Developing a micro-hydrogeneration plant to supply carbon dioxide-free electricity at their stone processing yard has given Forest of Dean Stone Firms the greenest stone in the country.
Nick Horton likes lying in bed listening to thunder storms. “I think: Yes! I’m making money.” He’s making money because the more rain there is the more electricity he can produce on the Ossberger water-powered generator he has installed at Forest of Dean Stone Firms, where he is Managing Director.
He officially switched on his micro-generation plant in January. In the first month he had generated 4,500kW, most of which the government pay him 22.9p per kilowatt for, which is the feed-in rate of 19.9p per kilowatt for generating it plus another 3p per kilowatt for putting it on to the National Grid.
And that is just part of the equation. Because he is generating most of the electricity he needs in the stone company’s well-equipped processing yard he saves himself the expense of buying in the same amount from his electricity supplier at nearly 10p per kilowatt on the fixed-price contract he has with N-Power. Stone Firms believe their electricity bill from N-Power will fall from £18,000 last year to about £2,000 this year. They retain two hefty diesel generators to get their big primary saws working and to take over when the National Grid goes down, as it does now and again.
Going into electricity generation has required Stone Firms to jump through more hoops than they expected, has taken a year longer to achieve than planned and has gone 50% over the original budget of £80,000. And it’s still worth it.
It is not just the cash benefit that makes it worthwhile, either. Stone Firms’ public relations agency, Pentacom, have made the most of the publicity opportunity going into micro-generation has offered – not least of which is that it gives FoD Stone Firms’ Forest Pennant the lowest carbon footprint of any stone in the world… probably.
Stone Firms and the Forest Pennant sandstone they produce have been featured on Gloucester Radio and BBC SouthWest television, as well as in local newspapers and business-to-business magazines. At the end of last year they won The Forester newspaper Business of the Year Award. They have also won a Sustain magazine energy award and at the Natural Stone Show in March won the Stone Federation’s inaugural Sustainability Award for Innovation.
There were some particular circumstances that have led to the hydrogeneration project. One is Cannop Ponds, which owe their existence to the Forest of Dean’s historic iron industry. The ponds were created in 1753 to drive a water wheel used in the steel works that once occupied the site. The mill race still existed next to FoD Stone Firm’s processing yard.
The development might still not have come about if Nick Horton had not lived in a mill in the Mendips. He explored the possibility of generating electricity at his home. That proved not to be feasible, but the exploratory work provided him with a lot of information he was able to use for the Stone Firms project.
Some of the hoops they had to jump through to bring the project to fruition were, at least to some extent, simply because there were no similar projects to set a precedent about how to go about it.
There was some seemingly unnecessary toing and froing over planning permission and licences. The company had to carry out all the necessary site surveys and get planning permission, then had to consult with various departments of the Environment Agency (fisheries, biodiversity, development control), none of which seemed to communicate with each other, in order to get Abstraction and Empowerment licences to use the water.
The Environment Agency required an eel ladder to be constructed because eels are being decimated by a Japanese virus and need protecting. Adding an eel ladder that would remain wet all year meant diverting 20% of the water flow away from the generator. That required alterations to the proposals, which meant going back to the planning authority to change the consented plans.
“At first I said I wouldn’t do it. So they said I couldn’t use the water then. So I had to comply, but it took another 12 months,” says Nick. He even spoke to Oliver Letwin, the West Dorset MP who is the Minister in the Cabinet Office responsible for co-ordinating government policy. “He seemed to agree but I don’t know if he’s going to do anything about it.”
Stone Firms needed Environment Agency approval to obtain an Abstraction Licence to use the water, even though they don’t extract it but simply direct it through the generator and out the other side – none is lost. And they had to have an Empowerment Licence that allows them to contain the water.
The process of getting all the required approvals began in 2006. It was June 2010 before everything was in place to begin the civil engineering required to create a new opening from Cannop Ponds to take the water through a sluice to the generator. Stone from Stone Firms’ Barnhill quarry was used. Even if they could have obtained permission to use concrete they didn’t want to because stone would look nicer, especially as the generator is near a Site of Special Scientific Interest (SSSI).
“Also,” says Nick, “part of the reason for doing this was to establish our credentials for being green. We wanted the project to look green, and lots of concrete doesn’t.”
Ideally, Stone Firms would have liked to have sited the turbine shed further down the fall in order to increase the head of water, but an oak tree was in the way and part of the planning consent required the retention of the tree. Also, the further downstream the turbine was sited the nearer it was to the SSSI.
Stone Firms had to sacrifice 1.45m head of water – and there is a straight line correlation between the head and the amount of electricity generated – although they believe the 7.8m they have will enable them to produce electricity at least 95% of the time most years.
The civils took six months. Then, when everything was ready for the turbine to be installed, the Department of Energy & Climate Change said the turbine had to be supplied and installed by an accredited company under the Microgeneration Certification Scheme, which more commonly relates to photovoltaic (PV) cells.
Ossberger, the Germans supplying the turbine, are not certified, so Stone Firms applied for certification themselves, which requires them to join the Renewable Energy Assurance (REA) scheme – more paperwork, a fee of £170 and nobody at REA who seemed to understand what hydrogeneration was about.
Just as Stone Firms felt they were getting somewhere, Nick Horton called the person he had been dealing with only to find they had gone and he had to try to get someone else to understand they were not dealing with PV cells.
The one other main requirement of electricity generation is that you can stop generating in less than a second if you need to in an emergency. It is called a G83/1 safety system.
Making the move into environmentally friendly electricity generation has not been the easiest investment Stone Firms have ever made, but there are not many other investments that would be giving them the 14% return they are expecting each year from micro-hydro electricity generation.