“We’re diverting huge amounts of food waste from going to landfill where it would break down to produce methane – a dangerous greenhouse gas.”
Colin Lindsay Operations Manager, Scottish Water Horizons
Since 2010, Deerdykes has saved more than 170,000 tonnes of carbon. That’s like driving over six million miles in a car – or to the Moon and back 12 times.
The facility harnesses gas from food waste using anaerobic digestion to generate green energy using a combined heat and power engine (CHP).
Food waste is broken down in sealed, oxygen-depleted tanks to produce energy-rich biogas. This is then converted into electricity through the CHP engines, as well as a natural fertiliser for use in agricultural land spreading.
Colin Lindsay, Operations Manager at Scottish Water Horizons said: “The numbers are impressive but quite difficult to visualise – particularly if you try to imagine 500 million kettles being boiled at once, or driving six million miles in your car.
“There is the added bonus that we are diverting huge amounts of food waste from going to landfill where it would break down to produce methane – a dangerous greenhouse gas.”
Around a million tonnes of food is thrown away in Scotland each year. A number of local authorities across west-central Scotland transport waste to Deerdykes along with waste from many food producers and businesses.
Scottish Water Horizons is the commercial arm of Scottish Water and plays an important part in helping the organisation meet its Net Zero ambitions, by maximising opportunities for green energy production on Scottish Water sites.
Scottish Water was a proud participant at the recent COP 26 – the 2021 United Nations Climate Change Conference held in Glasgow.
As Scotland’s public water and waste water services provider, protecting and enhancing the environment is a priority. Scottish Water has already committed to reaching Net Zero by 2040 – five years ahead of the Scottish Government’s national targets.
As well as transforming the delivery of key services, Scottish Water works with a wide range of partners to contribute towards wider carbon reductions.
A Chivas Brothers tanker delivering residues from the production of Scotch Whisky to Nigg during the co-digestion trial
“The Nigg trial is an excellent example of collaboration in action, driving sustainability in Scotland’s food and drink sector, and making a tangible contribution to a circular economy and a Net Zero society.”
David Harley SEPA’s Interim Chief Officer, Circular Economy
The successful trial involving Scottish Water, SEPA and major distiller Chivas Brothers saw distillery residue brought into Aberdeen’s Nigg Waste Water Treatment Works for the first time, with promising results.
A process called ‘co-digestion’, means that the residues from distilleries and breweries in the area can be added to sewage sludge processed at Nigg, as part of a system which produces biogas – an alternative fuel used to run the site’s boilers and Combined Heat and Power (CHP) engines.
The facility already has a process to turn sludge produced during waste water treatment into biogas – this is then used on site instead of oil or diesel. Since October 2021 the sludge treatment centre has trialled co-digestion – in other words, processing residues brought in from Chivas Brothers’ distilleries and breweries alongside the sludge – and this has noticeably increased the amount of biogas being produced.
Scottish Water’s Chief Scientist Elise Cartmell said: “The team at Chivas Brothers approached us because the various residues created as part of the distillery process are often rich in energy, and they were keen to find alternative outlets to capture and use it. Fortunately this aligned very well with Scottish Water’s existing ambitions to investigate co-digestion, extending work we had already begun with SEPA, so we decided this would be the perfect opportunity to try out this process.
“It’s turning out to be a win-win for both parties: the distilleries are provided with an outlet for treatment which helps this key regional industry become more sustainable, while we at Scottish Water benefit from a boost in production of green energy at our site, which reduces our reliance on fossil fuels and helps our journey to net zero.”
With the addition of the distillery and brewery residues, the plant saw a saving of 58 tonnes of carbon over the 12-week trial period, which equates to 250 tonnes per year – the same as 250 passenger return flights from Paris to New York.
Chief Scientist Elise Cartmell said: “We’re very pleased with the findings which show that the trial boosted biogas production and significantly reduced the site’s need for oil to power its on-site boiler. Just as importantly, there was no adverse impact on the operation of the site or on the quality of the biosolids that are also produced for recycling to land.
“We believe there is excellent potential for this approach to be used at Nigg in the future and for it to be rolled out to other sites across Scottish Water.”
The trial was made possible by close collaboration between the industry, the Scottish Environment Protection Agency (SEPA) and Scottish Water. It was led by the publicly owned water company’s commercial subsidiary, Scottish Water Horizons.
Through collaborative working and close monitoring throughout the Nigg trial, the teams involved have laid the groundwork to explore further opportunities in the future to support businesses and green energy production across the country through co-digestion.
Chivas Brothers’ Environmental Sustainability Manager Ronald Daalmans said:
“The trial with Scottish Water has shown that residues from our effluent treatment process still have an energy value that can contribute to a more circular and sustainable economy and provide an alternative outlet for distillery residues when other routes are full.
“We hope the trial will open up further opportunities for collaboration between the Scotch Whisky sector and utility operators.”
David Harley, SEPA’s Interim Chief Officer, Circular Economy, stated:
“Against a backdrop of climate and nature emergencies, there’s a real environmental imperative for us all to act. But more than that, innovative partnerships like this between SEPA, Chivas Brothers and Scottish Water are real economic and social opportunities.
“The Nigg trial is an excellent example of that collaboration in action, driving sustainability in Scotland’s food and drink sector, and making a tangible contribution to a circular economy and a Net Zero society.”
Cutting Carbon
One of the Combined Heat and Power engines which convert biogas into heat and green electricity at Nigg WWTW.
The proposed photovoltaic panels will offset more than 20 per cent of the electricity needed to operate the facility.
The company’s commercial subsidiary Scottish Water Horizons is proposing to install 560 photovoltaic (PV) panels at Skellyton near Larkhall.
The carbon reducing technology will offset more than 20 per cent of the electricity needed to operate the facility and generate over 150MWh of electricity each year – the same amount of energy needed to boil a kettle 1.5 million times or watch a million hours of television.
Donald MacBrayne, Business Development Manager at Scottish Water Horizons, said: “Offsetting energy usage through renewable generation is a key part of delivering on our commitment to achieving net zero carbon emissions by 2040.
“This scheme will not only help Skellyton treatment works on the way to energy self-sufficiency it will also contribute around 12 per cent of the generated electricity to the national grid, helping to off-set carbon emissions further afield.”
The installation of the solar PV array will cut carbon dioxide emissions associated with the site by over 20 tonnes a year.
PV panels will be installed in an area of scrub, brownfield land within the boundaries of the existing works.
The Skellyton project is the latest in a long list of renewables schemes already installed at many treatment works and other Scottish Water assets across Scotland.
Scottish Water has committed to reach net zero carbon emissions by 2040 with an interim target to host or self-generate three times its annual electricity consumption by 2030.
Almost 80 of the company’s water and waste water treatment works are now either self-sufficient or partly sufficient in their power requirements.
“This scheme will not only help Skellyton treatment works on the way to energy self-sufficiency it will also contribute around 12 per cent of the generated electricity to the national grid, helping to off-set carbon emissions further afield.”
Donald MacBrayne Business Development Manager, Scottish Water Horizons
The new batteries will enable solar energy to be used at any time of the day or night.
The flagship scheme, delivered by framework contractor Absolute Solar & Wind Ltd, is part of a £2 million renewables project which includes the company’s largest single solar energy array to date.
Four vanadium flow batteries, manufactured by Invinity Energy Systems, have recently been installed at the waste water treatment works that serve the city of Perth. The batteries are capable of storing up to 0.8 megawatt hours (MWh) of energy and will be used to store power generated from more than 2,520 solar panels, with a combined output of over 1 megawatt (MW).
By enabling solar energy to be used at any time of the day or night, the battery system will allow around 94% of the renewable power generated to be used on site – a significant step forward in the company’s decarbonisation ambitions.
By combining battery storage and solar power, the carbon footprint of the treatment works will be cut by around 160 tonnes of CO2 per annum – the equivalent of offsetting 580,000 miles from the average passenger car. The scheme will also help to power the utility’s first rapid electric vehicle charging points which have been installed at the site; and will reduce energy costs of the treatment works by approximately 40%.
This installation is the latest investment by Scottish Water Horizons, the public utility’s commercial subsidiary, who are developing a programme of opportunities for battery storage across Scottish Water’s asset portfolio.
Scottish Water Horizons Business Development Manager, Donald MacBrayne, said:
“We’re excited to have our first battery facility up and running to help reduce emissions and tackle climate change. The ability to maximise green energy production as well as store and release this energy when we need it is a vital part of our journey to net zero.
“By harnessing this technology, we now have a much wider opportunity to install renewables schemes that were previously unviable due to grid constraints. It’s a massive step forward for us and will form an integral part of how we cut our emissions in the coming years.
“It’s fantastic news for the customers in Perth as they can now benefit from a treatment service with a significantly lower carbon footprint, helping them with their ambition to become the most sustainable small city in Europe.”
The utility-grade vanadium flow batteries were assembled by Invinity Energy Systems at their manufacturing and assembly facility in West Lothian. Invinity’s patented vanadium flow battery technology is already making its mark in the energy storage market world-wide as a safer, more durable and sustainable alternative to traditional lithium-ion batteries.
Matt Harper, Chief Commercial Officer at Invinity Energy Systems, said:
“We are very proud to be supporting the decarbonisation of essential public infrastructure in the UK. Utility-grade energy storage, such as our vanadium flow batteries, has a key role to play in unlocking the low-cost, low-carbon energy we require to reach net zero, while helping to shield companies from rising commercial energy prices.”
A key component to the success of the battery and solar hybrid scheme is the intelligent battery software and control system that coordinates the production, storage and release of the energy generated. The digital optimisation platform, Dynamic Demand 2.0, supplied and installed by Open Energi, provides a steady supply of energy during periods of low renewable generation whilst keeping energy costs down.
David Hill, Chief Commercial Officer, Open Energi said:
“Open Energi are thrilled to be part of such a pioneering project. The use of vanadium flow storage enables Scottish Water to soak up a greater proportion of their on-site solar generation when compared to conventional lithium-ion storage. Our micro-grid optimisation tool, which uses highly localised solar, demand and wholesale energy price forecasting capabilities, ensures not a single drop of sun’s energy is wasted.
“When you look at the recent surge in power prices, driven by high gas prices, we see this type of ‘Energy as a Service’ proposition, which bundles zero carbon technology into a simple value proposition, becoming the norm for all energy consumers.”
The battery project in Perth joins a long list of renewables schemes already installed at many treatment works and other Scottish Water assets across Scotland.
Renewable energy experts Absolute Solar and Wind delivered the onsite solar scheme earlier this year whilst adhering to ongoing Covid guidance.
Scottish Water has committed to reach net zero carbon emissions by 2040 with an interim target to host or self-generate three times its annual electricity consumption by 2030. Almost 80 of the company’s water and waste water treatment works are now either self-sufficient or partly sufficient in their power requirements.
Replanting this hillside close to Loch of Lintrathen with a mix of conifers and native trees will improve wildlife habitats and boost biodiversity.
“This kind of mixed woodland is a much more attractive place for birds, insects and mammals to live and will massively improve biodiversity in this area.”
Mark Williams, Sustainability and Climate Change Manager, Scottish Water
Scottish Water is creating a brand new area of woodland in Angus aimed at improving biodiversity and wildlife habitats.
The utility company is transforming 100 hectares of hillside close to Lintrathen Reservoir which was previously a mixture of mature conifers and rough grassland. The process of rewilding the site with a combination of native pine and broadleaf trees is underway as part of Scottish Water’s route to net zero. When it matures, the new woodland is expected to be much more beneficial for local wildlife, as well as capturing a significant amount of carbon.
Scottish Water’s Sustainability and Climate Change Manager Mark Williams said: “As part of our overall strategy, we’ve pledged to find opportunities to use the land that we own to increase biodiversity and enhance the natural environment – and that’s exactly what we’re doing here.
“We’ve removed the plantations of conifers currently at this site because they’ve reached the end of their productive lives. They’re being replaced by a mixture of native conifers and broadleaf trees such as ash, oak and birch. This kind of mixed woodland is a much more attractive place for birds, insects and mammals to live and will massively improve biodiversity in this area.
“Not only that, but this new woodland will lock up a huge amount of carbon – we estimate that within about 10 years it will begin to capture around 1000 tonnes of carbon per year, which will be a major contribution towards our net zero goals.”
The logs cut at the Lintrathen site have been sent for processing to James Jones Sawmill in Lockerbie, which also puts sustainability at the heart of its operations. The trees will be used to produce furniture and construction materials.
Stuart McArtney, Forest Manager with Bell Ingram said: “Replanting this land will make a real difference to the wildlife in the area. Dense, monoculture planting provides only a very limited habitat, but this new mixed woodland means we’ll see more birds nesting, insects will come in to pollinate the tree flowers and it could also help to boost the numbers of native species like red squirrels and black grouse.
“These young trees will soon become a fantastic green space for the local community, for wildlife and will make a really important contribution to reducing the effects of climate change.”
Scottish Water is looking for further opportunities to create woodland on its land throughout Scotland, as part of its commitment to reach net zero and improve biodiversity. The utility company has pledged to reach net zero carbon emissions by 2040.
“The ICC will become even more important in future to ensure that vital services can be monitored and maintained in the face of challenges caused by a rapidly-changing climate.”
Michael Matheson Scotland’s Cabinet Secretary for Net Zero, Energy and Transport
Michael Matheson toured Scottish Water’s Intelligent Control Centre (ICC) to see first-hand how technology is helping maintain services in the face of changing weather resulting from climate change.
During winter storms, our customers were largely protected from outages caused by power failures thanks to the vital role the ICC plays in supporting our field teams deliver service to domestic customers and businesses across the length and breadth of Scotland.
Serving 5 million customers and 2.6 million households, the country uses 1.5 billion litres of water a day and Scottish Water treats more than a billion litres of waste water daily.
It is responsible for a massive network of above-ground and underground assets which allows water to flow to taps and waste water to be removed from properties.
Scottish Water provides a vital public service which is critical to daily life and any disruption to customers – including vulnerable customers – is a priority.
Mr Matheson met Scottish Water’s Chief Executive Douglas Millican, Chief Operating Officer Peter Farrer, its Chair Dame Susan Rice, and Sharon Hamilton, the ICC manager, during his visit to the centre in our offices near Glasgow.
Mr Millican said: “Over the past 20 years that Scottish Water has been responsible for delivering the country’s water services, there has been a revolution in how we monitor and manage Scotland’s water requirements.
“The use of, and investment in, technology increasingly enables us to provide ever more resilient water and waste water services and enables us to anticipate and forecast issues and, when any disruption does occur, helps us ensure we can return to normal as quickly as possible. Recent winter storms have shown how a smart, swift customer-focused response can support communities’ return to normality after adverse events.
“With aging infrastructure, increasingly challenging weather patterns which impact our networks and customers at the heart of what we do, the ICC and the people in it connect right across our organisation to ensure communities can rely on us around the clock, whatever the weather.”
Sharon Hamilton, Scottish Water’s ICC Manager, said: “The ICC team are a key operational team within Scottish Water. Providing a 24/7/365 service, monitoring our assets to understand risk to ensure we protect Public Health, the Environment and our people and deliver the best possible service to our customers. They liaise directly with a range of Scottish Water staff both during and outwith core working hours to ensure the appropriateness of the business response to areas of potential service impact.
“The team utilise a range of business systems developed to protect and enhance the customer experience including telemetry data from assets, logger data from our networks, security systems and supporting knowledge management systems.
“In addition, the team use a range of tools developed to ensure they understand key areas of service impact associated with factors like weather conditions to ensure areas that result in significant business impact are well understood.”
She added: “The future evolution of our ICC is a critical enabler of Scottish Water’s future transformation and the achievement of Scottish Water’s Strategic Ambitions.”
Mr Matheson said: “Scottish Water’s extensive water and sewerage networks provide an impressive level of coverage across the country, and I am reassured that Scottish Water will continue to react quickly to any unforeseen issues on its networks.
