If you're serious about helping the environment, you may well have to spend more as changing to a green energy policy can make your bills a little more expensive. However, you'll be safe in the knowledge that you are doing your bit, and the more people that sign up, the more government support will be lent to greener energies.

Many of us don't have the funds to install solar panels and wind turbines, but there are other more affordable options. Have a look at the policies on offer from regular domestic electricity suppliers. Many suppliers offer special environmentally-friendly products that you can opt for.

From April 2004, UK energy companies have had to ensure that a minimum of 4.9% of the energy they provide has been sourced from renewable sources. Some UK energy companies are doing better than others with this target, so have a look at some energy company websites and choose a supplier whom you are convinced is doing their bit or the evironment.

Some companies who have not reached their 4.9% target have chosen to buy certificates from smaller green energy-only companies or companies who have bettered the 4.9% target. However, this system does not increase overall demand for renewable energies, so look out for companies who operate in this way.

If you're looking to switch to a green energy-only supplier then we have compiled a list of some of the most popular. Have a look through their details, and remember, by doing a quick bit of research online, you'll be able to find may more green suppliers to choose from, who may offer cheaper policies:

Green Energy 100 ? If you're looking for an ethically-minded provider, this forward-thinking company ticks all the boxes. As well as providing green energy for their customers, Green Energy 100 invests 50% of its profits to the production of green electricity. So not only is their electricity green, but their profits are too.

Ecotricity ? A fledgling company, Ecotricity provides 0.1 units of green electricity for each electricity unit bought by the customer. This figure is to increase by 10% each year as the company grows, and profits will be invested in wind farm technology.

Besides these green-only providers, here are some domestic energy producers who have made a move into the green energy market:

Scottish Power ? Scottish Power's Green Energy Fund gives ?15.75 to green energy projects every year for each of its Green Energy Fund customers, and at the end of each year Scottish Power matches the total amount of green investment too.

Powergen and London Energy ? Powergen now offer their GreenPlan, while London Energy have introduced their own Green Tariff ? with both of these plans ensuring that one unit of green electricity is supplied for every unit of electricity bought by customers.