Last week, Romain talked about his biomass energy study in Cambodia. Today, he share with us some of the results…

To begin, could you remind us what does energy efficiency mean?

Romain: Yes, of course. To analyse in-depth energy efficiency of a particular fuel, we have to take into account all the different steps needed to produce it until it arrives in your cooking device.

First, there is the primary energy (fuel, in the rough). Then comes the conversion (only concerns some fuels like charcoal, LPG…). The 3rd step is related to the final energy (processed fuels), and finally the useful energy (fuel transferred from the fuel and through the cooking device, in our case).

What’s more efficient, charcoal or wood?

Romain: First of all, we can have the impression that charcoal is the more efficient fuel. However, we have to include primary energy in our calculation and thus we realize that charcoal is the result of a huge energy waste in Cambodia.

Let’s compare charcoal and wood:

Charcoal production represents 56% of woodfuel for domestic cooking and provides only 20% of the final energy services. Whereas wood for firewood is 44% of woodfuel but represents around 70% of the final energy services provided.

Indeed, the wood conversion to make charcoal leads to a 77% energy loss, only 23% of the total energy is conserved during this step. Firewood doesn’t need this conversion step. Thus, charcoal is in a way more energy-guzzling (and its conversion process can be improved) compared to firewood.

To go further in our comparison, let’s consider a family living in a peri-urban area on the outskirts of Phnom Penh.

For cooking, they use a NLS with 75% of charcoal and 25% of firewood.

If we compare the fuel costs (USD/kg) and the costs of the energy contained in the fuels after their conversion (USD/GJ, final energy), we get very different results. It turns out one Gigajoule (GJ) contained in firewood costs 6.3 USD whereas one GJ contained in charcoal costs 11 USD. Regarding LPG, one GJ contained in it costs 25.6 USD (biggest cylinder).

About the final energy, we should stress that wood is only twice less expensive than charcoal, whereas if we compare one kilo of firewood and one of charcoal, the latter is almost three times more expensive. Let’s do the same exercise with LPG. For one kilo, it’s almost 16 times more expensive than firewood. For one Tj, it’s only 7 times more expensive than firewood.

Why. Because gas contains more energy than wood.

Now, let’s see how much useful energy costs to a family in Stung Manchey.

If we add the ICS cost (5.7 USD a year) to the charcoal and wood costs, the total is 143 USD a year. Thus, the family will spend 149 USD a year.

Let’s change the scenario: if 75% of the time a KhRoS (rocket stove) is used with  charcoal and 25% of the time a NLS is used with wood, the family will spend 7.6 USD a year for the devices, and in total 141.6 USD a year. It’s the less expensive scheme!

If the family cooks only with LPG, the devices would cost 17.1 USD a year and the fuel 160 USD. It’s one of the most expensive options.

We should keep in mind that the fuel costs vary according to the area (urban, peri-urban, and rural) and the devices. Also, the cost of charcoal is becoming more expensive. If we add less than 5 cents to the actual price of the charcoal, it will become more expensive to cook with charcoal than with LPG.

To compare energy prices, it’s not enough to take in account only the fuel costs but to compare the costs of the energy contained in these fuels and the cost of the device used.


To date, you say that households use 2.6 devices on average to cook, why this mix of devices?

Romain: Traditionally, the 3-stone fire and the Mong (also called Siam) were used. The latter is still in use and households who live in stilt houses on the water like it because it’s on the ground, they can feed the device with wood and it’s not too risky for their wooden houses.

Traditional stoves are cheaper and enable all kinds of cooking processes. You can grill, stir fry, simmer all different ingredients and they match perfectly with cooking the traditional meals like grilled fish, soup, stew…

To date, the TLS [traditional stove in Cambodia] represents 47% of the market share, it’s newer than the 3 stone or the Mong and it’s more efficient and cleaner. Next, comes LPG stoves, and then the improved cookstoves named NLS (designed and implemented by GERES), after that, the rice cooker, the NKS (another improved cookstoves designed by GERES) and then the Mong and the 3-stone fire.

However, some people can afford to cook only with gas, why keep traditional methods of cooking?

Romain: Yes, that’s true. The main reason not to cook with gas, and that’s very understandable, is the high number of explosions in Cambodia because of security reasons, quality of the material in use (cylinder, pipe and their connections, etc.) and bad practices.  About 27% of the population states that they know someone who has been directly involved in a gas accident.

Secondly, people argue that gas is expensive. The users often imagine that cooking with gas is expensive. Indeed, if we compare on a piecemeal basis, it seems more expensive; but if you compare the aggregate cost per year, buying a LPG stove (with a longer lifespan than other devices) and fuel all over the year costs only 177 USD. Meanwhile it costs 149 USD using an improved cookstoves fuelled mainly by charcoal.

Thus, the investment to buy a gas cylinder and the device is a real psychological barrier. At the same time, the poorest households can face big financial issues with such a big investment, even if it’s amortized after some months.

To date, wood consumption as a main fuel is diminishing (65%) and gas is increasing (13%) while the share of charcoal stagnates (18%).

However, if you compare fuel prices, you will notice that if the costs of the charcoal increase is less than 0.10 USD, it will be cheaper to cook with gas (15kg bottle) over one year.

At last, as it was mentioned previously, we have to keep in mind that Cambodian households don’t own one but several devices most of the time for different uses. For example, some families have an improved or a traditional cookstove to grill fish and meat or to boil water and gas is dedicated for other cooking processes (soups, stews…)


Your study brings an overall snapshot of the sector, what’s next?

Romain: Thanks to this study, we are bringing a strong knowledge database on the biomass energy sector in Cambodia. Today, the question is, how to update this data set regularly?

We still have to find some forms of cooperation which would include the government, civil society and other stakeholders interested in project development or either politics according to these data to design new projects.

Finally, it would be interesting to analyse investment capacities of those people, where to find financing opportunities, how to become solvable, etc.

A lot has been done, but a lot still needs to be done!