Posted by Ady1 on 17/01/2021 19:38:56:
The cost has been very high, power bills went through the roof to pay for it all
Always good to put numbers on energy costs because they are changing. This lot are from Lazard, October 2020. They show investment in alternative energy sources is already paying.
From most expensive to cheapest, in US$ per megawatt hour:
- Solar (residential) 150-227
- Gas Peaker 151-198
- Nuclear 129-198
- Coal 65-159
- Wind offshore 86
- Geothermal 59-101
- Gas Combined Cycle 44-73
- Wind onshore 26-54
- Solar (utility) 29-42
The table is fuel for thought. Gut objections to 'Green' will focus on the high cost of residential solar, whilst ignoring utility solar which, on average, is the cheapest form of energy available. Dismiss gut and consult brain! Look deeper before deciding.
Residential solar is expensive because it doesn't achieve economies of scale. Small installations expensively engineered onto individual rooftops, few of which are optimally aligned to collect energy. Although they compare badly with large optimised solar installations (the cheapest electricity available today), the cost isn't much higher than gas peaker.
Gas peaker electricity is generated by fast response gas turbines. Their purpose is to cover peak demands to which other generators can't respond fast enough. Though coal is more nimble than nuclear, neither are well-suited to rapidly varying loads. Cranking coal up and down is liable to take longer than the peak lasts, so the system fails twice. By not meeting demand and and then wasting money as it shuts down. It's better to leave slow responding generators alone and manage peaks with a system that can stop and start quickly; guess what – Gas Peaker is expensive. But worth having!
Further down the table we find Gas Combined Cycle is about half the price of coal. Gas CC burns for maximum efficiency. The fuel is cheaper and cleaner than coal, hence the 'dash for gas', and lower maintenance, but the system is another slow responder. It's good, but imperfect, and it makes a lot of Greenhouse gas.
Nuclear is expensive to set up and even more expensive to decommission, but the energy is cheap. Nuclear power stations are best run flat out continuously. Maintenance is low compared with coal because the system runs at a lower temperature, there is no flame playing on metal parts, and no acid gases full of grit blasting through the boiler. An important advantage is Nuclear is resilient against economic and political turbulence because it doesn't depend on imported fuels. Shame about the clean up costs!
Lazard give the cost of each source of electricity as a range. This is because cost depends much on local circumstances. For example, UK coal is almost all imported from the USA, Brazil and Australia. A coal power station built next to the mine avoids transport costs and generates cheap electricity compared with came coal shipped half way around the world to be burnt in exactly the same type of power station in the UK. When the UK was a major coal producer, it made sense to generate electricity with coal here. Now coal is imported, it doesn't.
When considering energy, never wave the flag for a particular method without considering today's requirements. A system that was excellent in 1980 may not do what's needed now or be useful in the future.
Fairly obvious from Lazard's numbers why the UK has gone heavily for Wind. Onshore Wind is at least ⅔ cheaper than coal, it's cleaner, it doesn't have to be imported from abroad, and future supply is assured. Land being expensive tends to discourage large solar arrays particularly as we not blessed with reliable sunshine. Land costs also encourage off-shore wind-farms here, the downside being higher maintenance – difficult to reach and showered in salt-spray!
Also fairly obvious that none of these energy systems provide a complete answer on their own. At the moment green energy may be cheaper, but it's not reliable. There's an urgent need to find ways of storing green electricity in bulk. Last year the UK lost 3.6TWh of wind generated power because no-one wanted it and it can't be stored yet.
Fossil fuels can't be the answer to mankind's long-term energy needs because they are a diminishing resource. Coal and oil may have been cheap in our life-time but our grandchildren will suffer ever increasing fossil fuel costs. God isn't making fossil fuels any more. What worked for us won't work for them…
Dave