Impacts on climate change of transition to LPG for household cooking
What is LPG?
Liquefied petroleum gas (LPG), also called ‘bottled gas’, is a clean burning portable fuel and produced today primarily as a by-product of oil and natural gas production and oil refining. Small, but increasing amounts of bioLPG are now produced, which can be distributed through existing LPG storing, bottling and distribution infrastructure and combusted in all existing LPG stoves and other uses without additional investment . It has many applications, including cooking, heating, and in industrial processes (e.g. plastics production); currently, more than 2.5 billion people use it for cooking globally [1].
The International Energy Agency (IEA) has consistently recommended that LPG should play a substantial role in tackling household energy-related air pollution emissions. For example, in the 2017 ‘From Poverty to Prosperity’, LPG is proposed as a clean cooking solution for over half of the 2.8 billion people still needing access to clean cooking fuels and technologies [1]. The World Health Organization (WHO) also recognizes LPG as a clean fuel well suited to addressing the challenge of Household Air Pollution (HAP).
A global surplus of LPG exists and close to 30% of current global production is used as a feedstock for the manufacture of plastics in developed economies [2, 3]. As economically viable alternatives are available for this process, it would be much better to use this clean, efficient and convenient fuel to mitigate the global public health consequences from HAP) which still causes some 2 to 4 million premature deaths annually [4, 5].
Why is LPG considered a clean fuel?
LPG – unlike other fossil-derived fuels such as coal and kerosene – burns very cleanly in simple, widely available and relatively inexpensive devices (e.g. household LPG stoves) with almost no particulate formation [6]. LPG stove efficiencies in low and middle-income country settings are in the order of 51% ± 6% [7], and in contrast to solid biomass, LPG burns cleanly independent of user operations [7, 8]. Because of its chemical characteristics (LPG is a mix of propane and butane), it is easy to produce in a highly purified state without intrinsic contaminants, such as sulfur, that would produce health-damaging air pollution [6]. Completeness of combustion can be consistently achieved with LPG and this is the reason for the very low levels of climate forcers other than CO2 in emissions from burning this fuel [2, 6].
Does LPG for clean cooking contribute to climate change?
Although LPG is a fossil fuel, the net impact on climate change in settings where solid biomass fuel is the main alternative is neutral or actually beneficial. The growing body of evidence supporting this conclusion is summarised in a recent (2017) commission by KfW (the German Development Bank) and subsequent literature [9-11]. LPG use can protect forests from being depleted for charcoal and firewood production and use (primarily sold in urban and peri-urban markets), hence contributing to preserving the environment and capturing CO2 emissions. In addition, LPG combustion releases very low levels of short-lived climate pollutants (i.e. black-carbon and methane) in comparison with inefficient solid fuel stoves [12].
Gas-based cooking (including both LPG and natural gas) is recommended by the 2018 as mitigation measures to reduce BC emissions [13] while generating a negligible increase in CO2 emissions, which can in principle be offset by reduction in forest degradation/deforestation resulting from avoided wood-fuel and charcoal use [9]. Preservation of forests and habitat conservation through adoption of LPG for household cooking would contribute to the , an initiative that aims to deliver up to 30% of the climate solutions needed by 2030. Forest cover is also vital for soil stabilization, flood control and protection against extreme heat in urban and peri-urban settings.
Why is LPG recommended by the WHO, the IEA and leading experts on health and climate change, as a clean cooking household fuel to address air pollution, protect health and the environment?
Switching to LPG for cooking in developing countries will reduce the health burden associated with household air pollution and other problems associated with solid fuel use. The World Health Organization (WHO) Indoor Air Quality Guidelines for Household Fuel Combustion recommends that community-wide transition to clean fuels such as LPG, biogas and electricity is required if air quality is to consistently achieve WHO guideline levels of particulate matter (PM)[14]. LPG provides significant direct health benefits and associated climate and environmental co-benefits [1, 2]. It also provides important quality-of-life benefits as it saves time for cooking, cleaning (e.g. soot-blackened cooking utensils and walls) and fuel gathering; women in particular, as well as school-aged children, will have more free time in which to pursue educational, income-generating or leisure activities [1].
Rosenthal et al. in the figure below show modeled impacts on health and climate change from stove replacement programs using LPG compared to improved and advanced biomass cookstoves. As reported by the authors: ‘these results suggest that the median country (i.e. the median of the distribution of model outputs) would avert the loss of 4x more Disability Adjusted Life Years (DALYs) and avert over 100,000 more tons of CO2 equivalents by instituting a 25,000-household LPG intervention compared to one using a basic improved biomass stove. Averted Global Warming Commitment (GWC) will be highest for countries with high rates of non-sustainable biomass use, but under all scenarios LPG outperforms improved biomass stoves’. Even in comparison to advanced biomass stoves assisted by fan (whose performance is still dependent on fuel moisture content and users operations), LPG would provide slightly better benefits on health and climate.
Source: reproduced by Rosenthal et al. 2018 [15]. The figure illustrates Averted Disability Adjusted Life Years (DALYs) and Global Warming Commitment (GWC) in each of 40 countries for three stove intervention scenarios (LPG, advanced biomass stoves with fan and improved biomass cookstoves) both with the fraction of non-renewably harvested biomass (fnrb) below and above 50%.
Are there any studies that quantify the climate impacts of country-level transitions to LPG for clean cooking?
A number of studies have been published on this topic. Two recent ones are summarized here, covering India and Cameroon.
Singh et al. 2017 estimated a saving of 7.2 million tons of firewood between 2001 and 2011 attributed to adoption of LPG as a cooking fuel in India. This study, based on census data and nationally representative survey data, estimates net emission reductions of 6.73 MtCO2e due to firewood displacement from increased access to and consumption of LPG as primary and secondary cooking fuel. This estimate is based on taking into account both Kyoto and non-Kyoto climate active emissions and assuming 0.3 as the fraction of non-renewable biomass harvested [9]. Considering only Kyoto gases, authors estimate a net emissions decrease of 0.03 MtCO2e, which is still protective for the climate.
In Cameroon, a study by the Centre for International Climate and Environmental Research (CICERO) and the University of Liverpool[1] estimates the projected climate and health impacts of government planned LPG expansion (National LPG Master Plan) to meet the announced national goal of 58% of the population having access and sustainably using LPG for cooking in 2030, compared to less than 20% in 2014 [16].
Results include:
- 23,000 lives saved and 760,000 averted disability-adjusted-life-years compared to the observed and projected ‘business as usual’ trend in LPG adoption (which projects an increase to 32% by 2030);
- reduced climate emissions of more than a third, leading to net emission reductions of -4.4 Mt CO2-equivalent;
- a global cooling of -0.1 milli °C in 2030 (calculated assuming 50% renewable biomass, given the uncertainty range of 0-50% for the fraction of non-renewable wood harvesting (fNRB) in Cameroon [17]);
- over a longer timeframe, it is estimated a global cooling of -0.64 milli °C (assuming 100% renewable biomass) or -0.93 milli °C (with 50% renewable biomass) will be achieved if LPG reaches 73% of the population in 2100 [16, 18].
Can LPG be produced from renewable resources and still be used for household cooking?
BioLPG is a fully renewable fuel made from a mix of wastes and residues. The fuel is identical to fossil-fuel derived LPG and can be stored, distributed and burned using the existing LPG infrastructure, cylinders, regulators and stoves. BioLPG production was initiated in 2015 in Rotterdam for the European autogas (transport) market. If bio-LPG production is increased and made available for residential use, households in developing countries could benefit from a clean and modern fuel, which is also fully renewable.
Would large-scale investment in LPG make it harder to develop other forms of clean energy for cooking?
In the transition towards universal use of clean cooking fuels, country governments will be looking at strategies that address the energy needs of their varied populations over time, involving a portfolio of energy carriers and technologies to meet cooking and other household requirements. LPG has an important role to play in this transition, especially over the period to 2030, as it is the fastest scalable solution. This potential for rapid scale-up has been demonstrated by Indonesia and India [19], where many millions of households have adopted LPG as a cooking fuel in just a few years. While LPG does require investment in import terminals, storage facilities, cylinder assets and distribution, this is less intensive and more adaptable across national territories than the investment required for electric grid and natural gas distribution [2].
LPG is one of several modern, clean and efficient cooking solutions, all of which need to be considered for national energy sector and overall development planning. Governments would need to decide on the role LPG should play in their energy strategies and for which sub-groups of their populations, noting that these groups will evolve over time with economic growth, demographic change and energy investment. India has demonstrated that after establishment of LPG distribution in urban areas, cylinders can quickly be transferred to peri-urban and rural areas leaving urban areas to adopt other modern forms of energy (e.g. grid electricity and natural gas). In rural areas, LPG will most likely continue to co-exist with use of biomass, unless specific strategies are in place to make LPG easily available, reliably distributed and affordable among for these populations.
Finally, if bio-LPG is made more widely available in the future, there will be no need for further investment in the supply chain as it can be blended with conventional LPG and used by all existing appliances suitable for LPG use.
What about the environmental impacts of the overall process of LPG production, supply, distribution and use? Are there any studies comparing LPG with the main cooking alternatives?
The types of study that comprehensively examine and evaluate the impacts of all stages of production, supply and use are known as ‘life-cycle analyses’. Two recent studies of this type conducted by the US EPA have looked at overall emissions in each step of the fuel cycle (from sourcing to end use) for a number of cooking fuels, including LPG in India and China [8], and the same study has more recently been revisited and expanded to Kenya and Ghana [12].
Results from the life cycle analysis across four stages (production, processing, distribution and use) show that emissions resulting from fuel/stove combinations at point of use (i.e. stove emissions) are the most important contributors to overall climate impact, for both CO2 and BC equivalents [12].
Of the two production routes for LPG, namely through natural gas production and crude oil extraction and refining, the former has the lower Global Climate Change Potential (GCCP) between the two. These studies show that LPG has a lower environmental impact in comparison with solid fuel cooking (firewood and charcoal), especially when less than 60-70% of the biomass is renewably harvested and LPG is produced from natural gas. For BC-equivalent emissions (i.e. all short-lived climate pollutants), the impact of LPG was very much less than that of biomass, and similar to other clean fuels such as natural gas, biogas and ethanol [8, 12].
Would flaring of LPG be bad for the climate?
LPG is an inevitable by-product of natural gas and oil refining. Where not extracted and captured during the operations, the gas is flared into the atmosphere contributing to greenhouse gas. There are already initiatives underway e.g. by the World Bank to reduce gas flaring in countries such as Nigeria. An increase in LPG production and capturing, with optimization in industrial gas separation plants, would reduce the climate warming caused by flaring and result in more LPG being available to the household residential or other markets [20].
How does the IPCC Special Report on 1.5°C consider LPG?
In of the latest IPCC report, Section 4.3.6 - Short Lived Climate Forcers, gas-based cooking is included as one of the options to reduce short-lived climate pollutant emissions (black carbon) consistent with a 1.5°C scenario. In addition, the report acknowledges that lack access to clean and affordable cooking energy is a major policy concern and recognises that stringent policies to reduce warming to a 1.5°C temperature increase can negatively affect the transition to clean cooking fuels, such as LPG or electricity (see - Lack of Energy Access/Energy Poverty, copied below).
Is the climate-protective role of LPG for cooking recognised by the Gold Standard and eligible for carbon credits?
Yes. A number of LPG projects are registered under the Gold Standard, including the by Practical Action and the UK-based company Carbon Clear. This is a microcredit intervention initiated in 2010, with over 11,700 LPG start-up equipment sets sold to date and emissions savings sold as carbon credits. The project received the . Gold Standard-registered projects like this, where carbon emissions are verified, contribute to the evidence base on the relatively benign role of LPG-burning cookstoves in respect of the climate and positive contribution to forest protection.
Prepared by Dr. Elisa Puzzolo, Senior Research Fellow affiliated with the Department of Health and Policy at the University of Liverpool.
References
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14. WHO, Indoor Air Quality Guidelines: Household Fuel Combustion. 2014: Geneva: World Health Organization.
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16. Kypridemos, C., et al., The Climate and Health Impacts of Achieving National Target Levels of Liquefied Petroleum Gas (LPG) Adoption in Cameroon: Findings from Policy Modelling According to the Cameroon National LPG Masterplan. 2018: ISES-ISEE 2018 Abstract Book. Addressing Complex Local and Global Issues in Environmental Exposure and Health.
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18. Kypridemos, C., et al., Health and climate impacts of scaling adoption of liquefied petroleum gas (LPG) for clean household cooking in Cameroon: a modelling study. Submitted to Environmental Health Prespectives, 2018.
19. Thoday, K., et al., The Mega Conversion Program from kerosene to LPG in Indonesia: Lessons learned and recommendations for future clean cooking energy expansion. Energy for Sustain Dev, 2018. 46: p. 71-81.
20. Bahmani M, Shariati J., and Rouzbahani A. N, Simulation and optimization of an industrial gas condensate stabilization unit to modify LPG and NGL production with minimizing CO2 emission to the environment. Chinese Journal of Chemical Engineering,, 2017. 25(3): p. 338-346.
[1] Manuscript submitted for peer-review. and refereed conference abstract publicly available.