What Determines Generator Price?

Two quotes for the same power rating, for example 500 kVA, can differ significantly in price. The difference usually lies in the scope of the quote: whether the power rating is standby or prime, whether a canopy is included, and whether the ATS and transport are included. Choosing the lowest quote without checking these items can lead to additional costs and lost time later.

A generator price is not a single number. It is a list of items. In this article we open that list the way someone on site sees it. We give no figures, because the price is calculated differently for every project and given in a quote. But if you know which item pushes the price up and why, you can compare quotes properly.

1. Engine: the biggest item

In a diesel generator, the engine is usually the largest part of the cost. Between engines of the same power, the price difference comes from the brand, country of origin, emission level, fuel system (mechanical or electronic) and the duty the engine was designed for.

The Terex Diesel range includes options with Perkins, Baudouin, Cummins, FPT Iveco, Kofo, Kubota, Quartz, Scania, SDEC, Volvo Penta, Yangdong and Yuchai engines. Which one fits is decided by the site as much as by brand preference: fuel quality, running hours, ambient temperature, local service and parts availability. There is no single “best engine”. There is the engine that suits the job.

2. Alternator

After the engine, the alternator is the second biggest item. Its price depends on the brand, insulation class, temperature rise class and excitation system. Options such as permanent magnet generator (PMG) excitation keep voltage more stable during motor starting and with harmonic loads, but add cost. On some projects the alternator is upsized by one frame. That shows up in the price too.

3. Power: kVA and rating class

This is the item that misleads most. The same set is labelled at one value as standby and at a lower value as prime. Typically, prime power is around 90% of standby power. If one quote gives a standby figure and the other a prime figure, you are not comparing the same product. For details, see our article on standby, prime and continuous power.

The second trap: buying a bigger set than you need. Excess power raises both the initial investment and the problems of running at low load. Pin down the requirement first: power calculator.

4. Canopy and noise level

There is a clear price difference between an open-type set and one with a soundproof canopy. Within canopies the difference is large too. A canopy aiming for around 75 dB(A) at 7 metres is not the same as one aiming for around 65 dB(A). A quieter canopy means thicker insulation, larger air paths and usually a bigger enclosure. Sheet thickness, paint system and anti-corrosion treatment also go into the cost.

5. Control panel, ATS and synchronization

A basic manual-start panel and an automatic mains-monitoring controller are not the same thing. Add an ATS transfer panel, a remote monitoring module, or synchronization equipment for paralleling several sets, and the price goes up. Check whether the quote states the ATS current rating and number of poles.

6. Fuel tank

A standard base frame tank is usually sized for a few hours of running. If long autonomy is required, you need an enlarged base tank or an external tank. Options such as a double-walled tank, a level sensor or an automatic fuel transfer pump add cost.

7. Transport, installation and commissioning

An “ex-works” price and a “delivered and running on site” price are not the same thing. Transport, crane, exhaust line, cabling, earthing, fuel connection and commissioning tests are separate items. For export, add packing, customs and the delivery terms (Incoterms).

8. Exchange rate and raw materials

A large share of engine, alternator and panel components are priced in foreign currency. Steel, copper and freight prices also move from period to period. That is why quotes are usually issued with a set validity period.

9. After-sales

Warranty cover, scheduled maintenance, spare parts availability and service support are part of the total cost. Warranty terms vary by engine brand and product, and should be stated in writing in the quote. At Terex Diesel the warranty covers the whole set: 5 years or 3,000 operating hours for Quartz-engined sets and 2 years or 1,000 operating hours for other engine brands. Warranty outside Türkiye: 12 months or 1,000 operating hours for all engine brands.

Common mistakes on site

• Comparing standby with prime. Same kVA on paper, a different set on site.
• Thinking about the canopy later. When a neighbour complains or regulations apply, an extra canopy cost appears.
• Forgetting the ATS. The set arrives, but the panel that would bring it online automatically was never in the quote.
• Missing the installation items. Exhaust, cabling and earthing costs are left to the end.
• Looking only at the initial investment. Over the set’s life, fuel and maintenance can exceed the purchase price. Use the fuel consumption calculator for an estimate.

Quote comparison checklist

• Is the power standby or prime? Under what conditions is the figure given?
• Are the engine make and model stated?
• Are the alternator make, model and class clear?
• Are the canopy type and the noise level at a stated distance given?
• Which controller model, and with what features?
• Is the ATS included? Current rating and number of poles?
• What is the fuel tank capacity, and how many hours of running does it cover?
• Are transport, installation and commissioning included?
• Are the warranty period and terms in writing?
• What are the quote’s validity period and currency terms?

Next step

Price only means something once your requirement is clear. Share your load list, type of use and installation location, and we will prepare a quote with every item spelled out. To see suitable models, use the product finder; for a quote, contact us.