Achieving Net-Zero Through Solar Optimisation – Mawdsleys

Mawdsleys Solar Battery Optimisation Project

Wattstor helps the UK’s largest independent pharmaceutical distributor to reach net zero.

The Challenge

Mawdsleys is the UK’s largest independent pharmaceutical distributor, with a large operating fleet and multiple sites across the country. While planning the construction of a new flagship temperature-controlled warehouse, their aim was to generate as much (if not more) electricity as they consume. They wanted to do this by maximising the installed capacity of solar panels on the roof.

The forecasted demand in the warehouse averaged out at around 170 kilowatts each hour, equating to 1.5 gigawatt hours (GWh) of consumption a year. You would need a 1700 kilowatt solar array on the roof to generate that amount of power.

The local distribution network operator (DNO) in charge of the network, however, would only allow them to connect 750 kilowatts of onsite generation, which would only allow them to self-generate 40% of what they were aiming for.

The Wattstor Solution

We deployed our DC direct coupled battery solution to enable Mawdlseys to maximise the size of its solar array. This setup decouples the sizing of the installed solar project from the sizing of the alternating current (AC) generation connection. By using batteries – that are direct current (DC) devices, the same as solar panels – we can control the distribution of the solar generation as it comes off the roof, choosing when to convert it into 400v AC, to serve the Mawdsleys site load and how much to export/sell to the local grid network.

Mawdsleys DC Coupled Solution

For Mawdsleys, this meant connecting a 2500kWh battery to the solar array via a “DC/DC converter”. This is a Wattstor system of power electronics that moderates the flow of energy from the solar panels out to the grid. It allows as much direct current (DC) energy to flow from the solar panels into the converter as possible, but then controls how much flows out on the other side. The Wattstor system decides how much power is sent to the battery and how much is sent out to the site.

Normal site usage is expected to average 170kW, so initially some 25% of the annual solar production will be exported. As Mawdsleys expand their site operations, potentially introducing EV trucks in a few years’ time, they are therefore future-proofing the business with this 25% surplus solar production available to support that load growth.


Mawdsleys Solar Battery Optimisation Project

Kevin Ball & Stephan Marty explain the battery installation work to Ed Miliband, Shadow Minister for Energy

Introducing Podium

We optimise all this with our energy management system (EMS), Podium. Our EMS, which predicts the total solar array output, the site load, and the forward market power price – all a day ahead of time – means we therefore maximise the value of every kW of solar production, every day. This solution – by installing 10x the Solar kW compared to their average kW power demand – has achieved Mawdsleys ambition of becoming Net-Zero. In addition, they can expect a “net- zero” energy bill at the end of each year.

Mawdsleys Solar Battery Optimisation Project – Wattstor helps the UK’s largest independent pharmaceutical distributor to reach net zero.


solar installed

means “net- zero” energy bills at the end of each year


solar production

surplus made available to support future load growth

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