Renewable energy can provide for our needs?

Can renewable energy provide for our needs? Easily, yes.

Now onto a serious question, i`m not going to answer this one - just share a few pertinent (?) thoughts.

Can we decarbonise the global electricity sector by 2050?
A few points:

1. Our consumption of electricity is increasing rapidly.
2. Increasing energy prices would have a serious impact on those who can least afford electricity but for whom it provides many valuable functions.
3. Renewables are typically smaller in unit size and have availability charachtersistics that are different from large traditional power stations.
4. Increasing a proportion in a growing energy pie is a formidable challenge.
5. We are starting from a very low base.
6. Many people support an energy system more fully integrated through electricity as the carrier i.e electric cars or onsite H2 generation from electricity (less common).

Straight to Hell: We are on the right path.

If you have ever read the IEA energy projections then you will know what a roadmap straight to hell looks like. Globally emissions to 2030 are predicted increase by an eneromous amount (roughly a doubling?) rather than the dramatic cuts that we need.

How ambitious are the IEA projections for renewable energy? Surely they must be wholly conservative values.

IEA Projections for the USA a focus on renewables.

In 2002 the primary energy supply of the US is split between coal, oil, gas, waste/biomass, nuclear, hydro and other renewables.

Other renewables constitute 16 million tonnes of oil equivalent (Mtoe). By 2030 this figuer is predicted to climb to 77 Mtoe. An increase of 61Mtoe.

How much energy is 61Mtoe; lets look at this qauntity in terms of wind power.

61Mtoe is 708,000 GWhrs. A gigawatt hour is however, a qauntity of energy, how much installed wind power would we need to produce this much energy per year?

First off lets work out the qaunity of power per hour we need. 708,000 GWhrs divided by the number of hours per year (365*24) is 81 GW of installed capacity if energy is produced 100% of the time. Depending on where a wind farm is sited a capacity factor of somewhere over 30% may be expected. There are also, however backup costs, the degree of backup depends on many factors but given low wind penetrance in absoloute terms we will guess that 17% of our energy is wasted by backup. An effective capacity factor of 25% seems reasonable. This means that we require 324GW of installed wind to provide this qauntity of energy.

This looks like a huge number, largely due to this being a large number! On a yearly basis 13.5GW of wind power would need to be installed. Last year 6'000 MW or 6GW where installed in a record year.

A final thought. This scenario is the IEA's world destroying scenario leading to massively increased GHG emissions in the US. Renewables expandng at this rate in absoloute terms are being overwhellmed by parrallel increases in fossil fuel usage. The described renewable energy would consitute only 2% of primary energy demand by 2030.

Caveats and messages.

We are talking about primary energy demand. Other renewables could include solar, tidal, wave and perhaps significantly, ethanol.

Energy efficiency could lower this demand hugely as could good design of buildings and infrastructure.

However you look at it the challenge of greater total energy usage as a consequence of economic growth and lower total carbon emissions is an imense challenge that will require multiple agressively persued technologies and policies.

I hope this short article has provided a useful perspective on the second question that i posed above.


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