Homeowner Blog

Why does the solar panel output matter?

When installing solar panels there are many things to deliberate over, whether that be the price or aesthetics, but probably the most important metric to consider is the output. More often than not the price you pay for an installation will be relative to the power output of the system. The rated power output or wattage of a panel represents the theoretical power output under ideal conditions and is a strong indication of the amount of electricity a panel will generate. However; there are factors other than the panel’s wattage to consider when determining its output or energy generation. 

Why are solar panels blue (usually)?

The standard solar panels that you see most commonly on rooftops are a shimmering blue colour. This is because they are made from polycrystalline silicon - lots of crystals melted together.

But you may have also seen black solar panels - these are monocrystalline. Formed from single silicon crystals, they have a greater efficiency and (in many people’s opinion) a more attractive appearance.

This year saw the Feed-in Tariff closed to new applicants, leaving a very different landscape to the heady days of 2010, when the feed-in tariff scheme was first launched and the subsidy was around 43p per kWh.  So, are solar panels worth it today?

Speaking purely from a financial point of view, the answer is a resounding yes. Of course beyond the financial, there are many other environmental benefits to be gained from installing solar, installing residential battery storage, driving an electric vehicle etc. Not least because they all contribute directly or indirectly to tackling air pollution, which, we are told, is gradually destroying the nation's health.

Back to the financials. The solar subsidy may have fallen, but so has the cost of the technology. Overall the cost of domestic solar electricity is now around 9p per kWh. This is well below the 15p average domestic import cost from the grid (which, by the way, increased by 7% in the last 12 months...).

On 10th June, the government finally announced the details of the Smart Export Guarantee (SEG), the system to ensure people are paid for excess generated electricity they send to the grid.

This guarantee is seen as a replacement for the Feed-in and Export Tariffs, which ended on 31st March this year. Those schemes encouraged thousands of installs and helped bring the cost of solar down over 50% since 2011. The aim of the SEG is to continue promoting renewables but without costing consumers. Instead suppliers will have to start bidding competitively for the energy you generate.

The solar PV industry has faced a year of change in 2019, with more uncertainty lying ahead. First came the end of the Feed-in Tariff, the guaranteed payments for people generating solar energy. The 50% deemed Export Tariff for smaller systems ended at the same time and we’re still waiting to see what will fill the gap, to prevent customers with new solar systems from exporting excess electricity to the grid for free. (Don’t worry, this doesn’t impact people who installed their system before the final Feed-in Tariff deadline of 31st March 2019.) The current proposal from the government is the Smart Export Guarantee (SEG) - more on this below. As a final kick in the teeth to the industry, another threat to solar PV installation has resurfaced - a potential solar VAT rise on domestic systems from 5% to 20%.

So what does all this mean to you? Is solar PV still worth installing now, either as an extension to your existing system, or as a new system altogether, or should you wait? And what about a solar battery?

If you’re looking to maximise the value of the surplus energy generated by your PV system, diverting this to EV charging makes sense from both an economic and environmental perspective.

Yesterday I had my own modest version of a Victor Kiam moment.

If you are too young to remember Mr Kiam, spend 30 seconds watching this…. Mr Kiam's famous line ‘I loved the shaver so much I bought the company’ was the cornerstone of a hugely successful 1979 advertising campaign.

Mr Kiam was swept away by the joy of a sharp shave. For me it was Tesla and the sheer passion with which they are pursuing their mission ‘to accelerate the world’s transition to sustainable energy’.

Around 30 GigaWatts of the UK’s older fossil fuel and nuclear capacity is due to be de-commissioned by 2025. At the same time, more and more of us are taking delivery of our first electric car, pulling away from the lights much faster than the petrol heads whilst fuelling a significant increase in the national electricity demand.

Furthermore, with the advent of renewables, the problem of balancing supply and demand within the National Grid is become ever more challenging, leading to periods of excess demand and ‘negative electricity prices’. 

And with all this comes an increasing expectation of power cuts, grid constraints and increasing electricity costs.

Enter battery storage, and in particular, home battery storage. And smart meters, and smart electricity tariffs.

Is electricity cheaper at night?

If like me, your gut answer is ‘of course electricity is cheaper at night’, read on …

In January SunPower introduced the world’s first 400 Watt residential solar panels.

Utilising 104 Monocrystalline Maxeon Generation III solar cells, the panels have an efficiency of 22.6%. 

The panels have ‘standard’ panel dimensions of approximately 1.69m x 1.05m, giving an output of 226W per square metre.

As always with SunPower, the panels have a premium look….