Solar FAQs

In simple terms, commercial solar systems convert sunlight into electricity using photovoltaic (PV) panels.

The photovoltaic effect

PV panels are made of semiconductor materials, like silicon, that generate electricity when exposed to sunlight. This process is called the photovoltaic effect and occurs when sunlight dislodges electrons in the material and creates an electric current. PV panels mounted on rooftops are optimal as they are hit by maximum sunlight.

Fun fact: we are called Granyt as the quartz contained in granite rocks is the primary raw material for producing silicon, the key component in most PV panels. 

AC/DC (not the band)

The electricity produced by solar panels is direct current (DC) –  the photovoltaic effect causes electrons to flow in a single direction within the panel’s cells. However, most commercial and industrial equipment requires alternating current (AC), where the current alternates direction periodically. 

To convert DC into AC, solar systems use inverters, an electronic device that converts DC into AC electricity, which makes the energy usable by your business.

Energy flow and storage

If your solar system produces more electricity than your business consumes, the surplus can be exported to the grid or, if you have storage, saved in batteries for later use.

Without storage, excess energy cannot be retained, meaning it is either lost or sent to the grid (depending on your setup and agreements).

With storage, the excess energy can be stored and used during periods of low sunlight or high demand. Storage also allows you to arbitrage by drawing grid electricity at off-peak rates for on-peak periods, during winter months. 

System efficiency 

Commercial solar systems are most efficient when designed to match your energy needs and site conditions. This means understanding the operational patterns and energy requirements of your business. Factors like the tilt and orientation of the panels, shading, and local climate can affect overall performance. Most businesses save between 20% to 50% on grid electricity, depending on their operating patterns and site conditions.

Commercial solar lifespan

Commercial solar systems are built to last, with a typical lifespan of 25–30 years or more. The most critical components, like PV panels, come with performance warranties guaranteeing at least 80% efficiency after 25 years. Inverters may need replacing after 10–15 years, but advancements in technology are extending their durability. With proper maintenance, your solar system can continue generating significant energy savings well beyond its warranty period.

Many businesses in the UK wonder if solar energy is really viable, given the country’s infamously cloudy weather. The short answer is yes, it makes sense. Here’s why.

Solar likes clouds

Solar panels generate electricity by capturing sunlight, which can be direct sun or diffuse light, which occurs even on cloudy days. Solar panels perform well under light clouds, as sunlight is scattered but still reaches the panels. 

During thick cloud cover, solar output is reduced, as you would expect, but still captures diffuse sunlight and generates at modest levels. Solar technology is designed to maximise energy capture across all weather types, making it reliable even in the UK.

It’s all about the irradiation rate

It all comes down to the irradiation rate. The irradiation rate measures the amount of solar energy received per square meter of surface over a specific time period. We measure it in kilowatt-hours per square meter per day (kWh/m²/day). It represents the potential solar energy available in a given location and varies across the globe and across the UK. A higher figure means more solar energy can be generated per m² of panel.  The UK’s average irradiation rate is 4.7 and varies from 2.9 kWh/m²/day in Scotland to 5+ in Cornwall. 

For comparison sunny places like Spain and California are 5.0 to 6.5 kWh/m²/day and Germany, a global leader in commercial solar adoption, is similar to the UK at 2.9 to 4.2 kWh/m²/day.

Solar works well in the UK

Solar energy generation depends not just on the irradiance rate but also the number of hours of sunlight. The UK has long summer days, which bumps up solar generation over the spring and summer months. Our moderate irradiation rate, combined with sunlight hours makes solar very viable, despite our cloudy weather.

Fewer than 5% of UK commercial and industrial businesses have installed rooftop solar—a rate lagging behind many other countries. This is bananas as UK businesses face some of the highest electricity prices in the developed world. The average commercial electricity price in the UK is 25.85 pence per kWh, compared to 6.48 pence per kWh in the US and 17.9 pence per kWh in Germany. (Source: FT)

The issue isn’t the UK’s cloudy weather—solar works even under overcast skies. There are several reasons businesses are put off from installing solar.

The FiT legacy

From 2010 to 2019, the Feed-in Tariff (FiT) incentivised businesses to install solar by paying them to export energy to the grid. When the FiT ended, solar adoption slowed as the financial benefits temporarily diminished. However, with today’s high electricity costs, the savings from offsetting grid energy now far exceed the financial benefits enabled by the FiT.

Buying commercial solar is complicated

The solar installation process can seem daunting. Understanding technical aspects like system sizing, DC/AC conversion, and grid connections is challenging. Navigating planning permissions, Distribution Network Operator (DNO) agreements, and other bureaucratic hurdles is time-consuming. The market includes both reputable providers and less scrupulous operators, leaving businesses wary of overselling or being misled.

This is where Granyt steps in. We handle the complexity on your behalf, ensuring a smooth, transparent process.

Money, money, money

Finance continues to be an issue.  According to the Green Finance Institute, only 12% of businesses looking to invest in energy transition projects (like solar) succeeded in securing finance. Banks and lenders see solar as risky and businesses are put off as finance applications require excessive paperwork and time-consuming approvals.

Granyt solves this with our direct lease-to-own finance facility, included as part of our service. No brokers. No loan applications. Just straightforward financing tailored to your business needs.

Installing commercial solar panels offers a multitude of competitive and financial advantages for businesses. Here’s are some of the main benefits.

The solar competitive advantage

Installing commercial solar allows businesses to significantly reduce their electricity expenses. As more companies transition to solar, those relying solely on traditional energy sources will find themselves at a competitive disadvantage due to higher operating costs. In Germany, industrial businesses are racing to install solar to cut energy costs and enhance competitiveness as businesses that are not are losing market share because of price. (Source: Reuters) 

Net Zero hero

Many businesses made net zero commitments, not always with a clear plan of action. Installing commercial solar is a solid step to progress net zero commitments by decreasing energy-related carbon footprints. 

Get supply chain emission-ready

B2B customers are increasingly demanding their suppliers reduce their Scope 2 emissions. Scope 2 emissions are those that pertain to indirect emissions from purchased energy. 

Large businesses pass their own Scope 2 emissions reduction targets down their supply chains.  Businesses that proactively install solar panels not only reduce their own emissions but also become more attractive suppliers, and help to secure and retain valuable contracts.

Help your bank help you

Financial institutions are under pressure to reduce their Scope 3 emissions. Scope 3 emissions are indirect emissions associated with their lending and investment portfolios. Companies that invest in solar energy demonstrate a commitment to sustainability, potentially making them more favourable customers for banks and financing as they help the institutions to meet their Scope 3 reduction targets.

Protect your building valuation

For landlords, installing solar panels improve a property’s Energy Performance Certificate (EPC) rating, making buildings more attractive to tenants and buyers. Studies indicate that properties with rooftop commercial solar increase their valuation by 4.2%. (Source: CBRE)  This uplift reflects the growing market preference for energy-efficient buildings.

There are many ways commercial solar can give your business a competitive edge. Granyt is here to help you gain that edge by guiding you through the commissioning and installation process.

Energy savings attainable through solar depends on several factors. Here’s a breakdown of each.

The craziness of grid electricity prices

In the UK, electricity prices are structured using a marginal pricing system. The cost of  the most expensive energy source used at a given time sets the price for all energy sources in the stack. For example, during peak demand periods, natural gas (often the most expensive energy source) sets the electricity price—even though cheaper sources like solar, wind, or nuclear are also contributing to the supply. This pricing structure disproportionately inflates electricity costs for businesses, even when renewable energy forms a significant portion of the grid’s energy mix.

Working day or night?

Electricity prices are not fixed throughout the day. They vary in response to supply and demand as gaged through the National Grid’s bidding process. Prices are highest during peak demand (typically mid-morning and early evening) when expensive gas-fired power plants are brought online to meet demand. During low-demand times (overnight), cheaper energy sources like renewables dominate, and prices drop significantly.

Businesses that rely heavily on energy during peak hours have higher energy costs and stand to benefit more from solar installations to reduce grid dependency during these periods.

Driving energy savings

Commercial solar reduces your businesses’ reliance on grid electricity, allowing you to offset the price you would otherwise pay for imported energy. The more energy you use at peak times, the higher your energy savings using commercial solar. 

When energy prices spiked during the recent energy crisis, two million UK businesses locked into fixed-term contracts at those historically high rates. (Source: FT). These businesses now pay inflated prices for grid electricity (whether peak or off-peak). Installing commercial solar can make or break these businesses as they are locked into these contracts.

Savings depend on your operational profile

Ultimately the amount your business can save using commercial solar reflects the operational profile of your business (what time of day you use the most energy) and what rate per kWh you are paying for your electricity under your existing energy contract. 

Most UK businesses achieve solar savings of 20–50% of their total energy bill. Businesses with high daytime energy use that are on very high fixed tariffs, savings can reach 70%.

Solar for business is not just about sustainability; it’s a powerful tool for reducing operational costs and achieving long-term energy independence. By cutting reliance on expensive grid electricity and insulating against future price spikes, businesses can improve their competitiveness and financial resilience. Let Granyt help you quantify the savings potential for your business.

A Power Purchase Agreement (PPA) is a way for your business to get rooftop solar panels with no upfront cost. Instead of buying the system, you agree to buy the electricity it generates — usually at a lower rate than you’re currently paying your energy supplier.

The solar system is funded, installed, and maintained by Granyt. You simply pay for the power it produces, typically for a fixed term of 10 years.

💡 Why choose a PPA?

A PPA does more than just cut your bills — it gives your business protection against future energy price hikes.

By locking in a fixed price (usually linked only to inflation), a PPA acts as a hedge against:

• Spikes in wholesale electricity prices
• Volatility from global energy markets
• Rising grid costs and standing charges

That means predictable, cheaper electricity for years — even if market prices surge again.

🔧 What makes a Granyt PPA different?

Granyt’s PPA is built specifically for UK SMEs — businesses that want solar savings without complexity.

Here’s what you get:

• Zero upfront cost — we fund the system
• A fixed per-kWh price, adjusted only for inflation (RPI-linked)
• Full installation, monitoring, and maintenance
• A 10-year term, not 25 — with a buyout option from year 5
• No obligation to own, but you can switch to ownership if it makes sense

💰 Can I lower the PPA rate with a deposit?

Yes. If your business prefers (or if you are a higher credit risk), you can make a partial upfront payment (e.g. 10–20%) and receive a lower electricity rate in return — increasing your total savings over time.

Granyt offers two ways for SMEs to go solar — both with zero upfront cost, but with very different outcomes.

🔹 1. Power Purchase Agreement (PPA)

With a PPA, you don’t own the solar system. Granyt installs and funds it, and you agree to buy the electricity it generates — at a fixed, discounted rate compared to your grid price.

We own and maintain the system. You just pay for the power it produces — no capex, no risk.

PPA at a glance:

• Zero upfront cost
• You buy electricity at a fixed per-kWh rate (inflation-linked)
• 10-year contract
• No ownership or maintenance
• Optional buyout from year 5

This option is ideal if you want immediate savings with no responsibility — just cheaper, greener energy from your roof. 

🔹 2. Lease-to-Own

Lease-to-own is for businesses that want to own the solar system — but without a large capital outlay.

Here’s how it works:
You still pay nothing upfront, but instead of paying for electricity, you make a monthly lease payment that’s matched to your expected energy savings. In other words, you’re using your electricity bill to buy the asset — without dipping into working capital.

At the end of the term (typically 7–10 years), you own the system outright, and enjoy decades of free solar power.

Lease-to-own at a glance:

• Zero or low upfront cost
• Monthly payments made from savings
• You own the system at the end
• You benefit from 100% of the future savings
• Maintenance is your responsibility (but we can help)

This option is best if you want to build long-term asset value, control your own energy, and still keep cash in the business.

🧭 Which one should I choose?

• Choose a PPA if you want lower bills now and no ownership responsibilities.
• Choose lease-to-own if owning the system matters and you want to pay for it out of your energy savings — not your balance sheet