Supermarket CHP

10 July 2009

From pilot project to mobilisation across 18 stores, HSE Group has worked with Tesco to fulfill its low carbon objectives via combined heat and power at its stores across the country, some powered by renewable energy.

THE HSE GROUP HAS FORMED A PART OF THE TESCO SUPPLY chain for many years, designing and installing technical building services across a wide range of stores and projects. In more recent years the emphasis has been upon environmental engineering solutions that would significantly contribute towards achieving Tesco’s corporate objectives. Installations have included geothermal engineering, rainwater harvesting, solar panels and mechanical services systems, BMS and the targeting and remote monitoring of energy usage after project completion.

On the 18th January 2007, Sir Terry Leahy, Tesco’s chief executive gave a speech to invited stakeholders at a joint Forum for the Future, titled “Green Grocer, Tesco,Carbon and the Consumer”. He said, “I am determined that Tesco should be a leader in helping to create a low-carbon economy.” and “It requires a revolution in technology and a revolution in thinking. We intend to halve the total carbon footprint of our existing buildings worldwide by 2020. We are also growing responsibly by ensuring all new stores we build
between now and 2020 emit, on average, at least 50 per cent less carbon than an equivalent store
built in 2006.”

He confirmed Tesco’s commitment to the challenge of reducing energy consumption, CO2 emissions and the reduction of their carbon footprint by creating a £100m Sustainable Technology Fund. This fund would be used to help close the gap between the technology that is needed for Tesco to achieve their goals, and the technology that can be purchased and applied commercially.

The HSE Group, in collaboration with the Tesco Engineering Team, set about identifying those next generation technologies that would build upon current improvements and further contribute to Tesco achieving their future energy goals and targets. Sir Terry’s speech acknowledged the need to trial new technologies and Swansea was selected as the first store to have a combined heat and power (CHP) unit installation. After performance proving tests that verified the initial findings, Tesco confirmed that it would feature as a practical application in designated stores.

In May 2008 Tesco instructed the HSE Group to commence a survey of 65 stores that had the potential for microturbine CHP. This process took three months and resulted in 18 stores being selected, 12 on the UK mainland and six in Northern Ireland. The working design of the packaged microturbine CHP unit and its integration into the existing system was completed between May and August 2008. To enable the team to achieve the challenging project programme, plant and equipment had been pre-ordered and the off site prefabrication of the plantroom’s in Milton Keynes resulted in the first 6 units being delivered to Belfast in September 2008. The remaining twelve units were delivered to the UK mainland locations by the end of October 2008.

The M&E modifications necessary to integrate the CHP into the existing system were completed out of hours, in order to minimise the impact on retail operations. As December and January are busy trading periods, all outstanding works, including balancing, testing and commissioning recommenced in February and completed by the end of March 2009. Typically, the entire installation programme for a store took 10 –12 weeks.

The HSE Group formed a project team from the several group companies that participated in delivering the entire CHP solution. Project Directors, Chris Phillips and Marcus Sullivan headed a team of Operations Managers, Project Managers, Engineers, Supervisors and tradesmen, including Tesco approved contactors
in Northern Ireland.

The USA is at the forefront of developing micro turbine technology and UTC provided the HSE Group with the opportunity to speedily introduce microturbine based technology. The turbines were delivered to our Milton Keynes site and engineers from the USA joined our team and supervised the turbine assembly process. The project plan included the use of renewable fuel sources wherever possible. Stow on the Wold and Portstewart both operate on bio-fuel .

Key project objectives were:
.. To prove the viability of the retrospective introduction of micro turbine CHP
..The installation of quiet running units, consistent with Tesco’s social responsibility policy
..Provide significant energy cost reduction by reducing the need to buy from the grid
.. A 30 – 35 percent reduction in electrical energy
..The reduction of carbon emissions by 480 tonnes of CO2
.. Provide a major contribution towards a £750, 000 saving from the use of CHP systems in2008/09
..To maximise benefits of Renewable Obligation Certificate (ROC).

The emphasis was upon prefabricated plug and play plant where possible, this speeds up the on site installation and reduces systems and services downtime. Platignum Environmental, a HSE Group company, assembled, manufactured, delivered and positioned the prefabricated plantrooms. Although the technology is widelyused in the USA, it is new to the UK. HSE Group carried out performance validation tests to prove the technology prior to installing the first operational unit. Our design engineers worked with the client team by preparing and submitting information for planning approval, to ensure we complied with all environmental and planning regulations.

Our team took care of G59 approvals, which allow Tesco to generate electricity on site in parallel with the incoming electrical supply. This will eventually allow Tesco to export any surplus electricity into the grid when the feed-in tariffs come into effect in the UK in 2010. Part of the process required us to demonstrate that the supplies are synchronised and compatible, it also ensures safety of systems.

After developing and considering several conceptual designs, the team decided upon using two 65kWe UTC Power CA65 microturbines featuring a Capstone microturbine unit with exhaust gas heat recovery system to Low Temperature Hot Water (LTHW). These proprietary units, bio-fuel or gas, have proven characteristics and were supplied as factory designed and fabricated. We inserted the two microturbines into the packaged plantrooms, along with LTHW pump sets, pressurisation sets, pipework and associated controls to minimise site activity and speed the installation and commissioning process.

The units provide 130kW of electrical energy into the store incoming mains panel, in parallel grid connected mode, and are arranged to take on the base load of the store with typically 95 percent availability during the 6 - 9 months of the year that the units run. An exhaust gas heat recovery heat exchanger to LTHW system provides heating to Store air and Hot Water Services (HWS). A unique tank design ensures bio-fuel is stored at the optimum temperature and condition throughout all changing seasons. The tank is fitted with integral heating systems, insulation and fuel tank monitoring equipment.

A new range of pipework, including control valves, connects the microCHP heating circuit into a new central LTHW system, which serves a new duct mounted LTHW heating coil, the main entrance door heater and the domestic hot water system. The Low Voltage panel was modified to include motorised switchgear and an interface to enable parallel operation of onsite power generation with the incoming mains supply and existing mains failure generator. In adopting a Total Turnkey Project approach to the project, the HSE Group formed one focal point for Tesco using its in-house capability to design, manufacture and install the entire project, and manage the builder and related trades. After project completion it continued its involvement by maintaining and remotely monitoring the CHP and associated systems and by providing Tesco with weekly management information and confirmation of any adjustments we have made to enhance performance.

After the successful installation to 18 stores the initial results are:
..The application of improved technology is contributing towards energy reduction targets
..Learning can be applied to new stores
..Tesco is benefitting from Renewable Obligation Certificates (ROC)
..Estimated payback, gas – 6 years, bio diesel – 6.5 years, vegetable oil – 4.5 years.

Tesco understand that to ensure they, their customers and staff benefit form this level of investment in new technology, they must have accurate and timely information on the quantity of energy consumed within their nationwide stores, on a regular basis and in a format that is user friendly. Elite Controls Solution, a HSE Group company, has installed energy monitoring equipment to 487 stores including those with microturbine CHP. Elite Controls can identify energy fluctuations on a daily basis due to the quality and quantity of data received from the meters and loggers. Elite Control engineers provide assistance to Tesco’s management team by resolving system and plant issues that can impact upon energy usage.

Harry Sayer, Managing Director of the HSE Group, commented, “ I’m delighted that the HSE Group could prove to be a good partner to Tesco by using our in house capability and resources to provide the entire engineering solution, including plantroom manufacture and ongoing energy monitoring. We are applying the learning from this project and are continuing to work with other manufacturers of reciprocating engines and microturbines to enable us to supply a broad range of CHP solutions ”

Tesco will now incorporate CHP, as standard, in all future new stores and major extensions.

Tesco stores with CHP installed
Lisnagelvin, NI,
Lurgan, NI
Antrim, NI
Ballymoney, NI
Portadown, NI
Portstewart, NI
Tiptree, Essex
Great Notley, Essex
Marks Farm, Essex
Bordon, Hampshire
Maesteg, Wales
Caister, Norfolk
Illfracombe, Devon
Hook, Hampshire
Stow on the Wold, Gloucestershire
Princes Risborough, Buckinghamshire
Annfield Plain, Country Durham
Heanor, Derbyshire

CHP jargon buster
CHP – the simultaneous operation of usable heat and power in a single process.
ROC – Renewable Obligation Certificate is a green certificate issued to an accredited generator of eligible
electricity generated within the UK
G59 – All embedded generators have to comply with certain regulations applied by the electricity supply
authorities. The regulations in the UK are referred to as the ‘G59’ regulations
LTHW – low temperature hot water system
HWS – hot water services