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 Introduction:
Power supply- and power backup systems based on fuel cell technology have just recently been introduced to the market on pure commercial basis. The overall records for the use of this technology in telecom base stations has proven its reliability, durability and availability at a couple of thousands installations around the world on systems manufactured by the different providers on the market.
Dantherm Power is focusing on selling the products with a gross margin as one of the few suppliers in the market if not the only one. The rest of the providers are still dependent on subsidies and funding or sell the products with a significant loss.
We’ve managed to base our solutions on the simplest air-cooled technology that especially in systems below 5 kW net output power can be manufactured in a very cost efficient way. Also the simplicity of the system improves the reliability as there’s only very few mechanical parts within the system compared to the more complicated liquid cooled solutions that are based on a number of very special made mechanical components with a relative short lifetime. In addition to this the air-cooled systems are almost maintenance free where liquid cooled systems requires frequent service and maintenance.
With a new technology just being introduced to the market we can guarantee that cost will go down as volume goes up.
If you have a business case today you’ll definitely have it in the future…..
Fuel:
The fuel cell systems can be based on either pure hydrogen or some kind of liquid fuel. Systems based on pure hydrogen are the simplest products and these are already available from Dantherm. These systems are suitable in areas where power outages are quite rare. As hydrogen has a very low energy density in relation to its volume it’s difficult to use pure hydrogen as a fuel for installations in areas where power outages are very common.
The story of energy density is more or less the complete opposite when using fuel cell systems based on liquid fuel. Dantherm Power will soon be ready with systems based on a mixture of methanol and water (58% methanol and 42% water (vol%)). This solution is primarily optimal for use in areas with frequent power outages. The methanol water mix is inexpensive and very easy to store and transport. In addition to this it reduces the CO2 emission by more than 50% per kWh produced electricity compared with diesel gensets. As theft is a common issue in many areas where diesel or propane gensets are used the methanol water mix cannot be used in normal households due to the high water content. The methanol water mix has a freezing point as low as -54C, which means it can operate in very cold climate where diesel gensets cannot work. It’s easy to store 2-5000 ltrs on site. 1 ltr of methanol water mix gives 1,6 kWh’s of net electrical output.
Example based on Hydrogen:
For a site installation in a Western country the power outages are rare why it’s better to focus on preparing the infrastructure and supply of hydrogen on the rare situation that a long duration power outage do occur. In such a situation it’s far better being able to pay a relative high price when that situation occurs and then have the benefit of a reliable power backup that can continue to run as long as hydrogen is supplied to the system. For site installations in Western countries it’s recommended to remove the batteries and get the full benefit of an environmentally friendly power backup. When it comes to fire hazard the hydrogen is very flammable but when it escapes it dilutes quickly in the air and is therefore very safe to handle when the proper precautions are taken.
Example based on Methanol/water mix:
5 kW power backup system running at an average load of 3 kW that has to be operational 5 hours a day has to produce 15 kWh per day giving 105 kWh per week. A tank of 2000 ltr would give 3200 kWh of electrical output and hence there would be enough fuel for 30 weeks. In such a situation the site should only be visited once every 6 months! This means that it’s far easier to handle and by a proper planning 1 tank truck transporting the fuel should be able to service a high number of sites.
It’s important to mention that methanol is toxic and fatal if swallowed in certain quantities. It must be handled carefully. When it comes to fire hazard it’s less flammable than gasoline or propane but more flammable than diesel.
Fuel Cells compared with batteries:
Initial cost:
- Scrapping cost of batteries are expected to increase in future
- Future cost of batteries is not only depending on lead prices but as well on environmental taxes as used in California.
- Batteries require chargers with a capacity far higher than the nominal load of the equipment inside to ensure a fast recharging of the batteries after a deep discharge.
Operating cost:
- Increased cooling set point within cabinet or shelter as batteries are removed and all electronics can normally cope with + 40C if not higher. This means a big reduction in power consumption for cooling and also the potential of replacing air-cons with either air to air heat exchangers or free cooling units.
Flexibility:
- Fuel cell based power backup system can be installed inside the cabinet or shelter just like batteries but occupies normally less space and are much lighter. It’s typical that 200 kg of batteries can be replaced by 40 kg fuel cell backup system. This of course depending on how much backup time the batteries were providing.
- In installations with use of fuel cells it’s only required to have nominal capacity of the rectifiers as the fuel cell can backup if one module of the rectifiers are malfunctioning. In reality it means that it’s no longer necessary to have n+1 on rectifiers. +1 can instead be the fuel cell.
Reliability
- Difficult to predict the degradation of batteries. It’s often seen that operators expect having 3-4 hours of backup in their batteries but only have 20 minutes when tested.
- Degradation of batteries is constant no matter if used or not where fuel cells only degradate when in operation.
- Battery based backup system cannot handle a new power outage with full capacity until fully recharged. Fuel cells are just depending on either swap of hydrogen cylinders or when based on methanol water mix it will just use of another part of the big tank capacity.
Environment:
- Spillage of acid from batteries has a major impact on people, equipment and local environment.
FC compared with gensets:
Initial cost:
- Genset installations require batteries to obtain zero delay when going from normal power to backup mode.
- As gensets do not always start when supposed to and requires a lot of maintenance it’s often used to install 2 gensets as n+3 (batteries + 2 gensets).
- Installation of diesel gensets often requires a separate building to house the gensets to protect them against weather and as well to reduce the noise. This means a significant extra cost for site installation.
Operating cost:
- Gensets requires a lot of maintenance and expensive repairs.
- Fuel cells generally have higher efficiency at partial load where gensets have far lower.
- Theft of diesel or propane is an issue, where methanol water mix on the opposite cannot be used in normal households.
- Diesel generators located outside are more vulnerable than fuel cell systems installed inside a cabinet or a shelter. Vandalism can easily “kill” a genset. In many 3rd world countries it’s common to have each site protected with guards 24/7/365!
Reliability:
- Gensets do not always start when supposed to, which in critical installations means site visits are required weekly or monthly for starting them up manually.
- Gensets produces AC-power, i.e. it requires an AC/DC rectifier to power telecom equipment. This means it cannot backup a system when rectifiers are malfunctioning.
Flexibility:
- Fuel cells with methanol water fuel can operate in a very wide temperature range from -50 to +65C making it the right solution both in Siberia and Iraq. If the fuel is stored in underground tanks it can operate in even colder environments as the fuel cell backup system is installed inside a cabinet or shelter.
Environment
- The CO2 emission from a methanol water based fuel cell system is app. 400 g/kWh net electrical output where it’s app. 835 g/kWh electrical output from a diesel genset at the best. When operated at partial load the efficiency of the fuel cell system gets higher and hence the emission is reduced where the emission from a genset gets worse.
- Next to the CO2 emission the gensets pollutes the environment and ambient with other particles where the fuel cell is clean.
- The gensets are very noisy where the fuel cell is very quiet and as the fuel cell is located inside cabinet or shelter it’s completely noiseless on the outside.
- Methanol is primarily produced out of natural gas of which there are reserves for more than 100 years hence cost is independent of oil-pricing. This is evident when looking at the methanol price index compared with crude oil index. Sources for these informations are www.methanex.com for methanol and www.nymex.com for crude oil.
- There’s a big potential in producing methanol out of 2nd generation bio-fuel where it’s produced from waste.
- Spillage of diesel in the soil causes a severe pollution and will in some countries require a very expensive cleaning process of the soil. Spillage of methanol water mix can be washed out with water and can easily vaporize.
- Methanol is highly and easily soluble in water where diesel is insoluble in water.
- Gensets are in most cases oversized in capacity in order to overcome the starting torque of compressors in the air-cons. This means that they in 99% of the time will operate at a very low load and hence will have an even worse efficiency. With fuel cell systems it’s recommended to replace the air-cons with free cooling solution or heat exchangers as there are no batteries to keep cool. Alternatively it’s worth to consider use of DC-powered air-cons. In this case starting torque can easily be coped with by use of ultra capacitors which already are implemented within our solutions.
Dantherm Power can at present deliver solutions based on pure hydrogen. Solutions based on methanol water mix will be ready for deployment around 1st half 2009.
Dantherm Power have in several cases proved that use of fuel cells not only brings benefits as reliability and environmentally friendly power source to the customer but as well can contribute with a saving in Total Cost of Ownership (TCO). Normally batteries gets more expensive when backup time is more than 3-5 hours and diesel gensets when the power requirement is less than 6-8 kW and backup time is more than 3 hours per day.
Dantherm Power can assist in making the comparison in TCO but it’s required that the end customer is honest and open about all cost information related to the sites. We’ve often seen that some operators fully believe that batteries can last for 10 years even though they are installed in warm environments or a frequently discharged. |
