Well, I’m on a roll from the last post on eggs in the microwave. I had mentioned that boiling rice or anything on a stove is not very energy efficient. What a surprise I had! This exploration actually ended up showing that a gas hob uses approximately 2.55 times more actual energy but still cheaper, to cook the rice than with a microwave. Wrap your head around that!
I needed some boiled rice to go with my curry chicken. I couldn’t give a flying flamingo if you don’t like rice and/or curry chicken. Make my day, leave now! For those who want to learn more, I show the method and the energy issue. The following is provided for others at their own risk and cost.
Method:
- 185g of standard long grain rice.
- Microwavable container.
- 300ml of basic tap water.
- One working microwave with various power settings.
- Cover the rice with the water in the container and stir twice.
- Put in microwave.
- Turn on microwave at 950W x 4 min – this gets the water to boiling point.
- Then check and stir (wearing a helmet, protective goggles and bomb-disposal-suit are optional 😄🙈)
- Then reduce power to 300W and leave for 12 min. Stir once at about 6 min in this phase).
That’s it! Rice is ready! Not to hard or soft. Of course, I’ve done this several times before, so I know that the above works for my preferred texture of rice. The above may not work for everybody else.

Energy usage
Aspect | Gas Hob | Microwave | Savings with Microwave |
---|---|---|---|
Phase 1: Boiling for 4 minutes | |||
Time | 4 minutes | 4 minutes | 0 minutes |
Power | 2000 W | 950 W | |
Energy Used (Wh) | 133.33 Wh [2000 W x (1/15) h = 133.33 Wh] | 63.33 Wh [950 W x (1/15) h = 63.33 Wh (watt-hours)] | 70 Wh |
Energy Used (J) | 480,000 J | 228,000 J | 252,000 J |
Phase 2: Simmering | |||
Time | 12 minutes | 12 minutes | 0 minutes |
Equivalent Power | 300 W | 300 W | 0 W |
Energy Used (Wh) | 60 Wh | 60 Wh [300 W x (1/5) h = 60 Wh] | 0 Wh |
Energy Used (J) | 216,000 J | 216,000 J | 0 J |
Total Energy Used (Wh) | 193.33 Wh [133.33 Wh + 60 Wh = 193.33 Wh] | 123.33 Wh | 70 Wh |
Total Energy Used (J) | 696,000 J [193.33 Wh x 3600 J/Wh] | 444,000 J | 252,000 J |
Efficiency Calculations | |||
Efficiency | 40% | 65% | |
Actual Energy Used (J) – after efficiency correction. | 696,000/0.40 = 1,740,000 J | 444,000/0.65 = 683,077 | 1,056,923 J |
Approximate energy costs | (1,740,000 J / 3,600,000) kWh * £0.08/kWh = approximately £0.0387 [Divide by 3,600,000 to convert to kWH] | (683,077 J / 3,600,000) kWh * £0.28/kWh = approximately £0.0531 | Gas hob cost: £0.0387 – Microwave cost: £0.0531 = negative £0.0144 (costs slightly more) |
What it means
This means the gas hob uses approximately 2.55 times more actual energy to cook the rice than the microwave. [1,740,000 / 683,077 ≈ 2.55]
Disincentive
It is surprising that despite this significantly higher energy usage, the gas hob still works out to be slightly cheaper in this scenario. This highlights a key issue: The price of energy doesn’t always reflect its true environmental cost. Currently, in the UK, gas is significantly cheaper than electricity. This makes it more economical for consumers to use gas, even if it results in higher energy consumption and greater greenhouse gas emissions.
This pricing structure doesn’t incentivise energy efficiency or the transition to cleaner energy sources. Ideally, energy pricing would reflect the environmental impact of different energy sources, encouraging people to make more sustainable choices.
Consider this:
- Environmental externalities: The cost of gas often doesn’t fully account for the environmental damage caused by its extraction, processing, and combustion. These “externalities” are not reflected in the price consumers pay.
- Government policies: Government policies and subsidies can influence energy prices. Policies that support renewable energy and discourage the use of fossil fuels can help shift the balance.
- Consumer awareness: Increasing consumer awareness about the environmental impact of their energy choices can drive demand for cleaner energy sources and encourage energy efficiency.
The figures show a disincentive towards using electricity for cooking when gas is an option, especially in the UK. This is mainly due to the energy price differences.
Factors contributing to this disincentive:
- Cost of electricity: As we’ve calculated, even though the microwave might be more energy-efficient in some cases, the higher cost of electricity per unit of energy often makes it more expensive to run than a gas hob. This is a major deterrent for many people.
- Existing infrastructure: Many homes in the UK are already set up with gas connections for cooking, making it convenient to continue using gas appliances. Switching to electric cooking might require costly upgrades or renovations.
- Cooking habits and preferences: Some people simply prefer cooking with gas. They might find it easier to control the heat, or they might prefer the visual feedback of a gas flame.
- Lack of awareness: Many people might not be aware of the environmental benefits of electric cooking, especially if they use renewable energy sources.
Consequences of this disincentive:
- Higher greenhouse gas emissions: The lower cost of gas can encourage people to use it more, even when electric alternatives are available. This can lead to higher overall greenhouse gas emissions.
- Slower transition to clean energy: A strong disincentive towards electric cooking can slow down the transition to a cleaner energy system. Widespread adoption of electric cooking is essential for decarbonizing the residential sector.
While it might seem counterintuitive that the less energy-efficient option is cheaper, it’s important to remember the bigger picture. Choosing the microwave in this case might be slightly more expensive, but it could contribute to a lower overall carbon footprint. How? It is about ‘electricity generation’ (see below).
Ultimately, making informed decisions about energy use requires considering both the economic and environmental costs.
The choice is yours
Choosing the microwave more often could contribute to a lower overall carbon footprint, even if it’s slightly more expensive.
1. Electricity Generation:
- Fossil fuels vs. renewables: In the UK, electricity generation is a mix of sources, including fossil fuels (like natural gas and coal) and renewable sources (like wind, solar, and hydro).
- Carbon intensity: The carbon intensity of electricity (the amount of CO2 emitted per unit of electricity generated) varies depending on the mix of sources.
- Shift towards renewables: The UK is actively transitioning to a cleaner electricity grid with a growing share of renewable energy. This means the carbon intensity of electricity is decreasing over time.
2. Gas Combustion:
- Direct emissions: Burning gas for cooking directly releases CO2 into the atmosphere, contributing to greenhouse gas emissions.
- Methane leaks: Methane leaks throughout the natural gas supply chain also add to the carbon footprint of gas cooking.
3. Energy Efficiency:
- Conversion efficiency: Microwaves are generally more efficient at converting the energy they consume into heat for cooking compared to gas hobs. This means less energy is wasted in the process.
- Cooking time: Microwaves often cook food faster, which can further reduce overall energy consumption.
4. Overall Impact:
- Reduced reliance on fossil fuels: By choosing the microwave, you’re relying more on electricity, which is becoming increasingly cleaner as the UK transitions to renewable energy sources.
- Lower direct emissions: While electricity generation can have some emissions, using a microwave avoids the direct emissions from burning gas in your home.
- Potential for carbon neutrality: If your electricity comes from renewable sources, using the microwave could be close to carbon neutral, meaning it has a very low carbon footprint.
Conclusion
What a surprise the calculations revealed. I had naturally assumed – something I hate to do – that by using less energy cost would be better. Well no – your government and the energy giants don’t like that logic. While the gas hob might be cheaper in this specific scenario, the microwave could have a lower overall carbon footprint due to the UK’s shift towards cleaner electricity generation and the higher efficiency of microwaves.
By choosing the microwave, I’m essentially supporting the transition to a cleaner energy system and reducing your reliance on fossil fuels, even if it comes at a slightly higher cost in the short term.