The small number of large power stations we built decades ago are what we still rely on today. These fossil feuled dinosaurs waste 70% of the energy we put into them, as the heat generated while producing electricity is blown away in the cooling towers or into a local lake. More heat dissipates along the transmission lines, which are usually long as the large power plants are located some distance away from cities. The heat wasted is enough to supply a country's heating and hot water needs.
A Better Approach: Combined Heat and Power (CHP) - The single biggest solution for reducing CO2 emissions from electricity generation. Using smaller, cleaner, more efficient energy sources near to where they are needed allows the use of both the heat and electricity that are produced, with less transmission waste. The efficiency of CHP can be as much as 91% (vs. 30% from traditional power stations).
Netherlands - generators are smaller, cleaner, more efficient and more reliable. half of electricity comes from CHP plants. Having very many, smaller points of supply brings a much more stable and reliable total system. In one part of the Netherlands, a larger cogeneration plant is used to power 100,000 homes, and the heat is used in local greenhouses. The CO2 emissions are also used as a fertilizer in the greenhouses, before being released.
Ontario currently has 2300 MW out of 31200 MW from CHP.
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I just felt compelled to note a few things.
The thermodynamic efficiency of fossil fuel (coal, oil, gas) power plants can approach 40 - 50% since they operate at higher temperatures (supercritical steam). This concept is also being worked into the "next generation" nuclear plants - scheduled for 2025 - 2030.
Current generation CANDU nuclear stations, as an example, run at ~< 25-30% thermodynamic efficiency (eg, ~3000 MW(t) -> ~800 MW(e)).
The net of 2200 MW(t) is both dumped off in the condenser loops, and used to preheat the water as it enters the steam generators.
Regardless, there is still a LOT of heat being wasted.
Assuming that an average home could be heated with 3 - 5 kW(t), the 2000-odd MW(t) that needs to be disposed of could "heat" about a half million homes, assuming that there are no transport losses.
I think it would be great if the extra energy could be harnessed, but I don't think that efficiencies of 90%+ are possible in S. Ontario.
In Denmark, the average temperature is about 16 deg C in the summer, which implies the demand for residential heating.
By comparison, it is about 30 deg C out in S. Ontario today.
It is much more logical for the Danes to use a CHP system since they - for the most part - have a higher demand for heat.
Whereas in Ontario, most people only keep their heaters on for maybe 4 or 5 months a year.
I like the greenhouse idea though. If it weren't for the high capital costs involved, one could increase the annual crop yields per acre.
That in my mind perhaps more efficient than leaving fields unproductive through every winter.
Regardless, I agree that CHP is a good idea. However, I feel that at this point, it's probably only feasible in certain areas.
Well said.
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