what
probably would have been Dutch produce coming
into England and at the beginning and end of the season
some Spanish product.
So it gives a healthier product, a lot less food moulds,
and it's the way I've always wanted to go.
Just months into the first growing season,
the 300,000 plants in this single greenhouse
are bearing fruit.
Earnings are also growing for the investor.
Hi, James.
Afternoon.
My name's Persis.
Nice to meet you.
Greencoat Capital provided the £120m needed to build the two
greenhouses.
Earning rent, heating charges, and a vital government bonus
in return.
For each megawatt hour of heat that we sell them,
we claim a thing called the renewable heat
incentive, which is a government subsidy for renewable heating.
In this case, it provides more than half
of the revenue returns.
And Greencoat Capital says its greenhouses would not
be viable without it.
But that subsidy is due to close to new projects from March 2022
and similar incentives may well be
needed for other innovative carbon-saving designs,
like these, to take root and flourish.