We spoke to GreenSketch CEO Prashant Aggarwal about what’s needed to unlock the UK’s rooftop solar revolution.
October 5, 2026
Solar Software as a Service (SaaS) company GreenSketch launched into the UK at the end of September with a report claiming that the average UK home could save £946 annually by installing solar PV panels.
The self-produced research used GreenSketch’s proprietary AI platform, ‘Emily’ to model the projected performance of solar and battery systems across 15 million individual property addresses across the UK.
The modelling also showed that for a UK domestic property, the average payback for a solar-plus-storage installation is just under eight years.
GreenSketch was developed by Australian solar distributor OSW Group, and operates in Australia and Germany, having launched in the latter earlier this summer.
The company’s CEO, Prashant Aggarwal, described GreenSketch as “what an installer uses in between a homeowner saying they’re interested, a customer signing, and the installation”.
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Speaking exclusively to Solar Power Portal, Aggarwal explained how current processes rely on disparate tools for each stage of a rooftop solar installation. The Emily AI platform supports two offers from GreenSketch: the consumer-facing Energy Brain website, and a tool for installers that covers design, proposal, financing and delivery.
According to Aggarwal, “the UK doesn’t have a demand problem, it has a delivery problem”.
Increasing energy bills mean that homeowners are turning to renewable generation technologies as the cheaper solution. Indeed, the UK market differs from the Australian market in that, while it doesn’t have as much irradiance, “UK electricity is very expensive compared to Australia, so every unit that you generate is actually worth a lot more.”
However, while this is a driver of demand, the upfront cost of a solar installation is a real barrier for UK homeowners. According to GreenSketch’s modelling, which produced that 7.9-year ROI figure (which Aggarwal calls the best in the world), the average upfront investment required in the UK is around £7,800.
Aggarwal conceded that isn’t a straightforward or easy issue to overcome, but said “it is achievable”. He noted the range of support for financing, with the current government’s support for renewable energy giving rise to schemes such as zero-interest loans for rooftop solar (although this has yet to be officially rolled out).
According to him, part of what GreenSketch can do is reduce the upfront cost by streamlining processes for installers. “Today, installers are spending a significant amount of time looking for opportunities. With a tool like Emily, where the homeowners can check the value of their roof up front, that in itself reduces the effort that the installer has to put into the sales process.
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“It’s a highly qualified lead for the installer, so the conversion rates should be significantly higher”.
Notably, the business model does not rely on selling leads from interested homeowners to installers, the idea being that homeowners who use the tool will independently reach out once they have used the Energy Brain website to map the potential savings they could achieve.
Another barrier in the UK is the lack of available workforce. While government training initiatives are getting underway, the GreenSketch selling point is that a reduced workload for each individual installer frees up capacity amongst the existing workforce.
Aggarwal said, “at this stage,” the goal is efficiency, although he noted that the firm does have plans to put together installation guides to help installers get better training and support.
For him, UK homeowners will be seeing returns on rooftop solar PV installation by 2030, if three core elements are in place.
“The first is policy—a stable policy that runs longer than the next budget. We really want to know what’s happening with the zero VAT solar loans, with consultation running until March 2027. The industry is already making investments past that period now.
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“The second part is making finance simpler. The Warm Homes Plan is the right idea—it’s a great idea, but it only works if the loan is offered at the kitchen table, not weeks after, because in the moment that the decision is made people need comfort that the finance has been taken care of. I see that as something that needs to be resolved.
“Third is, of course, treating batteries [domestic energy storage systems] as core and not optional. It’s an easy win, the lowest-hanging opportunity; one of the fastest ways of accessing more clean energy today.”
The Energy Brain website includes a feature that allows homeowners to superimpose a battery energy storage system (BESS) onto a photograph of their home's exterior wall. The additional savings associated with using solar-generated stored energy during peak times when real generation is low are well documented.
“If those things can be resolved, and all of them come together, then doubling the UK’s rooftop solar PV capacity should be very possible.”
Read more about:
Molly Green
Section Editor, Informa
Molly joined the team in 2024 and has led coverage on the UK sites. Now shifting to a more global view, Molly is interested in how legislation shapes market dynamics, covering the intersection of policy design, investment patterns, and energy transition pathways.
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