Renewable energy can transform lives
Over a billion people the world over do not have access to electricity.* Renewable, locally sourced, sustainable energy solutions can help lift people in remote, rural communities that cannot access large-scale power grids out of poverty by improving health and wellbeing, enabling them to work and providing access to education.
Solar generated electricity, known as solar photovoltaic, or PV, and other stand-alone small-scale renewable technologies, such as wind, biomass and hydro systems, can help meet people’s basic needs and improve lives. In drought affected areas such as Kenya, for example, which has an abundance of sunshine, a solar powered water pump can pump over 30,000 litres of fresh, clean drinking water a day from a well 100 metres deep.
Wind energy has been used for pumping water and milling grain for hundreds of years. Today, like solar, it is also used for generating electricity. Small wind turbines can be used to charge batteries that can in turn supply houses, hospitals, farms, and telecommunications in remote parts of the world and they can operate in parallel with solar PV systems.
Renewable energy can help the planet
In the developed world, large-scale solar power stations have grown rapidly in both number and size over the last ten years as countries battle to halt climate change by displacing old fossil-fuelled-fired power stations to generate electricity with low carbon or carbon-free renewable plants. By 2014, renewables such as wind, solar, hydro and biomass were accounting for almost a tenth** of the world’s electricity. Today China and the United States have the largest solar PV power stations.
Closer to home, in Europe, total electricity generation from renewables increased by 191 % between 1990 and 2014.***. Hydropower plants, however, generate by far the largest share of electricity from renewable energy sources on the Continent.
Here in Jersey, around a third of all electricity consumed, that’s around 200 million units of electricity, is from renewable hydro sources in France imported through two 100MW subsea cables that come ashore at Longbeach, Gorey a, and Archirondel, St Martin.The rest of our imported power comes from low carbon nuclear sources. This means that at 33g CO2e/kWh our electricity here in Jersey is already 14 times cleaner than the UK’s electricity supply (462g CO2e/kWh) and around seven times cleaner than fossil fuels used locally.
Using solar panels to generate electricity will therefore not materially reduce carbon emissions as they do in countries that use coal-fired power stations. But used in conjunction with other renewables, such as air source heat pumps or solar thermal (to heat hot water) instead of gas, oil and coal certainly will reduce your carbon footprint and reduce your fuels bills.
Solar PV: PV cells are made from layers of semi-conducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. This is direct current (DC) electricity. An inverter converts this DC power into alternating current (AC) power that is the type of electricity used in your home. Groups of cells are mounted together in panels or modules that can be mounted on your roof or a free-standing array on the ground. They are rated by the maximum amount (kiloWatts) of electricity they can produce. This is known as kilowatt Peak or kWp for short.
This graphic is courtesy of SaveOnEnergy.com
For a more detailed explanation of how Solar PV works visit Jersey Electricity Energy Hub. Solar PV can also power boats, and aeroplanes.
Solar Thermal: Unlike Solar PV, Solar Thermal panels, or collectors, do not generate electricity they simply collect heat from the sun and use it to heat water stored in a hot water cylinder. An electric boiler or immersion heater can always be used as a back up to heat the water to the required temperature. When combined with an Air or Ground Source Heat Pump, Solar Thermal offers a renewable solution to meet all your space and hot water heating needs.
Heat Pumps, whether air, ground or water source produce around three times the amount of heat than the units of electricity used to power would on their own.
They work like a refrigerator in reverse.
Heat is drawn from the outside air, ground or water
This heat is transferred to the refrigerant inside the heat pump, raising its temperature and changing it from liquid to gas.
The refrigerant gas is then compressed, using an electrically driven compressor. This reduces its volume but significantly raises its temperature.
A heat exchanger (condenser) then extracts the heat energy from the hot refrigerant to heat your home and provide hot water.
After giving up its heat energy, the refrigerant turns back into a liquid and the cycle begins.
Therefore, your 1kW of electrical energy (powering the compressor) can be converted to between 2-4kW of usable heat.
Wind turbines: Harness the power of the wind by converting the rotation of turbine blades into electricity. Wind turbines can have a horizontal axis or a vertical axis and can either be mounted directly on to your house roof or on free standing towers or poles. Most vertical axis turbines are not self-starting and may consume some electricity to begin rotating. Mounting a turbine on your building avoids the cost of foundations for a free standing tower but may add stress to the fabric of your home so it is important to seek specialist advice before installing a building mounted turbine on the roof of your home. Free standing turbines are more effective than those mounted on a roof. The amount of electricity generated, of course, depends on the speed of the wind harnessed, which, in turn, is affected by the height of your turbine and its location.
**Global Trends in Renewable Energy Investment report