What is the definition of the term “Watt?” And when it says “This solar panel can supply 2kWh” what does this mean? This article briefly explains questions such as these, and gives an understanding of some other basics that will help you on the road to reducing carbon emissions, cutting your energy usage and most importantly, saving you money!
What is a Watt, ‘W’?
‘A watt is a rate of energy that is transformed or converted.’ What you will find on many domestic appliances and particularly light bulbs are ratings of Wattage. For example, a 40W light bulb is converting electrical energy at a rate of 40 Joules (a measure of energy) per second.
What is a kWh?
In terms of small electricity generators such as wind turbines or photovoltaic panels, the terminology most often used in measuring output is ‘kWh’ or ‘MWh’. Generators produce many thousands of Watts an hour. The ‘k’ in ‘kWh’ denotes kilo which means 1,000 Watts. ‘M’ in ‘MWh’ denotes 1,000,000 Watts.
A kilowatt hour (kWh) is the amount of energy converted in one hour at a rate of one kilowatt (or 1000 Watts).
So, a watt is the rating on an appliance of how much energy it can convert. The kWh’s is a measurement of the amount of energy that has been converted and used in the appliance over the period of an hour.
For example;
If you have an appliance that is rated as 3kW, such as a tumble dryer, and you need to dry your clothes off for 20 minutes (one third of an hour), then the energy that it uses is equal to 1kWh. It’s this 1kWh that your energy supplier will charge you for.
What is Your Carbon Footprint?
A ‘Carbon Footprint’ is the total amount of greenhouse gas (GHG) emissions caused directly and indirectly by an individual, event, organisation or product. This is expressed as a carbon dioxide equivalent (CO2e). A carbon footprint accounts for all six Kyoto GHG emissions’ [1]
If you have a product that contains any amount or number of these GHG emissions (such as CFC’s) then the equivalent impact of these can be translated in terms of carbon dioxide ‘equivalent’. This can then be added up to give you your ‘Carbon Footprint’.
You can calculate your carbon footprint by using an online automatic calculating tool, a carbon footprint related Consultancy Company, or even calculate it yourself!
You should start thinking now about your direct GHG emissions (such as driving a car, heating your house, and lighting). However indirect emissions are encompassed within food items from your weekly shop, the clothes that you buy and the paper you print on using your printer.
Why Should You Calculate Your Carbon Footprint?
Calculating your Carbon Footprint is a good starting point to highlight areas where there can be room for improvement with reducing your direct carbon emissions. By acting on this you can then indefinitely reduce your energy consumption, and save yourself money by making cost improvements to your dwelling. As these improvements are completed you will naturally move on to medium and higher cost improvements.
Feed-in-Tariff (FiT)
For those individuals who have been watching how Renewable Energy has been developed over the last few years, the new Feed-in-Tariff which was introduced in April 2010 has been an exciting new development.
(The Feed-in-Tariff is also known as ‘Clean Energy Cash Back’)
The government intends to have 2% of electricity generation coming from selected small-scale renewable energy technologies (RET’s). By introducing the FiT, RET’s should be much more attractive to householders and small businesses, and RET installers.
The FiT is subject to a lifespan of 20 years, with Photovoltaic’s as a special case, of 25 years and MicroCHP up to 10 years.
Two points to understand:
- The tariff level will reduce every year by a certain amount of p/kWh, this is because it is expected that the cost of RET’s will be reduced as well.
- Once a RET has been installed, the ‘generator’ (the ‘generator’ means the person who owns the RET and is selling the energy) will be assigned to that specific years tariff.
E.g. 4 kW Photovoltaic installation in 2010 = 41.3p/kWh for the entire 25 years.
Or 4 kW Photovoltaic installation in 2015 = 31.6p/kWh for the entire 20 years (remaining of lifespan).
Before 2010, you could access a grant of £2,500 under the Low Carbon Buildings Programme (LCBP) to put towards the installation. You would also be eligible for ROC’s (Renewable Energy Obligation Certificates), which per year would probably only accumulate to 2 ROC’s or £80 -£90 for a small installation.
The LCBP has now been disbanded for builds after April 2010. However, the FiT should earn a household a larger return (5% to 8+% of the original cost), but a more significant upfront capital will be required.
Due to this larger rate of return, the payback period is 10-14 years unlike the previous Low Carbon Buildings Programme, which could in some cases could exceed 20 years!
Two money saving and making points to understand;
- Generators will receive a generation tariff per kWh generated. This depends on the RET installed. This tariff will be paid whether the electricity is used or not!
- Generators will also receive an additional payment if they opt for the export tariff of 3p/kWh for every kWh exported to the grid, or they can opt to sell the electricity exported on the open market.
[1] http://www.carbontrust.co.uk/Publications/pages/publicationdetail.aspx?id=CTV043
