Erica Charles

Managing Director of Spirit Energy.

Recent Posts

Solar Panel Specifications: Reading a Solar Panel Datasheet

Erica Charles 25 Jul 2019

Solar panel key parameters

If you are trying to compare one PV panel to another, it is helpful to understand the key technical parameters - or solar panel specifications - that impact performance.

With this in mind, we’ve taken some extracts from the specification sheet for a standard polycrystalline solar panel (Trina Solar’s HoneyM Plus+ 265-275W range) and highlighted the key parameters.

We’ve then highlighted key differences between the Trina panel and SunPower’s Maxeon® 3 panel.


Topics: Solar PV

Bifacial Solar Panels and the Albedo Effect

Erica Charles 01 Jul 2019

One of the most notable trends in the solar PV market in the last couple of years has been the growth in bifacial solar panels.

The 2019 International Technology Roadmap for Photovoltaics (ITRPV) predicts that bifacial cells will increase their share of the solar PV market from around 15% in 2019 to 60% in 2029.

So, time to sit up and take notice. What are bifacial PV modules, and why are they set to dominate the market over the next 10 years?


Topics: Solar PV

The Current State of Solar Energy: Taking Stock of the PV Market

Erica Charles 05 Jun 2019

When you work at the coal face of the solar industry (get your head 🙃 around that one), it is sometimes interesting to take a step back to see where the market has come from and where it’s headed.

We’ve spent some time taking stock of the solar PV market. Here’s a summary…


Topics: Solar PV

Best Angle for Solar Panels in the UK and Beyond?

Erica Charles 03 May 2019

The best direction for a roof with solar panels is dead south. Except if you're in the Southern Hemisphere when you want it to be facing north. Which is why solar panels are like bath water spiralling down the plug hole. 

But few people in Guildford have a roof that faces exactly south. And few people in Guinea have a roof that faces exactly north. So the key question for many of us is, "How much solar generation do I lose if my panels don’t face exactly south?" 

Which is the best angle for solar panels?

The optimum roof angle of photovoltaic panels in the UK is 35-40 degrees. The exact angle depends on the latitude, which is why the best roof angle will be different in other parts of the world.

For various reasons we have recently been looking at the performance of solar panels in Africa, Mexico and Spain.

If like me, you are curious as to the performance of solar and the best orientation for solar panels in other parts of the world, here’s what we found.



Topics: Solar PV

BIPV Facades: Improve Building ROI with Photovoltaic Curtain Walling Systems

Erica Charles 15 Feb 2019

Research indicates the market for curtain walling is growing at a healthy rate of around 6% per annum. (A curtain wall is the non-structural weather proof covering of a building, generally associated with large multi-storey buildings.) This rise is driven both by new build construction and by energy efficient refurbishments of existing buildings.

Standard curtain walling improves the thermal insulation of the building, leading to reduced HVAC costs and reduced heat loss. It also improves the aesthetic appearance of the building.

A photovoltaic curtain wall has the added benefit of generating electricity over the building’s life.

Whilst it costs a bit more than standard curtain walling, the incremental cost of a BIPV facade will typically be paid back within around five years.


Topics: BIPV, Solar PV

Solar Panel Shortages: Order Ahead to Secure Panels for your Projects

Erica Charles 17 Jan 2019

If you have a requirement for Solar PV as part of any project in Q1 or Q2 this year, we recommend you place an order for the installation as soon as you can in order to secure stock, current low prices, and installation labour.

The overall trend in the solar PV industry is one of technological improvements (more Watts per 60 cell panel), and manufacturing improvements (lower prices), but in the first half of this year a perfect storm is brewing leading to limitations in supply, and the potential for increasing prices.

Three factors are at play:


Topics: Solar PV

Will 2019 be the Year Your Clients Ask for Solar PV Battery Storage?

Erica Charles 14 Dec 2018

With 11 days to go until Christmas, Michelle Obama has launched her bid to join Christmas bestseller lists across the globe, Simon Cowell et al have launched their usual bid for the Christmas Number 1 song slot, and the nation prepares once more to vote in the Strictly Come Dancing final tomorrow.

A similar end-of-year flurry is taking place in the Solar PV Battery Storage market, all with a view to turbo-charging the market in 2019.

In the last few weeks:


Topics: Battery storage, Solar PV

Easy Roof Evolution: In Roof Solar with Velux Windows

Erica Charles 07 Dec 2018

If you are building a new property or re-doing a roof and want to install solar PV, it makes sense to look at roof integrated solar panels.

There are a few systems on the market, for example Viridian Solar and GSE.  But one system in particular, Easy Roof Evolution, stands out if you want Velux® windows within the solar array.


Topics: In roof solar panels, Solar PV

Solar Panel Output Calculator: Commercial Solar PV

Erica Charles 30 Nov 2018

Two or three weeks ago we launched a 'Back-of-Envelope' Solar PV Calculator.

You can access it here:

Go to solar calculator

I have been using the calculator to get a rough idea of what the returns from solar PV look like in a post-subsidy world, without bothering our Estimating team (who, as you can imagine, are pretty busy in the run up to the Feed-in Tariff closure on 31st March 2019).

Here's an example of what 75kWp of un-subsidised solar PV looks like, retro-fitted to a factory roof....


Topics: Solar PV, Calculator

Road to Zero: Government Increases Workplace Charging Grant to £500 Per Socket

Erica Charles 20 Jul 2018

On 9th July, the government launched its “Road to Zero Strategy” to lead the world in zero emission vehicle technology.

Not to be confused with any other ‘Road to Zero’ or ‘Round in Circle’ government strategies, this one is all about ensuring at least 50% of cars are ultra-low emission by 2030, and ensuring that the infrastructure is in place to support this.

If you’re in charge of a ‘workplace’, the good news is that on the back of Road to Zero, the Workplace Charging Scheme will now contribute 75% of purchase and installation costs (up to a maximum of £500) towards the cost of each charging socket installed. 

The grant is available for to 20 chargepoints per applicant, across all sites.

In other words, up to £10,000 per business.


Topics: EV charging