Welsh science discovery centre Techniquest is building a £5.7m (US$7.4m, €6.6m) expansion that will more than double its exhibition space and use a remarkable power source – fish.

Techniquest’s new building, called Science Capital, sits on Cardiff Bay in the Welsh capital and the centre has consulted a number of STEM, energy and marine biology specialists across Wales for the Scale-ectric power project.

Bream, carp and rudd in the bay will be penned into a smaller area near the building for up to an hour a day. There, motion sensitive wires will capture their energy and transfer it back to Techniquest for use as power.

The Science Capital building will add around 60 per cent more exhibition space to Techniquest as well as housing a new community space, café, shop, roof terrace and courtyard.

"At Techniquest we have a proud tradition of introducing innovative new STEM-based education and ideas across Wales, and we feel that project Scale-ectric is absolutely in keeping with this," said Techniquest CEO Lesley Kirkpatrick.

"This ground-breaking initiative is in keeping with our ongoing mission to become more sustainable and promote greater sustainability across Wales, so we are delighted to officially announce it.

"Thanks to the support from some of Wales’s leading experts in both the energy and marine biology fields, we will be able to generate up to 30 per cent more energy for our expanded new building project in a clean and environmentally friendly manner.

"We will also be launching an exhibit in the new space to explore our new energy efficient concept, how it was created and its wide-ranging benefits.

"We hope that this will not just be interesting but educational for thousands of people who visit us from across Wales each year."