Solar set-up helps dodge diesel costs

Being off-grid usually means relying on diesel generators to power your farm business and home. But for Tony Davies, who runs a 680ha sheep farm in the Elan Valley, Powys, renewable energy has offered a reliable solution to his power needs.

And as the first farmer in the country to claim the Feed-in Tariffs (FiTs) against an off-grid system, he has made a it a cost-effective decision too.

Driven by rising diesel prices, Mr Davies started looking at alternative energy systems which could be utilised on his remote hill farm.

“I calculated that with current fuel prices, for an average small-scale farm it costs between 80p and £1/kWh to generate electricity with diesel,” he says.

“I thought there must be something more economical that allowed us to meet the farm’s and the family’s energy requirements without having diesel generators running all the time to supply us.”

Having decided against turbine systems because of maintenance issues, Mr Davies initially invested in a 1.7kW photovoltaic system in 2005.

He then upgraded the system last year so he could produce and store more energy to run his busy farmhouse, investing £17,000 to install a 3.8kW PV system on a single-axis tracker.

The upgrade also included investment in a bank of top-end, 800 Amp/hr, 48V batteries to store surplus electricity, allowing the farm to be self-sufficient on electricity for up to three days.


  •  3.8kW PV (BP190W panels) array on a Lorentz single-axis tracker
  • Sunny Boy 4000TL PV converter
  • Six 800 Amp/hr, 48V Canadian Rolls batteries with a 10-year warranty

“The majority of PV power is generated between 10am and 2pm and we tend to need the most electricity in the morning and late afternoon, so having a good storage system in place was important,” says Mr Davies.

“You can struggle with batteries as they don’t tend to last for more than five years and they are expensive. I decided to import Rolls batteries from Canada as they come with a 10-year guarantee and a life expectancy of 15 years. They were a big outlay, but hopefully they will be cheaper in the long term.”

As well as providing the energy the farm needs, Mr Davies has also been able to take advantage of Feed-in-Tariffs, despite not actually feeding energy to the National Grid.

“I was told I was the first person in the country to claim FiTs on an off-grid system,” he says. “The assumption is you can only claim if you are feeding the grid, but the big seven electricity supply companies have to accept off-grid installations.

“I went to Ecotricity and even though I am not supplying them, they are subsidising my system. It can be hard to make sense of it, but my system’s achieving the FiTs objectives as I am reducing CO2 emissions by not using diesel.”

To be able to claim FiTs, however, Mr Davies had to install a meter system accredited by the Microgeneration Certification Scheme (MSC). That created a problem as the only MCS-accredited meters monitor alternating current, while PV panels generate direct current.

“Batteries only store DC electricity, so to claim FiTs the PV energy has to go through an inverter to change it to AC just to meter it, then through another inverter/battery charger to charge the batteries,” he says.

It’s a conversion that means Mr Davies loses about 10-15% of the energy generated, but he still generates enough energy and receives enough from the FiTs to make it cost-effective.

“With the reductions in the FiTs it is doubtful that claiming it on an off-grid system would now be worth it,” he admits. “We receive 43p/kWh, but someone putting in a new system after 1 August will get just 14p.

“The PV systems have got cheaper to install, but those reductions are from cheaper panels, not inverters. We spent £1,400 on the extra inverter and that’s what raises the price for claiming FiTs.”

But for Mr Davies, as well as producing 80% of the farm’s electricity so far, the saving on using diesel and FiTs means he will get a payback from the investment in four to five years.

And he doesn’t want to stop there. Mr Davies is also investigating other renewable energy routes which he hopes will allow him and other upland farmers to develop alternative income streams.

He has secured a grant from Glasu – a rural development initiative that offers financial support via European Union and Welsh Government funding to businesses in Powys – to run a study on using a native grass as fuel.

Molinia caerulea, also known as purple moor grass, dominates about 10% of Britain’s uplands and covers about 300ha of Mr Davies’ farm. Samples from trial sites will be harvested at four points during the year at various stages of growth and tested for moisture content, ash volume and calorific value.

Purple moor grass

The grass with the highest calorific value and lowest ash volume will be made into briquettes and pellets which will then be tested in boilers and log burners and open fires.

“There’s a lot of this grass in mid-Wales and it’s considered a weed,” Mr Davies says. “The National Parks want to get rid of it because its a fire risk and palatability is poor for sheep, so finding a use for it as a fuel makes sense.”

As part of the funding, Mr Davies visited Green Flame in the Republic of Ireland, a farmer co-operative which has set up its own contract growing enterprise and a briquetting plant to process the grass.

He also plans to visit Smart Tech, a Northern Ireland company which operates and sells mobile briquetting machines which can travel from farm to farm processing grass into fuel.

“I would be interested in setting up a similar co-operative here in Wales to take advantage of the grass we have,” he says. “It makes sense to make use of an input we have in such good supplies.”