Solar energy, radiant light and heat from the sun

Figuring out an inexpensive and carbon-neutral way to produce an abundant amount of hydrogen will be key to the success of fuel cell vehicles

The sun delivers about 7000 times more energy than we currently consume globally. However, we cannot cover the whole surface of the Earth with solar energy collectors. How much of this energy can we collect? Will it be enough to replace fossil fuels?

Our global consumption of electricity in 2005 was 15,182 TWh/y (see The Little Green Handbook). However, 9,541 TWh/y of electricity was produced by fossil fuels and 2,555 TWh/y by nuclear power, or the total 12,096 TWh/y. Assuming the lowest solar potential and the lowest efficiency of solar cells we can calculate that we could produce 35 times more electricity than produced by fossil fuels and nuclear power. The additional advantage is that solar power is clean and last practically forever.

Even if we used only 1% of unused land area we could produce nearly 4 times more electricity than we produce using fossil fuels and nuclear power.

Coal generates 2,249 pounds of carbon dioxide, 13 pounds of sulfur dioxide and 6 pounds of nitrogen oxides for every megawatt hour of energy generated.

Biomass produces nitrogen oxides and small amounts of sulfur dioxide. The amount of carbon dioxide produced does not exceed that of the Earth's normal carbon cycle and is considered negligible.

"But if we could harness 0.1 percent of the energy in the ocean, we could support the energy needs of 15 billion people.

According to the government, geothermal has the potential to supply the United States with 20% of our electricity needs.

The capital cost of geothermal development is expensive, however; 2/3rds are drilling costs. Yet as we overcome some of these technology challenges and make the process more standardized it is believed that geothermal can supply up to 20% of the United States electricity needs by 2050. But innovation and investment in initial steps need to happen now.

Method Cents/kW-h Limitations and Externalities WindCurrently supplies approximately 1.4% of the global electricity demand. Wind is considered to be about 30% reliable. 4.0 - 6.0 Cents/kW-h Wind is currently the only cost-effective alternative energy method, but has a number of problems. Wind farms are highly subject to lightning strikes, have high mechanical fatigue failure, are limited in size by hub stress, do not function well, if at all, under conditions of heavy rain, icing conditions or very cold climates, and are noisy and cannot be insulated for sound reduction due to their size and subsequent loss of wind velocity and power. GeothermalCurrently supplies approximately 0.23% of the global electricity demand. Geothermal is considered 90-95% reliable. 4.5 - 30 Cents/kW-h New low temperature conversion of heat to electricity is likely to make geothermal substantially more plausible (more shallow drilling possible) and less expensive. Generally, the bigger the plant, the less the cost and cost also depends upon the depth to be drilled and the temperature at the depth. The higher the temperature, the lower the cost per kwh. Cost may also be affect by where the drilling is to take place as concerns distance from the grid and another factor may be the permeability of the rock. HydroCurrently supplies around 19.9% of the global electricity demand. Hydro is considered to be 60% reliable. 5.1 - 11.3 Cents/kW-h Hydro is currently the only source of renewable energy making substantive contributions to global energy demand. Hydro plants, however, can (obviously) only be built in a limited number of places, and can significantly damage aquatic ecosystems. SolarCurrently supplies approximately 0.8% of the global electricity demand. 15 - 30 Cents/kW-h Solar power has been expensive, but soon is expected to drop to as low as 3.5 cents/kW-h. Once the silicon shortage is remedied through alternative materials, a solar energy revolution is expected.

Tide 2 - 5 Cents/kW-h Blue Energy's tidal fence, engineered and ready for implementation, would provide a land bridge (road) while also generating electricity. Environmental impact is low. Tides are highly predictable.

Engineered geothermal systems (EGS) are based on a related principle, but they work even in parts of the world that are not volcanically active, by drilling thousands of metres underground to mimic the design of natural steam or hot-water reservoirs. Wells are bored and pathways are created inside hot rocks, into which cold water is injected. The water heats up as it circulates and is then brought back to the surface, where the heat is extracted to generate electricity. Because the Earth gets hotter the deeper you drill, EGS could expand the reach of geothermal power enormously and provide access to a virtually inexhaustible energy resource.

Enhanced geothermal systems (EGS), also sometimes called engineered geothermal systems, offer great potential for more than 100 GW of geothermal power which 40 times more than present geothermal power.

ultimately geothermal global resources amount to 50,000 times the energy of all oil and gas resources in the world.

Enhanced Geothermal Systems (EGS) – Often categorized under the antiquated term‘Hot Dry Rock,’ EGS is thought by several experts to refer to any resource that requires artificial stimulation. This includes resources that have to be fully engineered, or ones that produce hydrothermal fluid, but sub-commercially. Regarding the latter, one expert states that, ‘As we go further, there might be projects that require more and more stimulation.’ Although EGS technology is still young and many aspects remain unproven, several projects are currently underway. If EGS technology proves commercially successful, it is expected to allow significantly increased extension of and production from existing fields, as well as utilization of geothermal energy in previously implausible locations.

Future Of Geothermal Energy The future of geothermal energy depends on three factors: it's demand, supply and it's competitiveness among other renewable resources in terms of cost, availability, reliability etc.. Demand for geothermal energy is going to increase and increase with the increase in the population and extinction of other non-renewable sources. Moreover, today government also support the resources which are cleaner and do not spoil the environment. Supply of geothermal energy is limited and confined to certain areas only.

Like many renewable resources, geothermal resources need relatively high initial investments to access the heat, hot water and steam. But the geothermal "fuel" cost is predictable and stable. Fossil fuel supplies will increase in cost as reserves are exhausted. Fossil fuel supplies can be interrupted political disputes abroad. Renewable geothermal energy is a better long term investment.

Examples are the huge costs of global climate change; the health effects from ground level pollution of the air; future effects of pollution of water and land; military expenditures to protect petroleum sources and supply routes; and costs of safely storing radioactive waste for generations. Geothermal energy can already compete with the direct costs of conventional fuels in some locations and is a clean, indigenous, renewable resource without hidden external costs.

Estimates of the electricity generating potential of geothermal energy vary from 35 to 2,000 GW.[2] Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW),[3] Philippines, and Indonesia.

The coal powder mixes with hot air, which helps the coal burn more efficiently, and the mixture moves to the furnace. The burning coal heats water in a boiler, creating steam. Steam released from the boiler powers an engine called a turbine, transforming heat energy from burning coal into mechanical energy that spins the turbine engine. The spinning turbine is used to power a generator, a machine that turns mechanical energy into electric energy. This happens when magnets inside a copper coil in the generator spin.

Electricity-generating plants send out electricity using a transformer, which increases the voltage of the electricity based on the amount required and the distance it must travel. Voltages are often as high as 500,000 volts at this point.  Electricity flows along transmission lines to substation transformers. These transformers reduce the voltage for use in the local areas to be served.  From the substation transformers, electricity travels along distribution lines, which can be either above or below the ground, to cities and towns. Transformers once again reduce the voltage—this time to about 120 to 140 volts—for safe use inside homes and businesses. The delivery process is instantaneous. By the time you have flipped a switch to turn on a light, electricity has been delivered.

Geothermal Energy produces no pollution. There are virtually no greenhouse gases given off. There is no pollution.

What is geothermal energy? Simply put, it is energy from the Earth. Geo refers to the solid part of the Earth and thermal refers to heat energy. Anywhere the Earth's surface is in close proximity to magma or volcanic activity under or near the Earth's surface, we can harness the energy.