6

How coal was formed Regarding coal, from trees, it's not simply a question of the area whether it was a continent-size landmass, but more of the temporal side of things -- how long a time period the land was covered. Coal was laid down from plant matter during the Carboniferous period, which lasted 60 million (60,000,000) years. For most of that time the ...


5

I am not an expert on mining, but I do know my way on fossil fuel extraction. Getting oil from the earth and making it into fuel is not as easy as it sounds, and really the process is way more contaminant than extracting metals from the ground. To make it more clear I can try to explain it in parallel, in both you extract the resource from the ground, ...


5

Your friend is wrong and here's why. Lithium is mined once and can be reused in any number of vehicles. When the vehicle breaks, its lithium will replace newly mined lithium. If we need let's say 2 billion cars on the road with batteries, they need a certain fixed amount of lithium. If we need 2 billion oil-burning cars on the road, they will continuously ...


3

CHP combines a thermal power station with a system for distributing spare heat to customers near the power plant. Thermal power stations driven by fossil fuels have no future, but there is likely to be continuing demand for thermal power stations driven by bio-fuels or hydrogen, as these technologies provide an affordable means of storing energy until it is ...


2

A combined-heat-and-power system can use the waste heat of a solid-oxide-fuel-cell to steam hydrogen out of natural-gas or out of propane. Then the hydrogen easily produces electricity using the SOFC. However, the waste heat can also easily go into a boiler that is connected to steam radiators for primary building heat. Here is a supporting link for a ...


2

In terms of efficiently using sun's energy. Let's not forget passive solar. With no mechanical parts to break, a sufficiently heavy or phase change thermal mass can go a long way when the house is properly insulated. 4 m2 of windows (40 sq ft) is close toe 4 kW. (circa 12 000 BTU )


2

There's an interesting summary of the situation in the UK here. In short, the most widespread option is likely to be heat pumps, despite some significant disadvantages, such as cost, and that fact that they don't always work well with existing heating infrastructure. It may be that hydrogen, generated by renewable power, will also play a significant role - ...


1

The European Court of Justice (ECJ) ruled in March 2019, that there is - legally speaking - no subsidy of renewable energies in Germany: see here. What actually happens is the following: Power producers get a fixed and guaranteed price per kWh they feed - or could feed - into the grid. This money comes from the consumers, who pay currently almost 7 €-cent/...


1

Where I live, forests reach a density of 100-200 cubic meters of growing stock per hectare. One cubic meter equals one tonne of carbon dioxide. From 1870 to 2014, cumulative carbon emissions totaled about 545 GtC. This is about 2000 GtCO2. So, you need 10-20 gigahectares of land. It is 100-200 million square kilometers. Unfortunately, world forest area is ...


1

As a guide, mature sitka spruce forest in the UK has 500m3 of wood per hectare report; This wood has a density of 450 kg/m3 density tables, to that makes 225 tonnes of wood per hectare. The wood is about 50% carbon, so that would convert to 110 tonnes of coal per hectare (the carbon content for wood is discussed by Lamlon in Biomass and Energy). This ...


1

I don't think this question can have a very definite answer because of the enormous time involved. It takes time for mountains to break up into chemical rich dust, and it is really only on land that has risen out of the sea that things could start to grow at first. There may have been enormous tracts of desert for many eons, with plants gradually spreading ...


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