5

**Figure 1 History of LPG prices in the Arab Gulf in 2022 U.S. dollars**

<!-- Start of picture text --> $1,600<br>$1,400<br>$1,200<br>$1,000<br>$800<br>$600<br>$400<br>$200<br>$0<br>Price of LPG in US$ per tonne<br>Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09 Jan-10 Jan-11 Jan-12 Jan-13 Jan-14 Jan-15 Jan-16 Jan-17 Jan-18 Jan-19 Jan-20 Jan-21 Jan-22<br><!-- End of picture text --> _Source_ : RIM LPG Intelligence Daily. _Note_ : Prices are the average of Saudi Aramco contract prices for propane and butane.

The harm caused by the inadequate rate of progress is even greater than what the statistics about primary cooking energy suggest. This is because the metric defined for the purpose of measuring progress for SDG 7.1, “proportion of population with primary reliance on clean fuels and technology,” captures only two of several household activities—namely cooking and lighting but to date heating water, space heating, preparation of animal feed, and other activities have been excluded because such data are seldom collected systematically in national household surveys—and, even if all activities were to be captured, the metric still fails to capture important uses of polluting fuels:

- Information on primary reliance is usually obtained from national household surveys, almost all of which ask about the primary sources of energy for lighting and cooking. Many households use multiple fuels and technologies—referred to in the literature as fuel stacking or stove stacking— and it is unclear what criteria are used to identify primary sources. Is primary use defined by the number of hours each fuel or stove is used, the number of meals cooked, or the number of main dishes made? How do households account for the seasonality of the availability of different fuels, making them dependent on different fuels at different times of the year?

- These surveys offer wood, charcoal, agricultural residues, dung, and coal as solid fuel options to choose from without specifying the stove type. In particular, survey questionnaires to date have not asked about advanced-combustion biomass stoves. As such, households purchasing densified wood pellets and using advanced-combustion gasifier pellet stoves—admittedly very small in number at this time but could grow in the coming years—would be lumped together with households burning twigs and branches over three-stone-fire stoves.

Fuel and stove stacking substantially diminishes the benefits of primary reliance on clean fuels and technology. Primary reliance on clean cooking fuels and technology does not signal abandonment of polluting cooking practices, let alone polluting household energy use. A 2000 publication studying household use of fuels in rural Mexico was among the first to challenge the previously held so-called energy ladder theory (Masera, Saatkamp, and Kammen 2000). The bottom of the ladder comprises wood, agricultural residues, dung, and other potentially free but polluting fuels. As income rises, households move up the ladder to commercial but still polluting fuels such as charcoal, kerosene, and coal. At the top of the ladder is modern clean energy used exclusively by those in high-income countries: electricity,