It's a question we hear regularly: "How is the Windfall Battery different from existing home battery solutions like Tesla Powerwalls, PowerVault, and GivEnergy?" It's a fair question. After all, they're all batteries that store energy in homes. But here's the thing: while they might seem similar on the surface, they're solving completely different problems.

Two Problems, Two Solutions

In the world of home energy storage, there are two distinct challenges that batteries can address. One is a niche problem affecting a specific subset of homeowners. The other is a universal challenge that affects every household and is critical to the success of the clean energy transition.

Understanding which problem you're solving determines everything: your target market, your design choices, your business model, and ultimately, how quickly you can scale to make a meaningful impact.

In the 2010s, we saw an the beginnings of the rise of home solar. People were realising that they were generating more than they can use during the sunniest parts of the day, and they wants to save up that energy to use throughout the rest of the day. We saw home battery companies emerge, focusing on this:

How do we capture and store excess solar energy for later use?

Tesla Powerwalls, PowerVault, and other established home battery systems were designed to solve this specific challenge: maximising the value of rooftop solar installations. These systems capture "free" energy generated during sunny days and store it for use when the sun isn't shining.

Fast forward to 2025, home solar has continued to grow, but it’s scale is still limited by the availability of suitable roof space, and the upfront costs. Meaning that the addressable market for these home battery companies is limited to 5% of all homes in the UK.

The Bigger Problem: Matching Consumption to Renewables

At the same time as home solar has been developing, so has on-grid renewables. In 2024, over half of all energy on the grid came from renewables. However, renewables are variable, they don’t always produce energy when it’s needed.

This is the fundamental challenge of the energy transition. For decades, we've relied on turning gas power stations up and down to match our energy demand. But as we move towards a renewable-powered future, we need to flip this model on its head.

The new reality: We need to adapt our consumption to match when renewables are generating abundant, cheap energy.

A shift from flexible generation to flexible consumption

This leads us to a new problem statement:

How do we enable all homes to shift their energy consumption to when renewables are abundant and cheap?

This shift requires every home to participate: renters, apartment dwellers and house owners, those with solar and those without. We're talking about creating an equitable energy transition where everyone can benefit from clean, affordable energy.

This is a massive market opportunity. In the UK alone, there are over 28 million households. If even a fraction of these homes could participate in demand flexibility, we'd have the responsive energy system needed for a renewable-powered future.

This is the problem that needs solving for a successful energy transition. It's universal, it's urgent, and it requires a solution designed for universal access.

Can’t we use existing home batteries to solve this new problem?

They are too big, and too expensive

Existing home batteries are built for maximum capacity scenarios. They're sized to handle the biggest energy demands and, in extreme cases, allow homes to almost completely detach from the grid. But this "bigger is better" approach creates a fundamental issue: unused capacity kills ROI.

Most homes don't need 13.5kWh of storage (Tesla Powerwall capacity). When expensive battery capacity sits unused day after day, the financial returns don't work for most households.

Renters Are Excluded

The high power levels required for whole-home backup mean these systems need complex electrical installations with significant safety considerations. This creates multiple barriers:

Professional electrical work and safety assessments
Often structural modifications
Lengthy planning processes with multiple site visits
High upfront costs from complex installation

Result: renters are completely excluded. Complex installations require property ownership, or landlord permissions that most renters simply can't obtain.

Too Complex

These systems require customers to become energy management experts. Users need to understand tariffs, program schedules, and constantly manage their systems to optimise returns. This individual education approach works for motivated early adopters but doesn't scale to millions of households.

The Inevitable Result: Slow Adoption

With all these barriers in place, it's unsurprising that adoption has been slower than the climate challenge demands. These aren't flaws in the products, they're natural consequences of solving a niche problem. But when you're trying to transform the entire energy system, niche solutions with inherent scaling limitations aren't enough.

The Windfall Approach: Universal Solution by Design

Windfall Energy set out to solve this new problem:

How do we enable all homes to shift their energy consumption to when renewables are abundant and cheap?

We were not constrained by existing preconceptions of what a ‘home battery’ is. We researched what the real barriers are to solve this problem and designed a product which removes those barriers

Designed for Universal Access

Plug-and-play simplicity: Our reduced power levels enable safe installation without complex electrical work. This isn't just convenient, it's transformative. Renters can save money on their bills without needing landlord permission for major electrical modifications.

Energy supplier partnership model: Instead of forcing customers to become energy management experts, we work directly with energy suppliers. Your battery is automatically controlled based on real-time energy prices and grid conditions. You simply receive a discount on your energy bill, no programming, no tariff management, no complexity.

Accessible installation: The system arrives ready to use as a manageable unit that can be set up quickly and easily, not requiring crane installations or large delivery trucks. This simplicity also makes the battery movable, allowing renters to take it with them if they move.

Targeted capacity: Rather than over-engineering for maximum capacity, the Windfall Battery provides just enough storage to shift consumption away from the most expensive energy periods. This focused approach maximises ROI by ensuring every kWh of capacity is actively used.

Peak-shaving focus: Instead of trying to power entire homes during outages, we focus on reducing consumption during peak pricing periods when grid electricity is most expensive and carbon-intensive.

This approach delivers meaningful savings and environmental benefits while keeping costs accessible for a much broader range of households.

Built for Rapid Scaling

By removing installation barriers, eliminating customer education requirements, and working through energy suppliers rather than individual sales, we can reach households at the pace the climate challenge demands.

Same Technology, Different Markets

Yes, the Windfall Battery uses the same proven lithium-ion technology found in Tesla Powerwalls and PowerVault systems. The core battery chemistry and safety systems are well-established and reliable. But that's where the similarities end.

We're not building a better version of existing products, we're solving a fundamentally different problem for a fundamentally different market.

Both solutions have their place. Solar-plus-storage systems will continue to serve homeowners seeking energy independence, and they do that job exceptionally well. But achieving the scale and equity required for a successful clean energy transition demands a different approach.

Solving the grid flexibility problem requires a new solution: one that works for renters and homeowners alike, that's simple rather than complex, and that's accessible rather than exclusive.

The Windfall Battery isn't competing with existing home batteries, it's addressing an entirely different market. We're solving a problem that affects all 28 million UK households, not the niche problem that affects the subset with solar installations.

That's the difference between serving thousands of homes and serving millions. That's the difference between a niche solution and a universal one. And that's why the Windfall Battery represents a fundamentally different approach to home energy storage.

Same technology, different problem, different solution, and ultimately, a different vision for the speed and scale at which we can transform our energy system.

How we’re Addressing 95% of the Problem, Not Just 5%