The trial has been so successful that Yorkshire Ambulance Service intends to fit fuel cell units into 103 rapid response vehicles (RRVs) with its next order. The installation is projected to save YAS about £17 000 per RRV based on a three-year vehicle life, and up to 10 tonnes of carbon per year.
Rapid response vehicles are used by the Yorkshire Ambulance Service to respond to emergency calls. They have a target response time of 8 minutes, but often spend large parts of a shift ‘on call’, i.e. waiting to be sent to the next emergency.
YAS began looking for a system that would provide cost and carbon savings for its fleet of RRVs. While waiting for a potential call, the engine can be left running for 65% of a shift, using 0.9 litres of fuel per hour, in order to support electrical equipment such as radios, telephones, computers, and GPS units. But if a vehicle has a flat battery, it cannot respond to calls when required.
‘We have had many issues with diesel costs, and keeping the electric within our vehicles topped up with enough power,’ says Alexis Keech, Environmental & Sustainability Manager at YAS.
Antares (Europe) Ltd designs, builds and supplies auxiliary electrical power systems. It provided YAS with EFOY Pro 2200 direct methanol fuel cells produced by German-based SFC Energy, as well as M10 methanol fuel canisters, to provide battery charging between calls.
The system provided by Antares also includes a virtual alternator contactor set and charger, and is equipped with a text messaging service, to alert YAS when the methanol fuel needs to be replenished.
The fuel cell technology
The EFOY Pro 2200 – launched in late 2009 – has a nominal output voltage of 12 V/24 V and a nominal power output of 90 W. The 8.8 kg system uses fuel at a rate of 0.9 litres per kWh, and has a warranty for 3000 operating hours. In addition, the M10 fuel cartridge – which weighs approximately 8.4 kg – has a capacity of 10 litres, providing 9.1 kWh of energy.
Installation of the fuel cell is ‘brilliantly simple’, according to Antares’ Sales Director, Charles McClelland. ‘The fuel cell comes with the wires, and you just connect it to the battery posts,’ he explains.
The combined system is small enough to fit behind the rear seat in the pilot RRV, and can easily be retrofitted to an existing vehicle. (Another ambulance service is looking at putting it into the passenger footwell.)
The reason why Antares suggested a direct methanol fuel cell is, according to McClelland, that ‘it’s the safest [option] and it gives the longest life. Direct methanol is generally considered safer than, for example, hydrogen.’
Furthermore, it is a proven technology that SFC Energy has already implemented in about 20 000 recreational vehicles.
‘The useful life of the methanol fuel cell is measured in thousands of hours, so you turn it on, turn it off, measure how long you’ve used it for, and deduct that from the number of hours it will live for,’ explains McClelland.
‘If you have a hydrogen fuel cell, however, its life is measured in number of cycles, so if you run it for 10 minutes and then turn it off, that could be 1/500th of its life gone. Hydrogen fuel cells are more suited for applications such as overnight illumination of a footpath.’
In other words, if the fuel cell starts up just before the driver starts the vehicle’s engine, you have not lost much life if using a methanol fuel cell, as compared to a hydrogen system – which makes it the optimum solution for an RRV.
The system can also be used in larger trucks, where the driver spends the night in the cabin, to provide power for cooking facilities and DVD players. McClelland adds that Antares is providing fuel cells for weather stations such as flood warning systems, which are often run on batteries.
The facility for text-message alerts means that the operators do not have to travel out to check the battery, as the fuel cell system will automatically notify them when the fuel runs low.
The downside of using a methanol fuel cell is that methanol is an aggressive substance.
‘You need to be quite careful with the choice of materials [in the system],’ says McClelland. ‘If you go for lower costs you’ll find that the methanol will slightly damage the inside of the pipes, and you get impurities in the methanol. And it’s impurities in the methanol that define the service life of the stack.’
For this reason, Antares opted for the EFOY Pro range from SFC Energy, which it says has a higher material quality than lower-cost options.
The fuel cell system is ‘intelligent’ in that it regulates when it needs to switch on and off.
‘If they use the car every three hours, the fuel cost is nil as the fuel cell hasn’t switched itself on – it doesn’t need to,’ explains McClelland.
‘But if you get to perhaps eight hours and the car hasn’t been used, and the battery has gone down to a level where it’s questionable whether the vehicle will start, the fuel cell will switch on automatically, will bring the charge level up in the battery, and it will take it to fully charged unless it gets interrupted by the alternator.’
The system also alerts the user when the fuel gets low.
‘The methanol fuel cell has a SIM card installed that will send a text message to the suppliers and the ambulance service when the methanol needs topping up,’ says Alexis Keech. ‘A new batch of methanol is dispatched by the supplier when required.’
It takes about 30 seconds to change the methanol canister, and no tools are required. Furthermore, the fuel canister can be changed while the fuel cell is running.
The system’s virtual alternator system optimizes the alternator output to charge the auxiliary battery faster and better than the alternator could have done by itself, according to Antares. The virtual alternator also extends the life of the fuel cell.
‘The job of the virtual alternator is, when the engine is running, to charge the vehicle battery better than the vehicle’s alternator can on its own,’ explains McClelland. ‘That means that when the engine is turned off, you start with a higher battery, so the fuel cell has less work to do. In terms of days used, it lasts longer.’
Making the fuel cell last is important, with a cost range of £2600 to £8000 per system.
‘There are also some really nice side effects,’ adds McClelland. ‘The fuel cell will not allow itself to freeze. It creates heat and warms itself up, and if it’s in the cabin part of the vehicle or car, it means there’s no ice on the windscreen. You have a defrosted, nice warm car to get into even when the engine hasn’t been running.’
Another key benefit is that the vehicle’s user is guaranteed that the battery is in tip-top condition even after a night in the cold.
Does it pay?
Although methanol is more expensive than gasoline, YAS could save between £1.75 million and £2.4 million by not using the engines as battery chargers over the three-year lifetime on a fleet of 103 vehicles, which is the planned initial order from YAS.
‘We are looking at a payback period of between two and three years, dependent on the use of the vehicle and its operation,’ says Alexis Keech.
For Charles McClelland and Antares, it is all about savings: ‘We don’t regard it as a product sell – what we’re saying is: how much money do you want to save? Because if it isn’t going to save you money, it is entirely pointless having one.’
The fuel cell would not, for example, be cost-efficient in a normal private vehicle. RRVs are special in that they have to keep the electrical system running while the vehicle is parked.
‘Fuel cells will only save you money if you routinely turn the engine on just to ensure the battery is charged,’ explains McClelland. ‘Most car owners would get no benefit from a fuel cell.’
According to YAS’s calculations, the fuel cell has been saving between £150 and £400 per month in fuel based on a fuel price of £1.42 per litre for diesel. The carbon saving is an estimated 10–15 kg of CO2 per shift, or on average 5–10 tonnes of CO2 per annum.
For the fleet of 103 vehicles, the net savings after the fuel cell has been purchased have been estimated to be about £1.3 million.
YAS is now looking to retrofit fuel cells to its vehicles, as well as ensuring that new vehicles have fuel cells installed.
‘When budgets allow, we will upgrade our rapid response fleet, dependent on their locations of operation. We will be looking at up to half our fleet having fuel cells installed,’ says Alexis Keech. Half the fleet represents about 700 vehicles.
‘As it is not reliant on fuel stations and is only active when vehicles are on standby locations, the fuel cell is an efficient and cost-effective way of ensuring that batteries do not run flat,’ says Keech.
‘The fuel is considered less of an issue as it is sealed, and when a risk assessment was carried out, [it was found to be] less dangerous than petrol or diesel.’
This article was originally published in the October 2011 issue of Fuel Cells Bulletin