What is a CHP System?
Combined Heat & Power is a gas fuelled reciprocating piston engine, driven by three CHP fuel types- natural gas, biogas, or LPG. The CHP engine drives an alternator to generate electricity. The heat from the CHP engine is then recovered and made available as hot water or steam. This gives the best efficiency from the use of the fuel consumed, and provides very low cost power and heat energy to the client.
On certain combined heat and power models we can even recover waste heat from the alternator, further increasing efficiency.
Key Benefits of a CHP System
The many benefits of using a CHP unit include energy savings, carbon reduction, and greater electrical resilience.
- Reduced heat and electricity bills
- Reduced carbon footprint and CO2 emissions
- A unique ability to be able to modulate down to 50% of the maximum electrical output
- Choose between truly fixed maintenance costs or costs based on run hours
- Water cooled alternators on some of the units which mean no hot air discharge ductwork is needed keeping installation costs to a minimum
- The ability to synchronise with a mains utility supply and standby generator, or both at once
Looking for the Complete Combined Heat & Power System Service?
Our ability to deeply understand the technical needs of your CHP system installation provides added value, as we take a ‘whole project’ holistic approach and are known to have significant attention to detail. We don’t just think about CHP units, we think about optimising your energy usage as a whole, providing increased cost reductions all round..
Combined Heat and Power Project Management
Shenton Group will always provide a dedicated, single point of contact Project Manager to oversee all RAMS, site visits and administration. We also support clients with funding options and offer market-leading expertise in finance for CHP systems.
CHP Technical Information
The technical information below highlights some of the key considerations during the design and install of CHP systems. Our experts have delivered CHP projects including combined heat and power systems for residential use as well as for various other sectors, taking into account every key aspect in depth.
From an initial feasibility study, detailed design, chp installation, commissioning, to user training and on-going lifetime maintenance, Shenton Group will look after every phase of your project leaving your organisation free to concentrate on what you do best.
Acoustics are a major part of any CHP installation and need careful consideration when carrying out financial and spatial planning. From initial acoustic surveys through to the final installation, we will look after your requirements.
Our range includes open-frame CHPs, indoor acoustic enclosures, and external containerised units. We can also offer bespoke acoustic solutions.
We can also look after any necessary louvres that may be required and can supply and install secondary silencers within the flue to reduce the noise further.
Ventilation is key to any CHP system to ensure that the CHP doesn’t overheat. Getting the correct cooling/ combustion air to your CHP and discharge air can be achieved with the use of ductwork ventilation systems, and, if required, the use of extra fans.
In all CHP installations, some form of flue is required to conduct the exhaust gases outside. Shenton Group can supply and install bespoke flue systems including stainless steel, twin-wall insulated, metal-sprayed mild steel versions, coloured to blend in with architectural surroundings.
Not only is it important to get the size of the CHP correct, it is also equally important to install the CHP system correctly to maximise run time. Based on years of practical experience, learning what type of installations work best and where, we can comment on your design and suggest changes that may enable the CHP to run for more hours per day.
The connection of any form of generator device to run ‘in parallel’ or ‘synchronised’ with the mains electrical utility grid has certain regulations that must be complied with. These regulations are commonly known as the ‘G99’ requirements, and apply to Combined Heat & Power units, and Generators being used for peak-lopping, or grid parallel use.
The electricity grid operators (known as DNO – District Network Operators), refer to these units as ‘embedded’ generators, because they are embedded within the electricity grid, as opposed to being at the source of the national grid such as at a power station.
At Shenton Group, we have significant experience in this discipline, and can provide a turnkey service to take care of all G99 aspects for you. We can manage the entire formal application process to the DNO. We can supply the necessary G99 compliant devices and provide trained operators with certified equipment to carry out the final G99 witness test.
Delivery Lift & Shift
We specialise in getting CHP systems into the most difficult locations. From a standard HIAB delivery right through to crane contract lifts, skating or full break down and re-assembly of the unit. Regardless of the location, we have the expertise and experience to get it there.
Black Start and Island Operation
Most CHPs only operate ‘in parallel’ with a grid power supply. However many units in our range can be configured to run in island mode, in the absence of the grid. Additionally, some units can even self-start without any grid power being present. This provides significant flexibility for integration with client electrical infrastructure, including facilities for stand-by power etc.
In many instances, a thermal store is required to smooth out peaks and troughs in heat demand, and thus enable the CHP to keep running for as long as possible. We offer a comprehensive range of vessels for this, which can be installed along with the CHP. We are also able to comment on the sizing of these, as part of assisting you with design.
What is NOx?
NOx is the chemical abbreviation for the most common oxides of nitrogen, and other compounds most commonly associated with air pollution. When any fossil fuels are burned in an internal combustion engine, NOx is one of the by-products of combustion. The only way to filter out NOx from exhaust gases is by means of a catalytic converter, or a catalyst as they’re more commonly known. If using a standard catalyst, for NOx reduction to be effective, the exhaust gases passing through it from the engine need to result from perfect (or near perfect) combustion.
Perfect combustion is called stoichiometric combustion and this is when the exact amount of air required is mixed with the fuel during the combustion process. Often a combination of a stoichiometric engine and catalyst can result in NOx emissions as low as 20mg/Nm3.
Not all engines are able to be configured for stoichiometric combustion, due to the very high temperatures this produces. Under heavy loading an unsuitable engine would overheat. In CHP terms, this generally means stoichiometric methods for NOx reduction can only be used on smaller size units. In the Shenton Group range, these go up to 260 kWe.
For larger CHP systems, an engine with lean burn combustion must be used. This runs a lot cooler and can therefore be put under much heavier loads. The challenge with lean burn combustion is that the air to fuel ratio is much higher, resulting in non-stoichiometric combustion. This means a conventional catalyst as described earlier will not be effective in removing the toxic NOx gases.
Selective Catalytic Reduction
(SCR) uses urea as a reductant by injecting it into the exhaust pipeline where the aqueous urea vaporises to form ammonia. Within the SCR catalyst, the NOx gases are catalytically reduced by the ammonia into water and nitrogen, both of which are harmless.
Put simply, the injection of urea treats the exhaust gases to make them effective when passed through a catalyst. In the context of a CHP project, designers should take account of the considerable amount of space, and added complexity that an SCR installation requires.
CHP Assistance for Design Engineers
Are you a design engineer and need assistance in selecting the correct CHP system and buffer vessel size? We can give you access to our very own comprehensive desktop CHP sizing calculator! If you’d like to find out more, please contact us.
Additional CHP System Services
Looking for CHP maintenance?
We offer a range of different support contracts to keep your CHP in optimal condition, providing you the best ROI. Find out more about our CHP Maintenance Contracts.
Need help reducing your operating costs and energy bills, or wish to improve your power security?
Our combined heat and power consultancy service will review your facility to identify improvements further reaching than just CHP, providing you with the best solution to reducing your costs, power usage and CO2 emissions.
Sectors We Help
M & E Contractors
For the Building Services Engineer we offer significant support. From detailed design review, through assistance with sizing calculations, to control philosophy – Shenton Group is able to provide professional advice at all stages of your project. For the installing contractor we offer great support and many CHP units are held in stock to shorten lead times. We can assist with things such as BMS integration and hands-on advice on site when needed.
Energy Services Companies can enjoy the class-leading performance from our range of CHP units. With high efficiencies and exceptional return on capital cost, these CHPs are perfect for your energy solution clients. Whether you are delivering a Discounted Energy Purchase (DEP) contract, an On-Site Utility or an Energy Performance Contract (EPC), you can be sure that CHP from Shenton Group is backed up by a unique maintenance service that will deliver outstanding efficiency to your client and long-life low operating costs for your bottom line.
With several hundred units deployed in the UK market, many of our ESCo clients are now also using our CHP systems to participate in balancing services and other grid-related revenue streams.
Shenton Group has significant experience in supplying high-performance CHP units to biogas applications. Some special features of our units include high tolerance to H2S, high electrical efficiency, and exceptional service life. We also provide a unique maintenance package with 24/7 remote monitoring and a choice of response levels, including some of the fastest in the industry.
This all combines to provide outstanding performance and very high availability time. This ensures that you can maximise the revenue from your biogas plant year after year.