This article, by Gareth Simkins, was published on the Energy page of the Spring/Summer issue of Transition Free Press. This regular page focuses on sustainable energy for the future, including local initiatives such as Poole Tidal Energy Partnership. Other subjects covered in the past include, big biomass, community hydro and energy saving.
Wind turbines, micro-hydro schemes and solar panels are not the only way for community groups to generate their own energy. One scheme in Dorset has rather different plans – to produce heat and power from Poole Harbour.
The 36 square kilometre bay acts like a “massive solar heater,” says John Gillingham, a carpenter and one of the leaders of the Poole Tidal Energy Partnership (PTEP).
As the name suggests, PTEP’s original plan was to build the UK’s first ever community-owned tidal power project. The community interest company emerged three years ago, as a collaboration between Transition Town Poole, Bournemouth University and the borough of Poole.
But the tidal power proposal has proved too ambitious, at least at present. The harbour’s average depth is only 48 centimetres and there would be many competing interests to satisfy.
“It’s not viable to put a fairly large turbine there,” Gillingham explains, though harnessing the power of the bay’s tides is still on the cards.
For the moment, PTEP is undertaking a more modest project: extracting heat from a pond to warm a café and art gallery at Upton Country Park, just to the north of the harbour. This is intended to be a proof-of-concept scheme, a public demonstration of heat pump technology prior to the bigger plan – using the bay itself as a heat source for council buildings and local businesses.
The tea rooms in the park are notoriously poorly heated and have even had to be shut in the winter because of the cold. They’re a listed building, so demolition or major refurbishment is not an option. To solve this, PTEP is installing an underfloor heating system, connected to a heat pump, fed by water flowing through pipes in the pond.
Heat pumps are an old and established heat-exchange technology, most commonly used to keep fridges and freezers cold. However, they are increasingly being used, effectively in reverse, as heaters. Unlike normal electric heaters, they can produce far more heat energy than the electricity they consume.
If all goes to plan, the system, entirely funded by the council, should be operational next winter.
The scheme could increase public use of the park and will certainly cut electricity bills, probably by some £5,000 a year. It will also educate the public, and save 20 tonnes of carbon dioxide being tipped into the atmosphere – all of which will help the council meet its objective of a 20% reduction in carbon emissions by 2020.
Gillingham said the advantages are clear: “It will save quite a lot of money, cut carbon… and the public can see a working system.”
He admits heat pumps have a downside; although they are a low carbon source of heat, “we could be accused of using dirty energy” from the grid to power them. “It’s not all sweetness and light. Sometimes you have to walk before you can run – but we’re not disheartened.”
Gareth Simkins is an environmental journalist who edits the Energy page of Transition Free Press. He is also a member of Croydon Transition Town.