We've just spent a week-long road test in Ford's Fiesta ECOnetic. Unless you've been living under a rock for the past few months and haven't noticed, this is the car that is heading Ford's push in this green segment against Toyota's Hybrid Prius. The cars come from a totally different philosophy yet are aiming at the same result. Better economy and lower emissions. Prius is petrol/electric while the Fiesta ECOnetic is diesel-powered.

Official economy figures for Prius are 3.9 litres/100 km combined cycle. The Ford is 3.7 litres/100 kms. Brownie point to Ford. Prius emits 89 g/km compared to the Ford's 98 g/km. Brownie point to Toyota. An interesting point to this is as a motoring writer I often get asked about a car's economy. Not once have I been asked about a car's emissions.

Where comparisons between Prius and ECOnetic become significant is the bottom line. ECOnetic is $24,990 driveaway. Prius starts at $39,990 and that's before statutory government charges and delivery costs. Several brownie points to Ford. There's a cost attached to new technology as significantly different as the Prius which is a link vehicle between economical petrol-only cars and electric-only cars of the future. We have also fielded calls querying the ECOnetic's price compared to other Fiesta models, which start at $16,990. Kermit the frog used to say it wasn't easy being Green. Nor cheap it appears.

Fiesta ECOnetic fits into the picture as a mass-produced eco five-seat small car using refinements of existing technology. The diesel engine has been around almost as long as the automobile and recent improvements in injectors and fuel delivery systems, have resulted in a range of economical engines across all makers.

With ECOnetic Ford have taken the technology further by adding economy-based refinements to the Fiesta base. These are aimed at reducing fuel consumption and in doing so lowering emissions and include the specially calibrated 1.6 litre turbo-diesel engine, low rolling-resistance tyres, a unique transmission with taller final drive ratios, improved aerodynamics and weight reduction. In addition there's a driver's aid in the form of a green arrow in the instrument cluster that tells the driver the optimum time to select the next gear for peak economy. As you driver through the gears the green light arrow comes on suggesting you select the next gear. As someone who has been on many a economy run during car launches, the system is interesting in that you would think you are changing gears at too lower rev count. Which means I just learned something about driving more economically in all cars.

One of the fascinating elements of driving any car aimed at economy is you soon find yourself in a one on one battle with the digital instant fuel read out. Few is best and you will try just about anything to squeeze the car into giving you a lower read out. That has to be good as the lower the economy the lower emissions.

With perhaps the main driving difference between the ECOnetic and other members of the Fiesta clan being low rolling resistant tyres, the driving experience is much the same. In other words it's not a radical departure in driveability from any other Fiesta, not for that matter any other small, four-cylinder city-slicker car. With the current LX Fiesta the Australian Small car of the Year with the Motoring Clubs of Australia giving the award based on Fiesta's money, safety, security and space the ECOnetic comes highly recommended – apart from the money consideration.

Ford claims the ECOnetic will return 4.6 litres/100 km on city cycle and as little as 3.2 litres/100 km on highway running. During our week we were slightly above these figures, but still returned the car with enough diesel to last another three weeks at the same rate. Filling up once a month – now that's being kind to the wallet. Those shopping ECOnetic against Prius and Mini Cooper D will find the sums, on price alone, lead to ECOnetic. Fiesta-only shoppers may discover a different result. On driveability, economy, emissions, and price, the argument for ECOnetic is compelling.

CL 1.6 petrol $16,990

LX 1.6 petrol $18,790

Zetec 1.6 petrol $20,990

ECOnetic 1.6 diesel $24,990

(Add $1500 for 1.4 litre, automatic transmission variants in CL, LX and Zetec)

ABS Brakes: Standard

Air Conditioning: Standard

Automatic Transmission: N/A

CD Player: Standard

Central Locking: Standard

Cruise Control: Standard

Dual Front Airbags: Standard

Front Side Airbags: Standard

Stability Control: Standard

Traction Control: Standard

ENGINE:

Capacity: 1.6 litres

Configuration: In line

Head Design: 16 valve DOHC

Compression Ratio: 18.3:1

Bore/Stroke: 75.0 mm x 88.3 mm

Maximum Power: 66 kW @ 4000 rpm

Maximum Torque: 200 Nm @ 1750 rpm

Driven Wheels: Front

Manual Transmission: Five Speed

Automatic Transmission: N/A

Final Drive Ratio: 3.05

Length: 3950 mm

Wheelbase: 2489 mm

Width: 1722 mm

Height: 1471 mm

Turning Circle: 10.2 metres

Kerb Mass: 1088 kg

Fuel Tank Capacity: 40 litres

Towing Ability: N/A kg (kg with braked trailer)

Front Suspension: MacPherson struts

Rear Suspension: Twist beam and coils

Front Brakes: Ventilated discs

Rear Brakes: Drum

0-100 km/h Acceleration: N/A seconds

Type: Diesel

Combined Cycle (ADR 81/01): 3.7 L/100km

Greenhouse Rating: 9/10

Air Pollution Rating: 5/10

3 years/ 100,000 km