Renewable energy at Hardcastle Crags

Lit bulb in front of inverter technology

Gibson Mill at Hardcastle Crags is completely off the grid; this means that we have no mains power, water or sewage connections. Find out how we manage our renewable energy and our plans for future green technologies.

Gibson Mill, which is at the heart of Hardcastle Crags, was one of the UK’s first mills to power the Industrial Revolution. The mill was built around 1800 and driven by a water wheel to produce cotton cloth.

Fast forward 200 years and it now stands as the first renewable place looked after by the National Trust that’s completely off the grid. 

The start of something special

The restoration of Gibson Mill began in 2005. Due to its remote location the development needed to make use of the best available resources. Our vision was to create a fully sustainable off the grid building that would offer a cafe and visitor centre.

A renewable energy system was installed by leading renewable energy company - Dulas LTD. Their work included the restoration and reinstatement of the cotton mill’s original 1926 Francis hydro turbine, the installation of a smaller Crossflow hydro turbine, a solar photovoltaic system, and a battery storage system.

Energy is harnessed from the river
River flowing into a grate
Energy is harnessed from the river

The mill’s roof-mounted solar panels and the water turbines, which harness energy from the river, provide almost all of the power for the mill and the café. A boiler that uses sustainably-sourced logs from the surrounding woodland heats spring water for the café. Food waste is composted on site and resident tiger worms are used to compost waste from the toilets.

This system allows us to operate without a connection to the outside world for energy, water and waste.

The challenges

With no connection to the National Grid, energy is stored in batteries for when it's needed most. These are the nerve centre of the renewable energy system.

Just like household rechargeable batteries, they lose their ability to store as much power over time, and at times there’s been insufficient power to fully run the café.

At times we were unable to serve hot drinks in winter or ice-creams in summer. For a site enjoyed by thousands of visitors every year this was a problem.

Working with BMW i to improve technology

Like us, BMW i are inspired by the power of nature, and are championing sustainable innovation with their range of electrified cars. Through our partnership they are helping the Trust make our places more sustainable, and their funding has enabled vital improvements to the energy system at Hardcastle Crags.

The modernisation work, carried out by the original installers, included the replacement of the original battery storage system. This new battery bank gives us 30% more storage capacity. The three inverters were also replaced and reconfigured.

With thanks to BMW i, we can now make sure that we’re able to offer the full café menu on cloudy days or days when river levels are low. It also means that we can run more events and ensure stability for the future.

The batteries store all the renewable power generated by the solar panels and water turbines
Close up of batteries
The batteries store all the renewable power generated by the solar panels and water turbines

The future of renewable energy at Hardcastle Crags

Our partnership with BMW i has also supported the installation of electric vehicle charging points at many of the places the Trust looks after, and we’ll soon be installing one in Midgehole car park

Due to its location, the charging point will be connected to the grid but will use energy from a renewable source.    

Our longer term plans include replacement of the solar photovoltaic panels on the mill’s roof.

By harnessing the power of nature and being careful with our energy use, we can keep Hardcastle Crags special forever.

With thanks to the new batteries we can now serve ice creams whatever the weather
Young boy enjoying an ice cream with parents
With thanks to the new batteries we can now serve ice creams whatever the weather