Building a cleaner energy future brick by brick

A 200-year-old British brickmaking business might not be the first place that comes to mind when thinking about the low carbon revolution. But Ibstock Brick’s Leicestershire headquarters is now drawing power from a new 4.9MW solar farm, thanks to its partnership with Lightsource bp 

It’s all part of Ibstock’s broader ‘sustainability roadmap’, says Ibstock’s land resources manager, Tony Fullagar. “Essentially, we decided a few years ago to stop talking and start doing something about our carbon footprint as we expand. We don’t want to put in factories that our children will later regret.”

Financed, built and operated by Lightsource bp (LSbp), the solar farm is ‘hard-wired’ into Ibstock’s private electricity network. With four manufacturing facilities at Ibstock – three brick and one concrete factory – the solar farm will supply up to 30% of the site’s electrical power needs at a fixed price through a 25-year power purchase agreement (see below for details). Any surplus energy is sold into the grid. 

Building a solar farm at a brick factory is no mean feat, given the kilns must typically be run 24 hours a day to avoid damage. “When construction took place, we were in the middle of a housing boom, which meant huge demand for our bricks,” says Tony. “We couldn’t afford to stop the factory, even for two minutes.” 

This posed something of a challenge for construction director Apostolos Kotsaris: “Because this is a direct connection into the factory, we had to manage that process in phases to avoid disrupting Ibstock’s core activities.” 

The solar technology revolution – bifacial panels

LSbp technical director Chris Buckland likens the solar industry to the early days of mobile phones, such is the pace of technological development.

To keep up, LSbp works about three years ahead, scanning for the next big breakthrough. When it spots an interesting opportunity, the company incorporates it within an existing site. “We always do it this way.” says Chris, “We run the new technology in the field for at least a year in order to get viable results. That’s how we innovate.”

That’s exactly what happened back in 2017, when LSbp heard about a new type of solar panel, capable of harvesting light on both sides, known as bifacial panels. 

Traditional panels are equipped with high-transmission glass, a series of silicon solar cells and a white backing to reflect any light that makes it past the cells. Bifacials work in exactly the same way, only the reflective sheet is replaced with glass, leaving the rear side open to capture any sunlight that hits the back directly. 

“We first installed some research panels at one of our sites in Northern Ireland,” Chris explains. “We did a lot of experimental work with them and discovered that by raising them higher off the ground and tilting them at 25 degrees, rather than the standard 20 degrees, we could harvest more sunlight via the back.” 

Indeed, the efficiency of energy transfer in a bifacial can be increased by as much as 14%, meaning more energy from the same amount of space.

Ibstock’s solar farm was the first full LSbp site to be fitted with the bifacials and the team is so pleased with their performance that they are now using them as standard in many of its projects. 

“Solar panels become less efficient if they get too hot, which isn’t ideal for countries nearer the equator,” says Chris. “What that means is that a UK site fitted with bifacials will outperform a site in Spain by about 5%.” 

The panels also have had an unexpected benefit in US states that experience heavy snowfall. The glass in solar panels is a poor insulator, so the additional heat melts the snow, allowing winter sunlight through. This is in addition to capturing energy from the underside of the panel from light reflected off the snowfall on the ground. “Normally, we’d budget for zero generation between about November and February,” says Chris, “but, with bifacials, we can harvest around 10% more sunlight.”

What’s a power purchase agreement? 

At its heart, says Zosia, a PPA is a guarantee that a business will buy power from LSbp for a fixed period of time. They are multi-decade, complex documents covering everything from price, renewable purchase guarantees and agreement on how the two sides will work together over the life of the contract. 

Understandably, negotiations take time. “It’s a huge decision for a business,” Zosia explains. “And the commercials behind them are quite complicated. In Ibstock’s case, we started talking to them in about 2016 and the PPA was signed in 2018.”

Taking that time is essential, though, if solar projects like Ibstock are to get off the ground. Once the PPA is signed, LSbp can raise the finance needed to build the farm and planning can begin in earnest. “Ibstock could have built their own solar farm, but this way there’s no capital expenditure so they pay as they consume over the lifetime of the agreement,” says Zosia. 

What’s more, LSbp absorbs a lot of risk and can take advantage of economies of scale. “It’s a brilliant way for us to secure funding in the knowledge that the farm will have a buyer for the power for its duration,” says Zosia.