Introduction

The “surgery” is a service by SSEN to allow prospective developers of energy generation and/or new significant consumers of power to gather pre-feasibility study information to help their planning.

There are broadly three places we can connect things to the power network, either to send power we generate or consume power such as an EV charger network or heat network (meaning at scale, not from individual homes)

1. Primary Transformer: This is located south of LME close to Minety, it’s called the “Minety Village Primary Transformer”. In theory, almost any capacity can be connected here, for example, a large solar farm, although as below there are some constraints
2. Secondary Transformers: These vary a lot in scale and therefore capacity. There are large ground-based ones, such as close to the Spa in LME that can take a quite large load and there are smaller ones, typically on poles that have a much lower capacity (max 200kW connection, often lower).
3. T-Connection: These are connections to existing cables at any point. SSEN would add a new transformer / substation along a cable and we’d connect to that.

Heat Network, Heat Pumps and EV Charging Network

Overall the initial review suggests the Parish of Somerford Keynes including the village itself, LME and Shorncote are in good shape to deliver significant capacity. A full submission would be required with a detailed plan of what we want to deploy and SSEN would then do a detailed analysis and come back with a proposal. It may be some smaller pole transformers need an upgrade or we connect to a different one(s), but there should not be any issues with the main cables of large transformer capacities.

We asked about how to tackle EV “public” charging at LME to avoid the need to go back and dig again to lay more cables and ducks. They suggested coming up with an end-state plan where we assume every car on LME is an EV and a consultant suggests EV charging locations for all of this, including both “public” EV charge points in the car parks and private connections for allocated spaces, together with a rough phasing plan of how we’d see this being rolled out over multiple years. Take this to the SSEN planning team who should be able to propose an approach. For example, laying cabling/ducts that have the capacity for additional phases of chargers without having to dig up the roads. and car parks again. Likely there would be some balance between initial cost vs future disruption – i.e. it might not be possible to avoid any future digging without too big an initial cost.

Local Community Solar

These are community solar panels that are larger than a typical home rooftop deployment but not as large as a full solar farm.

These could be ground-mounted on suitable land, maybe floating on a lake (would need environment study) or on large roofs, for example at LME on building such as the long storage barns, Spa, pool houses, etc. 

These are more expensive per kWh of generation than a full-scale solar farm, but could both be a good starting point and make sense where they can connect to nearby heavy consumers of power, for example, a heat network, swimming pools, Spa etc. 

An individual set of panels up to 50kW capacity is considered micro-generation and not subject to any network constraints, although it could require a local transformer upgrade depending on the specific capacity at that transformer. For a sense of scale a typical home solar install is 4kW, so this kind of installation can be ~12x larger than a home solar installation.

Greater than 50kW is possible, it just has more of a process. SSEN said our local network was good, so significant “local community solar” should be possible.

Note: While the discussion was on solar the same principles would apply if we had hydro generation locally. 

Solar Farms

These are typically at least 100’s of kW and often 1 or more MWs. Roughly a 1MW solar farm requires ~6 acres of land and generates enough to power ~300 homes. This suggests around 2MW would generate enough for all the homes in the parish (subject to feasibility study sizing) which would align with our NetZero goal and mean if we adopted the Energy Local model we could take maximum advantage of the low-cost locally generated electricity – this also infers the solar farm has large battery storage to deliver when its dark.

• This doesn’t mean we need to build 2+ MW, rather we get the biggest financial and CO2 benefits at a larger scale.

SSEN suggests locating this as close to the Mintey primary substation as this should give the lowest connection costs and network capacity considerations. However, other locations would still be possible. This suggests farmland south of LME.

However, there are capacity constraints on the national grid at Minety, where our primary substation connects. These constraints are projected to last until 2028 when the national grid completes its upgrades at Minety, which we believe are upgrades to the cables on the pylons and maybe to the national grid 400kV transformer.

Interesting one of the UK’s largest (150MW) battery farms is also connected to the national grid at Minety.

This isn’t a show stopper but will need to be factored into our technical and business plan and be an important consideration for the feasibility study.

Once we have the initial feasibility study and can submit a connection application SSEN would provide detailed information:

Firstly, when we could be connected will depend on if other connections are already submitted for the same sub-station, which they handle in order of submission (earliest first).

Secondly, they may make a high-powered solar farm(s) subject to curtailment until the 2028 upgrade is complete. This means they can cease or reduce taking generation from the solar farm at peak generation time (e.g. very sunny day!), this could affect either or both the income from selling power or the reduced tariff for local homes using our power (Energy Local model). We would need to understand this better as part of the initial feasibility, including whether we can mitigate with battery storage, how this affects the business plan, and suggest a staged deployment.

They commented that if we were considering ~1MW it is better to go just under (say 980kW) since the connection requirements are lower cost below 1MW.

For information we believe these are the are:

• Minety Village our primary transformer
• Minety national grid substation and battery farm

These links open Google Street View, click the map image bottom left in Google to see the map location.