At the moment, total power demand of the UK is between 30 and 40 gigawatts.

To put that in perspective, that'll be 10,000 of our Gatwick data centre, or a hell of a lot of kettles being boiled at the same time.

There are a number of questions to answer surrounding the energy supply in the UK, and hopefully I can help with that.

Where does the UK's energy come from?

According to Ofgem, the UK's power regulator, this has shifted massively over the last 10 years.

Previously, we had a large requirement on coal-fired power stations, and that was about 30% of generation. However, through those coal-fired power stations being decommissioned, we're now down to around 10% use of coal. However, we've seen a massive increase in wind power, going from about 1% 10 years ago, to 20% now.

Nuclear power has remained steady, at around 15% of the mix. And likewise, gas supplies have remained pretty consistent through that period of time as well. In addition to our own power generation, we have a number of interconnectors with neighbouring countries, allowing us to import and export power to them. This is with France, the Netherlands, Belgium, and Ireland. However, they account for a relatively small volume of electricity generation.

What affects the price of power?

There are three main components, which make up the raw cost of power. These are generation, so where the power is produced, transmission, so getting the power to the right places, and taxes and levys. We know the Treasury likes to have their slice of the cake.

In terms of the cost of generation, we haven't seen any significant changes over the last few years. It's remained relatively steady. However, demand does vary through the year, and it has a very cyclical nature, primarily due to the colder winters and longer nights we see in the UK.

Transmission accounts for about a third of the cost of power. Much of this transmission cost is to deal with the losses that occur, as power is transferred from higher voltages into lower voltages, and also via heat, on the transmission network.

And finally, we have the taxes and levys. Unfortunately over the last five years, we have seen an increase of close to 240%.

How does that impact on the price of power in a data centre?

The price of power for a data centre has two elements. The wholesale cost of power, and then a factoring for PUE, or power utilisation efficiency. The PUE figure takes into account the electricity used by your IT hardware, versus the overall building support services required. So things like the cooling systems, losses in UPS efficiency, and office areas.

Here at 4D, we have an industry-leading PUE, of between 1.1 and 1.2 That means for every kilowatt of energy that it takes to power your IT servers, we use between one and 200 watts of other energy, for cooling, for lighting, and for our offices. Based on research by techUK, the trade body for data centres in the UK, the average PUE is two, showing that 4D are running highly efficient data centres.

You can learn more about data centres like ours in the south east.