Power Sources

We hear a lot about renewables “powering a number of homes”, when actually what the proponents mean is that the electricity supply to those homes has been provided by wind, wave or solar-generated electricity.

However, this is misleading as the energy used by each of us is far more than the just the electricity used by our houses. Our energy use includes:

• the energy used to heat our homes
• the energy used to produce the food we eat
• the energy used to manufacture the items we use (TVs, Microwaves, washing machines, crockery, cutlery, cars, bicycles, furniture, clothes, shoes, pillows, duvets)
• the energy used to make the concrete, bricks, tiles, pipes, steel and glass to build our homes
• the energy used to transport all the food & items we use to the shops
• the energy used to build the roads & railways on which we travel and which allow the delivery of all the items we use
• the energy used to make the wires and pipes which bring electricity and water to our homes
• the energy used to pump the water in the water-supply systems
• the energy used to pump and process the sewage we produce
• the energy used to take away our waste
• the energy used to recycle and sort our recyclables

The list is almost endless, and that is just looking at what humans need.

We need sufficient surplus energy to be able to care for all the other inhabitants of this wonderful planet and to restore what we have already damaged. In other words, producing the energy we need must not put too much stress on the planet.

Switching off your lights when you are not in a given room is useful, but it will never ever solve this problem, or make much of a dent in it.

Going vegan might help a bit, but it is not going to solve the problem. Indeed, if instead of eating locally grown vegetables, we end up transporting in nuts that have taken vast amounts of artesian water to grow in California, or avocados, or soya beans which have been grown on areas which were once rain-forest, then it really might not help at all. Drinking almond-milk has a much higher carbon footprint than drinking locally produced cow’s milk.

We do need to look at the entire cycle of everything to work out what is good and what is bad in terms of energy usage and carbon production.

It is easier to think in terms of energy, and we need energy on an industrial scale, not just enough “electricity” to turn the lights on in our homes.

So – looking at renewable energy, if we do a full cycle analysis, electricity from both solar PV and Wind is basically good, but it is very variable. Sadly, solar electricity is not usually produced at the times when there is the highest demand for electricity.

Wind power is variable – sometimes the wind blows & sometimes it does not.

At the moment, in order to smooth out the supply and demand, we typically use gas-fired generators, burning  “natural gas” i.e. methane, a carbon fossil fuel, to produce electricity when there is not enough being generated by Wind and Solar.

Because we do not currently store industrial quantities of electricity, we actually switch off wind turbines when there is more electricity being produced than is needed at a given time.

Both these are crazy – gas-fired turbines produce CO₂ – so are definitely not Carbon-Free. Some designs could try to capture the CO₂, but this dramatically reduces their efficiency.

Switching off Wind turbines because the electricity is not needed at that moment, when it would be needed later, is really sad.

So – we need some way of storing power-station amounts of electricity at least over the span of a day, in order to be able to use all the potential wind and solar power.

If we could store all the electricity produced from renewables, including Hydro-electric and Wave power – would that be enough?

Unfortunately, though it would be a big improvement, the answer is no (see Sustainable Energy without the hot air)