But as the biofuels crusade heated up in Zimbabwe last year backed by high economic and environmental concerns, Mr Murehwa had his small car fitted with a conversion system from Green Fuel that allows for use of ethanol-blended fuels. However, a few months later, the taxi driver has dumped ethanol-blended fuels after the 270km visit to his rural home in Gutu, Masvingo on E85 in February proved wasteful, renewing simmering worries on the true socio-economic impacts of biofuels.
"Compared to unleaded (petrol), the ethanol blend is used up fast. I am not going back to ethanol," charged Mr Murehwa in an interview last week.
On E85, the blend of 85 percent ethanol and 15 percent unleaded, Murehwa used 10 litres more than he normally would on unleaded petrol, on the same Gutu journey.
That set the taxi driver back US$3 after believing initially he had saved US$11 from purchasing the low-priced E85.
Murehwa represents only one among many drivers who have complained about the inefficiencies of ethanol blended fuels. Others claim it damages vehicles.
Green Fuel, Zimbabwe's biggest producer of ethanol, has routinely dismissed those concerns, despite evidence to the contrary. The Zimbabwe Energy Regulatory Authority says ethanol blended fuel is safe.
Biofuels such as ethanol or biodiesel have emerged as an important energy source worldwide. They achieve the twin benefits of minimising the production of climate-change causing greenhouse gases and meeting national energy requirements that yield greater socio-economic benefits.
However, could cases like that of Mr Murehwa, the taxi driver, influence Government to review its policy on biofuels?
Or at least tighten policy, to ensure the motoring industry realises optimum benefits from biofuels use?
There is already deep concern over the economic viability of biofuels, their impact on food security and whether biofuels yield the real environmental benefits they are said to bring by private companies seeking profit.
Apart from the national savings on fuel imports, which reached US$20 million during the first three months of mandatory blending, drivers have not really realised the benefit both in terms of efficiency and price. E10, which is 10 percent ethanol and 90 percent petrol, the most widely traded blend in Zimbabwe, costs nearly or the same price with unleaded at between $1,48c per litre and $1,50c per litre.
The real price difference is seen on E85. At $1,15c per litre, the higher blended fuel costs 23 percent less than unleaded petrol. However, such immediate savings will only become artificial to people like Mr Murehwa.
Certainly, environmental benefits have been achieved, but not quantified. That may not happen for a long time mainly due to a lack of finances at central Government level needed to undertake such complex processes.
But what role can the private sector play in tracking their own carbon emissions and or savings from offsetting initiatives?
Can companies like Green Fuel collect and provide actual data on the extent of the environmental benefits accruing to Zimbabwe specifically from ethanol use as opposed to providing blanket, globalised benefit oratories?
The UN's World Water Development Report 2014 says that biofuel development needs to be considered in the context of food security, energy needs, land availability, and other national priorities.
"Biofuels are neither good nor bad and are subject to the same constraints and challenges as the rest of the agricultural sector," said the report, which was released in the US recently.
"What is essential is that the biofuel options be viewed as an agriculture investment option that needs to be sustainable and small holder inclusive in order to target poverty reduction and rural development and to safeguard food security."
Is ethanol production in Zimbabwe putting pressure on food security? That would be a major concern if the main feedstock was maize, the country's staple, and not sugarcane as is currently the case, even when the cane is key in sugar production, another heavily consumed resource in the country. Historically, the Chisumbanje area where 1 000 hectares of land have been placed under irrigated sugarcane is not known for producing maize but sugarcane.
Most of Zimbabwe's food is produced in the ecological regions two and three; those are the areas predominantly in the Mashonaland and Manicaland Provinces.
At household level, food may become a serious concern in Chisumbanje and the surrounding areas if the cane failed due to bad weather or climates, or if prices were severely depressed that they fail to generate sufficient incomes for farmers to buy food.
That region of Zimbabwe is generally hot and dry, with annual precipitation of below 400mm and prone to droughts. Sugarcane and other small grains like sorghum do better under such climates and these are widely grown in Chisumbanje.
Green Fuel chairman Mr Basil Nyabadza says the existing sugarcane projects are supporting 4 000 farmers, according to recent media reports.
The figure is expected to reach 6 000 this year when the firm expands land under irrigation by 500 hectares.
From the irrigation perspective, biofuels can be argued to be exerting pressure on the water as a resource that may have been otherwise channelled towards production of food crops.
The land under which the sugarcane is grown could also have been utilised for food production.
Biofuels use water for both feedstock production and processing stages. Consequently, biofuels produced from irrigated crops can have much larger water requirements than fossil fuel resources (although fossil fuels can have much larger environmental impacts).
However, the current shortages of food in Zimbabwe, particularly maize, have nothing to do with ethanol production, itself only a recent occurrence after Government abandoned ethanol use for obscure reasons early in the 1990s.
The food problems are more structural and due to lack of adequate financial and technical support to the new breed of indigenous farmers, poor farming practices and as a result of climate change.
God is faithful.
Since the early 1980s, Zimbabwe has always managed to produce maize in surplus and simultaneously grow tobacco, the main cash crop which peaked at 256 million kg in 1998.
The pressure on food from ethanol production in Zimbabwe is, therefore, remote, under existing circumstances.
But climate change and other national ineffiencies in agriculture such as dependency on rainfed farming are real food security threats.
Worldwide, the UN report said the demand for agricultural feedstock for biofuels is the largest source of new demand for agricultural production in decades, and it was a major factor behind the 2007?2008 spike in world commodity prices.
It is estimated that biofuels accounted for about one-third of the maize price increase. However, this raises concerns about the implications that global biofuel production may have on food security in developing countries.
In October last year Zimbabwe adopted a policy of mandatory blending of petrol with ethanol on an ascending basis, starting at a rate of 5 percent before rising to 10 percent in the same year.
As ethanol blend use grew, central Government pushed the rate of blending to 15 percent in January, but that has now been reversed owing to supply bottlenecks at Green Fuel. Barring supply-side constraints that rate would have reached 20 percent this March. Zimbabwe's actions are in line with its policy targets as contained in the National Energy Policy of 2012, which aims to increase the share of biofuels in the liquid fuels mix by a minimum 20 percent ethanol blend by 2015 and 5 percent for biodiesel by 2020.
God is faithful.