Domestic Energy

Think about your evening routine when you come home from college or sixth form. What do you usually do?

You'll probably eat a cooked dinner, make a cup of tea, and have a shower. You might also watch TV, do homework on the computer, or play video games. All of these activities require energy.

Domestic Energy: Meaning

Let's start off with a definition.

Energy is needed in the home for cooking, heating, powering electrical appliances and devices.

Energy and Living Standards

Domestic energy plays an important role in improving material living standards.

Household energy consumption is positively correlated with GDP per capita (up to a threshold).

Access to safe, clean energy aids economic and social development. It contributes to production, healthcare, education, and improved living standards. Unfortunately, millions of people around the world experience energy poverty.

Approximately three billion people rely on wood, coal, charcoal, or animal waste for domestic energy. Using these combustible fuels can lead to indoor air pollution, which can cause respiratory illness and death. Indoor air pollution is estimated to have caused 4.3 million deaths in 2012, disproportionately impacting women and girls. As a result, it's crucial to ensure domestic energy availability for all.

Domestic Energy Monitors

Domestic energy monitors are self-explanatory; they measure the energy usage of the home. They display real-time electricity use. Some models can show comparative usage over a period of time (e.g. the last week or month) or even alert you when you have reached a predetermined level of energy usage.

Smart Meters

Smart meters are a step up from regular domestic energy monitors. They display the electricity usage of individual appliances and devices, helping people to target wasteful appliances and reduce their energy consumption. This saves money and the environment!

Smart meters use wireless networks to communicate remotely with the household's energy supplier to ensure that bills are correct.

Domestic Energy Efficiency

What is efficiency?

A device with a high energy efficiency will waste very little energy.

Calculating Energy Efficiency

$Efficiency=\frac{usefulpowertransferred\left(W\right)}{totalpowersupplied\left(W\right)}$

The efficiency can then be converted to a percentage:

Worked Example

A rice cooker transfers 750W of the 900W of power supplied to it.

What is the percentage energy efficiency?

$0.833=\frac{750}{900}$

The efficiency of the rice cooker is 83.3%.

Wasted Energy

Devices and appliances waste energy in many ways, including:

• Sound energy dissipated to the surroundings

• Thermal energy dissipated to the surroundings

• Electrical resistance

• Friction between moving parts

Devices and appliances can be made more efficient by reducing energy that is wasted or dissipated.

It's impossible for a device to have an energy efficiency of 100%, but there are other ways to improve domestic energy efficiency. They include:

• Turning off appliances that are not in use – beware of 'standby mode'

• Keep freezers clean and defrosted

• Dry clothes outside as much as possible

• Filling dishwashers to capacity

• Batch cooking

• Only use central heating during cold weather

Increasing domestic efficiency reduces the demand for energy, saving money and carbon emissions.

Renewable Domestic Energy

It's possible for households to generate their own renewable electricity instead of using the National Grid. It can be used to power household appliances and charge electric cars. Having a source of renewable electricity can save money on electricity bills and reduce carbon emissions.

There are two main methods of generating renewable energy in the home: solar panels and wind turbines.

Solar Panels

Solar energy is a clean, zero-carbon source of renewable energy. Solar panels use photovoltaic (PV) cells to convert sunlight energy into electricity. The stronger the sunshine, the more electricity is generated.

Alternatively, a solar-assisted heat pump can be placed on a roof. The pump captures heat energy from sunlight and uses it to heat water without the use of a boiler. Solar-assisted heat pumps can even meet the heating requirements of a small, well-insulated house.

Solar energy technology is most effective on unshaded, south-facing roofs.

Fig. 1 - Installing solar panels on your roof can help you save on your electricity bills - and even increase the value of your house by up to 4.1%. Unsplash

Wind Turbines

Wind turbines harness the energy of the wind and convert it into electricity. There are two kinds of wind turbine suitable for domestic electricity. Pole-mounted turbines are freestanding and are erected in an exposed position. They generate approximately 6kW of electricity. Building-mounted turbines are smaller and are erected on roofs, generating around 2kW of electricity.

Wind turbines are best suited for rural areas that experience frequent, sustained winds.

Domestic Use of Geothermal Energy

This energy usually manifests as volcanoes or hot springs. And guess what country has an abundance of volcanoes and hot springs?

Domestic Geothermal Energy in Iceland

Iceland is located on a constructive plate boundary – where two tectonic plates move apart. Magma rises to fill the gap between the plates, forming volcanoes and new crust.

Geothermal energy from volcanoes heats rocks below the ground. The hot rocks heat underground water, so it rises to the surface as hot water and steam, where it's used to drive turbines and generators. Alternatively, deep wells are drilled down to the hot rocks. Water is pumped down to the rocks, where it is heated and returns to the surface as hot water and steam.

Geothermal energy provides over half of the country's energy supply and heats almost 90% of households.

Iceland's extensive use of geothermal energy and hydropower make it the biggest power producer relative to the size of its population.

Fig. 2 - Reykjavík, the capital of Iceland, uses more geothermal energy than any other city. Unsplash

Geothermal Heat Pumps

Unfortunately, most of the world is unable to exploit geothermal energy. But it's possible to use geothermal heat pumps around the globe.

Air temperature fluctuates depending on seasons, but the temperature below ground remains near constant year-round. This results in a significant temperature difference between the air and the ground. Geothermal heat pumps take advantage of this difference, heating houses during winter and cooling them during summer.

How Do Geothermal Heat Pumps Work?

Antifreeze is circulated in a closed loop underground. The heat pump cycles a refrigerant between the house and the antifreeze loop, where a heat exchanger transfers thermal energy to the desired location. This enables heat transfer into the house during winter and underground during summer.

I hope that this article has clarified domestic energy for you. Domestic energy is energy that used in the home for cooking, heating, and powering electrical devices and appliances. Energy monitors can be used to help people reduce their energy consumption, saving money and the environment. It's possible for households to generate their own domestic energy using renewable sources such as solar power, wind turbines, and geothermal energy.

^{1. Askja Energy, Geothermal Diversity, 2022}

^{2. EON, Smart Meters, 2022}

^{3. Josh Jackman, Do Solar Panels Affect Your Property’s Value?, The Eco Experts, 2022}

^{4. Orkney Renewable Energy Forum, Wind, 2022}

^{5. Ragnhildur Sigurdardottir, Geothermal Powerhouse Iceland Hit by Lack of Electricity, Bloomberg, 2022}