Renewable energy

Sources of renewable energy include:

sunlight
wind
rain
tides
waves
geothermal heat

They are renewable because they replenish themselves naturally in a human lifetime.

The National Grid uses renewable energy to help supply our homes and businesses. It is becoming a greater part of our lives.

By building renewable energy into our homes, we can help reduce our carbon footprints.

Current and emerging renewable energy options for our homes are explained below.

Current technologies

Solar Photovoltaics (PV)

Solar PV is the conversion of light into electrical energy.

Solar PV panels are built into arrays on south facing roofs. They generate an electric current which can be used in the home and reduces your consumption from the National Grid. An average panel would generate 0.25 watts. A recommended system size would be 12 panels, providing 3 kilowatts.

You can read more about solar PV on the Energy Saving Trust and Green Match websites.

Solar thermal collectors

A solar thermal collector absorbs sunlight and converts it to heating, providing hot water to your home. Solar thermal collectors are often seen as tubes on south facing roofs.

Air source heat pumps

Air source heat pumps transfer heat from the air through a heat exchanger to provide hot water to heat your home.

Your home will also need a hot water storage cylinder.

They produce heat at a lower temperature than gas boilers and work best with underfloor heating coils on hard floors.

They can be used with standard central heating systems but you may need to install oversized radiators to provide the same level of heat.

Air source heat pumps often need to be on day and night to provide the same heat as traditional gas or oil boilers.

You can read more about air source heat pumps on the Energy Saving Trust website.

Ground source heat pumps

These work in a similar way to air source pumps, extracting residual heat from the ground instead. Either a deep borehole or coils are dug into the ground to provide the energy source. Heat pumps are costly to install and need a large installation area. For this reason, it can be more efficient to install them when supplying a number of homes together.

AirEx bricks

AirEx is a smart air brick which allows ventilation to the underfloor space in your home. They replace conventional air bricks and reduce uncontrolled ventilation. They reduce heat loss, movement and draughts and, as a result, produce heat loss savings of around 12% to 16%.

You can watch a video explaining AirEx technology on the AirEx website.

Battery storage from solar panels

The excess energy produced form solar PV panels can be stored in a battery and used when required. Typically, this is in the evenings when your energy demand is higher. Batteries are then replenished the following day.

Batteries help reduce the need to buy electricity from the grid. It is important to bear in mind that solar PV panels produce more energy in the summer than in the winter.

You need to consider the return on investment for this product. Purchase and installation costs are high. However, increases in grid energy prices may make this investment worth considering.

You can read more about energy storage on the Energy Saving Trust website.

Emerging technologies

Hydrogen boilers

Many replacement gas boilers of today may be hydrogen ready for the future. Trials are underway in the UK looking at the feasibility of hydrogen as a heating replacement for natural gas.

However, this is still a very long way off with the government aiming for 2035 at the earliest.

The main benefit of hydrogen is that it is a cleaner, low carbon alternative to gas. Hydrogen boilers could help the UK reduce its the CO2 emissions.

If the electricity used to manufacture hydrogen from water is generated from renewable sources, then hydrogen becomes 100% emissions free.