What quantity of natural gas is required for producing 1 MW hrs of electricity.?

Question

What will be the most economical method of production of electricity from natural gas, what is the current price of gas and what will be the cost of per hr / unit of electricity production. Will it vary if along with the unit a desalination plant is also established? What will be the project cost in each case. Who are the world reknown equipment suppliers.
You may contact me at [e-mail] if you can provide any assistance. Will appreciate any help.

We are planning to set up a project of 1000MW for electricity production along with desalination plant, in Gulf using natural gas. What will be the natural gas requirement for such a mega project and estimated capital goods cost?

Answer 1

The most simple to answer is the first question. 1MWhrs of electricity is 3,6 GJ of electricity and if produced by a large modern combined cycle plant (consisting of a gasturbine, a HRSG (Heat recovery Steam Generator) and a steamturbine) that is a moderate climate at sea level can achieve upto 58% efficiency will need about 7 GJ of natural gas (which is about 70 therm or 70x100000 BRU. The production cost depend ona lot of factors, capital cost of the equipment, local gas prices, operational cost (water, salaries, chemicals a.s.o) and these change with time and place.
The largest scale yields the cheapets capital cost and thus the cheapest electricity. I am talking about scales of 380 MWe or bigger. Lets consider an example:

I assume throughout 8000 h of operation per year.

A large scale combined cycle plant can be installed for eg 700 US$/kW, so for 700$ one produces 8000 kWh per year. Suppose you want your investment back in 5 years than you produce 40000 kWh -> 700$/40000kWh = 1.75 US$ct/kWh.

Natural gas might sell for 7 $/GJ. 1 GJ is about 278 kWh. And because the efficiency is max 58% one needs 1.72 GJ gas to produce 278 kWhe. 7$/GJ * 1.72 GJ / 278 kWh = 4,3 US$ct/kWh.

Lets make a short cut now and assume all other cost to be 1 US$ct/kWh then the full price is:

1.75 + 4.3 + 1 = 7.05 US$ct/kWh

For this you have electrcity at the terminals of the powerplant. On top of this comes all the transformation cost and distribution cost, power lines a.s.o.

If one chooses to do this small scale (output 1 MWe) the numbers change considerable. Efficiency is rather 29%, consumer gasprices might be double, capital per kW might be triple, operation per kWh double. This yields (same summation)

5.25 + 13.6 + 2 = 20.85 US$cts/kWh

To build a desalination plant choice has to be made out of 3 variants:the first two are quite robust and don't need specialized labour, the third is more sensitive, but yiels the lowest cost water. These are "multi-effect distillation", " "Mechanical vapour compression" and "reversed osmosis". The first two at world scale (several 100000 m3 / year) can result in water prices of around 1 US$/m3 and the third perhaps 20% less.

To build these plants normally a tender is organised among some large scale engineering firms (Fluor, Badger, Jacobs, many others) and they will tender on your behalf with gasturbine manufacturers like GE or Siemens or others. Desalination eg. is designed and installed eg. by IDE technologies or Sidem

Answer 2

You will have to tell complete specifications:- Size of Gas turbine Generator,type of cycle process. Purchase price per unit(tariff of electricity sold). Cost shall be enormous including your initial installation cost. Break even point shall be some 5 years or later.Know about some of such plants in Gujarat?.may visit there.

After Sjors_d:-
Has given complete picture. There is no option except Gas as your main fuel.The efficiency of the plant (Heat Rate) may vary slightly with the design of Power Plant ( GTs).So you will have to choose more efficient plant keeping in consideration of the price of it. The Total Cost Of Your Plant may be 1500- 2000 Million $ (USD). t what you are considering now( ie variable costs ),is a future scenario and is ruled out completely as you don't have another fuel choice.

Answer 3

You seem to be from India. So, I'll convert all the calculations to Indian units for you... 1 kg of butane (cooking gas) gives 13 units (kWhr). So, for a unit, you need 1/13 = 77 g of gas.

Butane costs Rs. 150 per 14 kg cylinder (subsidized price for household use), so a unit of electricity will cost you 82 paise, assuming 100% efficiency of conversion.

In practice, you will only get about 50% efficient machine. So, it'll cost you Rs. 1.6 per unit.

Many companies such as Kirloskar engines, Praj industries make generators in India. You may even float tenders in a newspaper for your project. But, IMHO, the main hurdle for your ambitious plans is - regular supply of gas (there's shortage of LPG in India) and the equipment cost. That's why industries, who generate thousands of MW of energy use coal based turbines. Depending upon the location, hydro power is also quite cheap.

Answer 4

Hello All,

If I have a Bio-Gas Production Plant in India. Any my plant produces 1000 M3 of Bio-Gas. How much of Electricity can be produced from the quantity of Gas?

Answer 5

Can't answer the question without knowing how you are proposing to do the conversion, you don't get electricity from gas by doing nothing you will incur energy losses in your conversion so add these to the 1mw then convert into gas.

Answer 6

Combustion of one cubic metre of commercial quality natural gas yields 39 megajoules (10.6 kWh). Equivalently, one cubic foot of natural gas produces 1031 British Thermal Units (BTUs).

In the USA, at retail, natural gas is often sold in units of therms (th); 1 therm = 100,000 BTU. Wholesale transactions are generally done in decatherms (Dth), or in thousand decatherms (MDth), or in million decatherms (MMDth). A million decatherms is roughly a billion cubic feet of natural gas. 1MW = 94 Cubic Meters used

Answer 7

I only wish someone could send me the link of a plud-and-play excel template for calculating power output of CNG gas engines vs Mscf of gas consumption; heat rate; etc.

Answer 8

2 tons

Answer 9

1000mw

Answer 10

Am sorry, I don't know :(