June 6, 2019: The first heritage site in the UK to operate 100% off-grid, using lead-acid batteries to store electricity generated by hydro and solar technologies, has replaced the system with more lead batteries, the National Trust announced on June 5.
The original 48-volt battery bank, which was installed 14 years ago, was a Sonnenschein gel battery bank of 24 cells.
The new system, also 48 volts and 24 cells, is a VRLA gel cell system from BAE with 30% more energy density.
“The existing lead acid system has worked effectively for 14 years without issue,” said Chris White, technical consultant at Dulas, a renewable energy installer and consultancy.
“We chose lead acid because of its lower cost relative to lithium ion. It’s also simpler to connect lead acid to the existing battery charge controllers and battery inverters. There are some incompatibility problems with certain lithium ion batteries and charge controllers/inverters that we have experienced in the past.
“There is no space constraint on this site, and with the damp environment within the mill we considered lead batteries would be better. We also have greater field experience of using them relative to lithium ion.”
Work is due to be completed within a couple of weeks.
Gibson Mill is a visitor centre at the Hardcastle Crags beauty spot in Yorkshire, at the edge of Hebden Bridge.
Built in around 1800 as one of the first cotton mills in the industrial revolution era in Britain, after a century the building was converted to a place of entertainment, containing a dance hall, skating rink and refreshments.
It fell into disuse and was bought by the National Trust, a charity for environmental and heritage conservation in England, Wales and Northern Ireland, in 1950.
In 2005 Dulas was brought in to help make the site entirely energy sufficient.
This meant restoring the original Francis hydro turbine and installing a smaller Crossflow hydro turbine along with a solar photovoltaic system and battery system.