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Beyond picture-perfect: What a small Spanish winery has learned becoming 95% solar-powered

A graphic showing, on the left, an aerial view of rooftop solar panels on a building surrounded by vineyards. On the right is a headshot of Rafael de Haan next to the IWCA logo, with the text "In conversation with Rafael de Haan, Herencia Altes"

Oh, those idyllic pictures of solar panels nestled amongst rolling vineyards… They often come to mind first when we think of “sustainability.” And indeed, renewable energy is frequently one of the first investments a winery makes to reduce its environmental footprint. It’s a key GHG emissions “hotspot” to tackle: according to IWCA member data, electricity purchased from the grid is one of the Top 5 highest-emitting activities in a winery’s value chain.

Wineries such as IWCA Member Herència Altés in Terra Alta, Spain have slashed that emissions figure.

Today, 75% of the winery’s energy is provided by solar. It’s an inspiring achievement — and the result of years of learning-by-doing that, admittedly, wasn’t always picture-perfect.

We spoke with Herència Altés co-owner and winemaker Rafael de Haan to uncover the process. The interview has been condensed and edited for clarity.

For Herència Altés, the decision to adopt solar initially came out of necessity.

“We built the Herència Altés winery in 2016 on beautiful and historic — but remote — grounds in Terra Alta, Spain. The challenges of accessing electricity quickly became clear. Obtaining a high-voltage grid connection from Spain’s energy companies was going to come at an astronomical cost, so I thought it would be interesting to try to circumvent the energy companies altogether. Wind turbines are fairly controversial in our area, one reason why we quickly settled on solar.

At that point, we didn’t really have a clear sustainability roadmap. It was an implicit principle, but the decision to adopt solar was a practical one. It wasn’t until later that sustainability became a driving priority for our winemaking team.”

Aerial view of a long narrow white building covered in rooftop solar panels. In the background are vineyards and patches of trees in rural Spain.
"The decision to adopt solar was a practical one."

As a small family-run winery of “not engineers,” they learned as they went.

“I knew nothing about solar power and batteries back in 2015. I was more of a romantic winemaker… not an engineer!

We wanted to work with local suppliers as much as possible, so we partnered with someone locally to advise us. In retrospect, we should have employed a top-notch engineer to find the best suppliers, the best technology, etc. Instead, we went with what we knew, and what was available locally: solar panels with lead batteries. Little did I know that this technology was about to be obsolete and a big mistake (more on that later…).

The decision to install solar panels and batteries was easy. Then came the tougher realities.

When you start a solar project, you try to estimate how much energy you’re going to consume. For a new business like ours, it’s a hypothetical calculation. You don’t know how much energy you’ll need until you’re fully operational.

We initially installed 35KW of solar panel capacity with 100KW of lead battery storage. We soon realized we were underpowered. We had to supplement our energy supply with a diesel-run generator.

Aerial view of a long narrow white building covered in rooftop solar panels. In the background are rows of vineyards at Herència Altés vineyards. Against a cloudy sky are a few wind turbines..
"The decision to install solar panels and batteries was easy. Then came the tougher realities."

Then, we found that we weren’t charging the batteries fast enough and they were depleting so fast that the generator had to kick in two or three times a day. Not only that, but we learned that you can only deplete lead batteries to around 50% without significant degradation, unlike lithium batteries which can be depleted to around 20%. This caused us to have to replace one of our three units at great expense.

These are things we learned as we went. Obviously, we ideally would have had this information beforehand, but we’re not experts. That’s just how it works in a small family-run business!”

Managing loads and battery storage would prove to be a continuous challenge.

“In 2020, we doubled our solar panel capacity. That allowed us to cover more of our peak energy consumption during the day. But we still couldn’t make it through the night on battery power, causing us to rely even more on our diesel generator — not ideal from an environmental perspective, and it degraded the machine. Power outages were causing all kinds of problems: fridges would break down, our bottling machine suffered maintenance issues…

We had to face the hard truth: we best solution would be to replace our entire system.”

After a number of obstacles, the winery expanded and revamped its battery storage system.

Floor-to-ceiling banks of batteries as part of Herència Altés' solar and battery storage system.
The winery's new battery system.

“This May, we removed the lead batteries and installed lithium batteries. We’re already seeing a huge impact. The batteries are providing more storage; we’re able to use more solar energy; we’re dramatically decreasing our use of the diesel-run generator.”

The winery is now working to become 95% solar-powered.

“We’ve made huge strides: we’re now meeting 75% of our energy needs through solar. With further investments in battery storage, I believe we can continue reducing the use of the generator and become 95% solar powered. It would be a huge achievement.

In addition to adding battery capacity, we also need to expand our conversion capacity: in other words, converting stored battery energy into usable energy. We’re maxing out currently. When our big cooling fridge revs up every half hour, we have a surge in energy consumption. We need our power system to be able to cope with that.

We’re never going to be 100% solar-powered but we want to get as close as possible. If it’s overcast all day, we can’t fully charge the batteries, which requires the generator to kick in. But even then, we can meet most of our energy needs with solar, which is exciting.”

So… was it all worth it, despite the ups-and-downs?

“Absolutely! We’ve amortized our investments several times over. That’s even more true now given the rise in energy costs over the past year.

It makes sense economically: you save money. It makes sense in terms of the ethics of sustainability: you lower your carbon footprint. It even makes sense in terms of your marketing: it becomes a value add. Who doesn’t want to support a business working hard to be more sustainable?

I’m absolutely convinced about solar energy. I would absolutely do it all over again — but better, with more information and research! That’s just part of the learning experience!”

A close-up aerial view of solar panels on the roof of a long narrow building. Surrounding the building are vineyards, fields, and trees, with some mountains visible in the background against a cloudy sky.
"We’ve amortized our investments several times over. "

To close: here is Rafael’s advice for others embarking on a similar journey.

  • Fully research different suppliers and options for both solar panels and battery storage upfront. Stay up-to-date with the latest technology.

  • Be realistic: you’re going to need a backup solution. Try to make it the right one, whether it’s a gas generator or a diesel generator, by scaling it properly to your needs. For instance, in our case, we should have invested in two small generators rather than one big one, so that we can have a backup if one breaks down and so that we don’t need to fire up such a big generator for limited usage. If you need additional power, like during harvest, you can always rent an extra machine.

  • Look into any grants in your area that could help with the upfront capital investment. Herència Altés was able to recover a substantial amount of the cost of new batteries with governmental grant support.


Our thanks to Rafael de Haan for sharing his candid insights! IWCA is proud to champion the sustainability efforts of wineries like Herència Altés. To learn more about our inspiring community of wineries and how we facilitate knowledge exchange on climate action strategies, contact us.

A close-up of a row of spaced out vines along a dirt path. In between the plants are various wildflowers. The sun is shining bright on the horizon against a blue sky.


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