The 'green' watermill restoration that's powering 30 homes

Howsham Mill - love at first sight in 2003.
Howsham Mill - love at first sight in 2003.
Ten years ago, Mo and Dave fell in love, writes Helen Leavey - with a ruinous but romantic water mill in Yorkshire. It was the beginning of a fabulous restoration adventure, and the mill is now an exemplar of renewable energy generation and a thriving education centre.
Hydropower is a currently under-used resource in the UK - it is less visible and controversial than wind, and there is a lot of scope for small-scale developments.

A passion for drama is to be expected from a former theatre manager.

And Mo MacLeod, whose last theatrical job was for award-winning playwright Alan Ayckbourn, certainly seems to have thrived in her own real-life Yorkshire saga. 

Over the past decade she has faced vandals, thieves and financial crises to realise her and husband Dave Mann's green vision.

They've transformed a dilapidated Georgian watermill into an environmental education centre, generating hydro-electricity with a device likely to have been used in ancient Egypt, then improved by Greek scientist Archimedes more than 2,000 years ago.

You don't have to be unhinged to work here, but ...

The project incorporates an 'Archimedes screw' - one of the first to be installed in the UK used to generate electricity. It was an outlandish idea from the start, says Mo (see photo).

"I think anyone embarking on a project like this has to be slightly unhinged to start it in the first place. However, an unerring conviction that it would eventually be fabulous has always been the driving force, and you know how you get so far along the road, you just have to keep going."

Mo has raised grants and donations of more £1.2 million and encouraged 200 volunteers (including her own two children, now aged 15 and 12) to get their hands dirty with her restoring the Gothic-style Howsham Mill, near Malton, about nine miles from York.

The official opening was in December 2013. Electricity generated from the screw and waterwheel can power about 40 average houses if river conditions are right. Meanwhile electricity sales and the 'feed-in tariff' generate around £30,000 per year, which is ploughed back into the running of the mill.

A romantic ruin

In 2003 the family was living in Norway where Dave (see photo) was a seismologist for an oilfield services firm. When he was made redundant, he decided to pursue his interest in green issues and set up a renewable energy consultancy firm. Around the same time he spotted the ruins of the 1755 mill on an Ordnance Survey map.

Designed by renowned architect John Carr, who designed Fairfax House in York, the ornate building milled flour for the owners of Howsham Hall for almost 200 years before falling into disrepair, evolving through neglect and vandalism into a roofless ruin with plants growing luxuriantly out of its decaying walls.

But Mo and Dave saw the potential. Their application to live in the mill was turned down as it is in a conservation area, area of outstanding beauty and site of special scientific interest, but they decided to restore the building anyway.

The lengthy process involved setting up a charity, the Renewable Heritage Trust (which owns the mill), and roping in a small army of people. "For the first six years, the project was pretty much all about mud", says Mo, who met Dave when they were both university students in York.

Hydropower is a currently under-used resource in the UK - it is less visible and controversial than wind, and there is a lot of scope for small-scale developments.

"Our volunteers spent an inordinate amount of time digging the mill out of the built-up silt, removing vegetation and sorting fallen masonry - and all of this for no more than a cup of tea and a jacket potato off the bonfire. People really are wonderful."

Very clever man, that Archimedes ...

Looking for a solution to install a fish-friendly turbine, Dave finally found a suitable Archimedean screw system in Germany. The screw was originally designed to raise water from one level to another for irrigation and would have been powered by oxen or people thousands of years ago.

Some historians believe Archimedes improved the screw, around 250 BC, while others think he invented it. Nowadays, when used as a hydro turbine, river water flows down through the screw, rotating it and thus creating energy, which a generator converts into electricity.

Dave persuaded the Environment Agency to let the technology be tested at Howsham Mill, along with monitoring of the river's population of lampreys (a rare native species of parasitic fish) as part of the deal.

The basis of a whole new business

Howsham's was the first Archimedes screw to be installed for power generation in the UK, however it was pipped at the post when it come to generating electricity, says Mo.

"As it turned out, because of river conditions and funding issues, our installation at the River Dart Country Park in Ashburton, Devon turned out to be the first one actually hooked up and generating, but the precedent that allowed this equipment to be used at all in the UK was set by the Howsham Mill project."

Mo and Dave began specialising in the screw systems in 2005, importing them into the UK. Costing between £50,000 and £500,000, the firm has already installed 35, with more than 80 sites in various stages of the design process.

Clients include local councils, the National Trust, speculative investors, community groups and private individuals - all "with a green agenda and a river at the bottom of their garden", says Mo.

Floods and high waters

And was this year's wet winter good for electricity generation, if for little else? Unfortunately, it does not necessarily follow that the more rain there is, the more electricity there is.

The screw systems produce power by making use of the drop in a river, or 'head' - the greater the head, and the flow, the more power can be generated. However, in extreme flood conditions no power is generated as the available head disappears under the surging waters.

Research is under way, though, to make the system more efficient, and overall Mo believes much more should be done with water: "Hydropower is a currently under-used resource in the UK - it is less visible and controversial than wind, and there is a lot of scope for small-scale developments."

China is the leading producer of hydroelectricity, but very few countries actually use hydroelectricity as their major form of power. Norway leads the way in that, with water generating about 99% of the country's total power production.

Mo certainly thinks living in Norway affected her family's 'green' thinking. "The Norwegians are streets ahead of us in so many ways where power generation, building insulation and recycling are concerned."

Open to visitors

Norway might be too far away for many to visit to learn more about hydro-electricity, but Howsham Mill could be an option for UK readers. The restored mill is open on Sundays and for pre-arranged visits / events and is already paying its way.

Cash earned from electricity sales and the feed-in tariff will pay for a part-time education / events officer to continue working when the current grant money runs out.

The electricity sales also help to pay for courses at the mill and will hopefully support transport costs for schools wishing to visit. There are several activities offered which link into the National Curriculum and the Learning Outside of the Classroom initiative.

As for Mo and Dave, they are raising funds for the Trust to add a second Archimedes screw - which will increase both electricity generation, and income. But they have also begun a new project, recycling an old log cabin picked up on eBay.

Once a camping shop in Manchester, the cabin will become the family home - complete with rainwater harvesting, grey water recycling, a water-source heat pump and solar panels.

This environmental drama in rural Yorkshire is one that looks set to continue.



Helen Leavey is a freelance journalist. She is currently based in Yorkshire after living in China for several years. There she learned Mandarin, worked in communications in the non-profit sector, and further developed her social conscience. She has worked in print, radio and television, including a stint for the BBC in London and Taiwan. More information on Linked-in.

Find out more at Howsham Mill.