Installations of PV systems in the United Kingdom will amount to 96MegaWatt (MW) in 2010, up an astounding 1,500% from 6MW in 2009. While the country’s growth will start from a nearly negligible level in 2009, the expansion will dramatically outpace the growth of the next fastest-growing nation—Spain—which will rise by approximately 730% in 2010.

“When you think of weather in the UK, London fog comes to mind more readily than bright sunshine,” said Dr. Henning Wicht (right), senior director and principal analyst for iSuppli .

“However, things definitely are looking brighter for the solar market in the UK in 2010, as the country has adopted attractive Feed-in-Tariffs (FIT) to promote PV adoption. Furthermore, with leading solar country Germany cutting its FITs, the focus of the PV world is shifting to places with more favorable incentives—making the UK a solar hotspot this year.”

While growth in the United Kingdom is expected to slow down from such a blistering rate after 2010, PV installations will continue to rise in the 50% range for each year through 2014.
 
Giving the solar market FITs
FITs promote the use of solar energy by guaranteeing utility companies will buy excess electricity produced by solar installations. This helps individuals or organisations to defray the upfront costs of investing in a PV system.

Extensive use of FITs has helped Germany to become the world’s leading country for PV, with 3.8 GigaWatts (GW) worth of installations in 2009. However, German government’s move to reduce FITs will cool off growth in the country from 2012 on.
 
Energy in the UK
The overall goal of the UK’s programme is to encourage smaller, distributed, self-generation in an effort to reduce CO2 emissions and to contribute to the renewing of the UK energy park. The UK is using an above-market FIT rates to incentivise PV adoption.

The average residential price for electricity in the UK is currently £0.12 per kilowatt hour (kWh). A residential PV system of up to 4KW in size can earn £0.36 for every generated kWh that is consumed by the owner itself, or £0.39  for every kWh fed into the grid. This translates into a financial benefit of £0.48  per kWh for self-consumption.

According to the UK’s Department of Energy and Climate Change, a typical household that installs a "well-positioned" 2.5 KW system could save £140 per year on its electricity bill. Installations conducted since July 2009 retroactively qualify for the tariff. Returns on Investment (ROIs) for advantageous residential projects can approach 12%, iSuppli calculates.

iSuppli’s initial estimate is that the UK PV installation market will reach 214MW in 2012 and 501 MW in 2014. This assumption is modelled after the ramp rates of other countries and by accounting for the UK’s level of insolation, or the amount of sunlight it receives.

How wind energy works

Some great benefits of wind energy, writes Mary Jones author of Residential Windturbines, are that it is virtually free (after you purchase the equipment) and there's no pollution. Disadvantages include the fact it's not a continuing source (the velocity varies and many times it is insufficient to make electricity) and it typically requires about one acre of land.

The amount of power which can be found varies by wind speed. The quantity available is called it's power density and it is measured in watts per square meter. For this reason, the U.S. Department of Energy has separated wind energy into classes from 1 to 7. Standard wind speed for class 1 is 9.8 mph or less while the average for a class 7 is 21.1 or more. For effective power production, class 2 winds (11.5 mph average speed) are usually required.

Generally, wind speeds increase as you get higher above the Earth. For this reason, the typical wind generator comes with a tower at least 30ft above obstructions.

There are 2 basic kinds of towers employed for residential wind power systems (free standing and guyed). Free standing are self supporting and are usually heavier which means they take special equipment (cranes) to place them. Guyed towers are supported on a concrete base and anchored by wires for support. They typically are not as heavy and most manufacturer's produce tilt down models which is often easily raised and lowered for maintenance.

The kinetic (moving energy) from the winds is harnessed by a device called a turbine. This turbine contains airfoils (blades) that capture the power of the wind and use it to turn the shaft of an alternator (like you have on a car only bigger).

There are 2 basic types of blades (drag style and lifting style). We all have seen pictures of old windmills with the large flat blades which are an example of the drag style of airfoil. Lifting style blades are twisted rather than flat and resemble the propellor of a small airplane.

A turbine is classified as to whether it is built to be installed with the rotor in a horizontal or vertical position and whether the wind strikes the blades or the tower first. A vertical turbine typically requires less land for it's installation and is an improved option for the more urban areas of the world. An upwind turbine is made for the wind to impact the airfoils before it does the tower.

These units normally have a tail on the turbine which is needed to maintain the unit pointed into the wind. A downwind turbine doesn't need a tail as the wind acting on the blades tends to maintain it oriented properly.

These turbine systems would be damaged if they were to be permitted to turn at excessive speeds. Therefore, units should have automatic over-speed governing systems. Some systems use electrical braking systems although some use mechanical type brakes.

The output electricity from the alternator is sent to a controller which conditions it for use in the home. The usage of residential wind power systems requires the home to either remain tied to the utility grid or store electricity in a battery for use when the wind doesn't blow sufficiently.

When the home is tied to the grid, the surplus electricity that is created by the residential wind power system can be sold to the utility company to reduce and sometimes even eliminate your utility bill. During periods with not enough wind, the home is supplied power from the utility company.


The US price of Wind Energy
Small residential wind power turbines can be an attractive alternative, or addition, to those people needing over 100-200W of power for their home, business, or remote facility. Unlike PV's, which stay at basically the same cost per watt independent of array size, wind turbines get more affordable with increasing system size. At the 50W size level, for instance, a small residential power wind turbine would cost about $8.00/W when compared with approximately $6.00/W for a PV module.

Eerything being equal, PV is cheaper for very small loads. As the system size gets larger, however, this "rule-of-thumb" reverses itself. At 300W the wind mill costs are down to $2.50/W, while the PV costs are still at $6.00/W. For a 1,500W wind system the cost is down to $2.00/W and at 10,000W the cost of a wind generator (excluding electronics) is down to $1.50/W.