Standby power is accepted as essential in an organisation’s armament in the battle for success, and the introduction of fuel cell standby power increases the options available. Karen Sperrey of UPS Systems asks which solution will be right for you?
It is an undisputed fact that many businesses will lose money if they suffer an interruption to their prime power source, even for just a few seconds. It is not just loss of an ability to actually work or receive customer calls. These are bad enough, but many service providers will lose revenue when systems based on automatic processes fail; web-hosting, data centres, on-line catalogues and call centres are just a few examples. If customers can’t access a product or service someone will lose out. Businesses deriving income from web-based information services are especially vulnerable. For core facilities such as emergency services, hospitals, research establishments and education standby power is vital and downtime is not an option that these or other businesses can tolerate. In some cases, non-stop power 24/7 must be guaranteed. Users and providers now talk about zero failure and power up-time in terms of six nines. Systems must be reliable for 99.9999% of the time.
Achieving this high power availability is a constant challenge for the standby power industry where a ‘one-size fits all’ approach is not the solution. As we know, when mains power goes off, the standby power system has to operate either by generating power from fuel or by using stored power. Most often, generated power comes from a diesel generator, and stored power from a UPS with lead-acid batteries and usually the two work together to ensure the even momentary gap (which is harmful to electronic equipment) between the power failing and the generator becoming operational is filled.
Which Option to Choose?
There are many factors that may need to be taken into account when deciding which option(s) to pursue. Some will be more important in certain situations than others. Some specifiers will always choose the cheapest option, but it is rare that all factors are equal when comparing various options and so an element of criteria weighting will be inevitable. These are some of the factors that should be considered:-
Location – Are there constraints about the floor area or ceiling height available? Does it need to be situated indoors or out? Will the existing floors carry the required weight of the unit? What is the lift load-carrying capacity? Are there awkward access arrangements for delivery and installation? Are there any restrictions in the building lease?
Rack mountable – Some users, especially in the IT environment prefer this approach. Can the unit(s) be mounted in a conventional rack?
Sizing – What size unit in terms of power capacity is needed? Can some of the load be segmented as non-critical and therefore switched off after a successful shut down? Is the capacity likely to be expanded in the future?
Automatic change over options – Are there always going to be personnel on site to deal with any power off situations? How will any automatic change over option work? How will the system notify people what is happening?
Maintenance – Who will look after the system? How often will scheduled maintenance be necessary? Will the system have to be shut down while it is carried out? What security problems may be encountered if this is to be done out of normal working hours?
Planning permission – If the unit is deployed outside, will this be necessary? How long will this process take? Will the land lord need to be involved?
Exhaust emissions and noise – This is often linked to planning permission but not always so. Is the system to be installed in or near a residential area where these issues may be more important?
Incorporating existing standby power products and upgradeability – No one likes to under-utilise an existing investment. Can it be integrated in some way? Can the unit be upgraded as required?
Ensuring evenly matched Genny and UPS – The generator must be large enough to support the load initially supported by the UPS and to ensure that there is sufficient extra capacity to recharge the UPS batteries. The installation must also comply with the current IEEE G53 guidelines on harmonics. This is a specialist area in itself.
Types of fuel – Is there an obvious fuel source already installed? If not, does the user have a preference? Can a new source be installed?
Refuelling – How often will this be necessary? Are the access arrangements awkward? Are personnel in attendance to organise this even in the event of a prolonged mains failure during the night? Will an automatic monitoring facility be required for low fuel or any other occurrence?
Availability – How soon can the unit be installed? Is there a long lead-time before delivery can be made?
Price - What does this include? What warranty is included? How much will delivery cost? How much will the installation cost?
If the decision is taken that extended auxiliary power is required a choice needs to be made between installing either large banks of batteries to keep the UPS powered for longer or a generator running on a separate fuel source. There are advantages and disadvantages with each solution although it is generally accepted that if all other factors are equal there is a financial advantage to a generator if the extended run following a power loss needs to be in excess of 4-8 hours. But there are many situations where a generator may not be a viable option and for those organisations another solution is needed.
The latest alternative is fuel cell standby power. Fuel cells can be regarded as generators but whereas conventional generators use internal combustion engines to rotate an alternator, fuel cells generate power by producing electrons directly, with no moving parts. As a result, they have the potential to be very efficient and reliable. Moreover, they are comparatively quiet and other than electricity and heat, they produce only water vapour. This makes them ideal for indoor use. With the maturing market in fuel cell technology and increasing awareness of environmental issues, a standby power solution incorporating a fuel cell is now the third alternative..
Why fuel cells now?
UPS Systems has been monitoring fuel cell developments for several years and we are convinced that fuel cells now offer a viable alternative in certain situations. There are areas where the current offerings aren’t suitable e.g. where system requirements are in excess of 60kW. However in the 10-60kW application range which incorporates a lot of smaller IT departments, the option could now be considered.
Firstly, let’s consider why a UPS only solution might be put forward:-
• The systems to be supported are not mission critical or require only limited auxiliary power before a safe shutdown is effected
• The power draw of the mission critical system is low enough that a single UPS can support it for many hours
• There is no room for anything else in or outside
• There are environmental issues if the unit is placed outside. Councils often place stringent restrictions on working equipment and require detailed planning permission
• There may be a company policy, biased against noise or pollution caused by generated power
• There may be personal expertise or preference to stay with one manufacturer
• Internal politics or budgets may prefer several smaller departmental units rather than a single large one
• Security and access policies may prevent equipment being sited outside
Then consider why a UPS and generated power solution might be put forward (whether conventional or fuel cell):-
• Where the size of the batteries needed is excessive
• Where there is more room available outside for generator than inside for batteries.
• 24/7 protection is required and a refuelling contract option needed
• Where shared resource is more economical between several departments or different companies operating within a whole building, especially if a landlord is contracted to provide support
• Where there is a requirement for air conditioning which is better protected by a generator
Now let’s look at the advantages of using a fuel cell as opposed to diesel generator:-
• Standard hydrogen bottles offer a green alternative to conventional fuel and/or batteries
• Unlimited runtime - simply increase the number of bottles
• Low audible noise – no fans and pumps- suitable for indoor installations
• Only heat and water by-products so safer for the environment
• In larger systems the waste heat from a fuel call can be used to provide hot water or space heating
• Easy indoor installation- no major planning permission required
• Modular rack integrated design – easy to add more power
• Few moving parts, so less need for maintenance
• Politically reduces dependence on oil
• Some factories and plants may already have hydrogen installations or can utilise hydrogen produced by existing processes
• Certainly lighter than batteries and lighter than many conventional generators
• More energy efficient in power terms than either a battery or generator
• Generated power close to or inside the computer room
And the advantages of a conventional generator:-
• Tried and tested technology
• More expertise around if there is a problem
• Established supply chain for fuel
• No ‘Hindenburg’ fear factor
• Currently cheaper than fuel cells
• Can deal with much larger loads in kVA terms
Making the right choice on your own will not be easy and we would always recommend working with an independent and impartial supplier that will remove any complexity from the purchasing cycle and help to match one of the three standby power alternatives to your individual requirementsu
- Font Size
- Reading Mode