SolarSub is a UK climate-tech startup founded in 2023 by University of Edinburgh engineering graduates Sebastiaan Schalkwijk and James Taylor. The company is developing passive cooling technology for photovoltaic panels, particularly floating solar installations.

The problem is straightforward: solar panels become less efficient as their temperature rises, while prolonged heat can accelerate degradation. SolarSub’s technology is designed to keep photovoltaic modules closer to their optimal operating temperature without pumps or moving parts, with the aim of increasing energy generation and extending panel life.

What this article covers

• SolarSub’s technology and the problem it addresses
• Its early support from Scottish innovation programmes
• The company’s £1.34 million financing in September 2026
• The combination of investment and public support
• What its funding journey shows for climate-tech entrepreneurs

From university innovation to commercial validation

SolarSub emerged from the University of Edinburgh’s engineering ecosystem. Its founders developed the company around the challenge of overheating in solar installations, with an initial focus on floating solar.

Floating photovoltaic installations can help address land constraints, but their exposure to strong solar radiation creates an important thermal challenge. SolarSub’s cooling approach is designed to improve performance without consuming additional energy for active cooling.

The company’s early development was supported by university and Scottish entrepreneurial programmes. In 2024, SolarSub was a runner-up in the Net Zero category of the Converge Challenge, receiving £10,000 in equity-free cash and £9,500 in business support.

The same year, SolarSub also won £10,000 through Scottish EDGE’s Young EDGE programme.

The company has also received a £100,000 Scottish Enterprise SMART grant and Interface Innovation Voucher, supporting the development of its cooling technology.

September 2026: £1.34 million financing round

The major financing milestone came in September 2026, when SolarSub completed a £1.34 million funding round.

The round was led by Sustainable Ventures, with participation from Zinc VC, Scottish Enterprise, Old College Capital, SFC Capital and the British Business Bank. The company also received support through Innovate UK’s Investor Partnership programme.

The new capital is intended to move SolarSub into the next stage of real-world validation and commercialisation.

The company plans to deploy three trials across two continents, working with industry, research and commercial partners to demonstrate the performance, reliability and scalability of its technology.

This is an important transition in the company’s development. Earlier support helped the founders develop and validate the concept; the September 2026 financing is focused on producing evidence under real operating conditions and preparing the technology for wider adoption.

Public and private financing

SolarSub’s journey is a clear example of a startup combining several types of funding.

Its early financing environment included equity-free awards from Scottish entrepreneurial programmes and public innovation support. The September 2026 round then brought together venture investors, public-backed financial organisations and support through Innovate UK’s Investor Partnership.

The different sources have supported different stages of the company’s development, from early validation and business development to larger-scale testing and commercialisation.

For climate-tech startups, this type of funding mix can be particularly relevant because technologies often require testing in real environments before commercial customers can commit to large deployments.

What SolarSub’s funding journey shows

SolarSub’s trajectory illustrates how academic innovation can gradually develop into an investable commercial proposition.

The founders did not move directly from university research to a large investment round. Their journey included competitions, equity-free awards, innovation support and development work before reaching the September 2026 financing.

Another important element is the connection between funding and technical milestones. The latest capital is being directed towards real-world trials rather than simply expanding the organisation. The objective is to generate evidence that can help demonstrate whether the technology performs reliably at commercial scale.

For entrepreneurs in climate tech, this suggests that early non-dilutive funding can have an important role in preparing a company for later private investment. Grants and competitions can provide resources for prototypes, validation and testing while reducing the amount of equity that needs to be given away at the earliest stage.

What this means for entrepreneurs

SolarSub’s journey shows why founders should look at the funding ecosystem as a sequence rather than a single pool of money.

University programmes, grants, competitions, venture investors and public-backed organisations can contribute at different stages. Building a financing plan around technical and commercial milestones can make it easier to identify which type of funding is appropriate at each point.

For climate-tech entrepreneurs, the key is often to demonstrate that a scientific or engineering solution can move beyond the laboratory and work reliably in real conditions.

Entrepreneurs who want to learn how to identify suitable funding programmes, prepare applications and structure a fundraising strategy can explore Fundingtrip’s funding courses.

About the author of this post

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Sara Gavidia
Content Creator
Communications Manager & Content creator
LinkedIn
[email protected]

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Hello! I’m Sara 👋🏻

I’m FundingTrip’s Content creator. I write posts about technology, funding and innovation. If you liked this one, subscribe to our newsletter to receive more updates!

Post reviewed by David Arias, funding expert.