Can solar power really work in the UK?

Solar power has emerged as a leading technology in the energy transition, providing an essential alternative to traditional fossil fuels. Solar already produces over 1000TWh (that’s a million megawatt hours) of power every year globally, with plans in place to achieve 7400TWh by 2030. In 2025, the International Energy Agency (IEA) expect solar power to overtake coal as the largest source worldwide. However, in the United Kingdom (UK), there is a lingering misconception that solar power is not financially viable or efficient, due to the country's overcast climate.

To understand if solar can work in the UK, first we need to understand how a solar panel works.

Photovoltaic (PV) panels, work by converting sunlight into electricity. They consist of solar cells made from semiconductor materials, typically silicon, which absorb photons from sunlight. This absorption creates a flow of electrons, generating direct current (DC) electricity, which is then converted into alternating current (AC) for household use.

The key point here is that solar panels do not require direct sunlight to function efficiently. While their effectiveness is maximized in direct sunlight, they can still generate electricity in cloudy conditions. Solar panels capture both visible and infrared light, with the latter actually being more prevalent during overcast days. Consequently, although energy production may be reduced on the type of cloudy, rainy day that the UK experiences so often, solar panels continue to operate, rendering them suitable for the UK's climate.

So solar in the UK works. But does it make financial sense? Will the consumer, who is ultimately picking up the tab, see any benefit? (Besides the obvious environmental advantageous vs coal or gas) 

Fortunately, the sun rises each day and bestows around 173,000 continuous terawatts of energy on earth completely free of charge. This means that, operationally at least, solar farms are very cheap. Operators just need to ensure the plants are properly maintained and cleaned. Most of what it costs to produce a unit of power from a solar farm is a function of how much it costs to buy the panels and build it.

To understand and compare these costs, we use an equation for finding the levelized cost of energy (LCOE). In simple terms, this comprises firstly of the upfront costs of the materials and installation, connecting to the grid and submitting a planning application, added to the operational costs, which could include rent for land and cleaning/maintenance fees. We then simulate, based on the project parameters and location, how much power the plant will generate over its lifetime. Once we have that, we divide the total cost by the power generation, leaving us with a useful cost per unit of solar power.

The graph below shows how solar’s LCOE has fallen dramatically since 2012 ultimately becoming the lower cost form of electricity generation in 2020.