The National Trust has installed a pico hydro turbine at one of its properties in Wales to control humidity levels in the house and protect its collection, including one of only 24 known copies of the first bible translated into the Welsh language.
Hydroelectric power is a renewable energy source that converts energy from flowing water into electricity. At Tŷ Mawr Wybrnant, a 16th-century farmhouse near Betws-y-Coed in Snowdonia, the pico hydro will borrow water from a nearby stream to generate up to 5kW of electricity, which will be used to control humidity levels in the house.  
It is estimated that the project, which is a first for the National Trust, will reduce the property’s greenhouse gas emissions by 5.2 tons of CO2 per year.
Tŷ Mawr Wybrnant was the birthplace of Bishop William Morgan, whose translation of the bible into Welsh, published in 1588, is considered a major step in ensuring the survival of the language today.
The rare bible on display in the house, along with more than 200 other bibles in different languages, are susceptible to moisture in the air. Increasingly heavy and persistent rainfall, flooding and damp have put the collection at risk.
“Earlier this year we experienced the worst flood at Tŷ Mawr Wybrnant in living memory and that extra moisture meant we needed to use more heating to ensure the humidity levels didn’t get too high,” says Keith Jones, the National Trust’s climate change adviser.
According to Jones, climate predictions indicate the severity and frequency of rainfall in the area is likely to rise as a result of the climate crisis.
“The hydro will only borrow a certain percentage of the water from the stream once the water levels reach a certain point,” Jones says. “This means we are generating the electricity when we most need it, when there’s more moisture in the air after rainfall.
“The energy is consumed directly onsite, solely for the conservation of this priceless bible collection. We must reduce our impact on the climate, but we can harness the tools nature gives us to adapt to the challenges we are facing.”
The trust will now explore if this sort of renewable energy could be used elsewhere across its properties.
Tim Pye, the National Trust’s libraries curator, says: “Extreme weather is one of the threats to our collections, with sensitive and fragile objects like books, manuscripts and other documents especially susceptible to conditions such as damp.
“The energy-efficient and sustainable pico hydro solution for Tŷ Mawr Wybrnant will help greatly in its efforts to safeguard the bible collection for today’s and future generations to enjoy.”