The Drive for Renewables and the need for Trenchers

More solar parks and onshore wind farms means increased demand for trenches which can be dug quickly, efficiently and accurately….

There’s no escaping the fact that the renewable energy sector in the UK is in the midst of something of a revolution. The initial commitment for the UK to reach net zero by 2050 was signed into law by the previous government in 2019, with practical efforts to make the changes needed bolstered by the Net Zero Strategy of 2021 and the Net Zero Growth Plan of 2023.

Despite publications of this kind, however, there was a fear that the last government was somewhat half-hearted in its commitment to net zero and other green policies, particularly in the midst of a cost of living crisis, and it was the election of a new government in July 2024 which really brought about a step change in the renewables sector.

In this article we’ll look at the practical outcomes likely to flow on from this step change, and more pointedly the impact which these outcomes are likely to have on demand for precision, reliable trenching equipment.

Put simply – energy generation and supply involves a lot of electricity flowing through a lot of cabling, and burying that cabling securely is the most effective way of maintaining safe and efficient operating conditions.

New solar projects

The scale of ambition the new government has for renewable infrastructure such as solar parks and wind farms became clear immediately following the election result. The first indication came, on 8^th July 2024, when Chancellor Rachel reeves announced the lifting of the de facto ban on the construction of more onshore wind farms which had been in place until then.

This was followed, less than a week later, by approval being given for three new solar farm projects located at Mallard Pass, on the border between Lincolnshire and Rutland, Gate Burton in Lincolnshire, and Sunnica on the Suffolk-Cambridgeshire border.

Estimates released by the Department for Energy Security and Net Zero (DESNZ) claim that these three sites could produce 1.4GW, which is enough energy to power 406,994 homes. To put this figure into perspective, it represents two thirds of the solar power capacity installed on rooftops and on the ground across the whole of 2023.

In a country which had already generated record levels of solar power across the 2024 summer, despite the fairly disappointing weather seen throughout, this represents a major infrastructure commitment, and it is by no means the end of the story. Multiple solar power projects across the UK, some of them with even greater capacity than those announced immediately post-election, are currently in various stages of development, and are expected to enter into commercial operation in the period between 2026 and 2030.

AFT Trenchers have been involved in many projects delivering solar power to the nation. In fact a recent project involved the AFT100 trencher being used for a CCTV cable ducting project at a Midlands based solar farm, led by Richard Formosa at Formosa Fencing.

He had this to say:

“Very impressed with the speed of the trencher and the cleanliness of the trench. Would have taken a least a day with a digger to do the same. Also, much easier to backfill with the finely chopped spoils. Our Fendt 211 is handling the AFT100 perfectly, with the trencher doing a fantastic job.”

In another recent project AFT Trenchers worked alongside Tugwell Contracting Group, an AFT customer since its inception, to provide a comprehensive array of solar park construction services, including fencing, road construction, drainage, and, notably, trenching and duct laying.

Tugwell also collaborates with farmers, who are often willing to transform low-quality land into a reliable source of income by leasing it to energy companies planning to install solar panels.

You can read more about this project in our news article here.

Onshore wind

While the push for solar power is already yielding practical results, the shift in onshore wind farm provision – something which had been on ice for several years – is likely to be slightly slower to move from aspiration to spades (or for that matter trenchers) in the ground.

Nonetheless, with the government firmly committed to doubling the capacity of UK onshore wind farm provision by 2030, it’s safe to assume that there will be an increased demand for the infrastructure needed to build and then support these onshore wind farms over the next few years and for some time to come.

Indeed, the first practical response to the lifting of the de facto ban on onshore wind farms in England was the announcement of plans to build what would be the biggest onshore wind farm in the country on the moors north of Manchester.

Cabling requirements of solar and wind farms

The vast bulk of the cabling needed to get a solar or wind farm up and running will relate to the panels and turbines themselves, and to the task of getting the energy being generated from the site of the park or farm and into the wider grid.

We’ll provide more detail on the complex set of requirements this involves shortly, but it’s important to remember that it’s not the beginning and end of the cabling needed when a renewable energy farm of this type is constructed.

One aspect which is easy to overlook is that of security. The fact that energy infrastructure represents a possible key target for possible terrorist attacks means that highly advanced CCTV systems need to be in place to monitor the site at all times.

In addition to the security consideration a factor which needs to be taken into account when monitoring sites of this kind is that they will almost always be located in rural locations, and that interaction with local wildlife is almost inevitable.

Given the sensitivity around constructing sites of this kind in hitherto unspoiled locations, the monitoring of any local wildlife is as much about ensuring the safety of that wildlife as it is about the security of the site.

To that end the CCTV system in any solar or wind farm will include the installation of thermal imaging cameras which are in operation 24 hours per day. Cameras of this kind, which are able to detect and distinguish between human and animal activity, will play a key role in protecting both the sites and the environment into which they have been inserted.

The cabling needed to power infrastructure of this kind needs to be installed with the strictest possible emphasis on security, and that means being buried, usually within protective ducting, beneath the surface of the ground.

The trenching needed to install cabling of this kind around the entire perimeter of a site such as the aforementioned Sunnica solar farm, an installation covering an area of 2,500 acres, needs to be dug at speed without sacrificing accuracy or quality, and that means working with precision trenching equipment.

Types of cable

The cabling needed to help maintain the security of a renewable energy site is only the start of the story. The complex process of turning sunlight into something that comes out of the plugs in homes many miles away is based, more than anything else, on mile upon mile of cable, and the vast bulk of that cable needs to be placed safely under the surface of the ground.

What follows is a simplified breakdown of the kind of cabling requirements involved in getting even the smallest solar park up and running:

• Direct Current (DC) cable – the DC cables are built to handle the direct current generated by the solar panels. They will be built to resist UV rays and weather, and to handle the high voltage current delivered by the panels. They need to be built and installed in a way that minimizes power loss between the solar panel and the solar inverter. In some solar parks each solar panel has its own mini-inverter attached, but as this is the more expensive option it is common for DC current to be carried from the panels, via DC cable, to a central inverter.
• Alternating Current (AC) cable – The DC from the solar panels is converted into AC by the inverter, following which the AC cable transports what is now usable electricity to the grid or the electrical load. Cables of this kind need to be thick enough to be insulated to deal with high voltages, and to comply with all relevant safety standards.
• Earthing Cable – the earthing cable is directly connected to a grounding system. This system ensures that any excess charge from the likes of electrical surges or lightning strikes is safely dissipated into the ground. Wires of this kind are made of highly conducive materials such as copper or aluminium. As with the AC and DC cables, the earthing cables need to be placed safely beneath ground level in ducting carried along trenches.

Trenching solutions

Although solar parks and wind farms differ in many respects, the cabling required for each location has fundamental similarities. In a solar park the DC cables will be routed via channels suspended under the solar panels before entering an underground duct at the end of each row of panels.

This duct will then run along the end of each row to feed into the units housing the inverter. There are strict safety rules governing the trenches used to carry cables of this kind, which must be dug to a depth of at least 0.6m.

In addition to this, the length of the cabling used is a significant factor when calculating the diameter of the wire carrying the AC. The length the current is carried is used together with the maximum current expected and the minimum desired voltage drop – loss of power as the current travels – in order to decide the optimum thickness and type of AC wiring to use.

This means it’s vital that the trenches cut for the wiring are as precise and accurate as possible in terms of length as well as depth. These requirements apply to wind farms as much as solar parks, as does the desirability of trenching equipment for aspects of renewable energy projects such as foundation work and drainage work, with the trenches in question being cut with minimal disruption to the surrounding area. In simple terms, the rush for renewables will help to develop the taste for trenchers…