The fast and wide diffusion of electricity was helped also by cheap prices. In Vietnam, the 2019 average retail electricity price was about 8.1 US cents/kWh, compared to 14 US cents/kWh in the United States and 31 US cents/kWh in Germany in 2018 (Phu, 2020). These low tariffs are maintained by government regulations. A subsidised scheme charges lower tariffs from small or marginalized users with financial difficulties and compensates with higher tariffs from large consumers of electricity (Phu, 2020).

The cheaper electricity in Vietnam compared to its neighboring countries had also an impact on the industrial development, fostering investments in energy-intensive industries, such as mining, steel and cement. As a result, Vietnam is currently the largest steel producer in Southeast Asia and the eighth largest cement exporter worldwide. However, Vietnam's steel and cement producers are highly energy inefficient and less competitive with respect to their regional counterparts (Hien, 2019). Inefficiencies depend also on Vietnam’s source of energy, which is a mix of oil, coal, natural gas and hydropower.

One of the consequences of the rapid growing energy consumption, is the inability of Vietnam to selfsupply its domestic demand. Since 2015, Vietnam became a net energy importer with negative potential consequences for energy security. The fast growth in energy consumption corresponded also to an increase of emissions per capita of 24.7% (GSO data). The 2018 index of renewable energy on total primary energy supply decreased by 10.1% (GSO data). This makes it challenging to meet Vietnam’s Nationally Determined Contributions to the Paris Agreement which target is a reduction of 8% GHG emissions by 2030. The most promising renewable energy sources for Vietnam are hydro, wind and solar energy, with contributions from biomass, biogas, geothermal and solid wastes (Shem et al., 2019). However, their market competitiveness is strongly challenged by the low electricity and coal prices.

In correspondence to the diffusion of electricity, also the telecommunication sector had a fast and wide development. Since 1995, the year of introduction in the country of the global system for mobile communication (GSM) and code division multiple access (CDMA), the telecom market has grown about 79% per year untill 2008 (Hwang et al., 2009). Initially, the Vietnamese telecom market was a monopoly with only one firm, the Vietnam Post and Telecommunications Corporation, and a weak competition between its two subsidiaries Vinaphone and Mobiphone (Hwang et al., 2009). Important reforms started at the beginning of the 2000s, when the government promoted competition by opening to foreign companies. The first Korean mobile telephone services started in 2003 and since then the competition continued growing, although the government set up a pricing control regulation (Hwang et al., 2009). A second policy stepstone was the 2005 “Program on the provision of public telecommunications services till 2010”. The objective of the programme was to improve telecom access to all households living in areas with a tele-density below 2.5 sets per 100 inhabitants by subsidizing: the development of telecom infrastructures in all districts; public telephone and internet centers; fixed telephone and internet services to rural users. In five years the program achieved many of its objectives. At the end of 2010 the tele-density raised to 16 sets per 100 inhabitants, the penetration of the internet services doubled, the public telephone and internet centers were operating in 97% of communes across the country (Thai and Falch, 2018).

# **3. Literature review**

In Vietnam the General Statistics Office (GSO) regularly collects household consumption data as part of the longitudinal household living survey. The first Vietnam Living Standards Survey (VLSS) was conducted in 1992 and the second in 1997. Since 2002, the Vietnam Household Living Standards Survey (VHLSS) is conducted every two years. This generated an abundance of household consumption data with respect to other countries that conduct household surveys less frequently. As a result, there exist a relatively high number of studies analyzing Vietnamese household consumption patterns and elasticities, especially with respect to studies fousing on Sub-Saharan African or Caribbean countries. In this review we focus on studies conducted in the last 20 years.

An advantage of looking at the literature on consumption elasticities in Vietnam is that, thanks to the above mentioned data availability and number of studies, it is possible to analyze differences across applications of different demand systems and econometric strategies. However, most of the studies on 5