The bigger the difference in temperature between the items, the heat movement will be faster. Heat Movement Assessment It is important that people know more about the movement of heat to full appreciate solar thermal energy. Passive solar energy applications use a lot of heat movement. The 3 common physical ways that heat moves include convection, conduction and radiation. At Present Today, Germany has become the primary PV market worldwide after they revised the feed-in tariffs for the Renewable Energy Sources Act. Spain has become the biggest PV market after 2007 after it adopted the same feed-in tariff structure. Spain installed half of the PVs all over the globe, accounting for about 45%. Alternative sources of power and energy will not only help you avoid burning fossil fuel to help provide electricity for your home, but will also help you save a considerable amount of money on the cost of your utility. One of those alternative energy sources is solar energy. There are actually a number of different solar energy systems that are available in the market today. Solar Pool Heater If your home, or work place, has a pool, then a solar pool heater is needed to keep that pool heated at a certain temperature. Solar energy is actually being used by over 300,000 pools in the U.S., and could dramatically lower your utility bill by a considerable amount. Solar Energy Net Metering Net metering is actually a means for people who use solar energy to power up their homes or work place to be able to sell back to the utility company whatever excess electricity that their home or work place is able to produce using solar energy technology, but is not able to use up. These systems are mainly used to power RV, lighting, backup power systems, portable power systems and cabins. The size of the array of photovoltaics or the number of solar panels, as well as the battery will rely on the individual power requirements. The solar panels charge the battery during daylight periods and the battery will provide power to the inverter whenever required. Once the solar energy runs out, electricity coming from the utility will take over. The flow of solar energy electricity is measured via a utility meter that spins forward and backward. The meter will move backward if more energy is produced than needed and the meter will move forward when extra power is required from the utility company.