A business built for the long term: Plug me in Solar at 15

Originally founded as Environmental Energies in 2011 by husband and wife team, Simon and Zara Glew, the business has weathered the industry’s many storms - from shifting government policies to market shocks and rapid sector evolution. 

 

Today, as part of the Calisen Group, our business is focused squarely on what we do best: delivering high-quality commercial renewable technologies, backed by experience, a highly skilled team and long-term stability.

 

In an interview with Zara Glew, General Manager and Mark Bramhall, Director of Commercial Strategy, we reflect on the journey so far - and look at ahead to what comes next.  

 

Zara, take us back to the start. Why did you set up the business in 2011?

Simon and I had always  been involved in construction, and had became increasingly interested in renewable energy sector and the role it could play in the future of the built environment. Solar was just beginning to take off with the feed-in tariff, and we believed it had real potential.

 

We started in the domestic market, but after two or three years we expanded into agricultural and then commercial projects. Before long, we were installing nationally.

 

The business grew quickly in those early years. What drove that success?

Zara: People and principles. We had very strong values, which remain at our core today. All our business came through referrals and repeat business. We didn’t actually conduct any proactive marketing until 2022, when we were ready to take the business to the next level. That kind of organic growth only happens if you look after customers properly. 

 

A huge part of our success also comes down to having a great team – and the majority of that original team are still with us today.

 

The solar market has had its ups and downs. How did the business survive the tougher periods?

Zara: The feed-in tariff was initially reduced in 2016 and ended in 2019 - and this had a significant impact across the entire solar industry. Overnight, the market changed and we all had to rethink how we operated.

 

I knew solar would come back and was determined to keep going. Global focus on decarbonisation was intensifying, businesses were under increasing pressure to reduce carbon emissions, and events like COP26 reinforced that renewable energy would become central to future policy and investment. 

 

So we made the decision to pivot into commercial new build and work lean for a period. Mark joined us during that time, bringing with him a wealth of experience and strong reputation in the new-build sector. Together we pushed forward, eventually moving back into the SME market.

 

Mark, from your perspective, what sets Plug me in apart?

I think it’s our longevity and like Zara said, the strength of our team. When Calisen acquired the business in 2024, there were only a small handful of UK solar companies of our size, operating nationally and at our scale – and that had been established as long as we had, with the skills, capabilities and people still in place.

 

Customers value that continuity. If we installed your system five or ten years ago, the people who designed and installed it are still in the business. That builds trust.

 

Zara - there’s been a lot of change over the last 18 months. How would you describe where the business is now?

Calisen acquired the business to grow its presence in renewables, which included heat pumps and EV charging. Following a change in direction last year, the decision was made to refocus Plug me in on its strongest and most established capability: commercial solar and battery.

 

Calisen is an infrastructure owner, so long-term asset performance and value are central to how they operate. That makes solar a natural fit. As a result, the business has returned to the leadership team that originally built and grew it. 

 

Today, it’s very much business as usual – with greater clarity and stability. I’ve come back into the business to support that transition, working alongside my original team and helping to set the business up for its next phase, with Mark stepping into the lead role over time.

 

Mark, how does being part of Calisen strengthen Plug me in’s proposition?

In a big way. Calisen is fully behind us and that support gives us confidence and our customers confidence, because it also gives us financial backing. 

 

What’s important is that there’s a strong alignment in how we operate. Calisen’s focus on integrity, long-term asset performance and doing things the right way mirrors the ethos we’ve built this business on from day one.

 

More tenders require significant turnover and balance-sheet strength. With Calisen behind us, we can access projects such as data centres, large commercial estates and frameworks, that simply wouldn’t have been possible before.

 

Crucially, we also have the capability to deliver them. That combination of financial backing and security, alongside experience and technical capability is very rare in this industry. 

 

Looking ahead, what excites you most about the next phase?

Zara: Opportunity. Solar and battery is now a mature, proven technology and it’s going to be the most cost-effective way for businesses to meet new legislative and carbon targets. With Calisen’s backing and the team we have in place, there’s no reason we can’t reach, and exceed, the level we originally set out to achieve.

 

Mark: Solar is increasingly being financed, not just purchased outright. That demands experienced, credible delivery partners. We’ve got the people, the track record and the backing to be one of the leading players in the UK.

 

We’ve been here 15 years. And we’re just getting started!